Compact circularly polarized filtering patch antenna

Abstract

The invention discloses a compact circularly polarized filtering patch antenna which comprises an upper dielectric substrate and a lower dielectric substrate, a positive 45-degree main radiation patch, a pair of inclined rectangular parasitic patches which are arranged in a positive 45-degree direction and are parallel to the main radiation patch, and a pair of L-shaped parasitic patches which are arranged in a diagonal line in the positive 45-degree direction are printed on the upper dielectric substrate; a pair of vertical rectangular parasitic patches which are arranged diagonally at minus 45 degrees are printed on the lower surface of the upper-layer dielectric substrate; a floor is printed on the upper surface of the lower dielectric substrate, a middle rectangular groove is etched in the middle lower portion of the floor, four edge rectangular grooves are etched in the edge of the floor, a microstrip feeder line and a branch knot are printed on the lower dielectric substrate, and signals enter from a port and are coupled to the main radiation patch through the middle rectangular groove in the floor via the microstrip feeder line. And the main radiation patch is coupled and excited to the peripheral parasitic patches. By using the compact circularly polarized filtering patch antenna provided by the invention, the circularly polarized radiation performance with a compact structure and good band-pass filtering response is realized.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency communications, and in particular to a compact circular polarization filtering patch antenna. Background Art

[0002] At present, antennas are an indispensable part of wireless communication systems. As a device for transmitting and receiving electromagnetic waves, they play a vital role in wireless communication. With the rapid development of mobile communication technology and various wireless systems, compact circularly polarized filter patch antennas that can significantly improve communication quality have gradually attracted widespread attention. Patch antennas are widely used due to their low profile, miniaturization, and low cost.

[0003] With the development of UAV technology and aerospace technology, the range that antennas need to cover has expanded. Linear polarization antennas can hardly meet the needs of applications. In comparison, circular polarization antennas have many advantages. At present, linear polarization working mode is commonly used in wireless communications, but a single polarization mode can no longer meet the needs of positioning and navigation. In particular, circular polarization antennas have the advantages of rain and fog protection, multipath interference resistance, and high receiving efficiency, so they are widely used in satellite navigation systems. At the same time, antennas and filters are the two most important components of RF front-end circuits, and their size and performance are crucial to the quality of the overall system. The traditional design method designs the antenna and filter separately, which causes the two devices to have a loss problem due to incomplete matching when cascaded. The filter antenna formed by integrating the antenna and the filter not only has both radiation characteristics and filtering characteristics, but also can greatly reduce the overall size of the circuit and unnecessary energy loss between devices. Therefore, the filter circular polarization antenna has also become a hot topic for domestic and foreign scholars.

[0004] In the context of the rapid changes in the communication technology era, researchers have proposed many solutions to integrate the filter antenna and circular polarization antenna, such as loading the filter circuit on the patch antenna. However, these methods have more or less defects that cannot be ignored, the most obvious of which is the serious gain reduction and too narrow bandwidth, which are difficult to meet the actual application requirements of the communication system. Therefore, it is necessary to design a new compact circular polarization filter patch antenna to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a compact circularly polarized filtering patch antenna to solve at least one technical problem existing in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A compact circular polarization filter patch antenna, comprising an upper dielectric substrate and a lower dielectric substrate, an air gap is provided between the upper dielectric substrate and the lower dielectric substrate, a main radiation patch at a positive angle of 45° is printed on the upper surface of the upper dielectric substrate, a pair of oblique rectangular parasitic patches parallel to the main radiation patch and placed along the positive angle of 45° of the upper dielectric substrate, a pair of L-shaped parasitic patches placed diagonally along the positive angle of 45° of the upper dielectric substrate, and a pair of vertical rectangular parasitic patches placed diagonally at a negative angle of 45° are printed on the lower surface of the upper dielectric substrate;

[0008] The lower dielectric substrate is located below the upper dielectric substrate, a floor is printed on the upper surface of the lower dielectric substrate, a middle rectangular groove in the y direction is etched in the middle and lower part of the floor, four edge rectangular grooves in the y direction are etched on the edge of the floor, and a microstrip feeder and branches are printed on the lower surface of the lower dielectric substrate. The signal enters from the port, is coupled to the main radiation patch through the microstrip feeder through the middle rectangular groove on the floor, and then is coupled and excited to the surrounding parasitic patches by the main radiation patch.

[0009] As a preferred embodiment of the present invention, the main radiation patch of the present invention is a slotted patch rotated 45°, the main part of the main radiation patch is a square patch, and two slots are etched on the edge of the main radiation patch along the negative 45° direction, namely the first main radiation patch slot and the second main radiation patch slot. The first main radiation patch slot and the second main radiation patch slot are located in the middle of the edge of the square patch. The signal enters from the port, is coupled to the slotted main radiation patch through the microstrip feed line and the middle rectangular slot on the floor, and generates the first circularly polarized radiation frequency point.

[0010] As a preferred embodiment of the present invention, the shape of the oblique rectangular parasitic patch of the present invention is rectangular, the number of the oblique rectangular parasitic patches is two, and the two oblique rectangular parasitic patches are respectively located between the main radiation patch and the L-shaped parasitic patch and between the main radiation patch and the rectangular parasitic patch. The slotted main radiation patch is coupled to the oblique rectangular parasitic patch parallel to it to generate a second circularly polarized radiation frequency.

[0011] As a preferred embodiment of the present invention, the L-shaped parasitic patch of the present invention is L-shaped, and there are two of them, which are placed diagonally along the positive 45° direction of the upper dielectric substrate. The first L-shaped parasitic patch includes a first rectangular patch component and a first L-shaped patch component, and the first rectangular patch component is placed adjacent to the first L-shaped patch component for adjusting impedance matching. The second L-shaped parasitic patch includes a second rectangular patch component and a second L-shaped patch component, and the second rectangular patch component is placed adjacent to the second L-shaped patch component for adjusting impedance matching. The lengths of the first rectangular patch component and the second rectangular patch component are smaller than the lengths of the first L-shaped patch component and the second L-shaped patch component, and the first rectangular patch component and the second rectangular patch component as well as the first L-shaped patch component and the second L-shaped patch component are all made of metal.

[0012] As a preferred embodiment of the present invention, the rectangular parasitic patch of the present invention is rectangular in shape, and there are two of them, which are placed along the negative 45° diagonal of the upper dielectric substrate. The first rectangular parasitic patch includes a first rectangular parasitic patch component and a second rectangular parasitic patch component, and the second rectangular parasitic patch component is placed adjacent to the first rectangular parasitic patch component for adjusting impedance matching. The second rectangular parasitic patch includes a third rectangular parasitic patch component and a fourth rectangular parasitic patch component, and the third rectangular parasitic patch component is placed adjacent to the fourth rectangular parasitic patch component for adjusting impedance matching. The lengths of the second rectangular parasitic patch component and the fourth rectangular parasitic patch component are shorter than the lengths of the first rectangular parasitic patch component and the third rectangular parasitic patch component, and the first rectangular parasitic patch component, the second rectangular parasitic patch component, the third rectangular parasitic patch component and the fourth rectangular parasitic patch component have the same width and are all made of metal.

[0013] At the same time, a pair of L-shaped parasitic patches and a pair of rectangular parasitic patches are loaded around the main radiation patch to generate a third circularly polarized radiation frequency point.

[0014] As a preferred embodiment of the present invention, the edge rectangular groove of the present invention includes an upper left rectangular groove, an upper right rectangular groove, a lower left rectangular groove and a lower right rectangular groove, the upper left rectangular groove, the upper right rectangular groove, the lower left rectangular groove and the lower right rectangular groove are of equal length and size, the etching positions of the upper left rectangular groove, the upper right rectangular groove, the lower left rectangular groove and the lower right rectangular groove are symmetrical about the center of the floor, and a controllable radiation zero point is generated at a low frequency through the upper left rectangular groove, the upper right rectangular groove, the lower left rectangular groove and the lower right rectangular groove etched on the edge of the floor.

[0015] As a preferred embodiment of the present invention, the microstrip feeder of the present invention includes a first microstrip, a second microstrip and a parallel branch node, which is used to adjust impedance matching. The width of the first microstrip is greater than the width of the second microstrip. The first microstrip is located at the starting end of the microstrip feeder, and the end is connected to one end of the second microstrip. The other end of the second microstrip is connected to the parallel branch node. The parallel branch node is located directly below the rectangular groove etched on the floor. The branch node is located directly above the open end of the microstrip feeder, generating a controllable radiation zero point at high frequency.

[0016] As a preferred embodiment of the present invention, the branch of the present invention is in an inverted U-shape.

[0017] Compared with the prior art, the compact circular polarization filter patch antenna provided by the present invention has the following beneficial effects:

[0018] 1. The antenna designed in the present invention can generate three circularly polarized radiation frequencies by etching a main radiation patch with two grooves in the negative 45° direction and loading a pair of oblique rectangular parasitic patches parallel to the main radiation patch, as well as loading parasitic patches on all sides, thereby achieving a wider circularly polarized bandwidth without increasing the antenna cross-section height and maintaining a compact antenna structure.

[0019] 2. The antenna designed by the present invention etches four edge rectangular grooves on the edge of the floor, so that a pair of vertical rectangular parasitic patches placed at a minus 45° diagonal on the upper dielectric substrate and the main radiation patch form a reverse current, thereby generating a radiation zero point. By adjusting the length of the edge rectangular groove, the position of the radiation point can be flexibly adjusted without affecting the performance of the antenna.

[0020] 3. The antenna designed in the present invention can form a reverse current in the x direction of the main radiation patch and generate a radiation zero point by loading an inverted U-shaped microstrip branch on the open end of the microstrip feeder. By adjusting the length of the inverted U-shaped branch in the x direction, the position of the radiation point can be flexibly controlled with little impact on the performance of the antenna.

[0021] 4. The antenna designed by the present invention adjusts the length of the four edge rectangular slots to produce a radiation zero point at low frequency, and then adjusts the length of the inverted U-shaped branch in the x direction to produce a radiation zero point at high frequency, ultimately enabling the antenna to achieve circularly polarized radiation performance with a compact structure and good bandpass filtering response.

[0022] Compared with other antennas, the antenna designed in the present invention has a more compact antenna structure, and does not need to generate a radiation zero point by adding a filtering network or superimposing a structure in the vertical direction, so as to achieve a bandpass filtering response, and the gain radiation pattern is stable and good. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the antenna structure of the present invention;

[0024] Figure 2 is a side view of the antenna structure of the present invention;

[0025] Figure 3 is a top view of the upper dielectric substrate;

[0026] Figure 4 is a bottom view of the upper dielectric substrate;

[0027] Figure 5 is a top view of the lower dielectric substrate;

[0028] Figure 6 is a bottom view of the lower dielectric substrate;

[0029] Figure 7 is a diagram of simulation results of S parameters and main polarization gain of the compact circularly polarized filter patch antenna of this embodiment;

[0030] Figure 8 is a diagram of the simulation results of the axial ratio of the compact circularly polarized filter patch antenna of this embodiment;

[0031] Fig. 9 is a simulation result diagram of the main polarization and cross-polarization gain of the compact circular polarization filter patch antenna of this embodiment varying with frequency;

[0032] Fig.10 is a simulation result diagram of the XOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 2.77 GHz;

[0033] Fig.11 is a simulation result diagram of the YOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 2.77 GHz;

[0034] Fig.12 is a simulation result diagram of the XOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 2.88 GHz;

[0035] Fig.13 is a simulation result diagram of the YOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 2.88 GHz;

[0036] Fig.14 is a simulation result diagram of the XOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 3.02 GHz;

[0037] Fig.15 is a simulation result diagram of the YOZ plane radiation pattern of the compact circular polarization filter patch antenna of this embodiment at a frequency of 3.02 GHz;

[0038] In the figure: 1. main radiation patch; 1a. square patch; 1b. first main radiation patch slot; 1c. second main radiation patch slot; 2. oblique rectangular parasitic patch; 3. L-shaped parasitic patch; 3a. first L-shaped patch assembly; 3b. first rectangular patch assembly; 3c. second L-shaped patch assembly; 3d. second rectangular patch assembly; 4. vertical rectangular parasitic patch; 4a. first rectangular parasitic patch assembly; 4b. second rectangular parasitic patch assembly; 4c. third rectangular parasitic patch assembly; 4d. fourth rectangular parasitic patch assembly; 5. upper dielectric substrate; 6. floor; 7. edge rectangular slot; 7a. upper left rectangular slot; 7b. upper right rectangular slot; 7c. lower left rectangular slot; 7d. lower right rectangular slot; 8. middle rectangular slot; 9. branch; 10. microstrip feed line; 11. lower dielectric substrate; 20. port. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0040] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] Please see attached Figure 1-6 As shown, this embodiment provides a compact circular polarization filter patch antenna including an upper dielectric substrate 5 and a lower dielectric substrate 11, an air gap is provided between the upper dielectric substrate 5 and the lower dielectric substrate 11, the upper surface of the upper dielectric substrate 5 is printed with a main radiation patch 1 at a positive angle of 45°, a pair of oblique rectangular parasitic patches 2 placed along the positive 45° direction of the upper dielectric substrate 5 and parallel to the main radiation patch 1, a pair of L-shaped parasitic patches 3 placed along the diagonal line of the positive 45° direction of the upper dielectric substrate 5, and a pair of vertical rectangular parasitic patches 4 placed at a negative 45° diagonal are printed on the lower surface of the upper dielectric substrate 5;

[0042] The lower dielectric substrate 11 is located below the upper dielectric substrate 5. A floor 6 is printed on the upper surface of the lower dielectric substrate 11. A middle rectangular groove 8 in the y direction is etched in the middle and lower part of the floor 6. Four edge rectangular grooves 7 in the y direction are etched on the edge of the floor 6. A microstrip feed line 10 and branches 9 are printed on the lower surface of the lower dielectric substrate 11. The signal enters from the port 20, is coupled to the main radiation patch 1 through the microstrip feed line 10 through the middle rectangular groove 8 on the floor 6, and then is coupled and excited to the surrounding parasitic patches by the main radiation patch 1.

[0043] In this embodiment, three circularly polarized radiation frequencies can be generated by etching a main radiation patch 1 with two grooves in the negative 45° direction and loading a pair of oblique rectangular parasitic patches 2 parallel to the main radiation patch 1, as well as loading parasitic patches on all sides, thereby achieving a wider circular polarization bandwidth without increasing the antenna cross-sectional height and maintaining a compact antenna structure. In addition, by etching four edge rectangular grooves 7 at the edge of the floor and loading an inverted U-shaped branch 9 at the open end of the microstrip feed line 10, a controllable radiation zero point is generated at the low frequency and high frequency respectively, thereby achieving a bandpass filtering response. However, the prior art rarely involves the integrated design of compact antenna structure characteristics, circular polarization characteristics and filtering characteristics.

[0044] In a specific embodiment, Figure 1-6 As shown, the main radiation patch 1 is a slotted patch rotated 45°, the main body of the main radiation patch 1 is a square patch 1a, and two slots are etched along the edge of the main radiation patch 1 in the negative 45° direction, namely the first main radiation patch slot 1b and the second main radiation patch slot 1c. The first main radiation patch slot 1b and the second main radiation patch slot 1c are located in the middle of the edge of the square patch 1a. The signal enters from the port 20, is coupled to the slotted main radiation patch 1 through the microstrip feed line 10 and the rectangular slot 8 on the floor 6, thereby generating the first circularly polarized radiation frequency point.

[0045] In this embodiment, a main radiation patch 1 rotated at a positive angle of 45° is printed on the upper surface of the upper dielectric substrate 5, and two grooves are etched on the edges of the main radiation patch 1 along the negative angle of 45°. The signal enters from the port 20, is coupled to the slotted main radiation patch 1 through the microstrip feed line 10 and the middle rectangular groove 8 on the floor 6, and can generate the first circularly polarized radiation frequency point (3.02 GHz).

[0046] In a specific embodiment, Figure 1-4As shown, the shape of the oblique rectangular parasitic patch 2 is rectangular, and the number of the oblique rectangular parasitic patches 2 is two. The two oblique rectangular parasitic patches 2 are respectively located between the main radiation patch 1 and the L-shaped parasitic patch 3 and between the main radiation patch 1 and the vertical rectangular parasitic patch 4. The slotted main radiation patch 1 is coupled to the oblique rectangular parasitic patch 2 parallel thereto to generate a second circularly polarized radiation frequency point.

[0047] In this embodiment, a pair of oblique rectangular parasitic patches 2 parallel to the main radiation patch 1 and placed at a positive angle of 45° are printed on the upper surface of the upper dielectric substrate 5, and are respectively located between the main radiation patch 1 and the L-shaped parasitic patch 3. The slotted main radiation patch 1 is coupled to the oblique rectangular parasitic patch 2 parallel thereto, so as to generate a second circularly polarized radiation frequency (2.88 GHz).

[0048] In a specific embodiment, Figure 1-3 As shown, the L-shaped parasitic patch 3 is L-shaped, and there are two of them, which are placed along the diagonal line of the positive 45° direction of the upper dielectric substrate 5. The first L-shaped parasitic patch 3 includes a first rectangular patch component 3b and a first L-shaped patch component 3a. The first rectangular patch component 3b is placed adjacent to the first L-shaped patch component 3a for adjusting impedance matching. The second L-shaped parasitic patch 3 includes a second rectangular patch component 3d and a second L-shaped patch component 3c. The second rectangular patch component 3d is placed adjacent to the second L-shaped patch component 3c for adjusting impedance matching. The lengths of the first rectangular patch component 3b and the second rectangular patch component 3d are less than the lengths of the first L-shaped patch component 3a and the second L-shaped patch component 3c. The first rectangular patch component 3b and the second rectangular patch component 3d as well as the first L-shaped patch component 3a and the second L-shaped patch component 3c are all made of metal.

[0049] In this embodiment, a pair of L-shaped parasitic patches 3 are printed on the upper surface of the upper dielectric substrate 5 and are placed diagonally along the positive 45° direction of the upper dielectric substrate. The pair of L-shaped parasitic patches 3 are composed of a shorter rectangular metal patch and a longer L-shaped metal patch. The shorter rectangular metal patch is placed adjacent to the long side of the L-shaped metal patch for adjusting impedance matching.

[0050] In a specific embodiment, Figure 1-4As shown, the vertical rectangular parasitic patch 4 is rectangular in shape, and there are two of them, which are placed along the negative 45° direction diagonal of the upper dielectric substrate 5. The first vertical rectangular parasitic patch 4 includes a first rectangular parasitic patch component 4a and a second rectangular parasitic patch component 4b, and the second rectangular parasitic patch component 4b is placed adjacent to the first rectangular parasitic patch component 4a for adjusting impedance matching. The second vertical rectangular parasitic patch 4 includes a third rectangular parasitic patch component 4c and a fourth rectangular parasitic patch component 4d, and the third rectangular parasitic patch component 4c is placed adjacent to the fourth rectangular parasitic patch component 4d for adjusting impedance matching. The lengths of the second rectangular parasitic patch component 4b and the fourth rectangular parasitic patch component 4d are shorter than the lengths of the first rectangular parasitic patch component 4a and the third rectangular parasitic patch component 4c, and the first rectangular parasitic patch component 4a, the second rectangular parasitic patch component 4b, the third rectangular parasitic patch component 4c and the fourth rectangular parasitic patch component 4d are all the same width, and are all made of metal.

[0051] At the same time, a pair of L-shaped parasitic patches 3 and a pair of vertical rectangular parasitic patches 4 are loaded around the main radiation patch 1 to generate a third circularly polarized radiation frequency point.

[0052] In this embodiment, a pair of vertical rectangular parasitic patches 4 are printed on the lower surface of the upper dielectric substrate 5, and are placed along the negative 45° diagonal of the upper dielectric substrate. The vertical rectangular parasitic patches 4 are composed of a shorter rectangular metal patch and a longer rectangular metal patch, and the two have the same width. The shorter rectangular metal patch is placed adjacent to the longer rectangular metal patch to adjust impedance matching. At the same time, a pair of L-shaped parasitic patches and a pair of rectangular parasitic patches loaded around the main radiation patch can generate a third circularly polarized radiation frequency (2.77GHz), thereby achieving a wider circularly polarized bandwidth without increasing the height of the antenna section, and maintaining a compact antenna structure.

[0053] In a specific embodiment, Figure 1-6 As shown, the edge rectangular groove 7 includes an upper left rectangular groove 7a, an upper right rectangular groove 7b, a lower left rectangular groove 7c and a lower right rectangular groove 7d, the upper left rectangular groove 7a, the upper right rectangular groove 7b, the lower left rectangular groove 7c and the lower right rectangular groove 7d are of equal length and size, and the etching positions of the upper left rectangular groove 7a, the upper right rectangular groove 7b, the lower left rectangular groove 7c and the lower right rectangular groove 7d are symmetrical about the center of the floor 6, and a controllable radiation zero point is generated at a low frequency through the upper left rectangular groove 7a, the upper right rectangular groove 7b, the lower left rectangular groove 7c and the lower right rectangular groove 7d etched on the edge of the floor 6.

[0054] In this embodiment, a floor 6 is printed on the upper surface of the lower dielectric substrate 11, a middle rectangular groove 8 in the y direction is etched in the middle and lower part of the floor 6, and four edge rectangular grooves 7 of equal length and size in the y direction are etched on the edge of the floor 6, and the etching positions of the four edge rectangular grooves are symmetrical about the center of the floor 6. By using the four edge rectangular grooves 7 etched on the edge of the floor 6, a pair of vertical rectangular parasitic patches 4 placed at a minus 45° diagonal of the upper dielectric substrate 5 and the main radiation patch 1 form a reverse current, thereby generating a radiation zero point, and then by adjusting the lengths of the upper left rectangular groove 7a, the upper right rectangular groove 7b, the lower left rectangular groove 7c and the lower right rectangular groove 7d, the zero point is located at a low frequency, and the impact on the performance of the antenna is small.

[0055] In a specific embodiment, Figure 1-6 As shown, the microstrip feed line 10 includes a first microstrip 10a, a second microstrip 10b and a parallel branch 10c, which are used to adjust impedance matching. The width of the first microstrip 10a is greater than the width of the second microstrip 10b. The first microstrip 10a is located at the starting end of the microstrip feed line 10, and the end is connected to one end of the second microstrip 10b. The other end of the second microstrip 10b is connected to the parallel branch 10c. The parallel branch 10c is located directly below the middle rectangular groove 8 etched on the floor 6. The branch 9 is located directly above the open end of the microstrip feed line 10 to generate a controllable radiation zero point at high frequency; the branch 9 is shaped like an inverted U.

[0056] In this embodiment, a microstrip feed line 10 and an inverted U-shaped branch 9 are printed on the lower surface of the lower dielectric substrate 11. The microstrip feed line 10 is composed of a parallel branch 10c and two microstrips of different widths and lengths, which are used to adjust impedance matching. The wider first microstrip 10a is located at the starting end of the microstrip feed line 10, and is then connected to the narrower second microstrip 10b. The parallel branch 10c is directly below the middle rectangular groove 8 etched on the floor 6; by loading the inverted U-shaped branch 9 at the open end of the microstrip feed line 10, a reverse current can be formed in the direction of the main radiation patch 1x to generate a radiation zero point. By adjusting the length of the inverted U-shaped branch 9 in the x direction, the radiation zero point is located at a high frequency, thereby achieving circularly polarized radiation performance with a compact structure and good bandpass filtering response.

[0057] Figure 7This is a simulation result diagram of the S parameters and main polarization gain of the compact circularly polarized filter patch antenna of this embodiment. The frequency band where the S parameter is lower than -10dB is 2.64-3.42GHz (25.74%), a radiation zero point in the low-frequency stop band is 2.41GHz, and a radiation zero point in the high-frequency stop band is 3.71GHz, so that the low frequency has a good out-of-band suppression effect from 2.25GHz upwards, and the high frequency also has a good out-of-band suppression effect from 3.75GHz upwards, and a good bandpass filtering response is obtained.

[0058] Figure 8 This is the axial ratio simulation result diagram of the compact circular polarization filter patch antenna in this embodiment. The axial ratio bandwidth below -3dB is 2.75GHz-3.04GHz (10.02%), and the three axial ratio frequencies are 2.77GHz, 2.88GHz and 3.02GHz respectively. The 2.77GHz is generated by a pair of "L"-shaped parasitic patches and a pair of rectangular parasitic patches loaded around the main radiation patch, the 2.88GHz is generated by a pair of rectangular parasitic patches placed parallel to the main radiation patch, and the 3.02GHz is generated by the main radiation patch with two grooves etched in the negative 45° direction.

[0059] Fig. 9 3 is a simulation result diagram of the main polarization and cross-polarization gain of the compact circularly polarized filter patch antenna of this embodiment varying with frequency. It can be seen that there is good cross-polarization within the axial ratio bandwidth.

[0060] Figure 10-11 2 is a simulation result diagram of the XOZ plane and YOZ plane radiation pattern of the compact circularly polarized filter patch antenna of this embodiment at a frequency of 2.77 GHz. It can be seen that the circular polarization direction of this frequency point is right-hand circular polarization (RHCP);

[0061] Figure 12-13 2 is a simulation result diagram of the XOZ plane and YOZ plane radiation pattern of the compact circularly polarized filter patch antenna of this embodiment at a frequency of 2.88 GHz. It can be seen that the circular polarization direction of this frequency point is right-hand circular polarization (RHCP);

[0062] Figure 14-15 3 is a simulation result diagram of the XOZ plane and YOZ plane radiation pattern of the compact circularly polarized filter patch antenna of this embodiment at a frequency of 3.02 GHz. It can be seen that the circular polarization direction of this frequency point is right-hand circular polarization (RHCP);

[0063] In summary, by etching a main radiation patch 1 with two grooves in the negative 45° direction and loading a pair of oblique rectangular parasitic patches 2 parallel to the main radiation patch 1, as well as loading parasitic patches on all sides, three circularly polarized radiation frequencies can be generated, thereby achieving a wider circularly polarized bandwidth without increasing the antenna cross-sectional height, maintaining a compact antenna structure, and by etching four edge rectangular grooves 7 on the edge of the floor 6 and loading an inverted U-shaped microstrip branch 9 at the open end of the microstrip feed line 10, a controllable radiation zero point is generated at the low frequency and high frequency respectively, thereby achieving a bandpass filtering response, and solving the problems of gain reduction and large size caused by the introduction of the filtering circuit.

[0064] Compared with other antennas, the antenna designed in the present invention has a more compact antenna structure, and does not need to generate a radiation zero point by adding a filtering network or superimposing a structure in the vertical direction, so as to achieve a bandpass filtering response, and the gain radiation pattern is stable and good.

[0065] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A compact circular polarization filter patch antenna, characterized in that: The invention comprises an upper dielectric substrate (5) and a lower dielectric substrate (11), wherein an air gap exists between the upper dielectric substrate (5) and the lower dielectric substrate (11), wherein the upper surface of the upper dielectric substrate (5) is printed with a main radiation patch (1) at a positive angle of 45°, a pair of oblique rectangular parasitic patches (2) placed along the positive 45° direction of the upper dielectric substrate (5) and parallel to the main radiation patch (1), a pair of L-shaped parasitic patches (3) placed along the diagonal line of the positive 45° direction of the upper dielectric substrate (5), and a pair of vertical rectangular parasitic patches (4) placed at a negative 45° diagonal line are printed on the lower surface of the upper dielectric substrate (5); The lower dielectric substrate (11) is located below the upper dielectric substrate (5); a floor (6) is printed on the upper surface of the lower dielectric substrate (11); a middle rectangular groove (8) in the y direction is etched in the middle and lower part of the floor (6); four edge rectangular grooves (7) in the y direction are etched on the edge of the floor (6); a microstrip feed line (10) and a branch (9) are printed on the lower surface of the lower dielectric substrate (11); a signal enters from a port (20), is coupled to a main radiation patch (1) through the microstrip feed line (10) and the middle rectangular groove (8) on the floor (6), and is then coupled and excited to surrounding parasitic patches by the main radiation patch (1).

2. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The main radiation patch (1) is a slotted patch rotated by 45 degrees. The main body of the main radiation patch (1) is a square patch (1a). Two slots are etched along the edge of the main radiation patch (1) in the negative 45 degree direction, namely a first main radiation patch slot (1b) and a second main radiation patch slot (1c). The first main radiation patch slot (1b) and the second main radiation patch slot (1c) are located in the middle of the edge of the square patch (1a). A signal enters from a port (20), is coupled to the slotted main radiation patch (1) through the microstrip feed line (10) and the middle rectangular slot (8) on the floor (6), thereby generating a first circularly polarized radiation frequency point.

3. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The shape of the oblique rectangular parasitic patch (2) is rectangular. There are two oblique rectangular parasitic patches (2). The two oblique rectangular parasitic patches (2) are respectively located between the main radiation patch (1) and the L-shaped parasitic patch (3) and between the main radiation patch (1) and the vertical rectangular parasitic patch (4). The slotted main radiation patch (1) is coupled to the oblique rectangular parasitic patch (2) parallel thereto to generate a second circularly polarized radiation frequency point.

4. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The L-shaped parasitic patch (3) is L-shaped, and there are two of them, which are placed along the diagonal line of the upper dielectric substrate (5) in the positive 45° direction. The first L-shaped parasitic patch (3) comprises a first rectangular patch component (3b) and a first L-shaped patch component (3a). The first rectangular patch component (3b) is placed adjacent to the first L-shaped patch component (3a) and is used to adjust impedance matching. The second L-shaped parasitic patch (3) comprises a second rectangular patch component (3d) and a second L-shaped patch component (3c). The second rectangular patch component (3d) is placed adjacent to the second L-shaped patch component (3c) and is used to adjust impedance matching. The lengths of the first rectangular patch component (3b) and the second rectangular patch component (3d) are shorter than the lengths of the first L-shaped patch component (3a) and the second L-shaped patch component (3c). The first rectangular patch component (3b) and the second rectangular patch component (3d) as well as the first L-shaped patch component (3a) and the second L-shaped patch component (3c) are all made of metal.

5. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The vertical rectangular parasitic patches (4) are rectangular in shape, two in number, and are placed along the negative 45° diagonal of the upper dielectric substrate (5); the first vertical rectangular parasitic patch (4) comprises a first rectangular parasitic patch component (4a) and a second rectangular parasitic patch component (4b); the second rectangular parasitic patch component (4b) is placed adjacent to the first rectangular parasitic patch component (4a) for adjusting impedance matching; the second vertical rectangular parasitic patch (4) comprises a third rectangular parasitic patch component (4c) and a fourth rectangular parasitic patch component (4d). , the third rectangular parasitic patch component (4c) is placed adjacent to the fourth rectangular parasitic patch component (4d) for adjusting impedance matching, the lengths of the second rectangular parasitic patch component (4b) and the fourth rectangular parasitic patch component (4d) are shorter than the lengths of the first rectangular parasitic patch component (4a) and the third rectangular parasitic patch component (4c), the first rectangular parasitic patch component (4a), the second rectangular parasitic patch component (4b), the third rectangular parasitic patch component (4c) and the fourth rectangular parasitic patch component (4d) are all of the same width and are all made of metal; At the same time, a pair of L-shaped parasitic patches (3) and a pair of vertical rectangular parasitic patches (4) are loaded around the main radiation patch (1) to generate a third circularly polarized radiation frequency point.

6. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The edge rectangular groove (7) comprises an upper left rectangular groove (7a), an upper right rectangular groove (7b), a lower left rectangular groove (7c) and a lower right rectangular groove (7d); the upper left rectangular groove (7a), the upper right rectangular groove (7b), the lower left rectangular groove (7c) and the lower right rectangular groove (7d) are of equal length and size; the etching positions of the upper left rectangular groove (7a), the upper right rectangular groove (7b), the lower left rectangular groove (7c) and the lower right rectangular groove (7d) are symmetrical about the center of the floor (6); and a radiation zero point is generated at a low frequency through the upper left rectangular groove (7a), the upper right rectangular groove (7b), the lower left rectangular groove (7c) and the lower right rectangular groove (7d) etched on the edge of the floor (6).

7. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The microstrip feed line (10) comprises a first microstrip (10a), a second microstrip (10b) and a parallel branch (10c), which are used to adjust impedance matching. The width of the first microstrip (10a) is greater than that of the second microstrip (10b). The first microstrip (10a) is located at the starting end of the microstrip feed line (10), and the end is connected to one end of the second microstrip (10b). The other end of the second microstrip (10b) is connected to the parallel branch (10c). The parallel branch (10c) is located directly below the middle rectangular groove (8) etched on the floor (6). The branch (9) is located directly above the open end of the microstrip feed line (10), generating a radiation zero point at high frequencies.

8. A compact circular polarization filter patch antenna according to claim 1, characterized in that: The branch (9) is in an inverted U shape.

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