CN117748080A - Circuit-to-waveguide conversion structure - Google Patents

Abstract

The invention discloses a circuit-to-waveguide conversion structure, comprising: the waveguide is fixedly connected with the medium substrate, a waveguide port is arranged on the waveguide and used for energy transfer with the medium substrate, an inwards concave energy limiting part is arranged around the waveguide port and connected with the medium substrate to form a cavity, a space above the opposite space of the cavity presents a high impedance surface to electromagnetic waves of a target working frequency band, the high impedance surface can inhibit the propagation of electromagnetic waves at a gap between the upper surface of the medium substrate and the lower surface of the waveguide, the transmission of space electromagnetic waves is inhibited, a circuit transmission line and a quasi waveguide feed part are arranged on the medium substrate, the quasi waveguide feed part and the waveguide port are oppositely arranged, the tail end of the circuit transmission line is connected with the quasi waveguide feed part and used for transmitting energy on the circuit transmission line to the quasi waveguide feed part and generating excitation, and the electromagnetic wave transmission mode of the quasi waveguide feed part is consistent with the electromagnetic wave transmission mode in the waveguide.

Description

Circuit-to-waveguide conversion structure

Technical Field

The invention relates to the technical field of electromagnetic fields and microwaves, in particular to a circuit-to-waveguide conversion structure.

Background

In order to successfully deploy a microwave millimeter wave system, various types of transmission lines are generally used, and electromagnetic waves are converted from one type of transmission line to another type of transmission line through proper transition, so that the transition of wave conversion is particularly important. Rectangular waveguide is very popular in millimeter wave technology due to its small loss and excellent performance, and is often used for transmitting and radiating millimeter wave signals, while microstrip lines, coplanar waveguides, strip lines, grounded coplanar waveguides and other planar transmission lines are very suitable for microwave and millimeter wave integrated circuits. Thus, to facilitate integration with active circuits and chips, the metal waveguide should transition to a planar transmission line. The performance of the circuit-to-waveguide conversion structure directly affects the performance of the whole microwave millimeter wave system, and the design of the circuit-to-waveguide conversion structure with low loss, wide frequency band, low cost, easy processing and good stability in the millimeter wave system using the integrated chip is required.

Currently, conventional circuit-to-waveguide conversion structures often have problems. Common methods for implementing the circuit-to-waveguide conversion are printed antennas based on an inserted waveguide structure or slot microstrip coupling structures, but the former has high parasitic back radiation level and large dielectric loss, and the latter has a narrow bandwidth. In addition, impedance matching between the circuit signal and the waveguide is also a critical issue due to the difference in the ground current paths. Second, the circuit structure is typically realized based on a dielectric substrate, while the waveguide is typically a three-dimensional structure, with the two typically bonded together in a press-fit manner. Therefore, the contact interface between the two components inevitably has gaps, and the gaps can cause leakage of electromagnetic waves transmitted in the circuit and the waveguide, and the leakage can greatly increase the energy coupling influence between different ports, so that the isolation between the ports is deteriorated, and the risk of electromagnetic interference and electromagnetic compatibility problems of the system is increased.

In summary, how to keep lower loss and stable transmission characteristics in a wide frequency band, and ensure robustness of the circuit and the waveguide during installation, and still ensure high isolation between ports during low electrical connection between the circuit and the waveguide, so as to reduce risks of EMI and EMC of the system is a problem to be solved.

Disclosure of Invention

The invention aims to provide a circuit-to-waveguide conversion structure which maintains low loss and stable transmission characteristics in a wide frequency band and ensures robustness in circuit and waveguide installation.

In a first aspect, the present invention provides a circuit-to-waveguide conversion structure comprising: the waveguide is fixedly connected with the dielectric substrate,

the waveguide is provided with a waveguide port for energy transfer with the medium substrate, an inwards concave energy limiting part is arranged around the waveguide port, the energy limiting part is connected with the medium substrate to form a cavity, the space above the opposite cavity presents a high-impedance surface for electromagnetic waves of a target working frequency band, the high-impedance surface can inhibit the gap propagation of the electromagnetic waves on the upper surface of the medium substrate and the lower surface of the waveguide, the transmission of space electromagnetic waves is inhibited, the high isolation between ports during multi-channel conversion is realized, and the radio frequency characteristics of the waveguide and the medium substrate during low-electric assembly are met;

the medium substrate is provided with a circuit transmission line and a quasi waveguide feed part, the quasi waveguide feed part and the waveguide port are arranged oppositely, the tail end of the circuit transmission line is connected with the quasi waveguide feed part, the circuit transmission line is used for transmitting the energy on the circuit transmission line to the quasi waveguide feed part and generating excitation,

the electromagnetic wave transmission mode of the quasi-waveguide feed portion is identical to the electromagnetic wave transmission mode in the waveguide.

Preferably, the quasi waveguide feeding section includes:

a feed probe for delivering energy on a circuit transmission line to excite the resonant cavity;

the resonant cavity is used for feeding the transmission cavity and is formed by metal Kong Wei, and one or more metal columns can be added in the resonant cavity for adjusting matching;

the transmission cavity is used for outputting the energy of the quasi waveguide feed part, and the output port of the transmission cavity and the waveguide port are arranged oppositely; part of medium is removed from the inside of the transmission cavity, and a plurality of metal holes are distributed around the transmission cavity; the internal transmission mode of the transmission cavity is consistent with the rectangular waveguide transmission mode, and is used for enabling electromagnetic waves to be continuously transmitted on an interface, so that transition from the medium substrate to the waveguide is realized;

and the matching cavity is used for optimizing the impedance matching of the quasi-waveguide feed part, the resonant cavity is formed by metal Kong Wei, and the matching cavity is positioned on one side or multiple sides of the transmission cavity.

Preferably, the output port of the transmission cavity is electrically connected with the waveguide port.

Preferably, the dielectric substrate is a multilayer board structure with more than or equal to 4 layers, and comprises a metallized hole, wherein the metallized hole and the dielectric substrate jointly form a resonant cavity, a transmission cavity and a matching cavity in the quasi-waveguide feed part.

Preferably, the resonant cavity, the transmission cavity and the matching cavity in the quasi-waveguide feed part are formed by transmission lines formed by the dielectric substrate, and the transmission lines comprise one or more of substrate integrated waveguides, gap waveguides or other quasi-waveguide transmission lines.

Preferably, the circuit transmission line comprises any one radio frequency transmission line of a coplanar waveguide, a grounded coplanar waveguide, a microstrip line, a strip line and a probe.

Preferably, a waveguide transmission line is arranged in the waveguide, and a step conversion waveguide is arranged between the waveguide port and the waveguide transmission line when the waveguide transmission line is horizontally distributed so as to realize the conversion of the propagation of electromagnetic waves in the vertical direction and the horizontal direction.

Preferably, the energy limiting part is a groove structure, and the depth and the width of the groove structure are adjusted to achieve the aim that a high-impedance surface is presented to electromagnetic waves of a target working frequency band in a cavity formed by the energy limiting part and the dielectric substrate.

Preferably, the conversion structure is configured as a single-channel or multi-channel structure.

In a second aspect, the invention also provides an electronic device comprising a circuit-to-waveguide conversion structure as claimed in any one of the preceding claims.

Compared with the prior art, the invention has at least the following beneficial effects: by designing the quasi-waveguide feed part, the energy on the circuit transmission line is transferred into the waveguide, on one hand, the transmission cavity in the quasi-waveguide feed part is consistent with the waveguide transmission mode, on the other hand, the transmission cavity is opposite to the waveguide, the transmission cavity transfers the energy of the quasi-waveguide feed part into the waveguide, the mode causes better continuity of propagation of the circuit layer and the waveguide layer at the interface, and during low-electric assembly, even if gaps exist between the circuit layer and the waveguide layer, the performance stability of the transition structure can be still met, and the performance requirements of low reflection coefficient, low loss and wide frequency band are realized. On the other hand, considering the application scene of actual multiple ports, an inward concave energy limiting part is introduced at the peripheral position of a waveguide port at the waveguide side, the energy limiting part is connected with the medium substrate to form a cavity, the space above the opposite cavity presents a high-impedance surface for electromagnetic waves of a target working frequency band, the gap propagation of the electromagnetic waves on the upper surface of the medium substrate and the lower surface of the waveguide can be restrained through the high-impedance surface, the transmission of space electromagnetic waves is restrained, the high isolation between ports during the multi-channel conversion is realized, and the high isolation between the waveguide and the medium substrate can be still kept when the waveguide and the medium substrate are assembled in a low electric mode; the risk of system electromagnetic interference and electromagnetic compatibility problems is reduced, and the system has the advantages of easy processing, easy assembly and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1-1 is an overall three-dimensional view of a grounded coplanar waveguide-to-waveguide transition structure in accordance with a first embodiment of the present invention;

FIGS. 1-2 are side views of a grounded coplanar waveguide-to-waveguide transition structure in an embodiment of the present invention;

FIG. 2-1 is a side view of a dielectric substrate of a grounded coplanar waveguide-to-waveguide transition structure in accordance with an embodiment of the present invention;

FIG. 2-2 is a top view of a dielectric substrate of a grounded coplanar waveguide-to-waveguide transition structure in accordance with an embodiment of the present invention;

FIG. 3-1 is a schematic three-dimensional view of the bottom of a waveguide 11 of an exemplary grounded coplanar waveguide-to-waveguide transition structure;

FIG. 3-2 is a schematic side view of a waveguide 11 of an exemplary grounded coplanar waveguide-to-waveguide transition structure;

FIG. 4-1 shows an example of a grounded coplanar waveguide-to-waveguide transition structure in accordance with an embodiment of the present invention, showing the electric field distribution in a transmission cavity in a dielectric substrate side waveguide feed;

FIG. 4-2 shows the electric field distribution at the waveguide port on the waveguide side for a grounded coplanar waveguide to waveguide transition structure in an embodiment of the present invention;

FIG. 5-1 is a schematic three-dimensional view of a two-channel circuit to waveguide switching structure in accordance with an embodiment of the present invention;

FIG. 5-2 is a side view of an exemplary two-channel circuit to waveguide conversion structure in accordance with embodiments of the present invention;

FIG. 6 is a graph of reflection coefficient of a two-channel circuit-to-waveguide conversion structure in accordance with an embodiment of the present invention;

FIG. 7 is a graph showing the contrast of insertion loss of a two-channel circuit to waveguide transition structure in accordance with an embodiment of the present invention, where the circuit and waveguide have different levels of gaps;

FIG. 8 is a graph showing the comparison of channel isolation between a circuit and a waveguide in the case of a circuit having different levels of gaps, according to the conversion structure from a two-channel circuit to a waveguide in an embodiment of the present invention;

FIG. 9 is a schematic diagram of the overall circuit-to-waveguide conversion structure of a two-channel embodiment of the present invention;

FIG. 10-1 is a top view of a dielectric substrate of a probe-to-waveguide conversion structure according to a second embodiment of the present invention;

FIG. 10-2 is a bottom view of a dielectric substrate of a probe-to-waveguide conversion structure of the second embodiment;

FIG. 11 is a top view of a conventional two-channel circuit-to-waveguide conversion structure;

FIG. 12 is a graph of insertion loss versus with and without a gap between a circuit and a waveguide for a conventional circuit-to-waveguide transition structure;

fig. 13 is a graph comparing the channel isolation between a circuit and a waveguide with and without a gap in a conventional circuit-to-waveguide switching structure.

Detailed Description

A circuit-to-waveguide switching structure of the present invention will be described in more detail below in conjunction with the schematic drawings, in which preferred embodiments of the present invention are shown, it being understood that one skilled in the art may modify the invention described herein while still achieving the advantageous effects of the invention. Accordingly, the following description is to be construed as broadly known to those skilled in the art and not as limiting the invention.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is more particularly described by way of example in the following paragraphs with reference to the drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention.

Example 1

As shown in fig. 1-1 and 1-2, the present embodiment provides a circuit-to-waveguide conversion structure, including: the device comprises a waveguide 11 and a dielectric substrate 12, wherein the waveguide 11 is fixedly connected with the dielectric substrate 12. As shown in fig. 2, the dielectric substrate in this embodiment has a 4-layer structure, and is a first metal layer 1201, a second metal layer 1202, a third metal layer 1203, and a fourth metal layer 1204 from top to bottom.

The waveguide 11 is provided with a waveguide port 26 for energy transfer with the dielectric substrate 12, an energy limiting part 27 recessed inwards is arranged around the waveguide port, the energy limiting part 27 is connected with the dielectric substrate 12 to form a cavity, a space above the opposite space of the cavity presents a high impedance surface for electromagnetic waves of a target working frequency band, and the high impedance surface can inhibit the electromagnetic waves from propagating in a gap between the upper surface of the dielectric substrate 12 and the lower surface of the waveguide 11; the opposite upper space thereof refers to a space above the groove toward the side of the dielectric substrate 12, i.e., a portion between the groove structure and the dielectric substrate 12.

The dielectric substrate 12 is provided with a circuit transmission line 20 and a quasi waveguide feed portion 21, and the quasi waveguide feed portion 21 includes a feed probe 22, a resonant cavity 23, a transmission cavity 24 and a matching cavity 25. The transmission cavity 24 is disposed opposite to the waveguide port 26, and the transmission end of the circuit transmission line 20 is connected to the feed probe 22, so as to transfer the energy on the circuit transmission line 20 to the feed probe 22 and excite the resonant cavity 23, and then to the transmission cavity 24.

The energy limiting part 27 suppresses the propagation of the space electromagnetic wave and realizes high isolation between ports during multi-channel conversion; the quasi-waveguide feeding portion 21 converts the mode transmitted on the circuit transmission line into a transmission mode in the rectangular waveguide, that is, the output mode of the transmission cavity is consistent with the transmission mode in the waveguide, so that the electromagnetic energy has better consistency when transiting from the dielectric substrate to the waveguide, and the radio frequency characteristics of the waveguide 11 and the dielectric substrate 12 in low electrical assembly are satisfied.

This embodiment is a circuit-to-waveguide conversion structure operating in the 76-81GHz band, and reference is made to fig. 1-1 for an overall schematic diagram of an embodiment circuit-to-waveguide conversion structure, comprising a waveguide 11 and a dielectric substrate 12.

Reference is made to fig. 2-1 and 2-2 for side and top views of a dielectric substrate of an embodiment grounded coplanar waveguide-to-waveguide transition structure. In this embodiment, the circuit transmission line 20 is a grounded coplanar waveguide, and the quasi-waveguide feeding portion 21 is based on a substrate integrated waveguide SIW structure. The quasi waveguide feed section 21 includes a feed probe 22, a resonant cavity 23, a transmission cavity 24, and a matching cavity 25.

The transmission end of the circuit transmission line 20 is connected to the feed probe 22, the feed probe 22 being realized by a metallized hole, inserted into the resonant cavity 23, transferring the energy on the circuit transmission line 20 to the feed probe 22 and exciting the resonant cavity 23.

The feed probe 22 is composed of a feed metal hole 2201 and a metal blind hole 2202, the feed metal hole 2201 is inserted into the resonant cavity 23 from the layer where the circuit transmission line 20 is located, and penetrates through to the top layer of the resonant cavity 23 in this embodiment, because the processing difficulty of the through hole is low, in this embodiment, the through hole is directly adopted, and the metal layers 1204 to 1201 are penetrated. Specifically, the adjustment may be performed according to the actual dielectric substrate structure, which is only exemplified herein and not limited thereto. The grounded metal blind via 2302 penetrates the metal layers 1204 and 1203, and is arranged around the metal pillar 2301, so as to prevent energy from propagating in the horizontal direction of the dielectric substrate, and cause unnecessary resonance or crosstalk.

The resonant cavity 23 is formed by arranging the grounded metalized holes 2302 in a certain period and surrounding the dielectric region 2301, wherein one or more matching posts 2303 can be added inside to adjust matching, and the matching is realized by the metalized holes. For convenience in processing, the grounding metallized holes 2302 in this example are through holes penetrating through four metal layers, and are used for connecting the layers of the dielectric substrate 12 and forming a resonant cavity, and the matching columns are also formed by metallized holes, in this example, a metallized through hole is respectively arranged at a certain distance between the upper and lower positions of the feed probe as a matching column, so as to achieve better impedance matching.

Energy passes through the resonant cavity 23 into the transfer cavity 24, the transfer cavity 24 being formed by the metallized holes 2402 surrounding the dielectric region 2401, wherein a partial region of the dielectric region 2401 is dielectric removed, forming an air-filled cavity structure 2403. The metallized holes 2402 are used for the layer-to-layer connection of the dielectric substrate 12 and limit the propagation of electromagnetic waves within the area surrounded by the metallized holes 2402. The air cavity reduces the dielectric loss caused by the medium on one hand, and on the other hand, the caliber size of the transmission cavity 24 is similar to the size of the waveguide port 26 on the waveguide side in fig. 3, so that the transition of electromagnetic waves at the interface is smoother, and the reflection of energy is reduced. Because the dielectric loss is reduced, the requirements of the overall design on the dielectric substrate material can be greatly reduced. When the circuit transmission line 20 is short in required length and has a loss in a connectable range, or the feeding probe 22 of the quasi-waveguide feeding section 21 is directly connected to a chip pad without the circuit transmission line 20, an expensive high-frequency board having a low loss characteristic at a high frequency can be replaced with a normal low-frequency board even in a millimeter wave band, greatly reducing cost. At the same time, the primary mode TE10 mode of transmission within the transmission cavity 24 coincides with the transmission mode within the waveguide port 26, with better continuity of transition. Fig. 4-1 shows the electric field distribution in the transmission cavity 24 in the dielectric substrate side waveguide feed and fig. 4-2 shows the electric field distribution at the waveguide side waveguide port 26, it being seen that the two parts of the electric field distribution have a consistency.

The transmission waveguide has a matching cavity 25 formed by a plurality of metal grounding through holes 2502 at a certain period, the metal grounding through holes 2602 penetrate through four copper layers for connection between the layers of the dielectric substrate 12, and form a matching cavity, so that the quasi-waveguide feeding portion 21 can achieve a wider matching bandwidth. The resonant cavity 23, the transmission cavity 24 and the matching cavity 25 are communicated with each other.

Referring to fig. 3, fig. 3-1 is a schematic three-dimensional view of the bottom of a waveguide 11 of a circuit-to-waveguide conversion structure, with a waveguide port 26 disposed opposite a transmission cavity 24 of a dielectric substrate 12. In order to enhance isolation between channels during multi-channel conversion, the periphery of the waveguide port 26 is provided with a recessed energy limiting part 27, and by reasonably adjusting the depth and width of the cavity, the space above the recessed structure opposite to the dielectric substrate 12 presents a high impedance surface for electromagnetic waves in a target working frequency band, and the high impedance surface can inhibit propagation of the electromagnetic waves in the horizontal direction, namely inhibit propagation of the electromagnetic waves in a gap between the upper surface of the dielectric substrate 12 and the bottom of the waveguide 11, and the depth of the groove is generally about 1/4 lambdag, so that the optimal size can be obtained through optimization. At this time, the electromagnetic wave on the surface of the waveguide port 31 is limited around the port by the surrounding energy limiting parts 32, so that the leakage of energy is reduced, the influence on the adjacent port is reduced, and the isolation is improved.

As shown in fig. 3-2, a waveguide transmission line is disposed in the waveguide 11, and when the waveguide transmission line is distributed horizontally, a step transition waveguide is disposed between the waveguide port and the waveguide transmission line to realize transition of electromagnetic wave propagation between a vertical direction and a horizontal direction. It can be understood that when the waveguide transmission line is distributed along the horizontal direction, a step transition waveguide can be added between the waveguide port and the waveguide transmission line, so as to better realize the transition of the propagation of the electromagnetic wave between the vertical direction and the horizontal direction.

Referring to fig. 1 and 3, in order to maintain low loss and stable transmission characteristics in a wide frequency band of the conversion structure, and ensure robustness in mounting the circuit and the waveguide, the present embodiment can still ensure high isolation between ports in low electrical connection between the circuit and the waveguide, and adopts the energy limiting portions 27 arranged around the waveguide port 26 to form a recess, so as to inhibit propagation of space electromagnetic waves. In addition, the quasi-waveguide feeding section 21 is designed to convert the mode transmitted on the circuit transmission line 20 into a transmission mode in a rectangular waveguide, that is, the transmission mode of the transmission cavity 24 is consistent with the transmission mode in the waveguide 11, the mode is consistent, the transmission has better continuity, so that the energy is better transferred from the dielectric substrate 12 into the waveguide 11, and when the waveguide 11 and the dielectric substrate 12 are assembled at low electrical level, good radio frequency characteristics are still maintained.

To illustrate performance at low electrical package levels, fig. 5-1 and 5-2 present three-dimensional schematic and side views of a two-channel circuit to waveguide transition structure, including waveguide 11 and dielectric substrate 12.

Referring to fig. 6, fig. 6 is a graph showing the reflection coefficient of a two-channel circuit-to-waveguide conversion structure having a reflection coefficient lower than-10 dB in the 76GHz-81GHz band. Referring to fig. 7, fig. 7 is a diagram showing the conversion structure from a circuit to a waveguide in a two-channel embodiment, in which the insertion loss of the dielectric substrate 12 where the circuit is located and the waveguide 11 are compared with each other in the presence of gaps of different degrees, it can be seen that when the air gap between the circuit and the waveguide is increased to 0.6mm, the insertion loss of the conversion structure in the target bandwidth is still relatively stable, and the maximum loss is lower than 1.4dB. Referring to fig. 8, fig. 8 is a diagram showing the conversion structure from a circuit to a waveguide of a two-channel embodiment, and comparing the channel isolation between the circuit and the waveguide with different degrees of gaps, it can be seen that when the air gap between the grounded coplanar waveguide and the waveguide is increased to 0.6mm, the isolation of the conversion structure is still greater than 48dB, and the isolation is higher. The two-channel circuit-to-waveguide conversion structure has the advantages that the input ports of the two-channel circuit-to-waveguide conversion structure have good impedance matching, meanwhile, the loss of each channel before and after conversion is small, and the two-channel circuit-to-waveguide conversion structure is suitable for the requirements of various scenes. The isolation between the ports also fully illustrates that the isolation scheme used in the design has great feasibility and advantages.

It should be noted that, the present embodiment only provides an explanation of the conversion structure from the two-channel circuit to the waveguide, and the structure may be a single-channel or two-channel or three-channel or four-channel conversion structure.

Example two

The present embodiment is a two-channel circuit to waveguide conversion structure operating in the 76-81GHz band, and referring to fig. 9, fig. 9 is an overall schematic diagram of the two-channel circuit to waveguide conversion structure of the embodiment, including the waveguide 11 and the dielectric substrate 12.

Referring to fig. 10-1 and 10-2, a top view of a dielectric substrate of a probe-to-waveguide conversion structure according to a second embodiment is shown. The dielectric substrate 12 is provided with a quasi waveguide feed portion 22, and the quasi waveguide feed portion 21 is composed of a feed probe 22, a resonant cavity 23, a transmission cavity 24 and a matching cavity 25. The feed probe 22 is directly connected to the chip pad. Energy is fed by the feed probe 22, exciting the resonant cavity 23, and the energy is then transferred to the transmission cavity 24, transitioning from the transmission cavity 2403 output to the waveguide 11. The output mode of the transmission cavity 2503 coincides with the transmission mode within the waveguide 11, which mode one results in a better transition of energy from the dielectric substrate 12 into the waveguide 11 and still maintains good radio frequency characteristics when the waveguide 11 is assembled with the dielectric substrate 12 at low electrical levels.

Referring to fig. 11, the conventional circuit-to-waveguide conversion structure realizes circuit-to-waveguide conversion by a microstrip coupling structure between a waveguide and a dielectric substrate, and the microstrip coupling structure can couple and excite resonance of a waveguide port, but its own radiation mode is inconsistent with the mode in the cavity waveguide. When there is a non-tight electrical connection between the dielectric substrate and the waveguide, i.e., a gap of 0.6mm between the two, the insertion loss and channel isolation of the conventional circuit-to-waveguide switching structure rapidly deteriorate. Referring to fig. 12 and 13, fig. 12 is a graph of insertion loss versus gap with and without a circuit and waveguide for a conventional circuit-to-waveguide switching structure, and fig. 13 is a graph of channel isolation versus gap with and without a circuit and waveguide for a conventional circuit-to-waveguide switching structure. The structure of the invention can still keep lower insertion loss and higher channel isolation when a 0.6mm assembly gap exists between the circuit and the waveguide.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A circuit-to-waveguide conversion structure comprising: the waveguide is fixedly connected with the dielectric substrate,

the waveguide is provided with a waveguide port for energy transfer with the medium substrate, an inwards concave energy limiting part is arranged around the waveguide port, the energy limiting part is connected with the medium substrate to form a cavity, the space above the opposite cavity presents a high-impedance surface for electromagnetic waves of a target working frequency band, the high-impedance surface can inhibit the gap propagation of the electromagnetic waves on the upper surface of the medium substrate and the lower surface of the waveguide, the transmission of space electromagnetic waves is inhibited, the high isolation between ports during multi-channel conversion is realized, and the radio frequency characteristics of the waveguide and the medium substrate during low-electric assembly are met;

the device is characterized in that a circuit transmission line and a quasi-waveguide feed part are arranged on the dielectric substrate, the quasi-waveguide feed part and the waveguide port are oppositely arranged, the tail end of the circuit transmission line is connected with the quasi-waveguide feed part and used for transmitting energy on the circuit transmission line to the quasi-waveguide feed part and generating excitation, and the electromagnetic wave transmission mode of the quasi-waveguide feed part is consistent with the electromagnetic wave transmission mode in the waveguide.

2. The circuit-to-waveguide conversion structure of claim 1, wherein the quasi-waveguide feed section comprises:

a feed probe for delivering energy on the circuit transmission line to excite the resonant cavity;

the resonant cavity is used for feeding the transmission cavity and is formed by metal Kong Wei, and one or more metal columns can be added in the resonant cavity for adjusting matching;

the transmission cavity is used for outputting the energy of the quasi waveguide feed part, and the output port of the transmission cavity and the waveguide port are arranged oppositely; part of medium is removed from the inside of the transmission cavity, and a plurality of metal holes are distributed around the transmission cavity; the internal transmission mode of the transmission cavity is consistent with the rectangular waveguide transmission mode, and is used for enabling electromagnetic waves to be continuously transmitted on an interface, so that transition from the medium substrate to the waveguide is realized;

and the matching cavity is used for optimizing the impedance matching of the quasi-waveguide feed part, the resonant cavity is formed by metal Kong Wei, and the matching cavity is positioned on one side or multiple sides of the transmission cavity.

3. The circuit-to-waveguide conversion structure of claim 2, wherein the output port of the transmission cavity is electrically connected to the waveguide port.

4. The circuit-to-waveguide conversion structure of claim 2, wherein the dielectric substrate is a 4-layer or more multilayer structure comprising metallized holes that together with the dielectric substrate form a resonant cavity, a transmission cavity, and a matching cavity in the quasi-waveguide feed.

5. The circuit-to-waveguide conversion structure of claim 2, wherein the resonant cavity, the transmission cavity, and the matching cavity within the quasi-waveguide feed section are formed by transmission lines formed by the dielectric substrate, the transmission lines comprising one or more of a substrate integrated waveguide, a gap waveguide, or other quasi-waveguide transmission lines.

6. The circuit-to-waveguide conversion structure of claim 1, wherein the circuit transmission line comprises any one of a coplanar waveguide, a grounded coplanar waveguide, a microstrip line, a stripline, a probe, and a radio frequency transmission line.

7. The circuit-to-waveguide conversion structure of claim 1, wherein a waveguide transmission line is provided in the waveguide, and a step conversion waveguide is provided between the waveguide port and the waveguide transmission line to realize conversion of propagation of electromagnetic waves between a vertical direction and a horizontal direction when the waveguide transmission line is horizontally distributed.

8. The circuit-to-waveguide conversion structure of claim 1, wherein the energy confinement portion is a groove structure that presents a high impedance surface to electromagnetic waves of a target operating frequency band within a cavity formed by the energy confinement portion and the dielectric substrate by adjusting a depth and a width of the groove structure.

9. The circuit-to-waveguide conversion structure of claim 1, wherein the conversion structure is provided as a single-channel or multi-channel structure.

10. An electronic device comprising a circuit-to-waveguide conversion structure as claimed in any one of claims 1-9.