A kind of mixed integrated duplexer with frequency selection coupling output characteristic structure in waveguide
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2025-12-26
- Publication Date
- 2026-06-23
Smart Images
Figure CN121618158B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of radio frequency microwave circuit technology, and specifically to a hybrid integrated duplexer with a waveguide structure having frequency-selective coupling output characteristics. Background Technology
[0002] A duplexer is a passive three-port network device used in microwave circuits, primarily for signal separation in the frequency domain. It can separate a single broadband composite signal (transmit and receive) into two independent signals based on frequency. Duplexers are widely used in microwave circuits, especially in modern full-duplex communication, base station, and radar systems, where they are crucial for ensuring simultaneous and non-interfering operation of the transmit and receive channels.
[0003] The technical specifications of a duplexer include its operating frequency range, passband insertion loss, out-of-band rejection, isolation between transmit and receive ports, and voltage standing wave ratio (VSWR) of the ports. Among these, the isolation between transmit and receive channel ports is a crucial indicator for evaluating duplexer performance.
[0004] In related technologies, commonly used dielectric cavity or planar circuit duplexers, in order to improve the isolation between the transmit and receive channels and achieve excellent filtering performance, typically employ separate high-performance transmit and receive filters, which are then combined through an impedance matching network at a common port to achieve high-isolation duplex functionality. Due to the characteristics of their circuit structure, these duplexers cannot effectively pre-separate frequencies in the input channel. Instead, frequency separation can only be achieved by connecting filters to the two output channels after the impedance matching network, resulting in a large overall circuit size that does not meet the requirements of some operating conditions. Summary of the Invention
[0005] This application provides a hybrid integrated duplexer with a waveguide structure having frequency-selective coupling output characteristics, in order to solve or improve the problem that the existing hybrid integrated duplexers have a large overall size and cannot meet the needs of some operating conditions.
[0006] This invention provides a hybrid integrated duplexer with a frequency-selective coupling output characteristic structure within a waveguide, comprising:
[0007] The first rectangular waveguide is used for inputting electromagnetic signals;
[0008] A dielectric substrate is attached to the bottom cross-section of the first rectangular waveguide;
[0009] A pair of circuits are disposed on the upper surface of the dielectric substrate. The circuits include a semi-circular ring circuit and a first bandpass filter. The first bandpass filter is connected to the semi-circular ring circuit via a slot coupling method. The semi-circular ring circuit and the first bandpass filter are both located inside the first rectangular waveguide, and the pair of semi-circular ring circuits and the pair of first bandpass filters are respectively located on two narrow sides of the first rectangular waveguide.
[0010] A second rectangular waveguide is connected to the lower surface of the dielectric substrate. The cross-sectional dimensions of the second rectangular waveguide are the same as those of the first rectangular waveguide. The second rectangular waveguide is short-circuited at its terminal.
[0011] In one alternative embodiment, the pair of semi-circular ring circuits and the pair of first bandpass filters on the dielectric substrate are located on both sides of the line connecting the centers of the two wide sides of the bottom cross-section of the first rectangular waveguide.
[0012] In one alternative embodiment, the circuit further includes an impedance matching circuit, a second bandpass filter, and a microstrip line output segment connected in sequence, wherein one end of the impedance matching circuit is connected to the first bandpass filter via a slot coupling.
[0013] In one alternative implementation, the pair of microstrip line output segments extend in opposite directions.
[0014] In one alternative embodiment, the straight segment of the semicircular circuit forming the semicircle has a break, so that the semicircular circuit forms two connection parts, and the first bandpass filter is connected to one of the connection parts located at the center of the narrow side of the first rectangular waveguide by a slot coupling method.
[0015] In one alternative embodiment, another of the connecting parts is connected to a grounding wire.
[0016] In one optional embodiment, the lower surface of the dielectric substrate includes a metal-free region and a copper-clad region, wherein the metal-free region is disposed with the same size as the second rectangular waveguide.
[0017] In an optional embodiment, the system further includes two channel structures extending from the first rectangular waveguide, the two channel structures being formed on two narrow sides of the first rectangular waveguide, and both channel structures being connected to the interior of the first rectangular waveguide.
[0018] The embodiments disclosed in this application provide a hybrid integrated duplexer with a frequency-selective coupling output characteristic structure within a waveguide. Utilizing a first rectangular waveguide, a second rectangular waveguide, a semi-circular ring circuit on a dielectric substrate, and a first bandpass filter circuit, the core filtering and frequency division functions are directly integrated within the first rectangular waveguide. This achieves an integrated architecture where coupling is also filtering, resulting in high isolation, low insertion loss, and excellent out-of-band rejection while reducing the overall circuit size, making the overall structure compact and meeting application requirements. Furthermore, as a basic duplexer design, a planar bandpass filter can be flexibly and conveniently cascaded on the output microstrip line of this circuit structure to enhance the duplexer's performance and meet different engineering application needs. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0020] Figure 1 This is a three-dimensional structural diagram of a hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide, according to an embodiment of this application.
[0021] Figure 2 for Figure 1 A schematic diagram of the decomposition process;
[0022] Figure 3 This is a schematic diagram showing the positional relationship between the semi-circular ring circuit and the first bandpass filter in an embodiment of this application;
[0023] Figure 4 for Figure 3 The back view;
[0024] Figure 5 This is a schematic diagram showing the positional relationship between the impedance matching circuit and the second bandpass filter in an embodiment of this application;
[0025] Figure 6 for Figure 5 The back view;
[0026] Figure 7 The input return loss (S) of the duplexer without a second bandpass filter in this embodiment of the application is... 11 ) and insertion loss (S 21 S 31 Simulation result diagram;
[0027] Figure 8The isolation between the output ports of the duplexer without a second bandpass filter in this embodiment of the application is (S). 32 Simulation result diagram;
[0028] Figure 9 The input return loss (S) of the duplexer equipped with a second bandpass filter in the embodiments of this application is... 11 ) and insertion loss (S 21 S 31 Simulation result diagram;
[0029] Figure 10 The isolation between the output ports of the duplexer equipped with a second bandpass filter in the embodiments of this application is (S). 32 Simulation results diagram.
[0030] Explanation of reference numerals in the attached figures:
[0031] 1. First rectangular waveguide; 2. Dielectric substrate;
[0032] 3. Circuit; 31. Semi-circular ring circuit; 32. First bandpass filter; 33. Impedance matching circuit; 34. Second bandpass filter; 35. Microstrip line output segment; 36. Disconnection section; 37. Grounding strip;
[0033] 4. Second rectangular waveguide; 5. Region without metal layer; 6. Copper layer region on dielectric substrate; 7. Channel structure. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0035] A duplexer is a passive three-port network device used in microwave circuits, primarily for signal separation in the frequency domain. It can separate a single broadband composite signal (transmit and receive) into two independent signals based on frequency. Duplexers are widely used in microwave circuits, especially in modern full-duplex communication, base station, and radar systems, where they are crucial for ensuring simultaneous and non-interfering operation of the transmit and receive channels.
[0036] The technical specifications of a duplexer include its operating frequency range, passband insertion loss, out-of-band rejection, isolation between transmit and receive ports, and voltage standing wave ratio (VSWR) of the ports. Among these, the isolation between transmit and receive channel ports is a crucial indicator for evaluating duplexer performance.
[0037] In related technologies, commonly used dielectric cavity or planar circuit duplexers, in order to improve the isolation between the transmit and receive channels and achieve excellent filtering performance, typically employ separate high-performance transmit and receive filters, which are then combined through an impedance matching network at a common port to achieve high-isolation duplex functionality. Due to the characteristics of their circuit structure, these duplexers cannot effectively pre-separate frequencies in the input channel. Instead, frequency separation can only be achieved by connecting filters to the two output channels after the impedance matching network, resulting in a large overall circuit size that does not meet the requirements of some operating conditions.
[0038] The following is combined Figures 1 to 10 This invention describes embodiments of the present application. The present invention provides a hybrid integrated duplexer with a frequency-selective coupling output characteristic structure within a waveguide, comprising a first rectangular waveguide 1, a dielectric substrate 2, a pair of circuits 3 disposed on the dielectric substrate, and a second rectangular waveguide 4.
[0039] Among them, such as Figure 1 , Figure 2 As shown, the first rectangular waveguide 1 is used to input electromagnetic signals. The length direction of the first rectangular waveguide 1 is arranged vertically. The two surfaces of the first rectangular waveguide 1 used for signal transmission are defined as the input surface and the output surface. Among the other four surfaces around the first rectangular waveguide 1, the surface with a relatively small area is defined as the narrow side and the surface with a relatively large area is defined as the wide side.
[0040] The dielectric substrate 2 is connected to the bottom cross-section of the first rectangular waveguide 1. A pair of circuits 3 are disposed on the upper surface of the dielectric substrate 2. The circuit 3 includes a semi-circular ring circuit 31 and a first bandpass filter 32. The first bandpass filter 32 is connected to the semi-circular ring circuit 31 by a slot coupling method. The semi-circular ring circuit 31 and the first bandpass filter 32 are both located inside the first rectangular waveguide 1, and the pair of semi-circular ring circuits 31 and the pair of first bandpass filters 32 are respectively located on the two narrow sides of the first rectangular waveguide 1.
[0041] As can be seen from the above scheme, the present invention is ingeniously designed, compact in structure, and easy to implement and install in engineering. By utilizing the first rectangular waveguide 1, dielectric substrate 2, semi-circular ring circuit 31, and first bandpass filter 32, the core filtering and frequency division functions are directly integrated into the first rectangular waveguide 1, thereby achieving an integrated architecture of coupling and filtering. This achieves high isolation, low insertion loss, and excellent out-of-band suppression while reducing the overall circuit size, making the overall structure compact and meeting application requirements. Furthermore, as a basic scheme for a duplexer, a planar bandpass filter can be flexibly and conveniently cascaded on the output microstrip line of this circuit 3, thereby enhancing the duplexer's performance and meeting different needs in engineering applications.
[0042] like Figure 3 , Figure 5 As shown, the annular surface of the semi-circular ring circuit 31 is connected to the dominant mode TE of the rectangular waveguide. 10 With the longitudinal magnetic field component of the mode perpendicular, the semi-circular ring circuit 31 is used to excite the output signal from the electromagnetic field of the waveguide master mode in a magnetically coupled manner, which can ensure that the power of the input electromagnetic signal is coupled and output.
[0043] It should be noted that by changing the structural dimensions of the semi-circular ring circuit 31 and the first bandpass filter 32 on the dielectric substrate 2, as well as their relative positions when inserted into the first rectangular waveguide 1, frequency pre-separation can be effectively performed in the input channel, thereby reducing the overall circuit size and making the overall structure more compact.
[0044] In one embodiment, a second rectangular waveguide 4 is further included. The second rectangular waveguide 4 is short-circuited at its terminal and connected to the lower surface of the dielectric substrate 2. The cross-sectional dimensions of the second rectangular waveguide 4 are the same as those of the first rectangular waveguide 1.
[0045] In this embodiment, as Figure 1 , Figure 2 As shown, the second rectangular waveguide 4 has the same wide and narrow side dimensions as the first rectangular waveguide 1. The second rectangular waveguide 4 is placed on the back side of the dielectric substrate 2, and its waveguide port precisely aligns with the waveguide port of the first rectangular waveguide 1. The first rectangular waveguide 1, the dielectric substrate 2, and the second rectangular waveguide 4 are tightly connected and assembled together. Furthermore, the back side of the dielectric substrate 2 at the point of contact with the second rectangular waveguide 4 is a region 5 without a metal layer. The second rectangular waveguide 4, with its terminal short-circuited, is part of the circuit structure for realizing two-way coupling output devices with different frequency bands. By optimizing the distance between the short-circuit surfaces of the dielectric substrate 2 and the second rectangular waveguide 4, the optimal output performance of the duplexer can be obtained.
[0046] In one embodiment, such as Figure 3 , Figure 5 As shown, a pair of semi-circular ring circuits 31 and a pair of first bandpass filters 32 on the dielectric substrate 2 are located on both sides of the waveguide 1 connecting the centers of the two wide sides of the bottom cross section of the first rectangular waveguide 1. Through the two independent sets of semi-circular ring circuits 31 and first bandpass filters 32, two output signals are led out from the centers of the two narrow sides of the first rectangular waveguide 1 to the outside of the first rectangular waveguide 1.
[0047] In one embodiment, circuit 3 further includes an impedance matching circuit 33, a second bandpass filter 34, and a microstrip line output segment 35 connected in sequence, with one end of the impedance matching circuit 33 connected to the first bandpass filter 32 via a slot coupling.
[0048] In this embodiment, as Figure 5As shown, one end of the impedance matching circuit 33 is connected to the first bandpass filter 32 via a slot coupling, and the other end of the impedance matching circuit is connected to the second bandpass filter 34. The other end of the second bandpass filter 34 is connected to the microstrip line output segment 35. This configuration, by further cascading the second bandpass filter 34, effectively enhances the performance of the duplexer, meeting various needs in engineering applications.
[0049] In one embodiment, such as Figure 1 As shown, a pair of microstrip line output segments 35 extend in reverse.
[0050] In one embodiment, such as Figure 3 , Figure 5 As shown, the semi-circular circuit 31 has a break 36 in the straight segment of the semi-circular circuit 31, so that the semi-circular circuit 31 forms two connection points. One of the break points is located at the center of the narrow side of the first rectangular waveguide 1, which is directly connected to the first bandpass filter 32, impedance matching circuit 33, second bandpass filter 34 and microstrip line output segment 35 at the rear end for output. The other break point is grounded by connecting to the grounding line 37.
[0051] In one embodiment, such as Figure 4 , Figure 6 As shown, the lower surface of the dielectric substrate 2 includes a metal-free region 5 and a copper-clad region 6. The metal-free region 5 is set with the same size as the second rectangular waveguide 4.
[0052] In one embodiment, such as Figure 1 , Figure 2 As shown, it also includes two channel structures 7 extending from the first rectangular waveguide 1. The two channel structures 7 are respectively formed on the two narrow sides of the first rectangular waveguide 1, and both channel structures 7 are connected to the interior of the first rectangular waveguide 1.
[0053] In one specific embodiment, a hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide is mainly implemented by circuits placed on the upper and lower surfaces of a dielectric substrate 2 on the cross-section of a rectangular waveguide. This embodiment uses a specific Ka-band duplexer circuit as an example for illustration.
[0054] In some embodiments, the dielectric substrate 2 is made of Rogers RT / duroid 5880 material with a thickness of 0.254 mm. The dielectric substrate 2, located inside the rectangular waveguide, consists of two sets of semi-circular ring circuits 31 on the left and right sides, respectively, and a first bandpass filter 32 connected thereto. The semicircular ring circuit 31 on the left has an inner radius of 1.21 mm, a distance of 2.03 mm between its breakpoint and the narrow sidewall of the waveguide, and a metal ring line width of 0.11 mm. The first bandpass filter 32 has a passband center frequency f1 of 28.4 GHz, a total filter line length of 3.6 mm, and a width of 0.13 mm. The semicircular ring circuit 31 on the right has an inner radius of 1.27 mm, a distance of 1.67 mm between its breakpoint and the narrow sidewall of the waveguide, and a metal ring line width of 0.31 mm. The first bandpass filter 32 has a passband center frequency f2 of 35.1 GHz, a total filter line length of 2.8 mm, and a width of 0.17 mm. The distance from the short-circuit surface of the second rectangular waveguide 4 to the back surface of the dielectric substrate is 1.49 mm. The two filtered output signals are led out of the waveguide via microstrip lines through the narrow sidewalls of the rectangular waveguides, completing the basic function of the duplexer.
[0055] Figure 7 This embodiment does not include the insertion loss (S) of the two channels of the Ka-band duplexer without a second bandpass filter 34. 21 S 31 ) and input return loss (S 11 The curve of ). Figure 7 It can be seen that the two output frequency bands of the duplexer are in the frequency ranges of 28.2-28.6GHz and 34.4-35.5GHz, respectively. The insertion loss of the output port in the passband is less than 0.5dB, the input return loss in the passband is better than -10dB, and the out-of-band rejection is better than -20dB.
[0056] Figure 8 This embodiment does not include the isolation (S) between the two output ports of the Ka-band duplexer without a second bandpass filter 34. 32 The curve of ). Figure 8 As can be seen, the isolation is better than -20dB in the Ka band, and exceeds -50dB at the highest point. Compared with the duplexer structure of the traditional external filter chain, this embodiment achieves good isolation performance while maintaining a compact structure.
[0057] Based on the above, in order to further improve out-of-band suppression and isolation, as shown in the figure, a second bandpass filter 34 is cascaded on the output microstrip line after each waveguide, and the output of the second bandpass filter 34 is used as the final output port of the duplexer circuit.
[0058] Figure 9This embodiment describes the insertion loss (S) of the two channels of the duplexer circuit equipped with the second bandpass filter 34. 21 S 31 ) and input return loss (S 11 The curve of ). Figure 9 It can be seen that after cascading the second bandpass filter 34 and further optimizing the overall performance, compared with the previous version without cascading the second bandpass filter 34, the input return loss is better than -15dB in the passbands of 28.2-28.6GHz and 34.4-35.5GHz; the out-of-band rejection index can be improved to better than -60dB.
[0059] Figure 10 This embodiment describes the isolation (S) between the two output ports of the duplexer equipped with the second bandpass filter 34. 32 The curve of ). Figure 10 It can be seen that after cascading the second bandpass filter 34 again, the isolation across the entire frequency band is significantly improved, generally better than -55dB, and can reach more than -80dB at some frequency points.
[0060] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.
Claims
1. A hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide, characterized in that, include: The first rectangular waveguide (1) is used to input electromagnetic signals; The dielectric substrate (2) is connected to the bottom cross-section of the first rectangular waveguide (1); A pair of circuits (3) are disposed on the upper surface of the dielectric substrate (2). Each circuit (3) includes a semi-circular ring circuit (31) and a first bandpass filter (32). The first bandpass filter (32) is connected to the semi-circular ring circuit (31) by a slot coupling method. The semi-circular ring circuit (31) and the first bandpass filter (32) are both located inside the first rectangular waveguide (1); Among them, one of the pair of semi-circular ring circuits (31) is located on one side of the line connecting the centers of the two wide sides of the bottom cross section of the first rectangular waveguide (1), and the other semi-circular ring circuit (31) is located on the other side of the line connecting the centers of the two wide sides of the bottom cross section of the first rectangular waveguide (1). In addition, one of the pair of first bandpass filters (32) is located on one side of the line connecting the centers of the two wide sides of the bottom cross section of the first rectangular waveguide (1), and the other first bandpass filter (32) is located on the other side of the line connecting the centers of the two wide sides of the bottom cross section of the first rectangular waveguide (1).
2. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 1, characterized in that, It also includes a second rectangular waveguide (4), the second rectangular waveguide (4) is short-circuited at its end and connected to the lower surface of the dielectric substrate (2), and the cross-sectional dimensions of the second rectangular waveguide (4) are the same as those of the first rectangular waveguide (1).
3. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 1, characterized in that, The circuit (3) further includes an impedance matching circuit (33), a second bandpass filter (34) and a microstrip line output segment (35) connected in sequence. One end of the impedance matching circuit (33) is connected to the first bandpass filter (32) via a gap coupling.
4. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 3, characterized in that, The impedance matching circuit (33) and the second bandpass filter (34) are located outside the first rectangular waveguide (1).
5. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 3, characterized in that, The pair of microstrip line output segments (35) extend in reverse.
6. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 1, characterized in that, The semi-circular circuit (31) has a break (36) in the straight segment of the semi-circular circuit (31) so that the semi-circular circuit (31) has two connection parts. The first bandpass filter (32) is connected to one of the connection parts located at the center of the narrow side of the first rectangular waveguide (1) by a gap coupling.
7. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 6, characterized in that, Another connection part is connected to a grounding wire (37).
8. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to claim 2, characterized in that, The lower surface of the dielectric substrate (2) includes a metal-free region (5) and a copper-clad region (6), wherein the metal-free region (5) is configured to correspond to the second rectangular waveguide (4) in the same size.
9. The hybrid integrated duplexer with frequency-selective coupling output characteristics within a waveguide according to any one of claims 1-8, characterized in that, It also includes two channel structures (7) extending from the first rectangular waveguide (1), the two channel structures (7) being formed on the two narrow sides of the first rectangular waveguide (1), and both channel structures (7) being connected to the interior of the first rectangular waveguide (1).