High isolation ku-band linear polarized duplexer for satellite communication

Abstract

The application discloses a high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication, an E-plane rectangular waveguide is used for connecting a base mode TE 10 mode in a vertical polarization form in an uplink and outputting to a first E-plane 90-degree twist waveguide, the first E-plane 90-degree twist waveguide rotates a propagation direction of the base mode TE 10 mode by 90 degrees and then outputs to a vanished-mode ridge waveguide band-pass filter, the vanished-mode ridge waveguide band-pass filter selects the base mode TE 10 mode in the uplink and outputs to a second E-plane 90-degree twist waveguide, the second E-plane 90-degree twist waveguide rotates a propagation direction of the base mode TE 10 mode by 90 degrees and then outputs to an orthogonal mode coupler, the orthogonal mode coupler is used for converting the base mode TE 10 mode into a base mode TE 11 mode and then outputting and converting the base mode TE 11 mode into TE 01 mode, and outputting the TE 01 mode to a stepped impedance filter, the stepped impedance filter selects TE 01 mode in a downlink, and outputting the TE 01 mode to a copper drum H-plane rectangular waveguide; the application has the advantages of simple structure, wide working frequency band and the ability to cover the whole Ku-band bandwidth.

Description

TECHNICAL FIELD

[0001] The present application relates to a linear polarized diplexer, in particular to a high-isolation Ku-band full-bandwidth linear polarized diplexer for satellite communication. BACKGROUND

[0002] In recent years, reflector antennas are widely used in satellite communication system links due to their high gain. Commercial satellites usually use vertical and horizontal linear polarized signals, and the bandwidth of the uplink ranges from 10.7 GHz to 12.75 GHz, and the bandwidth of the downlink ranges from 13.75 GHz to 14.5 GHz. In order to reduce the size of space and ground stations, the same antenna is usually used in the uplink and downlink, and the linear polarized diplexer plays an important role in the selection and separation of the uplink and downlink of the antenna. The linear polarized diplexer can be composed of a quadrature mode coupler and two filters of different frequency bands. The quadrature mode coupler is a key component for realizing dual-polarized feeding, which can distinguish two orthogonal main modes on the common port and convert them into a base mode provided to a single signal port, so that all electrical ports are matched and have high cross-polarization isolation between independent signals (related to the correlation between the two orthogonal modes in the common port). Another important point of the linear polarized diplexer design is to use devices with frequency selectivity (filters) to complete the separation and combination functions of the uplink signal and the downlink signal. The isolation between the ports of the linear polarized diplexer is derived from the isolation between the vertical polarization port and the horizontal polarization port of the quadrature mode coupler and the out-of-band suppression capability of the filter.

[0003] A wideband transceiving coaxial waveguide diplexer is disclosed in Chinese Patent No. 202111439077.5, which includes a coaxial waveguide inner waveguide, a coaxial waveguide outer waveguide, a low-frequency coupling waveguide, a short-circuit sheet, a cross door, an E-plane T-shaped synthesizer, and a waveguide load. The isolation of the two orthogonal polarized signals of the vertical and horizontal linear polarized signals is realized by arranging the short-circuit sheet in the coaxial waveguide inner waveguide, and the low-frequency coupling waveguide is used to transmit low-frequency signals, and the cross door structure is used to transmit high-frequency signals. However, this diplexer can only be used in the C-band (3.625 GHz-6.725 GHz) and cannot be used in the Ku-band. Moreover, it has many parts, a complex structure, and high manufacturing cost.

[0004] A diplexer is disclosed in Chinese Patent No. 202023276859.5, which includes a common port, a signal transmitting end, and a signal receiving end. There are filters between the common port and the transceiving port. This diplexer can simultaneously receive horizontal and vertical linear polarized signals in the 10.5 GHz-12.7 GHz frequency band, and the isolation meets the engineering design requirements. However, its structure is also relatively complex, and although it can work in the Ku-band, the working frequency band is narrow and cannot cover the full bandwidth of the Ku-band. Summary of the Invention

[0005] The technical problem this institute aims to solve is to provide a high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication that has a simple structure, wide operating frequency band, and can cover the entire bandwidth of the Ku band.

[0006] The technical solution adopted to solve the above-mentioned technical problem is as follows: a high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication, comprising, in order from right to left, an E-plane right-angle waveguide, a first E-plane 90° twisted waveguide, a vanishing mode ridge waveguide bandpass filter, a second E-plane 90° twisted waveguide, an orthogonal mode coupler, a stepped impedance low-pass filter, and an H-plane right-angle waveguide; the E-plane right-angle waveguide is used to access the fundamental mode TE propagating in vertical polarization in the uplink. 10 Model, and base model TE 10 The mode output is sent to the first E-plane 90° twisted waveguide, which is used to output the fundamental mode TE. 10 The mode propagation direction is rotated 90° and then output to the vanishing mode ridge waveguide bandpass filter. The vanishing mode ridge waveguide bandpass filter is used to transmit the fundamental mode TE from the output to its location. 10 Select the fundamental mode TE located in the uplink frequency band (13.75-14.5GHz) from the mode selection. 10 The mode output is sent to the second E-plane 90° twisted waveguide, which is used to output the fundamental mode TE. 10 The propagation direction of the mode is rotated 90° and then output to the orthogonal mode coupler. The orthogonal mode coupler is used to connect the fundamental mode TE output from the second E-plane 90° twisted waveguide. 10 The fundamental mode TE, which propagates in horizontal polarization in the access downlink, is also included. 11 When the orthogonal mode coupler is connected to the fundamental mode TE output from the second E-plane 90° twisted waveguide, 10 When the mode is in phase, the orthogonal mode coupler will convert the fundamental mode TE 10 Modulus to base mode TE 11 Post-mode output, when the orthogonal mode coupler is connected to the downlink, the fundamental mode TE propagating in horizontal polarization... 11 When the fundamental mode TE is used, the orthogonal mode coupler will couple the fundamental mode TE. 11 Model to TE 01 The analog output is fed to the stepped impedance filter, which is used to transfer the signal from the output to the TE at that location. 01 In the mode, select the TE in the downlink frequency band (10.7-12.75GHz). 01 The mode output is fed to the H-plane right-angle waveguide, which is used to transmit the TE output to it. 01 Output without loss.

[0007] The orthogonal mode coupler comprises a common waveguide, a vertical polarization channel and a horizontal polarization channel, the vertical polarization channel is used for accessing vertical polarization linear signals, the horizontal polarization channel is used for accessing horizontal polarization linear signals, the common waveguide is used for converting the vertical polarization linear signals from a fundamental mode TE 10 to a fundamental mode TE 11 and converting the horizontal polarization linear signals from a fundamental mode TE 11 to a fundamental mode TE 01 , the common waveguide comprises a first circular waveguide, a second circular waveguide, a third circular waveguide and a first square waveguide, the first circular waveguide, the second circular waveguide, the third circular waveguide and the first square waveguide are stacked in order from top to bottom, and the first circular waveguide, the second circular waveguide, the third circular waveguide and the first square waveguide are coaxial, the diameter of the first circular waveguide is greater than the diameter of the second circular waveguide, the diameter of the second circular waveguide is greater than the diameter of the third circular waveguide, the diameters of the first circular waveguide, the second circular waveguide and the third circular waveguide all meet the transmission requirements of a fundamental mode TE 11 , and only the propagation of a fundamental mode TE 11 is allowed, the cross section of the first square waveguide along the horizontal direction is a square, the side length of the square is less than the diameter of the third circular waveguide, the diagonal of the square is greater than the diameter of the third circular waveguide, and the first square waveguide can transmit a fundamental mode TE 01 and a fundamental mode TE 10The first square waveguide is arranged in the vertical polarization channel, and the upper surface of the first square waveguide is the first port of the common waveguide, and the lower bottom surface of the first square waveguide is the second port of the common waveguide; the vertical polarization channel comprises a second square waveguide, a first rectangular waveguide and a U-shaped bending waveguide arranged in sequence from top to bottom, the cross section of the second square waveguide is a square, and the side length of the square is smaller than the side length of the cross section of the first square waveguide, the center line of the second square waveguide coincides with the center line of the first square waveguide, the upper surface of the second square waveguide is attached to the lower bottom surface of the first square waveguide, the upper surface of the first rectangular waveguide is attached to the lower bottom surface of the second square waveguide, the center line of the first rectangular waveguide coincides with the center line of the second square waveguide, the width of the first rectangular waveguide along the left-right direction is smaller than the side length of the cross section of the second square waveguide, but the length of the first rectangular waveguide along the front-back direction is greater than the side length of the cross section of the second square waveguide; the U-shaped bending waveguide comprises a second rectangular waveguide, a third rectangular waveguide, a fourth rectangular waveguide, a first right-angled trapezoidal waveguide, a second right-angled trapezoidal waveguide, a third right-angled trapezoidal waveguide, a fourth right-angled trapezoidal waveguide, a first isosceles trapezoidal waveguide and a second isosceles trapezoidal waveguide. The second rectangular waveguide is located below the first rectangular waveguide, the upper end surface of the second rectangular waveguide is attached to the lower end surface of the first rectangular waveguide, the center line of the second rectangular waveguide and the center line of the first rectangular waveguide are on the same straight line, the length of the second rectangular waveguide along the front-back direction is greater than the length of the first rectangular waveguide along the front-back direction, but the width of the second rectangular waveguide along the left-right direction is smaller than the width of the first rectangular waveguide along the left-right direction, the third rectangular waveguide is located on the right side of the second rectangular waveguide, and there is a distance between the two, the front end surface of the third rectangular waveguide is located on the same plane as the front end surface of the second rectangular waveguide, the rear end surface of the third rectangular waveguide is located on the same plane as the rear end surface of the second rectangular waveguide, the left end surface of the third rectangular waveguide is located on the same plane as the left end surface of the second rectangular waveguide, the upper end surface of the third rectangular waveguide is located on the same plane as the upper end surface of the second rectangular waveguide, the lower end surface of the third rectangular waveguide is located on the same plane as the lower end surface of the second rectangular waveguide, the third rectangular waveguide is symmetrical to the second rectangular waveguide left and right, and the left-right symmetry plane of the third rectangular waveguide and the second rectangular waveguide is referred to as a first symmetry plane, the first right-angled trapezoidal waveguide is located below the second rectangular waveguide, the cross section of the first right-angled trapezoidal waveguide along the horizontal direction is a rectangle, and the cross section along the vertical direction is a right-angled trapezoid, and the lower bottom of the right-angled trapezoid is on the upper side, the upper bottom is on the lower side, the right angle waist is on the right side, and the other waist is on the left side, the upper end surface of the first right-angled trapezoidal waveguide is attached to the lower end surface of the second rectangular waveguide, and the length of the upper end surface of the first right-angled trapezoidal waveguide along the front-back direction is equal to the length of the second rectangular waveguide along the front-back direction,The length of the upper end surface of the first right trapezoidal waveguide along the left-right direction is equal to the length of the second rectangular waveguide along the left-right direction, the second right trapezoidal waveguide is located below the third rectangular waveguide and is left-right symmetrical with the second right trapezoidal waveguide relative to the first symmetry plane, the first isosceles trapezoidal waveguide is located below the first right trapezoidal waveguide and the second right trapezoidal waveguide, the cross section of the first isosceles trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the first isosceles trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the lower base of the isosceles trapezoidal is on the upper side, the upper base is on the lower side, one waist is on the left side, and the other waist is on the right side, the upper end surface of the first isosceles trapezoidal waveguide is fixedly connected with the lower end surface of the first right trapezoidal waveguide and the lower end surface of the second right trapezoidal waveguide, the length of the upper end surface of the first isosceles trapezoidal waveguide along the left-right direction is greater than the sum of the length of the lower end surface of the first right trapezoidal waveguide along the left-right direction and the length of the lower end surface of the second right trapezoidal waveguide along the left-right direction, the left end surface of the first isosceles trapezoidal waveguide is located in the same plane as the left end surface of the first right trapezoidal waveguide, the right end surface of the first isosceles trapezoidal waveguide is located in the same plane as the right end surface of the second right trapezoidal waveguide, the front end surface of the first isosceles trapezoidal waveguide is located in the same plane as the front end surface of the first right trapezoidal waveguide, the rear end surface of the first isosceles trapezoidal waveguide is located in the same plane as the rear end surface of the first right trapezoidal waveguide, the second isosceles trapezoidal waveguide is located below the first isosceles trapezoidal waveguide, the cross section of the first isosceles trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the first isosceles trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the lower base of the isosceles trapezoidal is on the upper side, the upper base is on the lower side, one waist is on the left side, and the other waist is on the right side, the upper end surface of the second isosceles trapezoidal waveguide is fixedly connected with the lower end surface of the first isosceles trapezoidal waveguide, the left side of the upper end surface of the second isosceles trapezoidal waveguide is flush with the left side of the lower end surface of the first isosceles trapezoidal waveguide, the right side of the upper end surface of the second isosceles trapezoidal waveguide is flush with the right side of the lower end surface of the first isosceles trapezoidal waveguide, the front end surface of the second isosceles trapezoidal waveguide is located in the same plane as the front end surface of the first isosceles trapezoidal waveguide, the rear end surface of the second isosceles trapezoidal waveguide is located in the same plane as the rear end surface of the first isosceles trapezoidal waveguide, the included angle between the upper end surface of the second isosceles trapezoidal waveguide and the left end surface thereof is smaller than the included angle between the upper end surface of the first isosceles trapezoidal waveguide and the left end surface thereof, the third right trapezoidal waveguide is located above the third rectangular waveguide, the cross section of the third right trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the third right trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the upper base of the isosceles trapezoidal is on the upper side, the lower base is on the lower side, the right angle waist is on the right side, and the other waist is on the left side, the lower end surface of the third right trapezoidal waveguide is fixedly connected with the upper end surface of the third rectangular waveguide, the left side of the lower end surface of the third right trapezoidal waveguide is flush with the left end surface of the third rectangular waveguide,The front end face of the third rectangular waveguide and the front end face of the third rectangular waveguide are located in the same plane, the rear end face of the third rectangular waveguide and the rear end face of the third rectangular waveguide are located in the same plane, the right end face of the third rectangular waveguide is located on the right side of the plane where the right end face of the third rectangular waveguide is located, the fourth rectangular waveguide is located above the third rectangular waveguide, the cross section of the fourth rectangular waveguide in the horizontal direction is rectangular, and the cross section of the fourth rectangular waveguide in the vertical direction is isosceles trapezoidal, and the upper base of the isosceles trapezoidal is on the upper side, the lower base is on the lower side, the right angle waist is on the right side, and the other waist is on the left side. The lower end face of the fourth rectangular waveguide is connected with the upper end face of the third rectangular waveguide, the left side of the lower end face of the fourth rectangular waveguide is flush with the left side of the upper end face of the third rectangular waveguide, the front end face of the fourth rectangular waveguide is located in the same plane as the front end face of the third rectangular waveguide, the rear end face of the fourth rectangular waveguide is located in the same plane as the rear end face of the third rectangular waveguide, the right end face of the fourth rectangular waveguide is located in the same plane as the right end face of the third rectangular waveguide, the angle between the left end face of the fourth rectangular waveguide and the lower end face thereof is smaller than the angle between the left end face of the third rectangular waveguide and the lower end face thereof, the fourth rectangular waveguide is located on the right side of the fourth rectangular waveguide and the third rectangular waveguide, the lower end face of the fourth rectangular waveguide is located in the same plane as the lower end face of the third rectangular waveguide, the upper end face of the fourth rectangular waveguide is located in the same plane as the upper end face of the fourth rectangular waveguide, the left end face of the fourth rectangular waveguide is connected with the left end face of the fourth rectangular waveguide and the third rectangular waveguide, the length of the fourth rectangular waveguide in the front-rear direction is greater than the length of the fourth rectangular waveguide in the front-rear direction, the distance from the front end face of the fourth rectangular waveguide to the front end face of the fourth rectangular waveguide is equal to the distance from the rear end face of the fourth rectangular waveguide to the rear end face of the fourth rectangular waveguide, the upper end face of the second rectangular waveguide is the first port of the vertical polarization channel, and the right end face of the fourth rectangular waveguide is the second port of the vertical polarization channel. The horizontal polarization channel comprises a fifth rectangular waveguide, a sixth rectangular waveguide, a seventh rectangular waveguide, an eighth rectangular waveguide, a ninth rectangular waveguide and a tenth rectangular waveguide, the tenth rectangular waveguide, the ninth rectangular waveguide, the fifth rectangular waveguide, the sixth rectangular waveguide, the seventh rectangular waveguide and the eighth rectangular waveguide are arranged in order from right to left, the fifth rectangular waveguide, the sixth rectangular waveguide, the seventh rectangular waveguide and the eighth rectangular waveguide are coaxial, the left end face of the tenth rectangular waveguide and the right end face of the ninth rectangular waveguide are connected,The left end face of the ninth rectangular waveguide and the right end face of the fifth rectangular waveguide are connected, the left end face of the fifth rectangular waveguide and the right end face of the sixth rectangular waveguide are connected, the left end face of the sixth rectangular waveguide and the right end face of the seventh rectangular waveguide are connected, the left end face of the seventh rectangular waveguide and the right end face of the eighth rectangular waveguide are connected, the lower end face of the tenth rectangular waveguide, the lower end face of the ninth rectangular waveguide and the lower end face of the fifth rectangular waveguide are in the same plane, the height of the ninth rectangular waveguide in the up-down direction is less than the height of the fifth rectangular waveguide in the up-down direction, the height of the tenth rectangular waveguide in the up-down direction is less than the height of the ninth rectangular waveguide in the up-down direction, the height of the fifth rectangular waveguide in the up-down direction is less than the height of the sixth rectangular waveguide in the up-down direction, the length of the fifth rectangular waveguide in the front-rear direction is less than the length of the sixth rectangular waveguide in the front-rear direction, the width of the fifth rectangular waveguide in the left-right direction is less than the width of the sixth rectangular waveguide in the left-right direction; the height of the sixth rectangular waveguide in the up-down direction is less than the height of the seventh rectangular waveguide in the up-down direction, the length of the sixth rectangular waveguide in the front-rear direction is less than the length of the seventh rectangular waveguide in the front-rear direction, the width of the sixth rectangular waveguide in the left-right direction is less than the width of the seventh rectangular waveguide in the left-right direction; the height of the seventh rectangular waveguide in the up-down direction is less than the height of the eighth rectangular waveguide in the up-down direction, the length of the seventh rectangular waveguide in the front-rear direction is less than the length of the eighth rectangular waveguide in the front-rear direction, the width of the seventh rectangular waveguide in the left-right direction is less than the width of the eighth rectangular waveguide in the left-right direction, the plane where the lower end face of the tenth rectangular waveguide is located is above the plane where the lower end face of the second rectangular waveguide is located, the right end face of the tenth rectangular waveguide and the left end face of the second rectangular waveguide are connected, the upper end face of the tenth rectangular waveguide and the lower end face of the first rectangular waveguide are connected, the right end face of the ninth rectangular waveguide and the left end face of the first rectangular waveguide are connected, the upper end face of the ninth rectangular waveguide and the lower end face of the second rectangular waveguide are connected, the right end face of the fifth rectangular waveguide and the left end face of the second rectangular waveguide are connected; the right end face of the eighth rectangular waveguide is the first port of the horizontal polarization channel, the second port of the common waveguide is connected with the first port of the vertical polarization channel, the first port of the common waveguide is the common waveguide port of the orthogonal mode coupler, the second port of the vertical polarization channel is the vertical polarization wave port of the orthogonal mode coupler, the first port of the horizontal polarization channel is the horizontal polarization wave port of the orthogonal mode coupler; when the antenna transmits a vertical polarization linear signal, the fundamental mode TE, 10 mode enters the vertical polarization channel through the vertical polarization wave port of the orthogonal mode coupler, the fundamental mode TE10 The fundamental mode TE 10 The fundamental mode TE 11 The fundamental mode TE 11 The fundamental mode TE 11 The fundamental mode TE 01 The fundamental mode TE 01 The fundamental mode TE

[0008] The lost foam ridge waveguide band-pass filter includes a cutoff waveguide, twelve metal ridge waveguides, an eleventh rectangular waveguide and a twelfth rectangular waveguide, the eleventh rectangular waveguide is located on the left side of the cutoff waveguide, the twelfth rectangular waveguide is located on the right side of the cutoff waveguide, the cutoff waveguide is rectangular, the eleventh rectangular waveguide and the twelfth rectangular waveguide are left-right symmetrical, the right end face of the eleventh rectangular waveguide and the left end face of the cutoff waveguide are connected, the left end face of the twelfth rectangular waveguide and the right end face of the cutoff waveguide are connected, the front end face of the eleventh rectangular waveguide, the front end face of the cutoff waveguide and the front end face of the twelfth rectangular waveguide are located on the same plane, the back end face of the eleventh rectangular waveguide, the back end face of the cutoff waveguide and the back end face of the twelfth rectangular waveguide are located on the same plane, the height of the cutoff waveguide along the up-down direction is less than the height of the eleventh rectangular waveguide along the up-down direction, the upper end face of the eleventh rectangular waveguide and the upper end face of the twelfth rectangular waveguide are located on the same plane, the lower end face of the eleventh rectangular waveguide and the lower end face of the twelfth rectangular waveguide are located on the same plane, the distance from the upper end face of the cutoff waveguide to the plane where the upper end face of the eleventh rectangular waveguide is located is equal to the distance from the lower end face of the cutoff waveguide to the plane where the lower end face of the eleventh rectangular waveguide is located, twelve metal ridge waveguides are distributed inside the cutoff waveguide, the twelve metal ridge waveguides are called first metal ridge waveguide, second metal ridge waveguide, third metal ridge waveguide, fourth metal ridge waveguide, fifth metal ridge waveguide, sixth metal ridge waveguide, seventh metal ridge waveguide, eighth metal ridge waveguide, ninth metal ridge waveguide, tenth metal ridge waveguide, eleventh metal ridge waveguide and twelfth metal ridge waveguide, the first metal ridge waveguide, the second metal ridge waveguide, the third metal ridge waveguide, the fourth metal ridge waveguide, the fifth metal ridge waveguide and the sixth metal ridge waveguide are arranged in sequence from left to right, the seventh metal ridge waveguide, the eighth metal ridge waveguide, the ninth metal ridge waveguide, the tenth metal ridge waveguide, the eleventh metal ridge waveguide and the twelfth metal ridge waveguide are arranged in sequence from left to right, the front end face of the first metal ridge waveguide, the front end face of the second metal ridge waveguide, the front end face of the third metal ridge waveguide, the front end face of the fourth metal ridge waveguide, the front end face of the fifth metal ridge waveguide and the front end face of the sixth metal ridge waveguide are located on the same plane as the front end face of the cutoff waveguide, the back end face of the seventh metal ridge waveguide, the back end face of the eighth metal ridge waveguide, the back end face of the ninth metal ridge waveguide, the back end face of the tenth metal ridge waveguide, the back end face of the eleventh metal ridge waveguide and the back end face of the twelfth metal ridge waveguide are located on the same plane as the back end face of the cutoff waveguide, the seventh metal ridge waveguide is located on the back side of the first metal ridge waveguide and the two are front-back symmetrical, the eighth metal ridge waveguide is located on the back side of the second metal ridge waveguide and the two are front-back symmetrical,The ninth metal ridge waveguide is located at the back side of the third metal ridge waveguide, and both are front-back symmetrical, the tenth metal ridge waveguide is located at the back side of the fourth metal ridge waveguide, and both are front-back symmetrical, the eleventh metal ridge waveguide is located at the back side of the fifth metal ridge waveguide, and both are front-back symmetrical, the twelfth metal ridge waveguide is located at the back side of the sixth metal ridge waveguide, and both are front-back symmetrical, the first metal ridge waveguide and the sixth metal ridge waveguide are left-right symmetrical, the second metal ridge waveguide and the fifth metal ridge waveguide are left-right symmetrical, the third metal ridge waveguide and the fourth metal ridge waveguide are left-right symmetrical, the seventh metal ridge waveguide and the twelfth metal ridge waveguide are left-right symmetrical, the eighth metal ridge waveguide and the eleventh metal ridge waveguide are left-right symmetrical, the ninth metal ridge waveguide and the tenth metal ridge waveguide are left-right symmetrical, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the front-back direction is equal, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the left-right direction decreases, and the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the up-down direction decreases; the left end face of the eleventh rectangular waveguide is used as the output port of the lost foam ridge waveguide band-pass filter, and the right end face of the twelfth rectangular waveguide is used as the input port of the lost foam ridge waveguide band-pass filter. The lost foam ridge waveguide band-pass filter is used for selecting vertical polarization linear signals, which only allows the frequency range corresponding to the uplink signal to pass, and filters out the frequency range that is not needed, especially filters out the downlink signal, which can also improve the port isolation of the overall diplexer.

[0009] The stepped impedance filter comprises a thirteenth rectangular waveguide and sixteen diaphragms, which are referred to as a first diaphragm, a second diaphragm, a third diaphragm, a fourth diaphragm, a fifth diaphragm, a sixth diaphragm, a seventh diaphragm, an eighth diaphragm, a ninth diaphragm, a tenth diaphragm, an eleventh diaphragm, a twelfth diaphragm, a thirteenth diaphragm, a fourteenth diaphragm, a fifteenth diaphragm and a sixteenth diaphragm; the first diaphragm, the second diaphragm, the third diaphragm, the fourth diaphragm, the fifth diaphragm, the sixth diaphragm, the seventh diaphragm and the eighth diaphragm are sequentially and spacedly arranged on the front side of the thirteenth rectangular waveguide from left to right; the ninth diaphragm, the tenth diaphragm, the eleventh diaphragm, the twelfth diaphragm, the thirteenth diaphragm, the fourteenth diaphragm, the fifteenth diaphragm and the sixteenth diaphragm are sequentially and spacedly arranged on the back side of the thirteenth rectangular waveguide from left to right; the first diaphragm and the ninth diaphragm are front-back symmetric; the second diaphragm and the tenth diaphragm are front-back symmetric; the third diaphragm and the eleventh diaphragm are front-back symmetric; the fourth diaphragm and the twelfth diaphragm are front-back symmetric; the fifth diaphragm and the thirteenth diaphragm are front-back symmetric; the sixth diaphragm and the fourteenth diaphragm are front-back symmetric; the seventh diaphragm and the fifteenth diaphragm are front-back symmetric; the eighth diaphragm and the sixteenth diaphragm are front-back symmetric; the first diaphragm and the eighth diaphragm are left-right symmetric; the second diaphragm and the seventh diaphragm are left-right symmetric; the third diaphragm and the sixth diaphragm are left-right symmetric; the fourth diaphragm and the fifth diaphragm are left-right symmetric; the ninth diaphragm and the sixteenth diaphragm are left-right symmetric; the tenth diaphragm and the fifteenth diaphragm are left-right symmetric; the eleventh diaphragm and the fourteenth diaphragm are left-right symmetric; the twelfth diaphragm and the thirteenth diaphragm are left-right symmetric; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are equal in length along the front-back direction; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are equal in width along the left-right direction; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are sequentially increased in height along the up-down direction; the left end face of the thirteenth rectangular waveguide serves as an output port of the stepped impedance filter; and the right end face of the thirteenth rectangular waveguide serves as an input port of the stepped impedance filter. The stepped impedance filter is used for selecting a horizontally polarized linear signal, allowing only a frequency range corresponding to a downlink signal to pass, and filtering out an unnecessary frequency range, especially filtering out an uplink signal, so as to improve port isolation of an overall duplexer.

[0010] The first E 90-degree twist waveguide includes a first input waveguide, a first transition structure and a first output waveguide. The transition structure includes a fourteenth rectangular waveguide, a fifteenth rectangular waveguide, a sixteenth rectangular waveguide, a seventeenth rectangular waveguide and an eighteenth rectangular waveguide arranged in sequence from back to front. The front side of the fourteenth rectangular waveguide is connected to the back side of the fifteenth rectangular waveguide, the front side of the fifteenth rectangular waveguide is connected to the back side of the sixteenth rectangular waveguide, the front side of the sixteenth rectangular waveguide is connected to the back side of the seventeenth rectangular waveguide, and the front side of the seventeenth rectangular waveguide is connected to the back side of the eighteenth rectangular waveguide. The left side of the fourteenth rectangular waveguide, the fifteenth rectangular waveguide, the sixteenth rectangular waveguide, the seventeenth rectangular waveguide and the eighteenth rectangular waveguide are located in the same plane. The right side of the fourteenth rectangular waveguide, the fifteenth rectangular waveguide, the sixteenth rectangular waveguide, the seventeenth rectangular waveguide and the eighteenth rectangular waveguide are located in the same plane. The height of the fourteenth rectangular waveguide along the up-down direction is less than the height of the fifteenth rectangular waveguide along the up-down direction. The length of the fourteenth rectangular waveguide along the front-back direction is greater than the length of the fifteenth rectangular waveguide along the front-back direction. The height of the fifteenth rectangular waveguide along the up-down direction is less than the height of the sixteenth rectangular waveguide along the up-down direction. The height of the sixteenth rectangular waveguide along the up-down direction is less than the height of the first output waveguide along the up-down direction. The length of the sixteenth rectangular waveguide along the front-back direction is less than the length of the first output waveguide along the front-back direction. The length of the sixteenth rectangular waveguide along the front-back direction is greater than the length of the fourteenth rectangular waveguide along the front-back direction. The fourteenth rectangular waveguide and the eighteenth rectangular waveguide are front-back center symmetric with respect to the center of the sixteenth rectangular waveguide. The fifteenth rectangular waveguide and the seventeenth rectangular waveguide are front-back center symmetric with respect to the center of the sixteenth rectangular waveguide. The central axis of the first output waveguide, the sixteenth rectangular waveguide and the first input waveguide along the left-right direction are on a straight line. The central line of the fourteenth rectangular waveguide and the fifteenth rectangular waveguide along the front-back direction are on a straight line. The right end surface of the first output waveguide is connected to the left end surface of the fifteenth rectangular waveguide, the left end surface of the sixteenth rectangular waveguide and the left end surface of the seventeenth waveguide, respectively. The back end surface of the fifteenth rectangular waveguide is located on the back side of the plane on which the back end surface of the first output waveguide is located. The left end surface of the first input waveguide is connected to the right end surface of the fourteenth rectangular waveguide, the right end surface of the fifteenth rectangular waveguide, the right end surface of the sixteenth rectangular waveguide, the right end surface of the seventeenth rectangular waveguide and the right end surface of the eighteenth rectangular waveguide, respectively.The rear end face of the fourteenth rectangular waveguide and the rear end face of the first input waveguide are located in the same plane, the front end face of the eighteenth rectangular waveguide and the front end face of the first input waveguide are located in the same plane, the lower end face of the fifteenth rectangular waveguide is located below the plane in which the lower end face of the first input waveguide is located and above the plane in which the lower end face of the sixteenth rectangular waveguide is located, the rear side face of the fourteenth rectangular waveguide and the rear side face of the first input waveguide are located in the same plane, the front side face of the eighteenth rectangular waveguide and the front side face of the first input waveguide are located in the same plane, the right side face of the first input waveguide serves as an input port of the first E-plane 90° twist waveguide, and the left end face of the first output waveguide serves as an output port of the first E-plane 90° twist waveguide.

[0011] The E-plane rectangular waveguide comprises a third rectangular trapezoidal waveguide, a fourth rectangular trapezoidal waveguide, a first rectangular triangular waveguide, a second rectangular triangular waveguide, a nineteenth rectangular waveguide, a twentieth rectangular waveguide and a twenty-first rectangular waveguide, the third rectangular trapezoidal waveguide, the nineteenth rectangular waveguide, the twentieth rectangular waveguide, the fourth rectangular trapezoidal waveguide and the twenty-first rectangular waveguide are arranged in the order from top to bottom, the cross section of the third rectangular trapezoidal waveguide along the vertical direction is a rectangular trapezoid, the upper base of the rectangular trapezoid is located at the top, the lower base is located at the bottom, the right side is located at the right side, the left side is located at the left side, the cross section of the fourth rectangular trapezoidal waveguide along the vertical direction is a rectangular trapezoid, the upper base of the rectangular trapezoid is located at the bottom, the lower base is located at the top, the right side is located at the right side, the left side is located at the left side, the lower end surface of the third rectangular trapezoidal waveguide is attached to the upper end surface of the nineteenth rectangular waveguide and they completely coincide, the left end surface of the third rectangular trapezoidal waveguide is flush with the left end surface of the nineteenth rectangular waveguide, the front end surface of the third rectangular trapezoidal waveguide is flush with the front end surface of the nineteenth rectangular waveguide, the rear end surface of the third rectangular trapezoidal waveguide is flush with the rear end surface of the nineteenth rectangular waveguide, the lower end surface of the nineteenth rectangular waveguide is attached to the upper end surface of the twentieth rectangular waveguide, the right end surface of the nineteenth rectangular waveguide is flush with the right end surface of the twentieth rectangular waveguide, the front end surface of the nineteenth rectangular waveguide is flush with the front end surface of the twentieth rectangular waveguide, the rear end surface of the nineteenth rectangular waveguide is flush with the rear end surface of the twentieth rectangular waveguide, the left end surface of the nineteenth rectangular waveguide is located at the left side of the plane where the left end surface of the twentieth rectangular waveguide is located, the upper end surface of the twenty-first rectangular waveguide is attached to the lower end surface of the twentieth rectangular waveguide, the right end surface of the twenty-first rectangular waveguide is flush with the right end surface of the twentieth rectangular waveguide, the front end surface of the twenty-first rectangular waveguide is flush with the front end surface of the twentieth rectangular waveguide, the rear end surface of the twenty-first rectangular waveguide is flush with the rear end surface of the twentieth rectangular waveguide, the left end surface of the twenty-first rectangular waveguide is located at the left side of the plane where the left end surface of the nineteenth rectangular waveguide is located, the upper end surface of the fourth rectangular trapezoidal waveguide is attached to the lower end surface of the twenty-first rectangular waveguide and they completely coincide, the left end surface of the fourth rectangular trapezoidal waveguide is flush with the left end surface of the twenty-first rectangular waveguide, the front end surface of the fourth rectangular trapezoidal waveguide is flush with the front end surface of the twenty-first rectangular waveguide, the rear end surface of the fourth rectangular trapezoidal waveguide is flush with the rear end surface of the twenty-first rectangular waveguide, the upper end surface of the first rectangular triangular waveguide is attached to the lower end surface of the nineteenth rectangular waveguide, the right end surface of the first rectangular triangular waveguide is attached to the left end surface of the twentieth rectangular waveguide, the front end surface of the first rectangular triangular waveguide is flush with the front end surface of the nineteenth rectangular waveguide,The rear end surface of the first right-angled triangular waveguide is flush with the rear end surface of the nineteenth rectangular waveguide, the lower end surface of the second right-angled triangular waveguide is attached to the upper end surface of the twenty-first rectangular waveguide, the right end surface of the second right-angled triangular waveguide is attached to the left end surface of the twentieth rectangular waveguide, the front end surface of the second right-angled triangular waveguide is flush with the front end surface of the twenty-first rectangular waveguide, the rear end surface of the second right-angled triangular waveguide is flush with the rear end surface of the twenty-first rectangular waveguide, the length of the upper end surface of the first right-angled triangular waveguide along the left-right direction is less than the distance between the plane where the left end surface of the nineteenth rectangular waveguide and the left end surface of the twentieth rectangular waveguide are located, the length of the lower end surface of the second right-angled triangular waveguide along the left-right direction is equal to the length of the upper end surface of the first right-angled triangular waveguide along the left-right direction, there is a distance between the lower end of the right end surface of the first right-angled triangular waveguide and the upper end of the right end surface of the second right-angled triangular waveguide, the left end surface of the nineteenth rectangular waveguide and the left end surface of the third right-angled trapezoidal waveguide serve as the output port of the E-plane right-angled waveguide, and the left end surface of the twenty-first rectangular waveguide and the left end surface of the fourth right-angled trapezoidal waveguide serve as the input port of the E-plane right-angled waveguide. The E-plane right-angled waveguide changes the transmission direction of the vertically polarized signal so that it can enter the BUC (up-conversion power amplifier) placed on the central axis of the rear-end antenna without obstruction.

[0012] The H-plane right-angle waveguide comprises a twenty-second rectangular waveguide, a twenty-third rectangular waveguide and a twenty-fourth rectangular waveguide arranged in sequence from front to back, the upper end face of the twenty-second rectangular waveguide, the upper end face of the twenty-third rectangular waveguide and the upper end face of the twenty-fourth rectangular waveguide are located in the same plane, the lower end face of the twenty-second rectangular waveguide, the lower end face of the twenty-third rectangular waveguide and the lower end face of the twenty-fourth rectangular waveguide are located in the same plane, the left end face of the twenty-second rectangular waveguide, the left end face of the twenty-third rectangular waveguide and the left end face of the twenty-fourth rectangular waveguide are located in the same plane, the rear end face of the twenty-second rectangular waveguide and the front end face of the twenty-third rectangular waveguide are attached, the rear end face of the twenty-third rectangular waveguide and the front end face of the twenty-fourth rectangular waveguide are attached, the length of the twenty-second rectangular waveguide along the left-right direction is greater than the length of the twenty-third rectangular waveguide along the left-right direction, but less than the length of the twenty-fourth rectangular waveguide along the left-right direction, the junction of the front end face of the twenty-second rectangular waveguide and the left end face of the twenty-third rectangular waveguide is chamfered, the junction of the left end face of the twenty-third rectangular waveguide and the rear end face of the twenty-fourth rectangular waveguide is chamfered, the right end face of the twenty-second rectangular waveguide serves as the output port of the H-plane right-angle waveguide, and the right end face of the twenty-fourth rectangular waveguide serves as the input port of the H-plane right-angle waveguide. The H-plane right-angle waveguide changes the transmission direction of the horizontally polarized signal, so that the horizontally polarized signal can enter the LNB (low frequency amplifier) arranged on the central axis of the rear-end antenna.

[0013] Compared with the prior art, the duplexers have the advantages that the high-isolation Ku-band full-bandwidth linear polarization duplexers for satellite communication are constructed by an E-plane right-angle waveguide, a first E-plane 90° twist waveguide, a dielectric ridge waveguide bandpass filter, a second E-plane 90° twist waveguide, an orthogonal mode coupler, a stepped impedance low-pass filter and an H-plane right-angle waveguide, the E-plane right-angle waveguide is used for accessing the fundamental mode TE 10 mode propagating in the uplink in the form of vertical polarization, and outputs the fundamental mode TE 10 mode to the first E-plane 90° twist waveguide, the first E-plane 90° twist waveguide is used for rotating the propagation direction of the fundamental mode TE 10 mode by 90° and then outputting the fundamental mode TE 10 mode to the dielectric ridge waveguide bandpass filter, the dielectric ridge waveguide bandpass filter is used for selecting the fundamental mode TE 10 mode in the uplink frequency band (13.75-14.5 GHz) from the fundamental mode TE 10The mode is output to the quadrature mode coupler after rotating 90° in the propagation direction, and the quadrature mode coupler is used for accessing the fundamental mode TE 10 The mode and the fundamental mode TE 11 The mode, when the quadrature mode coupler accesses the fundamental mode TE 10 The mode, the quadrature mode coupler converts the fundamental mode TE 10 The mode into the fundamental mode TE 11 The mode is output, when the quadrature mode coupler accesses the fundamental mode TE 11 The mode, the quadrature mode coupler converts the fundamental mode TE 11 The mode into the fundamental mode TE 01 The mode is output to the stepped impedance filter, and the stepped impedance filter is used for selecting the TE 01 Mode in the downlink frequency band (10.7-12.75GHz) from the TE 01 Mode output to the H-plane rectangular waveguide, and the H-plane rectangular waveguide is used for losslessly outputting the TE 01 Mode output to the H-plane rectangular waveguide, and the H-plane rectangular waveguide is used for losslessly outputting the TE The quadrature mode coupler in the application adopts the simplest and most compact asymmetric quadrature mode coupler structure, which is simple in structure and maintains high isolation (better than 60dB) and high quadrature mode polarization isolation between the vertical polarization wave port and the horizontal polarization wave port, and further improves the overall isolation of the diplexer, suppresses the out-of-band signal. The application has simple structure, wide working frequency band, can cover the whole bandwidth of the Ku frequency band, and the simulation results show that the reflection coefficient in the Ku working frequency band is greater than-20dB, and the overall isolation is high, better than 115dB. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is the overall structure diagram of the high-isolation Ku-band full-bandwidth linear polarization diplexer for satellite communication of the application;

[0015] Figure 2 It is the structure diagram of the quadrature mode coupler of the high-isolation Ku-band full-bandwidth linear polarization diplexer for satellite communication of the application;

[0016] Figure 3 It is the structure diagram of the evanescent mode ridge waveguide bandpass filter of the high-isolation Ku-band full-bandwidth linear polarization diplexer for satellite communication of the application;

[0017] Figure 4 It is the structure diagram of the stepped impedance filter of the high-isolation Ku-band full-bandwidth linear polarization diplexer for satellite communication of the application;

[0018] Figure 5This is a structural diagram of the first E-plane 90° twisted waveguide of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present invention.

[0019] Figure 6 This is a structural diagram of the second E-plane 90° twisted waveguide of the high-isolation Ku-band full-width linear polarization duplexer for satellite communication of the present invention;

[0020] Figure 7 This is a structural diagram of the E-plane right-angle waveguide of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication according to the present invention;

[0021] Figure 8 This is a structural diagram of the H-plane right-angle waveguide of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication according to the present invention;

[0022] Figure 9 The simulation and test results of the reflection coefficient and isolation of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication of the present invention are shown.

[0023] Figure 10 The figures show the simulation and test results of the insertion loss of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication according to the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] Example: Figure 1 As shown, a high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication includes, in order from right to left, an E-plane right-angle waveguide 1, a first E-plane 90° twisted waveguide 2, a vanishing mode ridge waveguide bandpass filter 3, a second E-plane 90° twisted waveguide 4, an orthogonal mode coupler 5, a stepped impedance low-pass filter 6, and an H-plane right-angle waveguide 7; the E-plane right-angle waveguide 1 is used to access the fundamental mode TE propagating in vertical polarization in the uplink. 10 Model, and base model TE 10 The mode output is sent to the first E-plane 90° twisted waveguide 2, which is used to transmit the fundamental mode TE. 10 After rotating the propagation direction of the mode by 90°, the output is sent to the vanishing mode ridge waveguide bandpass filter 3. The vanishing mode ridge waveguide bandpass filter 3 is used to transmit the fundamental mode TE from the output to its location. 10 Select the fundamental mode TE located in the uplink frequency band (13.75-14.5GHz) from the mode selection. 10 The mode output is fed to the second E-plane 90° twisted waveguide 4, which is used to output the fundamental mode TE at that location. 10The mode is output to the quadrature mode coupler 5 after rotating 90° in the propagation direction, and the quadrature mode coupler 5 is used to access the fundamental mode TE 10 mode and access the fundamental mode TE 11 mode in the downlink in the form of horizontal polarization 10 mode, the quadrature mode coupler 5 converts the fundamental mode TE 10 mode into the fundamental mode TE 11 mode, and the quadrature mode coupler 5 converts the fundamental mode TE 11 mode into the fundamental mode TE 11 mode, and the quadrature mode coupler 5 converts the fundamental mode TE 01 mode into the fundamental mode TE 01 mode, the quadrature mode coupler 5 converts the fundamental mode TE 01 mode into the fundamental mode TE 01 mode into the fundamental mode TE

[0026] In the embodiment, as shown in Figure 2 Fig. 1, the quadrature mode coupler 5 includes a common waveguide, a vertical polarization channel and a horizontal polarization channel, the vertical polarization channel is used to access the vertical polarization linear signal, the horizontal polarization channel is used to access the horizontal polarization linear signal, and the common waveguide is used to convert the vertical polarization linear signal from the fundamental mode TE 10 mode into the fundamental mode TE 11 mode and convert the horizontal polarization linear signal from the fundamental mode TE 11 mode into the fundamental mode TE 01 mode, the common waveguide includes a first circular waveguide 8, a second circular waveguide 9, a third circular waveguide 10 and a first square waveguide 11, the first circular waveguide 8, the second circular waveguide 9, the third circular waveguide 10 and the first square waveguide 11 are stacked in order from top to bottom, and the first circular waveguide 8, the second circular waveguide 9, the third circular waveguide 10 and the first square waveguide 11 are coaxial, the diameter of the first circular waveguide 8 is greater than the diameter of the second circular waveguide 9, the diameter of the second circular waveguide 9 is greater than the diameter of the third circular waveguide 10, and the diameters of the first circular waveguide 8, the second circular waveguide 9 and the third circular waveguide 10 all meet the transmission requirements of the fundamental mode TE 11 mode, and only the propagation of the fundamental mode TE 11 mode is allowed, the first square waveguide 11 has a square cross section in the horizontal direction, the side length of the square is less than the diameter of the third circular waveguide 10, the diagonal of the square is greater than the diameter of the third circular waveguide 10, and the first square waveguide 11 can transmit the fundamental mode TE 01 mode and the fundamental mode TE 10The upper surface of the first circular waveguide 8 is a first port of the common waveguide, and the lower bottom surface of the first square waveguide 11 is a second port of the common waveguide.

[0027] The vertical polarization channel comprises the second square waveguide 12, the first rectangular waveguide 13 and the U-shaped bending waveguide arranged in sequence from top to bottom. The cross section of the second square waveguide 12 is square, and the side length of the square is smaller than that of the cross section of the first square waveguide 11. The center line of the second square waveguide 12 coincides with the center line of the first square waveguide 11. The upper surface of the second square waveguide 12 is attached to the lower bottom surface of the first square waveguide 11. The upper surface of the first rectangular waveguide 13 is attached to the lower bottom surface of the second square waveguide 12. The center line of the first rectangular waveguide 13 coincides with the center line of the second square waveguide 12. The width of the first rectangular waveguide 13 along the left-right direction is smaller than the side length of the cross section of the second square waveguide 12, but the length of the first rectangular waveguide 13 along the front-back direction is greater than the side length of the cross section of the second square waveguide 12. The U-shaped bending waveguide comprises the second rectangular waveguide 14, the third rectangular waveguide 15, the fourth rectangular waveguide 16, the first right-angled trapezoidal waveguide 17, the second right-angled trapezoidal waveguide 18, the third right-angled trapezoidal waveguide 19, the fourth right-angled trapezoidal waveguide 20, the first isosceles trapezoidal waveguide 21 and the second isosceles trapezoidal waveguide 22. The second rectangular waveguide 14 is located below the first rectangular waveguide 13. The upper end surface of the second rectangular waveguide 14 is attached to the lower end surface of the first rectangular waveguide 13. The center line of the second rectangular waveguide 14 is on the same straight line as the center line of the first rectangular waveguide 13. The length of the second rectangular waveguide 14 along the front-back direction is greater than the length of the first rectangular waveguide 13 along the front-back direction, but the width of the second rectangular waveguide 14 along the left-right direction is smaller than the width of the first rectangular waveguide 13 along the left-right direction. The third rectangular waveguide 15 is located to the right of the second rectangular waveguide 14, and there is a distance between the two. The front end surface of the third rectangular waveguide 15 is on the same plane as the front end surface of the second rectangular waveguide 14. The rear end surface of the third rectangular waveguide 15 is on the same plane as the rear end surface of the second rectangular waveguide 14. The left end surface of the third rectangular waveguide 15 is on the same plane as the left end surface of the second rectangular waveguide 14. The upper end surface of the third rectangular waveguide 15 is on the same plane as the upper end surface of the second rectangular waveguide 14. The lower end surface of the third rectangular waveguide 15 is on the same plane as the lower end surface of the second rectangular waveguide 14. The third rectangular waveguide 15 is symmetrical to the second rectangular waveguide 14 along the left-right direction. The left-right symmetry plane of the third rectangular waveguide 15 and the second rectangular waveguide 14 is called the first symmetry plane. The first right-angled trapezoidal waveguide 17 is located below the second rectangular waveguide 14. The cross section of the first right-angled trapezoidal waveguide 17 along the horizontal direction is rectangular, and the cross section along the vertical direction is right-angled trapezoidal. The lower bottom of the right-angled trapezoidal is on the upper side, the upper bottom is on the lower side, the right angle waist is on the right side, and the other waist is on the left side. The upper end surface of the first right-angled trapezoidal waveguide 17 is attached to the lower end surface of the second rectangular waveguide 14. The length of the upper end surface of the first right-angled trapezoidal waveguide 17 along the front-back direction is equal to the length of the second rectangular waveguide 14 along the front-back direction. The length of the upper end surface of the first right-angled trapezoidal waveguide 17 along the left-right direction is equal to the length of the second rectangular waveguide 14 along the left-right direction.The first isosceles trapezoidal waveguide 21 is located below the first right-angled trapezoidal waveguide 17 and the second right-angled trapezoidal waveguide 18. The first isosceles trapezoidal waveguide 21 has a rectangular cross-section in the horizontal direction and an isosceles trapezoidal cross-section in the vertical direction, with the lower base on the top side and the upper base on the bottom side, one leg on the left and the other leg on the right. The upper end face of the first isosceles trapezoidal waveguide 21 is attached and fixed to the lower end face of the first right-angled trapezoidal waveguide 17 and the second right-angled trapezoidal waveguide 18. The length of the upper end face of the first isosceles trapezoidal waveguide 21 in the left-right direction is greater than the sum of the lengths of the lower end face of the first right-angled trapezoidal waveguide 17 and the second right-angled trapezoidal waveguide 18 in the left-right direction. The left end face of the first isosceles trapezoidal waveguide 21 is attached to the lower end face of the first right-angled trapezoidal waveguide 17 and the second right-angled trapezoidal waveguide 18 in the left-right direction. The left end face of the first isosceles trapezoidal waveguide 21 is on the same plane as the right end face of the second right trapezoidal waveguide 18. The front end face of the first isosceles trapezoidal waveguide 21 is on the same plane as the front end face of the first right trapezoidal waveguide 17. The rear end face of the first isosceles trapezoidal waveguide 21 is on the same plane as the rear end face of the first right trapezoidal waveguide 17. The second isosceles trapezoidal waveguide 22 is located below the first isosceles trapezoidal waveguide 21. The cross-section of the first isosceles trapezoidal waveguide 21 is rectangular in the horizontal direction and isosceles trapezoidal in the vertical direction, with the lower base on the upper side and the upper base on the lower side, one leg on the left and the other leg on the right. The upper end face of the second isosceles trapezoidal waveguide 22 is on the same plane as the lower end face of the first isosceles trapezoidal waveguide 21. The end faces are fitted together. The left side of the upper end face of the second isosceles trapezoidal waveguide 22 is flush with the left side of the lower end face of the first isosceles trapezoidal waveguide 21. The right side of the upper end face of the second isosceles trapezoidal waveguide 22 is flush with the right side of the lower end face of the first isosceles trapezoidal waveguide 21. The front end face of the second isosceles trapezoidal waveguide 22 is in the same plane as the front end face of the first isosceles trapezoidal waveguide 21. The rear end face of the second isosceles trapezoidal waveguide 22 is in the same plane as the rear end face of the first isosceles trapezoidal waveguide 21. The angle between the upper end face and the left end face of the second isosceles trapezoidal waveguide 22 is smaller than the angle between the upper end face and the left end face of the first isosceles trapezoidal waveguide 21. The third right-angled trapezoidal waveguide 19 is located above the third rectangular waveguide 15. The cross-section of the third right-angled trapezoidal waveguide 19 along the horizontal direction is... The first right-angled trapezoidal waveguide 19 is rectangular, with its vertical cross-section being an isosceles trapezoid. The upper base of this isosceles trapezoid is on the top side, the lower base is on the bottom side, the right leg is on the right, and the other leg is on the left. The lower end face of the third right-angled trapezoidal waveguide 19 is flush with the upper end face of the third rectangular waveguide 15. The left side of the lower end face of the third right-angled trapezoidal waveguide 19 is flush with the left end face of the third rectangular waveguide 15. The front end face of the third right-angled trapezoidal waveguide 19 is in the same plane as the front end face of the third rectangular waveguide 15. The rear end face of the third right-angled trapezoidal waveguide 19 is in the same plane as the rear end face of the third rectangular waveguide 15. The right end face of the third right-angled trapezoidal waveguide 19 is located to the right of the plane containing the right end face of the third rectangular waveguide 15. The fourth right-angled trapezoidal waveguide 20 is located above the third right-angled trapezoidal waveguide 19.The fourth right trapezoidal waveguide 20 has a rectangular cross section in the horizontal direction and an isosceles trapezoidal cross section in the vertical direction, and the upper base of the isosceles trapezoid is on the upper side, the lower base is on the lower side, the right angle leg is on the right side, and the other leg is on the left side. The lower end surface of the fourth right trapezoidal waveguide 20 is connected to the upper end surface of the third right trapezoidal waveguide 19, the left side of the lower end surface of the fourth right trapezoidal waveguide 20 is flush with the left side of the upper end surface of the third right trapezoidal waveguide 19, the front end surface of the fourth right trapezoidal waveguide 20 is located in the same plane as the front end surface of the third right trapezoidal waveguide 19, the rear end surface of the fourth right trapezoidal waveguide 20 is located in the same plane as the rear end surface of the third right trapezoidal waveguide 19, the right end surface of the fourth right trapezoidal waveguide 20 is located in the same plane as the right end surface of the third right trapezoidal waveguide 19, the angle between the left end surface of the fourth right trapezoidal waveguide 20 and the lower end surface thereof is smaller than the angle between the left end surface of the third right trapezoidal waveguide 19 and the lower end surface thereof, the fourth rectangular waveguide 16 is located to the right of the fourth right trapezoidal waveguide 20 and the third right trapezoidal waveguide 19, the lower end surface of the fourth rectangular waveguide 16 is located in the same plane as the lower end surface of the third right trapezoidal waveguide 19, the upper end surface of the fourth rectangular waveguide 16 is located in the same plane as the upper end surface of the fourth right trapezoidal waveguide 20, the left end surface of the fourth rectangular waveguide 16 is connected to the left end surfaces of the fourth right trapezoidal waveguide 20 and the third right trapezoidal waveguide 19, the length of the fourth rectangular waveguide 16 in the front-rear direction is greater than the length of the fourth right trapezoidal waveguide 20 in the front-rear direction, the distance from the front end surface of the fourth rectangular waveguide 16 to the front end surface of the fourth right trapezoidal waveguide 20 is equal to the distance from the rear end surface of the fourth rectangular waveguide 16 to the rear end surface of the fourth right trapezoidal waveguide 20, the upper end surface of the second square waveguide 12 is a first port of a vertical polarization channel, and the right end surface of the fourth rectangular waveguide 16 is a second port of the vertical polarization channel.

[0028] The horizontal polarization channel comprises a fifth rectangular waveguide 23, a sixth rectangular waveguide 24, a seventh rectangular waveguide 25, an eighth rectangular waveguide 26, a ninth rectangular waveguide 27 and a tenth rectangular waveguide 28, the tenth rectangular waveguide 28, the ninth rectangular waveguide 27, the fifth rectangular waveguide 23, the sixth rectangular waveguide 24, the seventh rectangular waveguide 25 and the eighth rectangular waveguide 26 are arranged in sequence from right to left, the fifth rectangular waveguide 23, the sixth rectangular waveguide 24, the seventh rectangular waveguide 25 and the eighth rectangular waveguide 26 are coaxial, the left end face of the tenth rectangular waveguide 28 and the right end face of the ninth rectangular waveguide 27 are connected in close contact, the left end face of the ninth rectangular waveguide 27 and the right end face of the fifth rectangular waveguide 23 are connected in close contact, the left end face of the fifth rectangular waveguide 23 and the right end face of the sixth rectangular waveguide 24 are connected in close contact, the left end face of the sixth rectangular waveguide 24 and the right end face of the seventh rectangular waveguide 25 are connected in close contact, the left end face of the seventh rectangular waveguide 25 and the right end face of the eighth rectangular waveguide 26 are connected in close contact, the lower end face of the tenth rectangular waveguide 28, the lower end face of the ninth rectangular waveguide 27 and the lower end face of the fifth rectangular waveguide 23 are located in the same plane, the height of the ninth rectangular waveguide 27 in the up-down direction is less than the height of the fifth rectangular waveguide 23 in the up-down direction, the height of the tenth rectangular waveguide 28 in the up-down direction is less than the height of the ninth rectangular waveguide 27 in the up-down direction, the height of the fifth rectangular waveguide 23 in the up-down direction is less than the height of the sixth rectangular waveguide 24 in the up-down direction, the length of the fifth rectangular waveguide 23 in the front-rear direction is less than the length of the sixth rectangular waveguide 24 in the front-rear direction, the width of the fifth rectangular waveguide 23 in the left-right direction is less than the width of the sixth rectangular waveguide 24 in the left-right direction; the height of the sixth rectangular waveguide 24 in the up-down direction is less than the height of the seventh rectangular waveguide 25 in the up-down direction, the length of the sixth rectangular waveguide 24 in the front-rear direction is less than the length of the seventh rectangular waveguide 25 in the front-rear direction, the width of the sixth rectangular waveguide 24 in the left-right direction is less than the width of the seventh rectangular waveguide 25 in the left-right direction; the height of the seventh rectangular waveguide 25 in the up-down direction is less than the height of the eighth rectangular waveguide 26 in the up-down direction, the length of the seventh rectangular waveguide 25 in the front-rear direction is less than the length of the eighth rectangular waveguide 26 in the front-rear direction, the width of the seventh rectangular waveguide 25 in the left-right direction is less than the width of the eighth rectangular waveguide 26 in the left-right direction, the plane where the lower end face of the tenth rectangular waveguide 28 is located is above the plane where the lower end face of the second rectangular waveguide 14 is located, the right end face of the tenth rectangular waveguide 28 and the left end face of the second rectangular waveguide 14 are in close contact, the upper end face of the tenth rectangular waveguide 28 and the lower end face of the first rectangular waveguide 13 are in close contact, the right end face of the ninth rectangular waveguide 27 and the left end face of the first rectangular waveguide 13 are in close contact, the upper end face of the ninth rectangular waveguide 27 and the lower end face of the second rectangular waveguide 12 are in close contact, the right end face of the fifth rectangular waveguide 23 and the left end face of the second rectangular waveguide 12 are in close contact;The right end surface of the eighth rectangular waveguide 26 is the first port of the horizontal polarization channel, the second port of the common waveguide is butted with the first port of the vertical polarization channel, the first port of the common waveguide is the common waveguide port of the orthogonal mode coupler 5, the second port of the vertical polarization channel is the vertical polarization wave port of the orthogonal mode coupler 5, and the first port of the horizontal polarization channel is the horizontal polarization wave port of the orthogonal mode coupler 5;

[0029] When the antenna transmits the vertical polarization linear signal, the fundamental mode TE 10 enters the vertical polarization channel through the vertical polarization wave port of the orthogonal mode coupler 5, and the fundamental mode TE 10 enters the common waveguide without reflection after passing through the vertical polarization channel, but cannot enter the horizontal polarization channel, and the common waveguide changes the fundamental mode TE 10 into the fundamental mode TE 11 , and finally outputs from the common waveguide port of the orthogonal mode coupler 5; when the antenna receives the horizontal polarization linear signal, the fundamental mode TE 11 enters the common waveguide from the common waveguide port of the orthogonal mode coupler 5, the first circular waveguide 8, the second circular waveguide 9 and the third circular waveguide 10 convert the fundamental mode TE 11 into the fundamental mode TE 01 , and transmit to the vertical polarization channel through the first square waveguide 11, since the width of the first square waveguide 11 along the front and back direction, the width of the first rectangular waveguide 13 and the second rectangular waveguide 14 along the front and back direction gradually narrow, the fundamental mode TE 01 cannot enter the U-shaped bending waveguide, and finally reflects back to output from the horizontal polarization wave port of the orthogonal mode coupler 5 through the horizontal polarization channel.

[0030] In the embodiment, as Figure 3As shown, the lost foam ridge waveguide bandpass filter 3 comprises a cutoff waveguide 29, twelve metal ridge waveguides, an eleventh rectangular waveguide 30 and a twelfth rectangular waveguide 31, the eleventh rectangular waveguide 30 is located on the left side of the cutoff waveguide 29, the twelfth rectangular waveguide 31 is located on the right side of the cutoff waveguide 29, the cutoff waveguide 29 is rectangular, the eleventh rectangular waveguide 30 and the twelfth rectangular waveguide 31 are left-right symmetrical, the right end face of the eleventh rectangular waveguide 30 and the left end face of the cutoff waveguide 29 are connected, the left end face of the twelfth rectangular waveguide 31 and the right end face of the cutoff waveguide 29 are connected, the front end face of the eleventh rectangular waveguide 30, the front end face of the cutoff waveguide 29 and the front end face of the twelfth rectangular waveguide 31 are located on the same plane, the back end face of the eleventh rectangular waveguide 30, the back end face of the cutoff waveguide 29 and the back end face of the twelfth rectangular waveguide 31 are located on the same plane, the height of the cutoff waveguide 29 along the up-down direction is less than the height of the eleventh rectangular waveguide 30 along the up-down direction, the upper end face of the eleventh rectangular waveguide 30 and the upper end face of the twelfth rectangular waveguide 31 are located on the same plane, the lower end face of the eleventh rectangular waveguide 30 and the lower end face of the twelfth rectangular waveguide 31 are located on the same plane, the distance from the upper end face of the cutoff waveguide 29 to the plane where the upper end face of the eleventh rectangular waveguide 30 is located is equal to the distance from the lower end face of the cutoff waveguide 29 to the plane where the lower end face of the eleventh rectangular waveguide 30 is located, the twelve metal ridge waveguides are distributed inside the cutoff waveguide 29, the twelve metal ridge waveguides are called first metal ridge waveguide, second metal ridge waveguide, third metal ridge waveguide, fourth metal ridge waveguide, fifth metal ridge waveguide, sixth metal ridge waveguide, seventh metal ridge waveguide 32, eighth metal ridge waveguide 33, ninth metal ridge waveguide 34, tenth metal ridge waveguide 35, eleventh metal ridge waveguide 36 and twelfth metal ridge waveguide 37, the first metal ridge waveguide, the second metal ridge waveguide, the third metal ridge waveguide, the fourth metal ridge waveguide, the fifth metal ridge waveguide and the sixth metal ridge waveguide are arranged in order from left to right, the seventh metal ridge waveguide 32, the eighth metal ridge waveguide 33, the ninth metal ridge waveguide 34, the tenth metal ridge waveguide 35, the eleventh metal ridge waveguide 36 and the twelfth metal ridge waveguide 37 are arranged in order from left to right, the front end face of the first metal ridge waveguide, the second metal ridge waveguide, the third metal ridge waveguide, the fourth metal ridge waveguide, the fifth metal ridge waveguide and the sixth metal ridge waveguide are located on the same plane as the front end face of the cutoff waveguide 29, the back end face of the seventh metal ridge waveguide 32, the eighth metal ridge waveguide 33, the ninth metal ridge waveguide 34, the tenth metal ridge waveguide 35, the eleventh metal ridge waveguide 36 and the twelfth metal ridge waveguide 37 are located on the same plane as the back end face of the cutoff waveguide 29, the seventh metal ridge waveguide 32 is located on the back side of the first metal ridge waveguide and the two are front-back symmetrical, the eighth metal ridge waveguide 33 is located on the back side of the second metal ridge waveguide and the two are front-back symmetrical, the ninth metal ridge waveguide 34 is located on the back side of the third metal ridge waveguide and the two are front-back symmetrical, the tenth metal ridge waveguide 35 is located on the back side of the fourth metal ridge waveguide and the two are front-back symmetrical,The eleventh metal ridge waveguide 36 is located at the back side of the fifth metal ridge waveguide and the two are front-back symmetrical, the twelfth metal ridge waveguide 37 is located at the back side of the sixth metal ridge waveguide and the two are front-back symmetrical, the first metal ridge waveguide and the sixth metal ridge waveguide are left-right symmetrical, the second metal ridge waveguide and the fifth metal ridge waveguide are left-right symmetrical, the third metal ridge waveguide and the fourth metal ridge waveguide are left-right symmetrical, the seventh metal ridge waveguide 32 and the twelfth metal ridge waveguide 37 are left-right symmetrical, the eighth metal ridge waveguide 33 and the eleventh metal ridge waveguide 36 are left-right symmetrical, the ninth metal ridge waveguide 34 and the tenth metal ridge waveguide 35 are left-right symmetrical, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the front-back direction is equal, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the left-right direction decreases, and the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the up-down direction decreases; the left end face of the eleventh rectangular waveguide 30 is used as the output port of the lost foam ridge waveguide band-pass filter 3, and the right end face of the twelfth rectangular waveguide 31 is used as the input port of the lost foam ridge waveguide band-pass filter 3.

[0031] In the embodiment, as Figure 4As shown, the stepped impedance filter comprises the thirteenth rectangular waveguide 38 and sixteen diaphragms, which are referred to as a first diaphragm 39, a second diaphragm 40, a third diaphragm 41, a fourth diaphragm 42, a fifth diaphragm 43, a sixth diaphragm 44, a seventh diaphragm 45, an eighth diaphragm 46, a ninth diaphragm 47, a tenth diaphragm 48, an eleventh diaphragm 49, a twelfth diaphragm 50, a thirteenth diaphragm 51, a fourteenth diaphragm 52, a fifteenth diaphragm 53 and a sixteenth diaphragm 54. The first diaphragm 39, the second diaphragm 40, the third diaphragm 41, the fourth diaphragm 42, the fifth diaphragm 43, the sixth diaphragm 44, the seventh diaphragm 45 and the eighth diaphragm 46 are sequentially and spacedly arranged on the front side of the thirteenth rectangular waveguide 38 from left to right, the ninth diaphragm 47, the tenth diaphragm 48, the eleventh diaphragm 49, the twelfth diaphragm 50, the thirteenth diaphragm 51, the fourteenth diaphragm 52, the fifteenth diaphragm 53 and the sixteenth diaphragm 54 are sequentially and spacedly arranged on the back side of the thirteenth rectangular waveguide 38 from left to right, the first diaphragm 39 and the ninth diaphragm 47 are front-back symmetric, the second diaphragm 40 and the tenth diaphragm 48 are front-back symmetric, the third diaphragm 41 and the eleventh diaphragm 49 are front-back symmetric, the fourth diaphragm 42 and the twelfth diaphragm 50 are front-back symmetric, the fifth diaphragm 43 and the thirteenth diaphragm 51 are front-back symmetric, the sixth diaphragm 44 and the fourteenth diaphragm 52 are front-back symmetric, the seventh diaphragm 45 and the fifteenth diaphragm 53 are front-back symmetric, the eighth diaphragm 46 and the sixteenth diaphragm 54 are front-back symmetric, the first diaphragm 39 and the eighth diaphragm 46 are left-right symmetric, the second diaphragm 40 and the seventh diaphragm 45 are left-right symmetric, the third diaphragm 41 and the sixth diaphragm 44 are left-right symmetric, the fourth diaphragm 42 and the fifth diaphragm 43 are left-right symmetric, the ninth diaphragm 47 and the sixteenth diaphragm 54 are left-right symmetric, the tenth diaphragm 48 and the fifteenth diaphragm 53 are left-right symmetric, the eleventh diaphragm 49 and the fourteenth diaphragm 52 are left-right symmetric, the twelfth diaphragm 50 and the thirteenth diaphragm 51 are left-right symmetric, the lengths of the first diaphragm 39, the second diaphragm 40, the third diaphragm 41 and the fourth diaphragm 42 in the front-back direction are equal, the widths of the first diaphragm 39, the second diaphragm 40, the third diaphragm 41 and the fourth diaphragm 42 in the left-right direction are equal, the heights of the first diaphragm 39, the second diaphragm 40, the third diaphragm 41 and the fourth diaphragm 42 in the up-down direction sequentially increase, the left end face of the thirteenth rectangular waveguide 38 is the output port of the stepped impedance filter, and the right end face of the thirteenth rectangular waveguide 38 is the input port of the stepped impedance filter.

[0032] In this embodiment, as shown in Figure 5As shown, the first E-plane 90° twist waveguide 2 comprises a first input waveguide 55, a first transition structure and a first output waveguide 56, the transition structure comprises a fourteenth rectangular waveguide 57, a fifteenth rectangular waveguide 58, a sixteenth rectangular waveguide 59, a seventeenth rectangular waveguide 60 and an eighteenth rectangular waveguide 61 arranged in sequence from back to front, the front side of the fourteenth rectangular waveguide 57 and the back side of the fifteenth rectangular waveguide 58 are connected in close contact, the front side of the fifteenth rectangular waveguide 58 and the back side of the sixteenth rectangular waveguide 59 are connected in close contact, the front side of the sixteenth rectangular waveguide 59 and the back side of the seventeenth rectangular waveguide 60 are connected in close contact, the front side of the seventeenth rectangular waveguide 60 and the back side of the eighteenth rectangular waveguide 61 are connected in close contact, the left sides of the fourteenth rectangular waveguide 57, the fifteenth rectangular waveguide 58, the sixteenth rectangular waveguide 59, the seventeenth rectangular waveguide 60 and the eighteenth rectangular waveguide 61 are located in the same plane, the right sides of the fourteenth rectangular waveguide 57, the fifteenth rectangular waveguide 58, the sixteenth rectangular waveguide 59, the seventeenth rectangular waveguide 60 and the eighteenth rectangular waveguide 61 are located in the same plane, the height of the fourteenth rectangular waveguide 57 along the up-down direction is less than the height of the fifteenth rectangular waveguide 58 along the up-down direction, the length of the fourteenth rectangular waveguide 57 along the front-back direction is greater than the length of the fifteenth rectangular waveguide 58 along the front-back direction, the height of the fifteenth rectangular waveguide 58 along the up-down direction is less than the height of the sixteenth rectangular waveguide 59 along the up-down direction, the height of the sixteenth rectangular waveguide 59 along the up-down direction is less than the height of the first output waveguide 56 along the up-down direction, the length of the sixteenth rectangular waveguide 59 along the front-back direction is less than the length of the first output waveguide 56 along the front-back direction, the length of the sixteenth rectangular waveguide 59 along the front-back direction is greater than the length of the fourteenth rectangular waveguide 57 along the front-back direction, the fourteenth rectangular waveguide 57 and the eighteenth rectangular waveguide 61 are front-back center symmetrical relative to the center of the sixteenth rectangular waveguide 59, the fifteenth rectangular waveguide 58 and the seventeenth rectangular waveguide 60 are front-back center symmetrical relative to the center of the sixteenth rectangular waveguide 59, the central axes of the first output waveguide 56, the sixteenth rectangular waveguide 59 and the first input waveguide 55 along the left-right direction are on a straight line, the central axes of the fourteenth rectangular waveguide 57 and the fifteenth rectangular waveguide 58 along the front-back direction are on a straight line, the right end surface of the first output waveguide 56 is connected in close contact with the left end surface of the fifteenth rectangular waveguide 58, the left end surface of the sixteenth rectangular waveguide 59 and the left end surface of the seventeenth waveguide respectively, the back end surface of the fifteenth rectangular waveguide 58 is located on the back side of the plane where the back end surface of the first output waveguide 56 is located, the left end surface of the first input waveguide 55 is connected in close contact with the right end surface of the fourteenth rectangular waveguide 57, the right end surface of the fifteenth rectangular waveguide 58, the right end surface of the sixteenth rectangular waveguide 59, the right end surface of the seventeenth rectangular waveguide 60 and the right end surface of the eighteenth rectangular waveguide 61 respectively, the back end surface of the fourteenth rectangular waveguide 57 and the back end surface of the first input waveguide 55 are located in the same plane, the front end surface of the eighteenth rectangular waveguide 61 and the front end surface of the first input waveguide 55 are located in the same plane,The lower end surface of the fifteenth rectangular waveguide 58 is located below the plane of the lower end surface of the first input waveguide 55 and above the plane of the lower end surface of the sixteenth rectangular waveguide 59, the rear side surface of the first input waveguide 55 is located in the same plane as the rear side surface of the fourteenth rectangular waveguide 57, the front side surface of the first input waveguide 55 is located in the same plane as the front side surface of the eighteenth rectangular waveguide 61, the right side surface of the first input waveguide 55 serves as the input port of the first E-plane 90° twist waveguide 2, and the left end surface of the first output waveguide 56 serves as the output port of the first E-plane 90° twist waveguide 2. The first E-plane 90° twist waveguide 2 is used to change the transmission direction of the vertically polarized linear signal, so that the direction of the vertically polarized linear signal in the original input waveguide is rotated by 90° and then output, but the fundamental mode TE, 10 is unchanged; as Figure 6 shown, the second E-plane 90° twist waveguide 4 and the first E-plane 90° twist waveguide 2 are left-right symmetrical with respect to the evanescent-mode ridge waveguide bandpass filter 3, the output port of the second E-plane 90° twist waveguide 4 is symmetrical with the input port of the first E-plane 90° twist waveguide 2, and the input port of the second E-plane 90° twist waveguide 4 is symmetrical with the output port of the first E-plane 90° twist waveguide 2.

[0033] In this embodiment, as Figure 7As shown, the E-plane rectangular waveguide 1 includes a third straight trapezoidal waveguide 62, a fourth straight trapezoidal waveguide 63, a first straight triangular waveguide 64, a second straight triangular waveguide 65, a nineteenth rectangular waveguide 66, a twentieth rectangular waveguide 67 and a twenty-first rectangular waveguide 68, the third straight trapezoidal waveguide 62, the nineteenth rectangular waveguide 66, the twentieth rectangular waveguide 67, the fourth straight trapezoidal waveguide 63 and the twenty-first rectangular waveguide 68 are arranged in order from top to bottom, the cross section of the third straight trapezoidal waveguide 62 along the vertical direction is a straight trapezoidal shape, the upper base of the straight trapezoidal shape is located at the top, the lower base is located at the bottom, the right side is located at the right side, the fourth straight trapezoidal waveguide 63 along the vertical direction is a straight trapezoidal shape, and the upper base of the straight trapezoidal shape is located at the bottom, the lower base is located at the top, the right side is located at the left side, the left side is located at the right side, the lower end surface of the third straight trapezoidal waveguide 62 and the upper end surface of the nineteenth rectangular waveguide 66 are attached and completely coincide, the left end surface of the third straight trapezoidal waveguide 62 is flush with the left end surface of the nineteenth rectangular waveguide 66, the front end surface of the third straight trapezoidal waveguide 62 is flush with the front end surface of the nineteenth rectangular waveguide 66, the rear end surface of the third straight trapezoidal waveguide 62 is flush with the rear end surface of the nineteenth rectangular waveguide 66, the lower end surface of the nineteenth rectangular waveguide 66 and the upper end surface of the twentieth rectangular waveguide 67 are attached, the right end surface of the nineteenth rectangular waveguide 66 and the right end surface of the twentieth rectangular waveguide 67 are flush, the front end surface of the nineteenth rectangular waveguide 66 and the front end surface of the twentieth rectangular waveguide 67 are flush, the rear end surface of the nineteenth rectangular waveguide 66 and the rear end surface of the twentieth rectangular waveguide 67 are flush, the left end surface of the nineteenth rectangular waveguide 66 is located at the left of the plane where the left end surface of the twentieth rectangular waveguide 67 is located, the upper end surface of the twenty-first rectangular waveguide 68 and the lower end surface of the twentieth rectangular waveguide 67 are attached, the right end surface of the twenty-first rectangular waveguide 68 and the right end surface of the twentieth rectangular waveguide 67 are flush, the front end surface of the twenty-first rectangular waveguide 68 and the front end surface of the twentieth rectangular waveguide 67 are flush, the rear end surface of the twenty-first rectangular waveguide 68 and the rear end surface of the twentieth rectangular waveguide 67 are flush, the left end surface of the twenty-first rectangular waveguide 68 is located at the left of the plane where the left end surface of the nineteenth rectangular waveguide 66 is located, the upper end surface of the fourth straight trapezoidal waveguide 63 and the lower end surface of the twenty-first rectangular waveguide 68 are attached and completely coincide, the left end surface of the fourth straight trapezoidal waveguide 63 is flush with the left end surface of the twenty-first rectangular waveguide 68, the front end surface of the fourth straight trapezoidal waveguide 63 is flush with the front end surface of the twenty-first rectangular waveguide 68, the rear end surface of the fourth straight trapezoidal waveguide 63 is flush with the rear end surface of the twenty-first rectangular waveguide 68, the upper end surface of the first straight triangular waveguide 64 and the lower end surface of the nineteenth rectangular waveguide 66 are attached, the right end surface of the first straight triangular waveguide 64 and the left end surface of the twentieth rectangular waveguide 67 are attached, the front end surface of the first straight triangular waveguide 64 and the front end surface of the nineteenth rectangular waveguide 66 are flush, the rear end surface of the first straight triangular waveguide 64 and the rear end surface of the nineteenth rectangular waveguide 66 are flush,The lower end face of the second right-angled triangular waveguide 65 is flush with the upper end face of the twenty-first rectangular waveguide 68; the right end face of the second right-angled triangular waveguide 65 is flush with the left end face of the twentieth rectangular waveguide 67; the front end face of the second right-angled triangular waveguide 65 is flush with the front end face of the twenty-first rectangular waveguide 68; the rear end face of the second right-angled triangular waveguide 65 is flush with the rear end face of the twenty-first rectangular waveguide 68; and the length of the upper end face of the first right-angled triangular waveguide 64 in the left-right direction is less than the plane containing the left end faces of the nineteenth rectangular waveguide 66 and the twentieth rectangular waveguide 67. The distance between them is such that the length of the lower end face of the second right-angled triangular waveguide 65 in the left-right direction is equal to the length of the upper end face of the first right-angled triangular waveguide 64 in the left-right direction. There is a distance between the lower end of the right end face of the first right-angled triangular waveguide 64 and the upper end of the right end face of the second right-angled triangular waveguide 65. The left end face of the nineteenth rectangular waveguide 66 and the left end face of the third right-angled trapezoidal waveguide 62 serve as the output ports of the E-plane right-angled waveguide 1. The left end face of the twenty-first rectangular waveguide 68 and the left end face of the fourth right-angled trapezoidal waveguide 63 serve as the input ports of the E-plane right-angled waveguide 1.

[0034] In this embodiment, as Figure 8 As shown, the H-plane right-angle waveguide 7 includes a twenty-second rectangular waveguide 69, a twenty-third rectangular waveguide 70, and a twenty-fourth rectangular waveguide 71 arranged sequentially from front to back. The upper end faces of the twenty-second rectangular waveguide 69, the twenty-third rectangular waveguide 70, and the twenty-fourth rectangular waveguide 71 are located in the same plane. The lower end faces of the twenty-second rectangular waveguide 69, the twenty-third rectangular waveguide 70, and the twenty-fourth rectangular waveguide 71 are also located in the same plane. The left end faces of the twenty-second rectangular waveguide 69, the twenty-third rectangular waveguide 70, and the twenty-fourth rectangular waveguide 71 are also located in the same plane. The rear end face of the twenty-second rectangular waveguide 69 and the front end face of the twenty-third rectangular waveguide 70 are also located in the same plane. The end faces are fitted together, with the rear end face of the twenty-third rectangular waveguide 70 and the front end face of the twenty-fourth rectangular waveguide 71 fitted together. The length of the twenty-second rectangular waveguide 69 in the left-right direction is greater than that of the twenty-third rectangular waveguide 70 in the left-right direction, but less than that of the twenty-fourth rectangular waveguide 71 in the left-right direction. The connection between the front end face of the twenty-second rectangular waveguide 69 and the left end face of the twenty-third rectangular waveguide 70 is rounded. The connection between the left end face of the twenty-third rectangular waveguide 70 and the rear end face of the twenty-fourth rectangular waveguide 71 is rounded. The right end face of the twenty-second rectangular waveguide 69 serves as the output port of the H-plane right-angle waveguide 7, and the right end face of the twenty-fourth rectangular waveguide 71 serves as the input port of the H-plane right-angle waveguide 7.

[0035] In this embodiment, the input port of the H-plane right-angle waveguide 7 is connected to the output port of the stepped impedance filter. The input port of the stepped impedance filter is connected to the horizontal polarization port of the orthogonal mode coupler 5. The vertical polarization port of the orthogonal mode coupler 5 is connected to the output port of the second E-plane 90° twisted waveguide 4. The input port of the second E-plane 90° twisted waveguide 4 is connected to the output port of the vanishing mode ridge waveguide bandpass filter 3. The input port of the vanishing mode ridge waveguide bandpass filter 3 is connected to the output port of the first E-plane 90° twisted waveguide 2. The input port of the first E-plane 90° twisted waveguide 2 is connected to the output port of the E-plane right-angle waveguide 1. When the antenna transmits a vertically polarized signal, the fundamental mode TE... 10 After the signal enters the E-plane right-angle waveguide 1, it is transmitted through the E-plane right-angle waveguide 1 to the first E-plane 90° twisted waveguide 2. The first E-plane 90° twisted waveguide 2 rotates the transmission direction of the signal transmitted there by 90 degrees and outputs it to the vanishing mode ridge waveguide bandpass filter 3. The vanishing mode ridge waveguide bandpass filter 3 selects the uplink frequency band range of the signal transmitted there and outputs it to the second E-plane 90° twisted waveguide 4. The second E-plane 90° twisted waveguide 4 rotates the transmission direction of the signal transmitted there by 90 degrees and outputs it to the vertical polarization channel of the orthogonal mode coupler 5. The vertical polarization channel of the orthogonal mode coupler 5, which is non-reflective, outputs the signal to the common waveguide. The common waveguide then converts the signal output there into a fundamental mode TE signal. 10 The mode is transformed into the fundamental mode TE 11 The fundamental mode TE is ultimately output from the common waveguide port. When the antenna receives a horizontally polarized signal, the fundamental mode TE is... 11 The fundamental mode TE enters the common waveguide through the common waveguide port of the orthogonal mode coupler 5 and propagates in the first circular waveguide 8, the second circular waveguide 9, and the third circular waveguide 10. 11 The mode is converted into the fundamental mode TE. 01 The mode enters the first square waveguide 11, and the first square waveguide 11 outputs the fundamental mode TE at that location. 01 The mode output is sent to the vertical polarization channel, at which point the fundamental mode TE output from the first square waveguide 11 is... 01 The signal cannot enter the U-shaped bend waveguide and is eventually reflected back through the horizontal polarization channel and output to the stepped impedance filter. The stepped impedance filter selects the signal within the downlink frequency band from the received horizontal polarization signal and outputs it to the H-plane right-angle waveguide 7 without reflection. Finally, it is output from the output port of the H-plane right-angle waveguide 7.

[0036] To verify the superior performance of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication of the present invention, simulation and experimental tests were conducted on the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication of the present invention. The simulation results and test results of the reflection coefficient and isolation of the high-isolation Ku-band full-bandwidth linearly polarized duplexer for satellite communication of the present invention are shown in the figures below. Figure 9The insertion loss simulation result chart and the test result chart of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application are shown in FIGS. 1 and 2, respectively. Figure 10

[0037] Analysis Figure 9 and Figure 10 It can be seen that the simulation result shows that the working range of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application covers the entire Ku-band (uplink frequency band: 13.75-14.5 GHz, downlink frequency band: 10.7-12.75 GHz). Within 10.7-12.75 GHz, the reflection coefficient |S 22 | on the input port of the E-plane rectangular waveguide 1 of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application is less than -20 dB, and within 13.75-14.5 GHz, the reflection coefficient |S 33 | on the output port of the H-plane rectangular waveguide 7 of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application is less than -20 dB. Within 10.7-14.5 GHz, the isolation |S 23 | between the input port of the E-plane rectangular waveguide 1 and the output port of the H-plane rectangular waveguide 7 of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application is greater than 115 dB. Due to the machining error, there is a slight deviation between the test result and the simulation result of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application. The reflection coefficient |S 22 | tested within 10.7-12.75 GHz is less than -15 dB, and the reflection coefficient |S 33 | tested within 13.75-14.5 GHz is less than -15 dB. Within 10.7-12.75 GHz, the insertion loss |S 12 | between the common waveguide port of the quadrature-mode coupler 5 and the input port of the E-plane rectangular waveguide 1 of the high-isolation Ku-band full-bandwidth linear polarization duplexer for satellite communication of the present application is less than 1.6 dB; within 13.75-14.5 GHz, the insertion loss |S 13 | between the common waveguide port of the quadrature-mode coupler 5 and the output port of the H-plane rectangular waveguide 7 is less than 1.6 dB, and the isolation between the input port of the E-plane rectangular waveguide 1 and the output port of the H-plane rectangular waveguide 7 is greater than 85 dB, meeting the requirements of engineering applications.​

Claims

1. A high-isolation Ku-band linear polarization duplexer for satellite communications, characterized by The waveguide includes, in order from right to left: an E-plane right-angle waveguide, a first E-plane 90° twisted waveguide, a vanishing mode ridge waveguide bandpass filter, a second E-plane 90° twisted waveguide, an orthogonal mode coupler, a stepped impedance low-pass filter, and an H-plane right-angle waveguide. The orthogonal mode coupler employs an asymmetric orthogonal mode coupler structure. The E-plane right-angle waveguide is used to connect the fundamental mode TE propagating in vertical polarization in the uplink. 10 Model, and base model TE 10 The mode output is sent to the first E-plane 90° twisted waveguide, which is used to output the fundamental mode TE. 10 The mode propagation direction is rotated 90° and then output to the vanishing mode ridge waveguide bandpass filter. The vanishing mode ridge waveguide bandpass filter is used to transmit the fundamental mode TE from the output to its location. 10 The fundamental mode TE is selected from the uplink frequency band, i.e., 13.75-14.5GHz. 10 The mode output is sent to the second E-plane 90° twisted waveguide, which is used to output the fundamental mode TE. 10 The propagation direction of the mode is rotated 90° and then output to the orthogonal mode coupler. The orthogonal mode coupler is used to connect the fundamental mode TE output from the second E-plane 90° twisted waveguide. 10 The fundamental mode TE, which propagates in horizontal polarization in the access downlink, is also included. 11 When the orthogonal mode coupler is connected to the fundamental mode TE output from the second E-plane 90° twisted waveguide, 10 When the mode is in phase, the orthogonal mode coupler will convert the fundamental mode TE 10 Modulus to base mode TE 11 Post-mode output, when the orthogonal mode coupler is connected to the downlink, the fundamental mode TE propagating in horizontal polarization... 11 When the fundamental mode TE is used, the orthogonal mode coupler will couple the fundamental mode TE. 11 Model to TE 01 The analog output is fed to the stepped impedance low-pass filter, which is used to transfer the signal from the output to the TE at that location. 01 The mode selects the TE in the downlink frequency band, i.e., 10.7-12.75GHz. 01 The mode output is fed to the H-plane right-angle waveguide, which is used to transmit the TE output to it. 01 Output without loss.

2. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 1, wherein The orthogonal mode coupler comprises a common waveguide, a vertical polarization channel and a horizontal polarization channel, the vertical polarization channel is used for accessing vertical polarization linear signals, the horizontal polarization channel is used for accessing horizontal polarization linear signals, the common waveguide is used for converting the vertical polarization linear signals from a fundamental mode TE 10 to a base mode TE 11 and converting the horizontal polarization linear signals from a fundamental mode TE 11 to a base mode TE 01 , the common waveguide comprises a first circular waveguide, a second circular waveguide, a third circular waveguide and a first square waveguide, the first circular waveguide, the second circular waveguide, the third circular waveguide and the first square waveguide are stacked in order from top to bottom, and the first circular waveguide, the second circular waveguide, the third circular waveguide and the first square waveguide are coaxial, the diameter of the first circular waveguide is greater than the diameter of the second circular waveguide, the diameter of the second circular waveguide is greater than the diameter of the third circular waveguide, the diameters of the first circular waveguide, the second circular waveguide and the third circular waveguide all meet the transmission requirements of a fundamental mode TE 11 , and only the propagation of a base mode TE 11 is allowed, the first square waveguide has a square cross section in the horizontal direction, the side length of the square is less than the diameter of the third circular waveguide, the diagonal of the square is greater than the diameter of the third circular waveguide, the first square waveguide can transmit a base mode TE 01 and a fundamental mode TE 10 , the upper surface of the first circular waveguide is a first port of the common waveguide, and the lower bottom surface of the first square waveguide is a second port of the common waveguide. The vertical polarization channel comprises a second square waveguide, a first rectangular waveguide and a U-shaped bending waveguide arranged in order from top to bottom, the cross section of the second square waveguide is square, and the side length of the square is smaller than the side length of the cross section of the first square waveguide, the center line of the second square waveguide coincides with the center line of the first square waveguide, the upper surface of the second square waveguide is attached to the lower bottom surface of the first square waveguide, the upper surface of the first rectangular waveguide is attached to the lower bottom surface of the second square waveguide, the center line of the first rectangular waveguide coincides with the center line of the second square waveguide, the width of the first rectangular waveguide along the left-right direction is smaller than the side length of the cross section of the second square waveguide, but the length of the first rectangular waveguide along the front-back direction is greater than the side length of the cross section of the second square waveguide; the U-shaped bending waveguide comprises a second rectangular waveguide, a third rectangular waveguide, a fourth rectangular waveguide, a first right-angled trapezoidal waveguide, a second right-angled trapezoidal waveguide, a third right-angled trapezoidal waveguide, a fourth right-angled trapezoidal waveguide, a first isosceles trapezoidal waveguide and a second isosceles trapezoidal waveguide; the second rectangular waveguide is located below the first rectangular waveguide, the upper end surface of the second rectangular waveguide is attached to the lower end surface of the first rectangular waveguide, the center line of the second rectangular waveguide and the center line of the first rectangular waveguide are on the same straight line, the length of the second rectangular waveguide along the front-back direction is greater than the length of the first rectangular waveguide along the front-back direction, but the width of the second rectangular waveguide along the left-right direction is smaller than the width of the first rectangular waveguide along the left-right direction, the third rectangular waveguide is located on the right side of the second rectangular waveguide, and there is a distance between the two, the front end surface of the third rectangular waveguide is located on the same plane as the front end surface of the second rectangular waveguide, the rear end surface of the third rectangular waveguide is located on the same plane as the rear end surface of the second rectangular waveguide, the left end surface of the third rectangular waveguide is located on the same plane as the left end surface of the second rectangular waveguide, the upper end surface of the third rectangular waveguide is located on the same plane as the upper end surface of the second rectangular waveguide, the lower end surface of the third rectangular waveguide is located on the same plane as the lower end surface of the second rectangular waveguide, the third rectangular waveguide is symmetrical to the second rectangular waveguide left and right, and the left-right symmetry plane of the third rectangular waveguide and the second rectangular waveguide is called the first symmetry plane, the first right-angled trapezoidal waveguide is located below the second rectangular waveguide, the cross section of the first right-angled trapezoidal waveguide along the horizontal direction is rectangular, and the cross section along the vertical direction is right-angled trapezoidal, and the lower bottom of the right-angled trapezoidal is on the upper side, the upper bottom is on the lower side, the right angle waist is on the right side, and the other waist is on the left side, the upper end surface of the first right-angled trapezoidal waveguide is attached to the lower end surface of the second rectangular waveguide, the length of the upper end surface of the first right-angled trapezoidal waveguide along the front-back direction is equal to the length of the second rectangular waveguide along the front-back direction, the length of the upper end surface of the first right-angled trapezoidal waveguide along the left-right direction is equal to the length of the second rectangular waveguide along the left-right direction, the second right-angled trapezoidal waveguide is located below the third rectangular waveguide,and the first isosceles trapezoidal waveguide is located below the first and second right-angled trapezoidal waveguides, the cross section of the first isosceles trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the first isosceles trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the lower base of the isosceles trapezoid is on the upper side, the upper base is on the lower side, one of the legs is on the left side, and the other leg is on the right side, the upper end surface of the first isosceles trapezoidal waveguide is fixedly connected with the lower end surface of the first right-angled trapezoidal waveguide and the lower end surface of the second right-angled trapezoidal waveguide, the length of the upper end surface of the first isosceles trapezoidal waveguide along the left-right direction is greater than the sum of the length of the lower end surface of the first right-angled trapezoidal waveguide along the left-right direction and the length of the lower end surface of the second right-angled trapezoidal waveguide along the left-right direction, the left end surface of the first isosceles trapezoidal waveguide is located in the same plane as the left end surface of the first right-angled trapezoidal waveguide, the right end surface of the first isosceles trapezoidal waveguide is located in the same plane as the right end surface of the second right-angled trapezoidal waveguide, the front end surface of the first isosceles trapezoidal waveguide is located in the same plane as the front end surface of the first right-angled trapezoidal waveguide, the rear end surface of the first isosceles trapezoidal waveguide is located in the same plane as the rear end surface of the first right-angled trapezoidal waveguide, the second isosceles trapezoidal waveguide is located below the first isosceles trapezoidal waveguide, the cross section of the second isosceles trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the second isosceles trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the lower base of the isosceles trapezoid is on the upper side, the upper base is on the lower side, one of the legs is on the left side, and the other leg is on the right side, the upper end surface of the second isosceles trapezoidal waveguide is fixedly connected with the lower end surface of the first isosceles trapezoidal waveguide, the left side of the upper end surface of the second isosceles trapezoidal waveguide is flush with the left side of the lower end surface of the first isosceles trapezoidal waveguide, the right side of the upper end surface of the second isosceles trapezoidal waveguide is flush with the right side of the lower end surface of the first isosceles trapezoidal waveguide, the front end surface of the second isosceles trapezoidal waveguide is located in the same plane as the front end surface of the first isosceles trapezoidal waveguide, the rear end surface of the second isosceles trapezoidal waveguide is located in the same plane as the rear end surface of the first isosceles trapezoidal waveguide, the included angle between the upper end surface of the second isosceles trapezoidal waveguide and the left end surface thereof is smaller than the included angle between the upper end surface of the first isosceles trapezoidal waveguide and the left end surface thereof, the third right-angled trapezoidal waveguide is located above the third rectangular waveguide, the cross section of the third right-angled trapezoidal waveguide along the horizontal direction is rectangular, the cross section of the third right-angled trapezoidal waveguide along the vertical direction is isosceles trapezoidal, and the upper base of the isosceles trapezoid is on the upper side, the lower base is on the lower side, the right angle leg is on the right side, and the other leg is on the left side, the lower end surface of the third right-angled trapezoidal waveguide is fixedly connected with the upper end surface of the third rectangular waveguide, the left side of the lower end surface of the third right-angled trapezoidal waveguide is flush with the left end surface of the third rectangular waveguide, the front end surface of the third right-angled trapezoidal waveguide is located in the same plane as the front end surface of the third rectangular waveguide, and the rear end surface of the third right-angled trapezoidal waveguide is located in the same plane as the rear end surface of the third rectangular waveguide.The right end face of the third right-angled trapezoidal waveguide is located on the right side of the plane where the right end face of the third rectangular waveguide is located. The fourth right-angled trapezoidal waveguide is located above the third right-angled trapezoidal waveguide. The cross section of the fourth right-angled trapezoidal waveguide in the horizontal direction is rectangular, and the cross section in the vertical direction is isosceles trapezoidal. The upper base of the isosceles trapezoid is on the upper side, the lower base is on the lower side, the right angle waist is on the right side, and the other waist is on the left side. The lower end face of the fourth right-angled trapezoidal waveguide is connected with the upper end face of the third right-angled trapezoidal waveguide. The left side of the lower end face of the fourth right-angled trapezoidal waveguide is flush with the left side of the upper end face of the third right-angled trapezoidal waveguide. The front end face of the fourth right-angled trapezoidal waveguide is located in the same plane as the front end face of the third right-angled trapezoidal waveguide. The rear end face of the fourth right-angled trapezoidal waveguide is located in the same plane as the rear end face of the third right-angled trapezoidal waveguide. The right end face of the fourth right-angled trapezoidal waveguide is located in the same plane as the right end face of the third right-angled trapezoidal waveguide. The included angle between the left end face and the lower end face of the fourth right-angled trapezoidal waveguide is smaller than the included angle between the left end face and the lower end face of the third right-angled trapezoidal waveguide. The fourth rectangular waveguide is located on the right side of the fourth right-angled trapezoidal waveguide and the third right-angled trapezoidal waveguide. The lower end face of the fourth rectangular waveguide is located in the same plane as the lower end face of the third right-angled trapezoidal waveguide. The upper end face of the fourth rectangular waveguide is located in the same plane as the upper end face of the fourth right-angled trapezoidal waveguide. The left end face of the fourth rectangular waveguide is connected with the left end faces of the fourth right-angled trapezoidal waveguide and the third right-angled trapezoidal waveguide. The length of the fourth rectangular waveguide in the front-rear direction is greater than the length of the fourth right-angled trapezoidal waveguide in the front-rear direction. The distance from the front end face of the fourth rectangular waveguide to the front end face of the fourth right-angled trapezoidal waveguide is equal to the distance from the rear end face of the fourth rectangular waveguide to the rear end face of the fourth right-angled trapezoidal waveguide. The upper end face of the second square waveguide is the first port of the vertical polarization channel. The right end face of the fourth rectangular waveguide is the second port of the vertical polarization channel. The horizontal polarization channel comprises a fifth rectangular waveguide, a sixth rectangular waveguide, a seventh rectangular waveguide, an eighth rectangular waveguide, a ninth rectangular waveguide and a tenth rectangular waveguide, the tenth rectangular waveguide, the ninth rectangular waveguide, the fifth rectangular waveguide, the sixth rectangular waveguide, the seventh rectangular waveguide and the eighth rectangular waveguide are sequentially arranged from right to left, the fifth rectangular waveguide, the sixth rectangular waveguide, the seventh rectangular waveguide and the eighth rectangular waveguide are coaxial, the left end face of the tenth rectangular waveguide and the right end face of the ninth rectangular waveguide are connected, the left end face of the ninth rectangular waveguide and the right end face of the fifth rectangular waveguide are connected, the left end face of the fifth rectangular waveguide and the right end face of the sixth rectangular waveguide are connected, the left end face of the sixth rectangular waveguide and the right end face of the seventh rectangular waveguide are connected, the left end face of the seventh rectangular waveguide and the right end face of the eighth rectangular waveguide are connected, the lower end face of the tenth rectangular waveguide, the lower end face of the ninth rectangular waveguide and the lower end face of the fifth rectangular waveguide are located in the same plane, the height of the ninth rectangular waveguide in the up-down direction is less than the height of the fifth rectangular waveguide in the up-down direction, the height of the tenth rectangular waveguide in the up-down direction is less than the height of the ninth rectangular waveguide in the up-down direction, the height of the fifth rectangular waveguide in the up-down direction is less than the height of the sixth rectangular waveguide in the up-down direction, the length of the fifth rectangular waveguide in the front-rear direction is less than the length of the sixth rectangular waveguide in the front-rear direction, the width of the fifth rectangular waveguide in the left-right direction is less than the width of the sixth rectangular waveguide in the left-right direction; the height of the sixth rectangular waveguide in the up-down direction is less than the height of the seventh rectangular waveguide in the up-down direction, the length of the sixth rectangular waveguide in the front-rear direction is less than the length of the seventh rectangular waveguide in the front-rear direction, the width of the sixth rectangular waveguide in the left-right direction is less than the width of the seventh rectangular waveguide in the left-right direction; the height of the seventh rectangular waveguide in the up-down direction is less than the height of the eighth rectangular waveguide in the up-down direction, the length of the seventh rectangular waveguide in the front-rear direction is less than the length of the eighth rectangular waveguide in the front-rear direction, the width of the seventh rectangular waveguide in the left-right direction is less than the width of the eighth rectangular waveguide in the left-right direction, the plane where the lower end face of the tenth rectangular waveguide is located is above the plane where the lower end face of the second rectangular waveguide is located, the right end face of the tenth rectangular waveguide and the left end face of the second rectangular waveguide are connected, the upper end face of the tenth rectangular waveguide and the lower end face of the first rectangular waveguide are connected, the right end face of the ninth rectangular waveguide and the left end face of the first rectangular waveguide are connected, the upper end face of the ninth rectangular waveguide and the lower end face of the second rectangular waveguide are connected, the right end face of the fifth rectangular waveguide and the left end face of the second rectangular waveguide are connected.The right end surface of the eighth rectangular waveguide is the first port of the horizontal polarization channel, the second port of the common waveguide is butted with the first port of the vertical polarization channel, the first port of the common waveguide is the common waveguide port of the orthogonal mode coupler, the second port of the vertical polarization channel is the vertical polarization wave port of the orthogonal mode coupler, and the first port of the horizontal polarization channel is the horizontal polarization wave port of the orthogonal mode coupler. When the antenna transmits a vertically polarized linear signal, the fundamental mode TE 10 enters the vertical polarization channel through the vertical polarization wave port of the quadrature mode coupler, the fundamental mode TE 10 enters the common waveguide without reflection after passing through the vertical polarization channel, but cannot enter the horizontal polarization channel, the common waveguide converts the fundamental mode TE 10 into the fundamental mode TE 11 , and finally outputs from the common waveguide port of the quadrature mode coupler; when the antenna receives a horizontally polarized linear signal, the fundamental mode TE 11 enters the common waveguide from the common waveguide port of the quadrature mode coupler, the first circular waveguide, the second circular waveguide and the third circular waveguide convert the fundamental mode TE 11 into the fundamental mode TE 01 , and transmit to the vertical polarization channel through the first square waveguide, since the width of the first square waveguide along the front-back direction, the width of the first rectangular waveguide and the width of the second rectangular waveguide along the front-back direction gradually narrow, the fundamental mode TE 01 cannot enter the U-shaped bent waveguide, and finally reflects back to output from the horizontal polarization wave port of the quadrature mode coupler through the horizontal polarization channel.

3. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 2, wherein The lost foam ridge waveguide band-pass filter includes a cutoff waveguide, twelve metal ridge waveguides, an eleventh rectangular waveguide and a twelfth rectangular waveguide, the eleventh rectangular waveguide is located on the left side of the cutoff waveguide, the twelfth rectangular waveguide is located on the right side of the cutoff waveguide, the cutoff waveguide is rectangular, the eleventh rectangular waveguide and the twelfth rectangular waveguide are left-right symmetrical, the right end face of the eleventh rectangular waveguide and the left end face of the cutoff waveguide are connected, the left end face of the twelfth rectangular waveguide and the right end face of the cutoff waveguide are connected, the front end face of the eleventh rectangular waveguide, the front end face of the cutoff waveguide and the front end face of the twelfth rectangular waveguide are located on the same plane, the back end face of the eleventh rectangular waveguide, the back end face of the cutoff waveguide and the back end face of the twelfth rectangular waveguide are located on the same plane, the height of the cutoff waveguide along the up-down direction is less than the height of the eleventh rectangular waveguide along the up-down direction, the upper end face of the eleventh rectangular waveguide and the upper end face of the twelfth rectangular waveguide are located on the same plane, the lower end face of the eleventh rectangular waveguide and the lower end face of the twelfth rectangular waveguide are located on the same plane, the distance from the upper end face of the cutoff waveguide to the plane where the upper end face of the eleventh rectangular waveguide is located is equal to the distance from the lower end face of the cutoff waveguide to the plane where the lower end face of the eleventh rectangular waveguide is located, twelve metal ridge waveguides are distributed inside the cutoff waveguide, the twelve metal ridge waveguides are called first metal ridge waveguide, second metal ridge waveguide, third metal ridge waveguide, fourth metal ridge waveguide, fifth metal ridge waveguide, sixth metal ridge waveguide, seventh metal ridge waveguide, eighth metal ridge waveguide, ninth metal ridge waveguide, tenth metal ridge waveguide, eleventh metal ridge waveguide and twelfth metal ridge waveguide, the first metal ridge waveguide, the second metal ridge waveguide, the third metal ridge waveguide, the fourth metal ridge waveguide, the fifth metal ridge waveguide and the sixth metal ridge waveguide are arranged in sequence from left to right, the seventh metal ridge waveguide, the eighth metal ridge waveguide, the ninth metal ridge waveguide, the tenth metal ridge waveguide, the eleventh metal ridge waveguide and the twelfth metal ridge waveguide are arranged in sequence from left to right, the front end face of the first metal ridge waveguide, the front end face of the second metal ridge waveguide, the front end face of the third metal ridge waveguide, the front end face of the fourth metal ridge waveguide, the front end face of the fifth metal ridge waveguide and the front end face of the sixth metal ridge waveguide are located on the same plane as the front end face of the cutoff waveguide, the back end face of the seventh metal ridge waveguide, the back end face of the eighth metal ridge waveguide, the back end face of the ninth metal ridge waveguide, the back end face of the tenth metal ridge waveguide, the back end face of the eleventh metal ridge waveguide and the back end face of the twelfth metal ridge waveguide are located on the same plane as the back end face of the cutoff waveguide, the seventh metal ridge waveguide is located on the back side of the first metal ridge waveguide and the two are front-back symmetrical, the eighth metal ridge waveguide is located on the back side of the second metal ridge waveguide and the two are front-back symmetrical,The ninth metal ridge waveguide is located at the back side of the third metal ridge waveguide, and both are front-back symmetrical, the tenth metal ridge waveguide is located at the back side of the fourth metal ridge waveguide, and both are front-back symmetrical, the eleventh metal ridge waveguide is located at the back side of the fifth metal ridge waveguide, and both are front-back symmetrical, the twelfth metal ridge waveguide is located at the back side of the sixth metal ridge waveguide, and both are front-back symmetrical, the first metal ridge waveguide and the sixth metal ridge waveguide are left-right symmetrical, the second metal ridge waveguide and the fifth metal ridge waveguide are left-right symmetrical, the third metal ridge waveguide and the fourth metal ridge waveguide are left-right symmetrical, the seventh metal ridge waveguide and the twelfth metal ridge waveguide are left-right symmetrical, the eighth metal ridge waveguide and the eleventh metal ridge waveguide are left-right symmetrical, the ninth metal ridge waveguide and the tenth metal ridge waveguide are left-right symmetrical, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the front-back direction is equal, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the left-right direction decreases, the length of the first metal ridge waveguide, the second metal ridge waveguide and the first metal ridge waveguide in the up-down direction decreases, the left end face of the eleventh rectangular waveguide is used as the output port of the lost foam ridge waveguide band-pass filter, and the right end face of the twelfth rectangular waveguide is used as the input port of the lost foam ridge waveguide band-pass filter.

4. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 3, wherein The stepped impedance low-pass filter comprises a thirteenth rectangular waveguide and sixteen diaphragms, which are referred to as a first diaphragm, a second diaphragm, a third diaphragm, a fourth diaphragm, a fifth diaphragm, a sixth diaphragm, a seventh diaphragm, an eighth diaphragm, a ninth diaphragm, a tenth diaphragm, an eleventh diaphragm, a twelfth diaphragm, a thirteenth diaphragm, a fourteenth diaphragm, a fifteenth diaphragm and a sixteenth diaphragm; the first diaphragm, the second diaphragm, the third diaphragm, the fourth diaphragm, the fifth diaphragm, the sixth diaphragm, the seventh diaphragm and the eighth diaphragm are sequentially and spacedly arranged on the front side of the thirteenth rectangular waveguide from left to right; the ninth diaphragm, the tenth diaphragm, the eleventh diaphragm, the twelfth diaphragm, the thirteenth diaphragm, the fourteenth diaphragm, the fifteenth diaphragm and the sixteenth diaphragm are sequentially and spacedly arranged on the back side of the thirteenth rectangular waveguide from left to right; the first diaphragm and the ninth diaphragm are front-back symmetrical; the second diaphragm and the tenth diaphragm are front-back symmetrical; the third diaphragm and the eleventh diaphragm are front-back symmetrical; the fourth diaphragm and the twelfth diaphragm are front-back symmetrical; the fifth diaphragm and the thirteenth diaphragm are front-back symmetrical; the sixth diaphragm and the fourteenth diaphragm are front-back symmetrical; the seventh diaphragm and the fifteenth diaphragm are front-back symmetrical; the eighth diaphragm and the sixteenth diaphragm are front-back symmetrical; the first diaphragm and the eighth diaphragm are left-right symmetrical; the second diaphragm and the seventh diaphragm are left-right symmetrical; the third diaphragm and the sixth diaphragm are left-right symmetrical; the fourth diaphragm and the fifth diaphragm are left-right symmetrical; the ninth diaphragm and the sixteenth diaphragm are left-right symmetrical; the tenth diaphragm and the fifteenth diaphragm are left-right symmetrical; the eleventh diaphragm and the fourteenth diaphragm are left-right symmetrical; the twelfth diaphragm and the thirteenth diaphragm are left-right symmetrical; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are equal in length along the front-back direction; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm are equal in width along the left-right direction; the first diaphragm, the second diaphragm, the third diaphragm and the fourth diaphragm increase in height along the up-down direction in sequence; the left end face of the thirteenth rectangular waveguide serves as an output port of the stepped impedance low-pass filter; and the right end face of the thirteenth rectangular waveguide serves as an input port of the stepped impedance low-pass filter.

5. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 4, wherein The first E 90-degree twist waveguide includes a first input waveguide, a first transition structure and a first output waveguide. The transition structure includes a fourteenth rectangular waveguide, a fifteenth rectangular waveguide, a sixteenth rectangular waveguide, a seventeenth rectangular waveguide and an eighteenth rectangular waveguide arranged in sequence from back to front. The front side of the fourteenth rectangular waveguide is connected to the back side of the fifteenth rectangular waveguide. The front side of the fifteenth rectangular waveguide is connected to the back side of the sixteenth rectangular waveguide. The front side of the sixteenth rectangular waveguide is connected to the back side of the seventeenth rectangular waveguide. The front side of the seventeenth rectangular waveguide is connected to the back side of the eighteenth rectangular waveguide. The left sides of the fourteenth rectangular waveguide, the fifteenth rectangular waveguide, the sixteenth rectangular waveguide, the seventeenth rectangular waveguide and the eighteenth rectangular waveguide are located in the same plane. The right sides of the fourteenth rectangular waveguide, the fifteenth rectangular waveguide, the sixteenth rectangular waveguide, the seventeenth rectangular waveguide and the eighteenth rectangular waveguide are located in the same plane. The height of the fourteenth rectangular waveguide along the up-down direction is less than the height of the fifteenth rectangular waveguide along the up-down direction. The length of the fourteenth rectangular waveguide along the front-back direction is greater than the length of the fifteenth rectangular waveguide along the front-back direction. The height of the fifteenth rectangular waveguide along the up-down direction is less than the height of the sixteenth rectangular waveguide along the up-down direction. The height of the sixteenth rectangular waveguide along the up-down direction is less than the height of the first output waveguide along the up-down direction. The length of the sixteenth rectangular waveguide along the front-back direction is less than the length of the first output waveguide along the front-back direction. The length of the sixteenth rectangular waveguide along the front-back direction is greater than the length of the fourteenth rectangular waveguide along the front-back direction. The fourteenth rectangular waveguide and the eighteenth rectangular waveguide are front-back center symmetric with respect to the center of the sixteenth rectangular waveguide. The fifteenth rectangular waveguide and the seventeenth rectangular waveguide are front-back center symmetric with respect to the center of the sixteenth rectangular waveguide. The central axes of the first output waveguide, the sixteenth rectangular waveguide and the first input waveguide along the left-right direction are in a straight line. The central lines of the fourteenth rectangular waveguide and the fifteenth rectangular waveguide along the front-back direction are in a straight line. The right end surface of the first output waveguide is connected to the left end surface of the fifteenth rectangular waveguide, the left end surface of the sixteenth rectangular waveguide and the left end surface of the seventeenth rectangular waveguide, respectively. The back end surface of the fifteenth rectangular waveguide is located behind the plane in which the back end surface of the first output waveguide is located. The left end surface of the first input waveguide is connected to the right end surface of the fourteenth rectangular waveguide, the right end surface of the fifteenth rectangular waveguide, the right end surface of the sixteenth rectangular waveguide, the right end surface of the seventeenth rectangular waveguide and the right end surface of the eighteenth rectangular waveguide, respectively. The back end surface of the fourteenth rectangular waveguide is located in the same plane as the back end surface of the first input waveguide.The front end face of the eighteenth rectangular waveguide is located in the same plane as the front end face of the first input waveguide, the lower end face of the fifteenth rectangular waveguide is located below the plane in which the lower end face of the first input waveguide is located and above the plane in which the lower end face of the sixteenth rectangular waveguide is located, the rear side face of the first input waveguide is located in the same plane as the rear side face of the fourteenth rectangular waveguide, the front side face of the first input waveguide is located in the same plane as the front side face of the eighteenth rectangular waveguide, the right side face of the first input waveguide serves as the input port of the first E-plane 90° twist waveguide, and the left end face of the first output waveguide serves as the output port of the first E-plane 90° twist waveguide; the second E-plane 90° twist waveguide and the first E-plane 90° twist waveguide are left-right symmetrical relative to the lost mould ridge waveguide bandpass filter, the output port of the second E-plane 90° twist waveguide is located at the position symmetrical to the input port of the first E-plane 90° twist waveguide in the second E-plane 90° twist waveguide, and the input port of the second E-plane 90° twist waveguide is located at the position symmetrical to the output port of the first E-plane 90° twist waveguide in the second E-plane 90° twist waveguide.

6. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 5, wherein The E-plane rectangular waveguide comprises a third rectangular trapezoidal waveguide, a fourth rectangular trapezoidal waveguide, a first rectangular triangular waveguide, a second rectangular triangular waveguide, a nineteenth rectangular waveguide, a twentieth rectangular waveguide and a twenty-first rectangular waveguide, the third rectangular trapezoidal waveguide, the nineteenth rectangular waveguide, the twentieth rectangular waveguide, the fourth rectangular trapezoidal waveguide and the twenty-first rectangular waveguide are arranged in the order from top to bottom, the cross section of the third rectangular trapezoidal waveguide along the vertical direction is a rectangular trapezoid, the upper base of the rectangular trapezoid is located at the top, the lower base is located at the bottom, the right side is located at the right side, the left side is located at the left side, the cross section of the fourth rectangular trapezoidal waveguide along the vertical direction is a rectangular trapezoid, the upper base of the rectangular trapezoid is located at the bottom, the lower base is located at the top, the right side is located at the right side, the left side is located at the left side, the lower end surface of the third rectangular trapezoidal waveguide is attached to the upper end surface of the nineteenth rectangular waveguide and they completely coincide, the left end surface of the third rectangular trapezoidal waveguide is flush with the left end surface of the nineteenth rectangular waveguide, the front end surface of the third rectangular trapezoidal waveguide is flush with the front end surface of the nineteenth rectangular waveguide, the rear end surface of the third rectangular trapezoidal waveguide is flush with the rear end surface of the nineteenth rectangular waveguide, the lower end surface of the nineteenth rectangular waveguide is attached to the upper end surface of the twentieth rectangular waveguide, the right end surface of the nineteenth rectangular waveguide is flush with the right end surface of the twentieth rectangular waveguide, the front end surface of the nineteenth rectangular waveguide is flush with the front end surface of the twentieth rectangular waveguide, the rear end surface of the nineteenth rectangular waveguide is flush with the rear end surface of the twentieth rectangular waveguide, the left end surface of the nineteenth rectangular waveguide is located at the left side of the plane where the left end surface of the twentieth rectangular waveguide is located, the upper end surface of the twenty-first rectangular waveguide is attached to the lower end surface of the twentieth rectangular waveguide, the right end surface of the twenty-first rectangular waveguide is flush with the right end surface of the twentieth rectangular waveguide, the front end surface of the twenty-first rectangular waveguide is flush with the front end surface of the twentieth rectangular waveguide, the rear end surface of the twenty-first rectangular waveguide is flush with the rear end surface of the twentieth rectangular waveguide, the left end surface of the twenty-first rectangular waveguide is located at the left side of the plane where the left end surface of the nineteenth rectangular waveguide is located, the upper end surface of the fourth rectangular trapezoidal waveguide is attached to the lower end surface of the twenty-first rectangular waveguide and they completely coincide, the left end surface of the fourth rectangular trapezoidal waveguide is flush with the left end surface of the twenty-first rectangular waveguide, the front end surface of the fourth rectangular trapezoidal waveguide is flush with the front end surface of the twenty-first rectangular waveguide, the rear end surface of the fourth rectangular trapezoidal waveguide is flush with the rear end surface of the twenty-first rectangular waveguide, the upper end surface of the first rectangular triangular waveguide is attached to the lower end surface of the nineteenth rectangular waveguide, the right end surface of the first rectangular triangular waveguide is attached to the left end surface of the twentieth rectangular waveguide, the front end surface of the first rectangular triangular waveguide is flush with the front end surface of the nineteenth rectangular waveguide,The rear end surface of the first right-angled triangular waveguide is flush with the rear end surface of the nineteenth rectangular waveguide, the lower end surface of the second right-angled triangular waveguide is attached to the upper end surface of the twenty-first rectangular waveguide, the right end surface of the second right-angled triangular waveguide is attached to the left end surface of the twentieth rectangular waveguide, the front end surface of the second right-angled triangular waveguide is flush with the front end surface of the twenty-first rectangular waveguide, the rear end surface of the second right-angled triangular waveguide is flush with the rear end surface of the twenty-first rectangular waveguide, the length of the upper end surface of the first right-angled triangular waveguide along the left-right direction is less than the distance between the plane where the left end surface of the nineteenth rectangular waveguide and the left end surface of the twentieth rectangular waveguide are located, the length of the lower end surface of the second right-angled triangular waveguide along the left-right direction is equal to the length of the upper end surface of the first right-angled triangular waveguide along the left-right direction, there is a distance between the lower end of the right end surface of the first right-angled triangular waveguide and the upper end of the right end surface of the second right-angled triangular waveguide, the left end surface of the nineteenth rectangular waveguide and the left end surface of the third right-angled trapezoidal waveguide serve as the output port of the E-face right-angled waveguide, and the left end surface of the twenty-first rectangular waveguide and the left end surface of the fourth right-angled trapezoidal waveguide serve as the input port of the E-face right-angled waveguide.

7. The high-isolation Ku-band linear polarization duplexer for satellite communications of claim 6, wherein The H-plane rectangular waveguide comprises a twenty-second rectangular waveguide, a twenty-third rectangular waveguide and a twenty-fourth rectangular waveguide arranged in sequence from front to back, the upper end face of the twenty-second rectangular waveguide, the upper end face of the twenty-third rectangular waveguide and the upper end face of the twenty-fourth rectangular waveguide are located in the same plane, the lower end face of the twenty-second rectangular waveguide, the lower end face of the twenty-third rectangular waveguide and the lower end face of the twenty-fourth rectangular waveguide are located in the same plane, the left end face of the twenty-second rectangular waveguide, the left end face of the twenty-third rectangular waveguide and the left end face of the twenty-fourth rectangular waveguide are located in the same plane, the rear end face of the twenty-second rectangular waveguide and the front end face of the twenty-third rectangular waveguide are attached, the rear end face of the twenty-third rectangular waveguide and the front end face of the twenty-fourth rectangular waveguide are attached, the length of the twenty-second rectangular waveguide along the left-right direction is greater than the length of the twenty-third rectangular waveguide along the left-right direction, but less than the length of the twenty-fourth rectangular waveguide along the left-right direction, the junction of the front end face of the twenty-second rectangular waveguide and the left end face of the twenty-third rectangular waveguide is chamfered, the junction of the left end face of the twenty-third rectangular waveguide and the rear end face of the twenty-fourth rectangular waveguide is chamfered, the right end face of the twenty-second rectangular waveguide serves as the output port of the H-plane rectangular waveguide, and the right end face of the twenty-fourth rectangular waveguide serves as the input port of the H-plane rectangular waveguide.

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