A transition between a waveguide and a microstrip

Abstract

The application discloses a transition structure between a waveguide and a microstrip, comprising: a first metal plate provided with a first signal feeding hole in communication with the waveguide; a second metal plate; a metal probe provided between the first metal plate and the second metal plate and connected with the microstrip at one end; and the first metal plate and the metal probe and the metal probe and the second metal plate are both filled with a dielectric. The first signal feeding hole in communication with the waveguide is formed on the first metal plate, so that the signal in the waveguide can enter the first metal plate and the second metal plate through the first signal feeding hole, and is transmitted to the metal probe between the first metal plate and the second metal plate through the dielectric filled between the first metal plate and the second metal plate, and then is transmitted to the microstrip connected with the metal probe at one end through the metal probe, so that the transmission of the signal between the waveguide and the microstrip is completed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wireless communication, in particular to a transition structure between a waveguide and a microstrip. BACKGROUND

[0002] W-band (75GHz-110GHz) is one of the millimeter wave atmospheric windows, with a frequency between microwaves and light, and has the advantages of both microwaves and infrared, and has broad application prospects in electronic warfare, radar seeker, broadband satellite communication, and cloud and rain detection radar, and research institutions at home and abroad are actively carrying out related research.

[0003] In hybrid integrated planar circuits, planar transmission lines such as microstrip lines, striplines, and coplanar waveguides are often used to transmit signals. However, in the W-band, directly using low-frequency microstrip lines results in high loss, which cannot meet the requirements of communication systems. Moreover, the connection between instrument test interfaces and components in the W-band usually uses standard rectangular waveguides. Therefore, to realize the connection between the interface and the integrated circuit, a waveguide-microstrip transition structure with wide bandwidth and low loss is needed. In addition, due to the high frequency and short wavelength of the millimeter wave band, the offset will be larger when passing through structures with the same processing precision or installation size, thereby requiring higher processing and installation difficulty. Therefore, researching a waveguide-microstrip transition structure that is easy to process and install is crucial for components and systems. SUMMARY

[0004] The present application aims to overcome the defects of the prior art and provide a transition structure between a waveguide and a microstrip, which can realize signal transmission between the waveguide and the microstrip.

[0005] To achieve the above purpose, the present application realizes the following technical scheme:

[0006] A transition structure between a waveguide and a microstrip, characterized by comprising: a first metal plate provided with a first signal feed hole in communication with the waveguide; a second metal plate; a metal probe provided between the first metal plate and the second metal plate, and connected to a microstrip line at one end; the first metal plate and the metal probe, and the metal probe and the second metal plate are both filled with a dielectric; the signal in the waveguide is transmitted to the microstrip line through the first signal feed hole, the dielectric, and the metal probe.

[0007] Preferably, the width of the metal probe gradually narrows along the signal transmission direction.

[0008] Preferably, the dielectric includes a plurality of first dielectric plates, and the first metal plate, the second metal plate, and the metal probe each include a metal plating layer plated on the surface of the first dielectric plate.

[0009] Further, the first dielectric plate is provided with first metal holes, and a plurality of the first metal holes are uniformly distributed around the metal probe and the first signal feed hole.

[0010] Further, the first dielectric plate is provided with second metal holes, and the second metal holes are located between the metal probe and the first metal plate.

[0011] Further, the metal probe is connected with the microstrip line feed port through a metal transition line, and the width of the metal transition line is smaller than the width of the metal probe and the microstrip line feed port.

[0012] Further, the transition structure further comprises a third metal plate located between the metal transition line and the microstrip line feed port and the first metal plate and grounded, the third metal plate comprises a metal plating layer plated on the surface of the first dielectric plate, and the first dielectric plate and the second metal plate are both provided with an opening so that the microstrip line feed port is exposed.

[0013] Further, the first dielectric plate is provided with ground holes, and the ground holes are distributed on both sides of the metal transition line.

[0014] Preferably, the transition structure further comprises a fourth metal plate provided with a second signal feed hole in communication with the waveguide, the second signal feed hole is larger than the first signal feed hole, the first metal plate is located between the fourth metal plate and the metal probe, the first metal plate and the fourth metal plate are filled with a second dielectric plate, the fourth metal plate comprises a metal plating layer plated on the surface of the second dielectric plate, the second dielectric plate is provided with third metal holes, and a plurality of the third metal holes are uniformly distributed around the first signal feed hole and the second signal feed hole, and the signal in the waveguide is transmitted to the microstrip line through the second signal feed hole, the second dielectric plate, the first signal feed hole, the first dielectric plate and the metal probe.

[0015] Further, the waveguide is in communication with the second signal feed hole through a metal gasket.

[0016] The present application has the following advantages in use:

[0017] The transition structure between the waveguide and the microstrip in the application has a first signal feeding hole communicated with the waveguide and opened on the first metal plate, so that the signal in the waveguide can enter the first metal plate and the second metal plate through the first signal feeding hole, and is transmitted to the metal probe located between the first metal plate and the second metal plate through the dielectric filled between the first metal plate and the second metal plate, and then is transmitted to the microstrip connected with one end of the metal probe through the metal probe, thereby completing the transmission of the signal between the waveguide and the microstrip. The transition structure between the waveguide and the microstrip in the application realizes the transmission of the signal between the waveguide and the microstrip, and the waveguide is connected with the instrument test interface and the microstrip is connected with the integrated circuit, thereby solving the problem of the connection and transmission of the W wave band signal between the instrument test interface and the integrated circuit. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description will be briefly introduced as follows. Obviously, the drawings in the following description are one embodiment of the present application, and other drawings can also be obtained by those skilled in the art without creative effort on the basis of these drawings:

[0019] Figure 1 It is an explosion structure schematic diagram of the transition structure between the waveguide and the microstrip in one embodiment of the present application;

[0020] Figure 2 It is a top perspective structure schematic diagram of the transition structure between the waveguide and the microstrip in one embodiment of the present application;

[0021] Figure 3 It is a three-dimensional structure schematic diagram of the transition structure between the waveguide and the microstrip in one embodiment of the present application;

[0022] Figure 4 It is an electromagnetic simulation test result diagram of the transition structure between the waveguide and the microstrip in one embodiment of the present application.

[0023] Explanation of reference signs:

[0024] 1: first metal plate;

[0025] 101: first signal feeding hole;

[0026] 2: second metal plate;

[0027] 3: metal probe;

[0028] 310: wide section;

[0029] 320: narrow section;

[0030] 4: first dielectric plate;

[0031] 401: first metal hole;

[0032] 410: first waveguide cavity;

[0033] 402: second metal hole;

[0034] 403: ground hole;

[0035] 5: metal transition line;

[0036] 6: microstrip feed;

[0037] 7: third metal plate;

[0038] 701: V-shaped groove;

[0039] 8: fourth metal plate;

[0040] 801: second signal feed hole;

[0041] 9: second dielectric plate;

[0042] 901: third metal hole;

[0043] 910: second waveguide cavity;

[0044] 10: molybdenum copper gasket;

[0045] 11: rectangular waveguide;

[0046] a: notch. DETAILED DESCRIPTION

[0047] The scheme proposed by the present application will be further described in detail below in combination with the drawings and specific embodiments. The advantages and features of the present application will be more apparent according to the following description. It should be noted that the drawings are very simplified and all use non-precise proportions, only for the purpose of facilitating and clarifying the purpose of assisting the description of the embodiments of the present application. In order to make the purpose, features and advantages of the present application more apparent and easy to understand, please refer to the drawings. It should be noted that the structure, proportion, size, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the limited conditions of the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0048] Since the W-band signal (75GHz-110GHz) belongs to the millimeter wave, it has the characteristics of being able to penetrate the dielectric but not the metal conductor, and being absorbed by the metal sheet. Among them, the dielectric includes a wide range of substances such as gaseous, liquid and solid, and also includes vacuum. Substances with resistivity exceeding 10 ohm-cm are classified as dielectrics, such as air, glass, mica sheet, bakelite, resin and high molecular polymer, etc.

[0049] On the other hand, since the millimeter wave frequency band has high frequency and short wavelength, taking the W-band signal (94GHz) in the embodiment as an example, its wavelength λ1 is about 3.2mm, compared with the X-band (for example, 10GHz), whose wavelength λ2 is 30mm. For example, in the case of the same physical processing precision or installation size deviation of 1mm, the deviation for the W-band of 94GHz is 1 / 3 of the wavelength, while the deviation for the X-band of 10GHz is only 1 / 30. It can be seen that the higher the frequency, the higher the requirement for processing and installation.

[0050] Therefore, as shown in Figures 1-3 The embodiment provides a transition structure between the waveguide and the microstrip, which comprises: a first metal plate 1 provided with a first signal feeding hole 101 in communication with the waveguide; a second metal plate 2; a metal probe 3 arranged between the first metal plate 1 and the second metal plate 2 and connected to the microstrip line at one end; and a dielectric filled between the first metal plate 1 and the metal probe 3 and between the metal probe 3 and the second metal plate 2. The signal in the waveguide is transmitted to the microstrip line through the first signal feeding hole 101, the dielectric and the metal probe 3.

[0051] The transition structure between the waveguide and the microstrip of the embodiment is provided with the first signal feeding hole 101 in communication with the waveguide on the first metal plate 1, so that the signal in the waveguide can enter the first metal plate 1 and the second metal plate 2 through the first signal feeding hole 101, and be transmitted to the metal probe 3 between the first metal plate 1 and the second metal plate 2 through the dielectric filled between the first metal plate 1 and the second metal plate 2, and then be transmitted to the microstrip line connected to the metal probe 3 at one end through the metal probe 3, thereby completing the transmission of the signal between the waveguide and the microstrip.

[0052] The metal probe 3 in the embodiment gradually narrows in width along the signal transmission direction. Specifically, the metal probe 3 is designed in a T shape, comprising a wide section 310 and a narrow section 320. As shown in Figure 2 The wide section 310 of the metal probe 3 is located directly below the first signal feeding hole 101, which ensures that the signal entering through the first signal feeding hole 101 can be received by the metal probe 3 to the greatest extent.

[0053] The dielectric in the embodiment includes a plurality of first dielectric plates 4, the first metal plate 1, the second metal plate 2 and the metal probe 3 all include metal plating layers plated on the surfaces of the first dielectric plates 4. The advantage of such arrangement is that the dielectric plates are used as substrates, and the dielectric plates and the metal plating layers are integrally processed in the manner of printed circuit boards. By adjusting the number of layers of the dielectric plates, the impedance between the metal plating layers can be adjusted, thereby achieving better signal transmission effect.

[0054] Specifically, the first dielectric plate 4 in the embodiment is provided with first metal holes 401, and the first metal holes 401 are uniformly distributed around the metal probe 3 and the first signal feed hole 101. The first metal holes 401 enclose a region between the first metal plate 1 and the second metal plate 2, forming a first waveguide cavity 410 in communication with the first signal feed hole 101, and the metal probe 3 is located in the first waveguide cavity 410. The first waveguide cavity 410 plays a role in reducing energy loss, thereby reducing the loss of the signal in the process of being transmitted from the first signal feed hole 101 to the metal probe 3 through the first dielectric plate 4. The first metal holes 401 in the embodiment extend from the surface of the first metal plate 1 to the surface of the second metal plate 2, and the inner walls of the holes are plated with metal plating layers, so that millimeter waves cannot penetrate. The metal holes can also be integrally processed with the dielectric plates in the manner of printed circuit boards.

[0055] More specifically, the first dielectric plate 4 in the embodiment is provided with second metal holes 402, and the second metal holes 402 are located between the metal probe 3 and the first metal plate 1. The second metal holes 402 are located in the region enclosed by the first metal holes 401, and the second metal holes 402 are used to destroy the original field distribution in the region enclosed by the first metal holes 401, thereby eliminating the resonance points generated in the passband of the transmission line. As shown in Figure 2 The second metal holes 402 in the embodiment are located directly above the narrow section 320 of the metal probe 3.

[0056] Specifically, the metal probe 3 in the embodiment is connected to the microstrip line feed 6 through a metal transition line 5, and the width of the metal transition line 5 is smaller than the width of the metal probe 3 and the microstrip line feed 6. Such design is to meet the need of impedance matching in the process of signal transmission conversion from the metal probe 3 to the microstrip line. The signal received by the metal probe 3 in the embodiment is transmitted to the microstrip line through the metal transition line 5 and the microstrip line feed 6.

[0057] As shown in Figure 1 and Figure 3As shown, more specifically, the transition structure between the waveguide and the microstrip in the embodiment further comprises a third metal plate 7, which is arranged between the metal transition line 5 and the microstrip line feed 6 and the first metal plate 1 and is grounded. The third metal plate 7 comprises a metal plating layer plated on the surface of the first dielectric plate 4. The first dielectric plate 4 and the second metal plate 2 are both provided with an aperture a, so that the microstrip line feed 6 is exposed to facilitate the connection with other circuit gold wire bonding.

[0058] Because the microstrip line feed 6 lacks a signal ground, a feed line signal ground needs to be provided on the first dielectric plate 4 to ensure signal feeding. In the embodiment, the third metal plate 7 serves as the feed line signal ground. Figure 2 As shown, the third metal plate 7 is provided with a V-shaped groove 701 above the connection between the metal probe 3 and the metal transition line 5 to optimize the impedance matching at the connection.

[0059] As shown, the third metal plate 7 is provided with a V-shaped groove 701 above the connection between the metal probe 3 and the metal transition line 5 to optimize the impedance matching at the connection. Figure 1 As shown, the embodiment comprises four layers of first dielectric plates 4, which are arranged in parallel from right to left. The metal plating layer on the right surface of the first layer of first dielectric plates 4 constitutes the first metal plate 1. The metal plating layer on the right surface of the third layer of first dielectric plates 4 constitutes the third metal plate 7. The metal plating layer on the left surface of the third layer of first dielectric plates 4 constitutes the metal probe 3, the metal transition line 5 and the microstrip line feed 6. The metal plating layer on the left surface of the fourth layer of first dielectric plates 4 constitutes the second metal plate 2.

[0060] In the embodiment, the edge of the fourth layer of first dielectric plates 4 is shorter than that of the third layer of first dielectric plates 4 by 0.2mm-0.4mm, so that the microstrip line feed 6 on the third layer of first dielectric plates 4 is exposed.

[0061] More specifically, the first dielectric plate 4 in the embodiment is provided with a ground hole 403, which is distributed on both sides of the metal transition line 5. The ground hole 403 serves to reduce the signal transmission loss on the metal transition line 5.

[0062] In the embodiment, the first metal hole 401 and the ground hole 403 penetrate through the first to fourth layers of first dielectric plates 4; and the second metal hole 402 penetrates through the first and second layers of first dielectric plates 4.

[0063] As a preferred embodiment, as shown in Figure 1As shown, the transition structure further comprises: a fourth metal plate 8 provided with a second signal feed hole 801 in communication with the waveguide, the second signal feed hole 801 being larger than the first signal feed hole 101; the first metal plate 1 is arranged between the fourth metal plate 8 and the metal probe 3, and the first metal plate 1 and the fourth metal plate 8 are filled with a second dielectric plate 9, the fourth metal plate 8 comprises a metal plating layer plated on the surface of the second dielectric plate 9; the second dielectric plate 9 is provided with third metal holes 901, and a plurality of third metal holes 901 are uniformly distributed around the first signal feed hole 101 and the second signal feed hole 801; the signal in the waveguide is transmitted to the microstrip line through the second signal feed hole 801, the second dielectric plate 9, the first signal feed hole 101, the first dielectric plate 4 and the metal probe 3.

[0064] The third metal hole 901 in the embodiment surrounds the area between the first metal plate 1 and the fourth metal plate 8, forming a second waveguide cavity 910 connecting the second signal feed hole 801 and the first signal feed hole 101, which can reduce the loss of the signal in the waveguide during the process of entering the first signal feed hole 101 from the second signal feed hole 801. And because the first signal feed hole 101 is smaller than the second signal feed hole 801, the energy density transmitted to the metal probe 3 can be improved, and the signal transmission effect can be improved.

[0065] As shown, Figure 1 In the embodiment, four second dielectric plates 9 are arranged in parallel from right to left, and the metal plating layer on the right surface of the first second dielectric plate 9 constitutes the fourth metal plate 8. The third metal hole 901 penetrates the first to fourth second dielectric plates 9 and extends from the surface of the fourth metal plate 8 to the surface of the first metal plate 1.

[0066] The waveguide in the embodiment is in communication with the second signal feed hole 801 through a metal gasket. The metal gasket covers the second signal feed hole 801, and the signal in the waveguide is transmitted to the second signal feed hole 801 through the metal gasket. Specifically, the metal gasket is a molybdenum copper gasket 10.

[0067] The waveguide, the metal gasket and the second signal feed hole 801 in the embodiment are sequentially decreasing in size, the second signal feed hole 801 is smaller than the opening size surrounded by the third metal hole 901, and the size of the first signal feed hole 101 is smaller than the opening size surrounded by the first metal hole 401 and the opening size surrounded by the third metal hole 901.

[0068] The waveguide in the embodiment is a rectangular waveguide 11, which is designed as a standard waveguide interface size (2.54mm×1.27mm), and the microstrip line feed 6 is set as a standard 50-ohm impedance line. The first signal feed hole 101 and the second signal feed hole 801 are both rectangular holes.

[0069] The dielectric constant of the first dielectric plate 4 and the second dielectric plate 9 in the embodiment is 5.5-6.5, and the thickness is 0.07-0.12 mm, preferably, the dielectric constant epsilon r is 6, and the thickness is 0.094 mm.

[0070] The center frequency of the transition structure in the embodiment is 94 GHz (passband 86 GHz-102 GHz), and simulation and debugging are performed by using an electromagnetic simulation software Ansys. Figure 4 The simulation result of the S parameter of the transition structure in the embodiment is shown. The simulation result shows that the transition structure has good transmission effect, the return loss is below 15 dB, and the insertion loss is below 0.6 dB.

[0071] The transition structure between the waveguide and the microstrip in the embodiment vertically penetrates the metal hole inside the multi-layer dielectric plate, and forms two upper and lower waveguide cavities with the surfaces of the three horizontal metal plating layers, respectively. The metal probe 3 is integrated inside the lower waveguide cavity, the energy is coupled into the lower waveguide cavity by opening a hole in the middle metal plating layer, and the upper waveguide cavity is interconnected with the molybdenum copper gasket 10 and the rectangular waveguide 11 by digging a hole in the top metal plating layer.

[0072] The signal in the embodiment is fed into the rectangular waveguide 11, and then enters the second waveguide cavity 910 through the molybdenum copper gasket 10 directly connected thereto, and then enters the first waveguide cavity 410 through the first signal feeding hole 101. The metal probe 3 is integrated inside the first waveguide cavity 410, and the signal is transmitted to the microstrip feeding port 6 through the metal probe 3, so that the energy is fed into the waveguide port and then output by the microstrip.

[0073] The transition structure in the embodiment has the advantages of being capable of being integrally processed with the circuit board, being simple to print, having high precision, having the characteristics of miniaturization and high integration, being free of external short-circuit surface installation, having good performance, and being very suitable for application in a millimeter wave radio frequency micro system, and having very broad application prospects.

[0074] In summary, the transition structure between the waveguide and the microstrip provided by the application realizes the transmission of the signal between the waveguide and the microstrip, the waveguide is connected with the instrument test interface, and the microstrip is connected with the integrated circuit, so that the problem of connection and transmission of the W waveband signal between the instrument test interface and the integrated circuit is solved.

[0075] Although the content of the application has been described in detail by means of the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the application. After reading the above content, various modifications and substitutions of the application will be apparent to those skilled in the art. Therefore, the protection scope of the application should be defined by the appended claims.

Claims

1. A transition structure between a waveguide and a microstrip, characterized in that, The application relates to a transition structure of a waveguide and a microstrip line, which comprises the following parts: a first metal plate provided with a first signal feeding hole in communication with the waveguide, a second metal plate, a metal probe provided between the first metal plate and the second metal plate and connected with the microstrip line at one end, the first metal plate and the metal probe and the metal probe and the second metal plate are both filled with a dielectric, the dielectric comprises a plurality of first dielectric plates, and the first metal plate, the second metal plate and the metal probe all comprise a metal coating plated on the surface of the first dielectric plate; a signal in the waveguide is transmitted to the microstrip line through the first signal feeding hole, the dielectric and the metal probe, the metal probe is connected with the microstrip line feeding port through a metal transition line, and the width of the metal transition line is smaller than the width of the metal probe and the microstrip line feeding port; the transition structure further comprises a third metal plate provided between the metal transition line and the microstrip line feeding port and the first metal plate and grounded, the third metal plate comprises a metal coating plated on the surface of the first dielectric plate, a gap is arranged on the first dielectric plate and the second metal plate so that the microstrip line feeding port is exposed.

2. The transition between a waveguide and a microstrip of claim 1, wherein, The width of the metal probe gradually narrows along the signal transmission direction.

3. The transition between a waveguide and a microstrip of claim 1, wherein, A first metal hole is arranged on the first dielectric plate, and a plurality of the first metal holes are uniformly distributed around the metal probe and the first signal feeding hole.

4. The transition between a waveguide and a microstrip of claim 3, wherein, A second metal hole is arranged on the first dielectric plate, and the second metal hole is located between the metal probe and the first metal plate.

5. The transition between a waveguide and a microstrip of claim 1, wherein, A ground hole is arranged on the first dielectric plate, and the ground hole is distributed on both sides of the metal transition line.

6. The transition between a waveguide and a microstrip of claim 1, wherein, The application further comprises: a fourth metal plate provided with a second signal feeding hole in communication with the waveguide, and the second signal feeding hole is larger than the first signal feeding hole, the first metal plate is arranged between the fourth metal plate and the metal probe, the first metal plate and the fourth metal plate are filled with a second dielectric plate, and the fourth metal plate comprises a metal coating plated on the surface of the second dielectric plate, a third metal hole is arranged on the second dielectric plate, and a plurality of the third metal holes are uniformly distributed around the first signal feeding hole and the second signal feeding hole, a signal in the waveguide is transmitted to the microstrip line through the second signal feeding hole, the second dielectric plate, the first signal feeding hole, the first dielectric plate and the metal probe.

7. The transition between a waveguide and a microstrip of claim 6, wherein, The waveguide is in communication with the second signal feeding hole through a metal gasket.

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