A millimeter wave multi-layer gap waveguide diplexer and a method for designing the same

Abstract

The application provides a millimeter wave multilayer gap waveguide duplexer and a design method thereof, the duplexer comprising two low-frequency bandpass filters, one high-frequency bandpass filter and two hybrid couplers; each part component is designed by using a periodic gap waveguide transmission line with a multilayer structure; the periodic gap waveguide transmission line with the multilayer structure is a double-layer gap waveguide transmission line structure in a back-to-back form, the transmission line has a three-layer structure, comprising upper and lower cover plate layers and a middle metal nail plate layer, the metal nail plate is attached with periodic square long columns, and the periodic square long columns are distributed on both sides of the metal nail plate. The duplexer can increase assembly error and reduce the overall size of the device to a certain extent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of duplexer design, in particular to a kind of millimeter wave multilayer gap waveguide duplexer and design method thereof. BACKGROUND

[0002] Duplexer is the key device to isolate transmitting signal and receiving signal, in frequency division duplex system, it is usually designed by a power distribution unit and two different passband filters as main unit. Among them, the performance and complexity of duplexer mainly depend on the composition of power distribution unit and the performance of each filter. Generally, the commonly used power distribution unit can be divided into T-junction structure and hybrid coupler structure, T-junction structure is easy to realize, and the volume is smaller, but the energy of the two frequency channels of the duplexer composed of it will be coupled with each other, and then affect the overall performance, its principle diagram is shown as Figure 1 ; and the duplexer using hybrid coupler is composed of three filter units, which leads to larger volume, but it has better isolation, and each filter unit will not be coupled with each other, its principle diagram is shown as Figure 2 .

[0003] E-band is 60-90GHz millimeter wave frequency band, there is higher dielectric loss and transmission loss, so in the design of duplexer, cavity waveguide method is usually used for design. In addition, with the increase of working frequency, the size of the device will also be smaller, and the precision requirement of device assembly is higher, so the traditional metal waveguide type device is difficult to meet the high performance requirement. In order to solve this problem, in recent years, gap waveguide structure is proposed for device design, but due to its periodic structure, the size of the device will be increased. Therefore, the present application proposes an E-band multilayer gap structure duplexer based on hybrid coupler structure and its design method, which can increase the assembly error, and can reduce the overall size of the device to a certain extent. SUMMARY

[0004] In view of the technical problems existing in the prior art, the present application provides a kind of millimeter wave multilayer gap waveguide duplexer and its design method. The duplexer can increase the assembly error, and can reduce the overall size of the device to a certain extent.

[0005] The present application is realized by the following technical scheme, the present application proposes a kind of millimeter wave multilayer gap waveguide duplexer, the duplexer includes two low-frequency band pass filter 1, one high-frequency band pass filter 2 and two hybrid couplers;It uses periodic gap waveguide transmission line with multilayer structure to design each part component;The periodic gap waveguide transmission line of multilayer structure is the double-layer gap waveguide transmission line structure of back-to-back form, the transmission line has three-layer structure, including upper and lower cover plate and middle metal nail plate layer, periodic square column is attached on the metal nail plate, and is distributed on both sides of metal nail plate.

[0006] Further, the three band-pass filters are designed by using five-order Chebyshev band-pass filters, which have five resonant cavities, and the input and output couplings are designed by using two ridges with the same length; the ridges with the same length and variable height are used between different cavities; the band-pass filters have two ports, which are an input port and an output port.

[0007] Further, the hybrid coupler structure is designed by using a five-branch hybrid coupler, which has a three-layer structure, upper and lower metal cover plates and a middle metal nail plate, and has five coupling slots on the middle metal nail plate, and the connecting parts between adjacent coupling slots are thinned to change the height and achieve better coupling matching effect; the structure has four ports, which are an input port, a straight-through port, a coupling port and an isolation port.

[0008] The application provides a design method of the millimeter wave multi-layer gap waveguide duplexer, and the design method specifically comprises the following steps: the duplexer has four ports, which are a common port, a matching port, a channel 1 and a channel 2; signals enter through the common port, are power-divided after the hybrid coupler, and the straight-through port and the coupling port are each half of the input power; since the straight-through port and the coupling port are connected with two low-frequency band-pass filters 1, the passband can be selected, signals with a certain frequency band BW1 are filtered through the two low-frequency band-pass filters 1 and then enter the next-stage hybrid coupler for power synthesis, are output at the channel 1, and the frequency band is BW1; signals not in the BW1 range are totally reflected at the filter 1, return to the port of the hybrid coupler, and the hybrid coupler has bidirectionality, so signals with other frequency bands are reflected to the isolation port of the first-stage hybrid coupler, are filtered again by high-frequency band-pass filters 2, are output at the channel 2, and the frequency band is BW2, so that the duplexing characteristic is realized; then, the designed hybrid coupler and the band-pass filter are connected with each other to complete the design of the duplexer.

[0009] The beneficial effects of the application can be summarized as follows:

[0010] 1. Since the gap waveguide transmission structure is used, the influence of the assembled air gap on the device performance can be greatly improved; and the periodic square nail structure is distributed on both sides of the middle layer, so that the influence of the air gap in the double-layer assembly process is further reduced.

[0011] 2. The connecting parts between adjacent coupling slots of the hybrid coupler designed based on the double-layer gap waveguide structure are thinned, so that the adjustable parameters are increased and the better performance index is easily optimized.

[0012] 3. The duplexers based on the hybrid coupler topology are easy to optimize, and the performance of the duplexers can be improved by designing each unit separately and then connecting them together. The double-layer gap waveguide structure is used to reduce the size of the device to some extent. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 Figure 1 is a schematic diagram of a T-junction duplex.

[0014] Figure 2 Figure 2 is a schematic diagram of a hybrid coupler duplex.

[0015] Figure 3 Figure 3 is a schematic diagram of a conventional stacked transmission line, wherein (a) is a top view, (b) is a front view, and (c) is a side view.

[0016] Figure 4 Figure 4 is a schematic diagram of a back-to-back transmission line used in the present application, wherein (a) is a top view, (b) is a front view, and (c) is a side view.

[0017] Figure 5 Figure 5 is a schematic diagram of a five-order Chebyshev bandpass filter, wherein (a) is a top view, (b) is a front view, and (c) is a side view.

[0018] Figure 6 Figure 6 is a schematic diagram of a five-branch hybrid coupler, wherein (a) is a top view, (b) is a front view, and (c) is a side view.

[0019] Figure 7 Figure 7 is a schematic diagram of a hybrid coupler duplex used in the present application.

[0020] Figure 8 Figure 8 is a schematic diagram of a duplex proposed in the present application, wherein (a) is a top view, (b) is a front view, and (c) is a side view. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0022] The application provides a millimeter wave multi-layer gap waveguide duplexer, which comprises two low-frequency bandpass filters 1, one high-frequency bandpass filter 2 and two hybrid couplers; in order to realize high assembly error performance of the duplexer and reduce the size of the device, a periodic gap waveguide transmission line with a multi-layer structure is used for designing each part component; due to the existence of a certain air gap allowed by the gap waveguide structure, no wave leakage occurs, and the device with high assembly tolerance is widely used. The application improves the traditional multi-layer gap waveguide stacked structure (as shown in the figure) Figure 3 The periodic gap waveguide transmission line of the multi-layer structure is a double-layer gap waveguide transmission line structure in a back-to-back form, and the structure is as shown in the figure Figure 4 The transmission line has a three-layer structure, comprising upper and lower cover plates and a middle metal nail plate layer, the metal nail plate is attached with periodic square long columns, and the long columns are distributed on both sides of the metal nail plate.

[0023] Three bandpass filters are designed by using five-order Chebyshev bandpass filters, which have five resonant cavities, and the input and output couplings are designed by using two ridges with the same height and length; the ridges with the same length and variable height are used between different cavities, and the structure is as shown in the figure Figure 5 The bandpass filter has two ports, which are an input port and an output port.

[0024] The hybrid coupler structure is designed by using a five-branch hybrid coupler, as shown in the figure Figure 6 The structure has a three-layer structure, comprising upper and lower metal cover plates and a middle metal nail plate layer, and the middle metal nail plate layer has five coupling slits, and the connecting parts between adjacent coupling slits are thinned to change the height and achieve better coupling matching effect; the structure has four ports, which are an input port, a straight-through port, a coupling port and an isolation port.

[0025] The application provides a design method of the millimeter wave multi-layer gap waveguide duplexer, and the principle is as shown in the figure Figure 7As shown, the design method is specifically: the diplexer has four ports, which are a common port, a matching port, a channel 1 and a channel 2, and the internal structure is composed of two hybrid couplers, two filters 1 and a filter 2, three kinds of five unit structures; the signal enters through the common port, is power-divided after the hybrid coupler, and the through port and the coupled port are each one half of the input power; since the through port and the coupled port access two low-frequency bandpass filters 1, the passband can be selected, a certain frequency band signal BW1 is filtered by the two low-frequency bandpass filters 1 and enters the next stage hybrid coupler for power synthesis, is output at the channel 1, and the frequency band is BW1; while the signal not in the BW1 range is totally reflected at the filter 1, returns to the port of the hybrid coupler, and the hybrid coupler has bidirectionality, so the other frequency band signal is reflected to the isolation port of the first stage hybrid coupler, and then is filtered again by the high-frequency bandpass filter 2, is output at the channel 2, the frequency band is BW2, and the diplexing characteristic is realized; then, the designed hybrid coupler and the bandpass filter are connected with each other to complete the design of the diplexer, as shown in Figure 8 The diplexer design has a three-layer structure, upper and lower metal cover plates, a middle metal nail plate layer, periodic square columns constituting the gap waveguide structure, coupling structure columns constituting the filter, and gaps forming the coupling relationship of the coupler, which are all located in the middle metal nail plate layer.

[0026] The above embodiments are only used to illustrate the present application, and are not intended to limit the present application. Although the related embodiments and drawings of the present application are disclosed for the purpose of illustration, those skilled in the art can understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present application and the appended claims. Therefore, all equivalent technical solutions also belong to the scope of the present application, and the patent protection scope of the present application should be defined by the claims, and should not be limited to the disclosed content of the best embodiments and drawings.

Claims

1. A millimeter-wave multilayer gap waveguide duplexer, characterized in that: The duplexer includes two low-frequency bandpass filters, one high-frequency bandpass filter, and two hybrid couplers. It employs a multi-layered periodic gap waveguide transmission line for each component design. The multi-layered periodic gap waveguide transmission line is a back-to-back double-layer gap waveguide transmission line structure. The transmission line has a three-layer structure, including upper and lower cover plates and a middle metal nail plate layer. Periodic square long pillars are attached to the metal nail plate and distributed on both sides of the metal nail plate. The hybrid coupler structure is designed as a five-branch hybrid coupler with a three-layer structure: upper and lower metal cover plates and a middle metal nail plate. The middle metal nail plate has five coupling slots, and the connection between adjacent coupling slots is thinned to change their height, thereby achieving better coupling matching effect. The structure has four ports: an input port, a through port, a coupling port, and an isolation port. The three bandpass filters are designed as fifth-order Chebyshev bandpass filters, which have five resonant cavities. The input and output coupling is designed using two ridges of equal height and length. The different cavities are designed using ridges of equal length and variable height. The bandpass filter has two ports, namely an input port and an output port. This duplexer has four ports: a common port, a matching port, channel 1, and channel 2. Signals enter through the common port and undergo power distribution after passing through the first-stage hybrid coupler. Both the through port and the coupled port receive half the input power. Since the through port and the coupled port are connected to two low-frequency bandpass filters, the passband can be selected. A signal BW1 of a certain frequency band is filtered by the two low-frequency bandpass filters and enters the next-stage hybrid coupler for power combining, outputting at channel 1 with the frequency band BW1. Signals outside the BW1 range undergo total reflection at the low-frequency bandpass filter, returning to the port of the first-stage hybrid coupler. Because the hybrid coupler is bidirectional, signals of other frequency bands are reflected to the isolation port of the first-stage hybrid coupler, then filtered again by a high-frequency bandpass filter, outputting at channel 2 with the frequency band BW2, thus achieving duplex functionality.

2. A design method for a millimeter-wave multilayer gap waveguide duplexer as described in claim 1, characterized in that, The design method is as follows: The duplexer has four ports: a common port, a matching port, channel 1, and channel 2. The signal enters through the common port and undergoes power distribution after passing through the first-stage hybrid coupler. The pass-through port and the coupled port each receive half of the input power. Since the pass-through port and the coupled port are connected to two low-frequency bandpass filters, the passband can be selected. A signal BW1 of a certain frequency band is filtered by the two low-frequency bandpass filters and enters the next-stage hybrid coupler for power synthesis, and is output in channel 1 with the frequency band BW1. Signals outside the BW1 range will undergo total reflection at the low-frequency bandpass filter and return to the port of the first-stage hybrid coupler. Since the hybrid coupler is bidirectional, signals of other frequency bands will be reflected to the isolation port of the first-stage hybrid coupler, and then filtered again by the high-frequency bandpass filter before being output in channel 2 with the frequency band BW2, thus achieving duplex characteristics. Finally, the designed hybrid coupler and bandpass filters are interconnected to complete the duplexer design.

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