Terahertz waveguide duplexer with high isolation

Abstract

The utility model relates to a terahertz waveguide duplexer with high isolation, which comprises a first linear waveguide, an input port is arranged on the left side of the first linear waveguide, and a first output port is arranged on the right side of the first linear waveguide; the first linear waveguide is provided with a six-order waveguide band-pass filter, the second linear waveguide is provided with a seven-order waveguide band-pass filter, and the top of the second linear waveguide is provided with a second output port. According to the utility model, the two filters are combined, mutual interference, reflection and standing waves between two channels are reduced, the device isolation is improved, and the terahertz waveguide duplexer with high isolation is further obtained.

Description

Technical Field

[0001] The utility model relates to the technical field of millimeter wave communication equipment and accessories used therein, and in particular to a terahertz waveguide duplexer with high isolation. Background Art

[0002] The terahertz wave (THz) frequency band usually refers to electromagnetic waves with frequencies between 0.1THz and 10THz, and its wavelength ranges from 0.03mm to 3mm. Terahertz waves have unique physical properties and broad application prospects, and have received increasing attention in recent years. Since terahertz waves can penetrate many non-conductive materials without causing damage to biological tissues, they have important applications in imaging, communications, sensing, detection, and security inspection. In terms of imaging, terahertz waves can be used for non-destructive testing and medical imaging. Terahertz imaging technology can penetrate non-metallic materials such as packaging materials and clothing to image objects hidden behind them, and has been widely used in security inspections, cultural relics identification, and industrial quality control. In the medical field, terahertz imaging can provide high-resolution images of biological tissues for early cancer detection. In terms of communications, terahertz waves have the characteristics of high frequency and large bandwidth, and can provide higher data transmission rates than existing wireless communication systems. Terahertz communication technology is expected to become an important development direction of future wireless communication technology. Especially in 5G and its subsequent technologies, terahertz communication can be used for short-distance and high-data-rate communication needs, such as indoor wireless networks and data center interconnections.

[0003] Traditional waveguide technology is mainly used in microwave and millimeter wave bands, while waveguide technology in the terahertz band faces many new challenges. Terahertz waveguides need to have low loss, high isolation and good mode characteristics to ensure the transmission efficiency and quality of signals. In addition, due to the shorter wavelength of the terahertz band, the design and manufacture of waveguide structures are more complicated. Common terahertz waveguides include metal waveguides, dielectric waveguides and photonic crystal waveguides. Among them, metal waveguides are usually used for high-frequency signal transmission due to their good conductivity. Dielectric waveguides use the low-loss characteristics of dielectric materials to effectively reduce transmission losses, but their manufacturing process is complex and costly. Photonic crystal waveguides use the photonic bandgap effect to achieve the confinement and transmission of waveguide modes, and have excellent transmission characteristics, but their design and manufacturing requirements are higher.

[0004] In view of the above-mentioned defects, the designers have actively carried out research and innovation in order to create a terahertz waveguide duplexer with high isolation to make it more valuable for industrial use. Utility Model Content

[0005] In order to solve any of the above technical problems, the purpose of the utility model is to provide a terahertz waveguide duplexer with high isolation.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A terahertz waveguide duplexer with high isolation comprises a first straight waveguide, an input port is arranged on the left side of the first straight waveguide, and a first output port is arranged on the right side of the first straight waveguide;

[0008] A sixth-order waveguide bandpass filter is arranged on the first straight waveguide, a second straight waveguide is arranged on the first straight waveguide on the left side of the sixth-order waveguide bandpass filter, the second straight waveguide and the first straight waveguide are arranged perpendicular to each other, a seventh-order waveguide bandpass filter is arranged on the second straight waveguide, and a second output port is arranged on the top of the second straight waveguide.

[0009] As a further improvement of the utility model, the sixth-order waveguide bandpass filter includes, from left to right, a sixth-order first resonant cavity, a sixth-order second resonant cavity, a sixth-order third resonant cavity, a sixth-order fourth resonant cavity, a sixth-order fifth resonant cavity and a sixth-order sixth resonant cavity; a sixth-order first coupling window is arranged between the input port and the sixth-order first resonant cavity, a sixth-order second coupling window is arranged between the sixth-order first resonant cavity and the sixth-order second resonant cavity, a sixth-order third coupling window is arranged between the sixth-order second resonant cavity and the sixth-order third resonant cavity, a sixth-order fourth coupling window is arranged between the sixth-order third resonant cavity and the sixth-order fourth resonant cavity, a sixth-order fifth coupling window is arranged between the sixth-order fourth resonant cavity and the sixth-order fifth resonant cavity, a sixth-order sixth coupling window is arranged between the sixth-order fifth resonant cavity and the sixth-order sixth resonant cavity, and a sixth-order seventh coupling window is arranged between the sixth-order sixth resonant cavity and the first output port.

[0010] As a further improvement of the utility model, the sixth-order first resonant cavity and the sixth-order sixth resonant cavity, the sixth-order second resonant cavity and the sixth-order fifth resonant cavity, the sixth-order third resonant cavity and the sixth-order fourth resonant cavity have the same structural composition; the sixth-order first coupling window and the sixth-order seventh coupling window, the sixth-order second coupling window and the sixth-order sixth coupling window, the sixth-order third coupling window and the sixth-order fifth coupling window are all symmetrical along the center of the sixth-order fourth coupling window in the middle.

[0011] As a further improvement of the present invention, the widths of the sixth-order first resonant cavity, the sixth-order second resonant cavity, the sixth-order third resonant cavity, the sixth-order fourth resonant cavity, the sixth-order fifth resonant cavity and the sixth-order sixth resonant cavity are all 1.092 mm.

[0012] As a further improvement of the utility model, the seventh-order waveguide bandpass filter includes, from bottom to top, a seventh-order first resonant cavity, a seventh-order second resonant cavity, a seventh-order third resonant cavity, a seventh-order fourth resonant cavity, a seventh-order fifth resonant cavity, a seventh-order sixth resonant cavity and a seventh-order seventh resonant cavity; a seventh-order first coupling window is arranged between the input port and the seventh-order first resonant cavity, a seventh-order second coupling window is arranged between the seventh-order first resonant cavity and the seventh-order second resonant cavity, a seventh-order third coupling window is arranged between the seventh-order second resonant cavity and the seventh-order third resonant cavity, a seventh-order fourth coupling window is arranged between the seventh-order third resonant cavity and the seventh-order fourth resonant cavity, a seventh-order fifth coupling window is arranged between the seventh-order fourth resonant cavity and the seventh-order fifth resonant cavity, a seventh-order sixth coupling window is arranged between the seventh-order fifth resonant cavity and the seventh-order sixth resonant cavity, a seventh-order seventh coupling window is arranged between the seventh-order sixth resonant cavity and the seventh-order seventh resonant cavity, and a seventh-order eighth coupling window is arranged between the seventh-order seventh coupling window and the second output port.

[0013] As a further improvement of the utility model, the seventh-order first resonant cavity and the seventh-order seventh resonant cavity, the seventh-order second resonant cavity and the seventh-order sixth resonant cavity, the seventh-order third resonant cavity and the seventh-order fifth resonant cavity are all symmetrical along the center of the seventh-order fourth resonant cavity in the middle; the seventh-order first coupling window and the seventh-order eighth coupling window, the seventh-order second coupling window and the seventh-order seventh coupling window, the seventh-order third coupling window and the seventh-order sixth coupling window, the seventh-order fourth coupling window and the seventh-order fifth coupling window have the same structural composition.

[0014] As a further improvement of the present utility model, the widths of the seventh-order first resonant cavity, the seventh-order second resonant cavity, the seventh-order third resonant cavity, the seventh-order fourth resonant cavity, the seventh-order fifth resonant cavity, the seventh-order sixth resonant cavity and the seventh-order seventh resonant cavity are all 1.092 mm.

[0015] As a further improvement of the present invention, the input port, the first output port and the second output port are all standard WR-4.3 waveguides.

[0016] As a further improvement of the present invention, the long sides of the waveguides of the input port, the first output port and the second output port are all 1.092 mm, and the short sides of the waveguides of the input port, the first output port and the second output port are all 0.546 mm.

[0017] By means of the above solution, the utility model has at least the following advantages:

[0018] 1. Wideband: The passband frequency bands are 210-216.5GHz and 223-231GHz respectively.

[0019] 2. High isolation: The isolation between passbands is less than -60dB.

[0020] 3. The utility model combines two filters to reduce mutual interference, reflection and standing waves between the two channels, improve device isolation, and thus obtain a terahertz waveguide duplexer with high isolation.

[0021] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic structural diagram of a terahertz waveguide duplexer with high isolation in the utility model;

[0024] Figure 2 yes Figure 1 A front view of

[0025] Figure 3 yes Figure 1 A schematic diagram of the partially enlarged structure of the sixth-order waveguide bandpass filter;

[0026] Figure 4 yes Figure 1 A schematic diagram of the local enlarged structure of the seventh-order waveguide bandpass filter;

[0027] Figure 5 This is a two-channel transmission test result diagram of the utility model duplexer;

[0028] Figure 6 This is a diagram of the isolation test results of the utility model duplexer.

[0029] The meanings of the various reference numerals in the figures are as follows.

[0030] Input port A, first output port B, second output port C, sixth-order waveguide bandpass filter D, seventh-order waveguide bandpass filter E;

[0031] Sixth-order first coupling window 1, sixth-order second coupling window 2, sixth-order third coupling window 3, sixth-order fourth coupling window 4, sixth-order fifth coupling window 5, sixth-order sixth coupling window 6, sixth-order seventh coupling window 7, sixth-order first resonant cavity 8, sixth-order second resonant cavity 9, sixth-order third resonant cavity 10, sixth-order fourth resonant cavity 11, sixth-order fifth resonant cavity 12, sixth-order sixth resonant cavity 13;

[0032] The seventh-order first coupling window 14, the seventh-order second coupling window 15, the seventh-order third coupling window 16, the seventh-order fourth coupling window 17, the seventh-order fifth coupling window 18, the seventh-order sixth coupling window 19, the seventh-order seventh coupling window 20, the seventh-order eighth coupling window 21, the seventh-order first resonant cavity 22, the seventh-order second resonant cavity 23, the seventh-order third resonant cavity 24, the seventh-order fourth resonant cavity 25, the seventh-order fifth resonant cavity 26, the seventh-order sixth resonant cavity 27, and the seventh-order seventh resonant cavity 28. DETAILED DESCRIPTION

[0033] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In order to make the technical personnel in the technical field better understand the scheme of the utility model, the technical scheme in the embodiment of the utility model will be clearly and completely described below in combination with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments. The components of the embodiment of the utility model usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model for protection, but only represents the selected embodiment of the utility model. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the utility model.

[0035] Example

[0036] like Figure 1 to Figure 6 As shown,

[0037] A terahertz waveguide duplexer with high isolation comprises a first straight waveguide, an input port A is arranged on the left side of the first straight waveguide, a first output port B is arranged on the right side of the first straight waveguide, a sixth-order waveguide bandpass filter D is arranged on the first straight waveguide, a second straight waveguide is arranged on the first straight waveguide on the left side of the sixth-order waveguide bandpass filter D, the second straight waveguide and the first straight waveguide are arranged perpendicular to each other, a seventh-order waveguide bandpass filter E is arranged on the second straight waveguide, and a second output port C is arranged on the top of the second straight waveguide.

[0038] The input port A, the first output port B and the second output port C are all standard WR-4.3 waveguides. The long sides of the waveguides of the input port A, the first output port B and the second output port C are all 1.092 mm, and the short sides of the waveguides of the input port A, the first output port B and the second output port C are all 0.546 mm.

[0039] 1. Sixth-order waveguide bandpass filter D:

[0040] The sixth-order waveguide bandpass filter D includes, from left to right, a sixth-order first resonant cavity 8, a sixth-order second resonant cavity 9, a sixth-order third resonant cavity 10, a sixth-order fourth resonant cavity 11, a sixth-order fifth resonant cavity 12 and a sixth-order sixth resonant cavity 13; a sixth-order first coupling window 1 is provided between the input port A and the sixth-order first resonant cavity 8, a sixth-order second coupling window 2 is provided between the sixth-order first resonant cavity 8 and the sixth-order second resonant cavity 9, a sixth-order third coupling window 3 is provided between the sixth-order second resonant cavity 9 and the sixth-order third resonant cavity 10, a sixth-order fourth coupling window 4 is provided between the sixth-order third resonant cavity 10 and the sixth-order fourth resonant cavity 11, a sixth-order fifth coupling window 5 is provided between the sixth-order fourth resonant cavity 11 and the sixth-order fifth resonant cavity 12, a sixth-order sixth coupling window 6 is provided between the sixth-order fifth resonant cavity 12 and the sixth-order sixth resonant cavity 13, and a sixth-order seventh coupling window 7 is provided between the sixth-order sixth resonant cavity 13 and the first output port B.

[0041] The sixth-order first resonant cavity 8 and the sixth-order sixth resonant cavity 13, the sixth-order second resonant cavity 9 and the sixth-order fifth resonant cavity 12, the sixth-order third resonant cavity 10 and the sixth-order fourth resonant cavity 11 have the same structural composition; the sixth-order first coupling window 1 and the sixth-order seventh coupling window 7, the sixth-order second coupling window 2 and the sixth-order sixth coupling window 6, the sixth-order third coupling window 3 and the sixth-order fifth coupling window 5 are all symmetrical around the center of the sixth-order fourth coupling window 4 in the middle.

[0042] The widths of the sixth-order first resonant cavity 8, the sixth-order second resonant cavity 9, the sixth-order third resonant cavity 10, the sixth-order fourth resonant cavity 11, the sixth-order fifth resonant cavity 12 and the sixth-order sixth resonant cavity 13 are all 1.092 mm.

[0043] Second, the seventh-order waveguide bandpass filter E:

[0044] The seventh-order waveguide bandpass filter E includes, from bottom to top, a seventh-order first resonant cavity 22, a seventh-order second resonant cavity 23, a seventh-order third resonant cavity 24, a seventh-order fourth resonant cavity 25, a seventh-order fifth resonant cavity 26, a seventh-order sixth resonant cavity 27 and a seventh-order seventh resonant cavity 28; a seventh-order first coupling window 14 is provided between the input port A and the seventh-order first resonant cavity 22, a seventh-order second coupling window 15 is provided between the seventh-order first resonant cavity 22 and the seventh-order second resonant cavity 23, and a seventh-order third coupling window 16 is provided between the seventh-order second resonant cavity 23 and the seventh-order third resonant cavity 24. A coupling window 16 is provided, a seventh-order fourth coupling window 17 is provided between the seventh-order third resonant cavity 24 and the seventh-order fourth resonant cavity 25, a seventh-order fifth coupling window 18 is provided between the seventh-order fourth resonant cavity 25 and the seventh-order fifth resonant cavity 26, a seventh-order sixth coupling window 19 is provided between the seventh-order fifth resonant cavity 26 and the seventh-order sixth resonant cavity 27, a seventh-order seventh coupling window 20 is provided between the seventh-order sixth resonant cavity 27 and the seventh-order seventh resonant cavity 28, and a seventh-order eighth coupling window 21 is provided between the seventh-order seventh coupling window 20 and the second output port C.

[0045] The seventh-order first resonant cavity 22 and the seventh-order seventh resonant cavity 28, the seventh-order second resonant cavity 23 and the seventh-order sixth resonant cavity 27, the seventh-order third resonant cavity 24 and the seventh-order fifth resonant cavity 26 are all symmetrical along the center of the seventh-order fourth resonant cavity 25 in the middle; the seventh-order first coupling window 14 and the seventh-order eighth coupling window 21, the seventh-order second coupling window 15 and the seventh-order seventh coupling window 20, the seventh-order third coupling window 16 and the seventh-order sixth coupling window 19, the seventh-order fourth coupling window 17 and the seventh-order fifth coupling window 18 have the same structural composition.

[0046] The widths of the seventh-order first resonant cavity 22, the seventh-order second resonant cavity 23, the seventh-order third resonant cavity 24, the seventh-order fourth resonant cavity 25, the seventh-order fifth resonant cavity 26, the seventh-order sixth resonant cavity 27 and the seventh-order seventh resonant cavity 28 are all 1.092 mm.

[0047] The first embodiment of the utility model:

[0048] A duplexer is an important microwave and terahertz waveguide component used to achieve bidirectional communication on the same transmission channel. A duplexer separates the transmit and receive signals so that the same device can transmit and receive at the same time. However, in the terahertz band, due to the high frequency and short wavelength, it is more challenging to design a duplexer with high isolation. High isolation is essential to prevent mutual interference between the transmit and receive signals, thereby ensuring the performance and stability of the system.

[0049] The utility model relates to a terahertz waveguide duplexer with high isolation, specifically a bandpass filter with Chebyshev response is realized by using a coupling window and a resonant cavity, and two bandpass filters are further combined into a terahertz waveguide duplexer with high isolation.

[0050] The utility model is realized by adopting the following technical scheme: the duplexer is composed of a sixth-order waveguide bandpass filter D and a seventh-order waveguide bandpass filter E respectively.

[0051] Electromagnetic waves of specific frequencies are selected through resonance characteristics. Each resonant cavity corresponds to a resonant frequency, which determines the center frequency and passband characteristics of the filter. The size, shape and material of the resonant cavity determine its resonant frequency and quality factor (Q value). A high-Q resonant cavity can provide higher selectivity and lower insertion loss, but with a narrower bandwidth; a low-Q resonant cavity is the opposite. The coupling window is used to transfer electromagnetic wave energy between resonant cavities. It determines the strength of energy coupling between resonant cavities, which in turn affects the bandwidth and selectivity of the filter. The size and position of the coupling window directly affect the coupling coefficient. A larger window will result in stronger coupling, thereby increasing the bandwidth of the filter; conversely, a smaller window will result in weaker coupling and a narrower bandwidth.

[0052] The transmission characteristics of the duplexer are adjusted by optimizing the geometric parameters of the resonant cavity and the coupling window. The duplexer operates in the 170-260GHz frequency band, and the input and output ports are both standard WR-4.3 waveguides with a long side of 1.092mm and a short side of 0.546mm.

[0053] The sixth-order waveguide bandpass filter D is a high-frequency filter, and the seventh-order waveguide bandpass filter E is a low-frequency filter.

[0054] Seventh-order waveguide bandpass filter E: This filter is symmetrical along the center, wherein the width of the resonant cavity is 1.092 mm, the lengths of the seventh-order first resonant cavity 22, the seventh-order second resonant cavity 23, the seventh-order third resonant cavity 24, and the seventh-order fourth resonant cavity 25 are different, the lengths of the seventh-order first coupling window 14, the seventh-order second coupling window 15, the seventh-order third coupling window 16, and the seventh-order fourth coupling window 17 are different, and the seventh-order first resonant cavity 22 and the seventh-order first coupling window 14 are respectively symmetrical with the seventh-order seventh resonant cavity 28 and the seventh-order eighth coupling window 21, and so on. The length of the resonant cavity and the length and width of the coupling window are simulated and optimized to achieve low-frequency filtering in the required frequency band.

[0055] Sixth-order waveguide bandpass filter D This filter is symmetrical along the center, and the width of the resonant cavity is 1.092 mm. The lengths of the sixth-order first resonant cavity 8, the sixth-order second resonant cavity 9 and the sixth-order third resonant cavity 10 are different. The lengths of the sixth-order first coupling window 1, the sixth-order second coupling window 2, the sixth-order third coupling window 3 and the sixth-order fourth coupling window 4 are different. The sixth-order first resonant cavity 8 and the sixth-order first coupling window 1 are respectively symmetrical with the sixth-order sixth resonant cavity 13 and the sixth-order seventh coupling window 7, and so on. The length of the resonant cavity and the length and width of the coupling window are simulated and optimized to achieve high-frequency filtering in the required frequency band.

[0056] The two filters are combined and the cavity geometry parameters (such as the intersection position of the two filters) are further optimized to reduce the mutual interference, reflection and standing waves between the two channels, improve the isolation of the device, and thus obtain a terahertz waveguide duplexer with high isolation.

[0057] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model 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 utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0058] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, it can be an electrical connection, it can be a direct connection, it can be an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A terahertz waveguide duplexer with high isolation, comprising a first straight waveguide, an input port (A) being arranged on the left side of the first straight waveguide, and a first output port (B) being arranged on the right side of the first straight waveguide; Features: A sixth-order waveguide bandpass filter (D) is arranged on the first straight waveguide, a second straight waveguide is arranged on the first straight waveguide on the left side of the sixth-order waveguide bandpass filter (D), the second straight waveguide and the first straight waveguide are arranged perpendicular to each other, a seventh-order waveguide bandpass filter (E) is arranged on the second straight waveguide, and a second output port (C) is arranged on the top of the second straight waveguide.

2. A terahertz waveguide duplexer with high isolation as claimed in claim 1, characterized in that: The sixth-order waveguide bandpass filter (D) comprises, from left to right, a sixth-order first resonant cavity (8), a sixth-order second resonant cavity (9), a sixth-order third resonant cavity (10), a sixth-order fourth resonant cavity (11), a sixth-order fifth resonant cavity (12) and a sixth-order sixth resonant cavity (13); a sixth-order first coupling window (1) is provided between the input port (A) and the sixth-order first resonant cavity (8), a sixth-order second coupling window (2) is provided between the sixth-order first resonant cavity (8) and the sixth-order second resonant cavity (9), and a sixth-order second coupling window (3) is provided between the sixth-order second resonant cavity (9) and the sixth-order third resonant cavity (13). A sixth-order third coupling window (3) is arranged between the sixth-order third resonant cavity (10), a sixth-order fourth coupling window (4) is arranged between the sixth-order third resonant cavity (10) and the sixth-order fourth resonant cavity (11), a sixth-order fifth coupling window (5) is arranged between the sixth-order fourth resonant cavity (11) and the sixth-order fifth resonant cavity (12), a sixth-order sixth coupling window (6) is arranged between the sixth-order fifth resonant cavity (12) and the sixth-order sixth resonant cavity (13), and a sixth-order seventh coupling window (7) is arranged between the sixth-order sixth resonant cavity (13) and the first output port (B).

3. A terahertz waveguide duplexer with high isolation as claimed in claim 2, characterized in that: The sixth-order first resonant cavity (8) and the sixth-order sixth resonant cavity (13), the sixth-order second resonant cavity (9) and the sixth-order fifth resonant cavity (12), the sixth-order third resonant cavity (10) and the sixth-order fourth resonant cavity (11) are all of the same structural composition; the sixth-order first coupling window (1) and the sixth-order seventh coupling window (7), the sixth-order second coupling window (2) and the sixth-order sixth coupling window (6), the sixth-order third coupling window (3) and the sixth-order fifth coupling window (5) are all symmetrical along the center of the sixth-order fourth coupling window (4) in the middle.

4. A terahertz waveguide duplexer with high isolation as claimed in claim 2, characterized in that: The widths of the sixth-order first resonant cavity (8), the sixth-order second resonant cavity (9), the sixth-order third resonant cavity (10), the sixth-order fourth resonant cavity (11), the sixth-order fifth resonant cavity (12) and the sixth-order sixth resonant cavity (13) are all 1.092 mm.

5. A terahertz waveguide duplexer with high isolation as claimed in claim 1, characterized in that: The seventh-order waveguide bandpass filter (E) comprises, from bottom to top, a seventh-order first resonant cavity (22), a seventh-order second resonant cavity (23), a seventh-order third resonant cavity (24), a seventh-order fourth resonant cavity (25), a seventh-order fifth resonant cavity (26), a seventh-order sixth resonant cavity (27) and a seventh-order seventh resonant cavity (28); a seventh-order first coupling window (14) is arranged between the input port (A) and the seventh-order first resonant cavity (22), a seventh-order second coupling window (15) is arranged between the seventh-order first resonant cavity (22) and the seventh-order second resonant cavity (23), and a seventh-order third coupling window (15) is arranged between the seventh-order second resonant cavity (23) and the seventh-order third resonant cavity (24). A seventh-order fourth coupling window (17) is provided between the seventh-order third resonant cavity (24) and the seventh-order fourth resonant cavity (25), a seventh-order fifth coupling window (18) is provided between the seventh-order fourth resonant cavity (25) and the seventh-order fifth resonant cavity (26), a seventh-order sixth coupling window (19) is provided between the seventh-order fifth resonant cavity (26) and the seventh-order sixth resonant cavity (27), a seventh-order seventh coupling window (20) is provided between the seventh-order sixth resonant cavity (27) and the seventh-order seventh resonant cavity (28), and a seventh-order eighth coupling window (21) is provided between the seventh-order seventh coupling window (20) and the second output port (C).

6. A terahertz waveguide duplexer with high isolation as claimed in claim 5, characterized in that: The seventh-order first resonant cavity (22) and the seventh-order seventh resonant cavity (28), the seventh-order second resonant cavity (23) and the seventh-order sixth resonant cavity (27), the seventh-order third resonant cavity (24) and the seventh-order fifth resonant cavity (26) are all symmetrical along the center of the seventh-order fourth resonant cavity (25) in the middle; the seventh-order first coupling window (14) and the seventh-order eighth coupling window (21), the seventh-order second coupling window (15) and the seventh-order seventh coupling window (20), the seventh-order third coupling window (16) and the seventh-order sixth coupling window (19), the seventh-order fourth coupling window (17) and the seventh-order fifth coupling window (18) are all the same in structure.

7. A terahertz waveguide duplexer with high isolation as claimed in claim 5, characterized in that: The widths of the seventh-order first resonant cavity (22), the seventh-order second resonant cavity (23), the seventh-order third resonant cavity (24), the seventh-order fourth resonant cavity (25), the seventh-order fifth resonant cavity (26), the seventh-order sixth resonant cavity (27) and the seventh-order seventh resonant cavity (28) are all 1.092 mm.

8. The terahertz waveguide duplexer with high isolation as claimed in claim 1, characterized in that: The input port (A), the first output port (B) and the second output port (C) are all standard WR-4.3 waveguides.

9. A terahertz waveguide duplexer with high isolation as claimed in claim 8, characterized in that: The long sides of the waveguides of the input port (A), the first output port (B) and the second output port (C) are all 1.092 mm, and the short sides of the waveguides of the input port (A), the first output port (B) and the second output port (C) are all 0.546 mm.

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