Waveguide transmission line for E-plane and H-plane conversion

Abstract

The invention relates to the technical field of waveguide transmission lines, and discloses an E-plane and H-plane conversion waveguide transmission line, which comprises an E-plane waveguide channel and an H-plane waveguide channel, an H-plane waveguide channel and a transition cavity; the E-plane waveguide channel, the transition cavity and the H-plane waveguide channel form a right-angle turning through cavity; according to the E-H surface conversion waveguide transmission line, the transition cavity is innovatively used for impedance matching and mode conversion, the polarization direction of electromagnetic waves can be changed by 90 degrees, the size is small, the structure is simple, machining and system integration are easy, and the E-H surface conversion waveguide transmission line has the advantages of being high in transmission coefficient and low in return loss; the design can adapt to rectangular waveguides of various sizes, and the tuning process is convenient and fast.

Description

Technical Field

[0001] The present invention relates to the technical field of waveguide transmission lines, and particularly relates to a waveguide transmission line for E-plane to H-plane conversion. Background Art

[0002] A waveguide is a common transmission line, which has a wide range of applications especially in the field of signal transmission in the millimeter-wave frequency band. According to the shape characteristics, it can be divided into rectangular waveguides, circular waveguides, ridge waveguides, etc. Compared with microstrip transmission lines, the advantages of rectangular waveguides mainly include low loss, high power capacity, high mechanical strength, good heat dissipation and excellent shielding performance.

[0003] Substrate integrated waveguide is a new type of waveguide. It covers metal on the upper and lower surfaces of the dielectric layer, and loads periodic metallized vias on both sides in the transmission direction to achieve an equivalent electric wall, simulating the transmission scenario of a rectangular waveguide. The transmission mode of the substrate integrated waveguide is the same as that of the rectangular waveguide, but the internal electromagnetic wave is transmitted in the dielectric, which will cause dielectric loss. Compared with the rectangular waveguide, the transmission efficiency of the substrate integrated waveguide is lower, and there is a certain degree of electromagnetic wave leakage problem.

[0004] Waveguide transmission lines such as rectangular waveguides can change the propagation direction by bending the trace, but cannot achieve the conversion between the E-plane and the H-plane.

[0005] In practical applications, radars using waveguide antennas or other systems applicable to waveguide transmission lines often involve the waveguide conversion between the E-plane and the H-plane due to the layout limitations of devices such as chips. The currently commonly used waveguide conversion transition structure between the E-plane and the H-plane is a twist waveguide. Its characteristic is that the wide-side and narrow-side directions at both ends are interchanged by 90°. After the electromagnetic wave is transmitted through the twist waveguide, the polarization direction changes by 90°, realizing the conversion between the E-plane and the H-plane, and at the same time its propagation direction remains unchanged. The length of the twist waveguide is relatively large, and the processing technology requirements are relatively high. In practical engineering applications, it faces problems such as difficult processing, difficult detection of dimensions, and difficult integration. Summary of the Invention

[0006] The main purpose of the present invention is to solve the technical problem that the rectangular waveguide cannot achieve the conversion between the E-plane and the H-plane in a high-integration system. A waveguide transmission line for E-plane to H-plane conversion includes: An E-plane waveguide channel; an H-plane waveguide channel and a transition cavity; The E-plane waveguide channel, the H-plane waveguide channel and the transition cavity are mutually connected; The through cavity with a right-angle turn formed by the E-plane waveguide channel, the transition cavity and the H-plane waveguide channel.

[0007] As a preferred technical solution, the E-plane waveguide channel, the H-plane waveguide channel and the transition cavity jointly form a continuous electromagnetic wave transmission path, and the electromagnetic wave transmission path is used for the polarization direction conversion from the E-plane to the H-plane.

[0008] As a preferred technical solution, the length of the wide side of the E-plane waveguide channel is A1, the length of the narrow side is B1, the length of the wide side of the H-plane waveguide channel is A2, the length of the narrow side is B2, the width of the transition cavity is W, the length is L, and the height is A1 - B2.

[0009] As a preferred technical solution, the value range of the width W of the transition cavity is [0.5B1, B1], where B1 is the length of the narrow side of the E-plane waveguide channel.

[0010] As a preferred technical solution, the value range of the length L of the transition cavity is [0.2A2, 0.5A2], where A2 is the length of the wide side of the H-plane waveguide channel.

[0011] As a preferred technical solution, the upper surface of the transition cavity is in the same plane as the lower surface of the H-plane waveguide channel, and the lower surface of the transition cavity is in the same plane as the lower surface of the E-plane waveguide channel.

[0012] As a preferred technical solution, the turning connection where the E-plane waveguide channel and the H-plane waveguide channel are connected is chamfered, and the chamfer radius is 0.01B1 to B1.

[0013] The present invention has the following beneficial effects: A waveguide transmission line for E-H plane conversion proposed by the present invention includes an E-plane waveguide channel, an H-plane waveguide channel, and a transition cavity. The E-plane waveguide channel and the H-plane waveguide channel are connected to form a through cavity with a right-angle turn. Such a structure that is simply connected without other transition devices will cause mode mismatch and result in a low transmission coefficient. The present invention is provided with a transition cavity at the right-angle turn. When the electromagnetic wave transmitted in the E-plane or H-plane waveguide channel passes through the transition cavity, its electric field vector will deflect. By reasonably designing the width and length of the transition cavity, the electric field vector of the electromagnetic wave can deflect by 90° after passing through the right-angle turn, completing the E-H plane conversion of the electromagnetic wave, and having a high transmission coefficient and low return loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the external structure of the waveguide transmission line for E-H plane conversion proposed by the present invention; Figure 2 is a schematic diagram of the internal cavity structure of the waveguide transmission line for E-H plane conversion proposed by the present invention; Figure 3 is a top view of the internal cavity structure of the waveguide transmission line for E-H plane conversion proposed by the present invention; Figure 4 is a side view of the internal cavity structure of the waveguide transmission line for E-H plane conversion proposed by the present invention; Figure 5 are the simulation results of the transmission loss of the waveguide transmission line for E-H plane conversion proposed by the present invention; Figure 6 are the simulation results of the reflection coefficient of the waveguide transmission line for E-H plane conversion proposed by the present invention. Detailed implementation manners

[0015] In the description of the present invention, it should be understood that the terms indicating the orientation or positional relationship are all based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the indicated elements must have a specific orientation, be constructed or operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0016] A waveguide transmission line for E-plane to H-plane conversion includes: an E-plane waveguide channel 1; an H-plane waveguide channel 2 and a transition cavity 3; the E-plane waveguide channel 1, the H-plane waveguide channel 2 and the transition cavity 3 are interconnected; The through cavity with a right-angle turn formed by the E-plane waveguide channel, the transition cavity, and the H-plane waveguide channel.

[0017] As Figures 1-4 shown, Embodiment 1 of the present invention provides a waveguide transmission line for E-plane to H-plane conversion. The waveguide transmission line includes an E-plane waveguide channel 1, an H-plane waveguide channel 2 and a transition cavity 3. The E-plane waveguide channel 1 and the H-plane waveguide channel 2 are connected to form a through cavity with a right-angle turn. At the turning connection where the E-plane waveguide channel 1 and the H-plane waveguide channel 2 are connected, there are an outer turning surface 22, an inner turning surface 23 and a transition cavity 3. The upper surface of the transition cavity 3 is connected to the lower surface of the H-plane waveguide channel 2. The lower surface of the transition cavity is in the same plane as the lower surface 12 of the E-plane waveguide channel. The transition cavity is connected to the outer turning surface 22, and the transition cavity is interconnected with the E-plane waveguide channel and the H-plane waveguide channel to form a through cavity.

[0018] Specifically, the function of the transition cavity is impedance matching and mode conversion. When electromagnetic waves pass through the transition cavity, the electric field vector will rotate. By reasonably designing the width and length of the transition cavity, impedance matching between the E-plane waveguide channel 1 and the H-plane waveguide channel 2 can be achieved. Based on the through cavity with a right-angle turn formed by the connection of the E-plane waveguide channel and the H-plane waveguide channel and the transition cavity, the polarization direction of the electromagnetic waves entering from the E-plane or H-plane waveguide channel can be changed by 90°, completing polarization conversion.

[0019] Specifically, the upper surface 11 of the E-plane waveguide channel 1 and the upper surface 21 of the H-plane waveguide channel 2 are in the same plane. The wide-side length of the E-plane waveguide channel 1 is A1, and the narrow-side length is B1. The wide-side length of the H-plane waveguide channel 2 is A2, and the narrow-side length is B2.

[0020] Specifically, the transition cavity 3 extends from the plane where one wide side of the E-plane waveguide channel 1 is located along the electromagnetic wave transmission direction in the H-plane waveguide channel 2, and the extension direction is away from the E-plane waveguide channel 1.

[0021] Specifically, the width of the transition cavity 3 is W, the length is L, and the height is A1 - B2. Adjusting the width W and length L of the transition cavity can change the characteristic impedance of the waveguide transmission line for E-H plane conversion proposed by the present invention, thereby adjusting the matching condition of the waveguide transmission line to change the transmission coefficient. The value range of W is 0.5B1 to B1, and the value range of L is 0.2A2 to 0.5A2.

[0022] More specifically, in this embodiment, A1 is set to 2.54 mm, B1 is set to 1.27 mm, A2 is set to 3.1 mm, B1 is set to 1.55 mm, W is set to 1.1 mm, and L is set to 1 mm.

[0023] Specifically, during actual processing and manufacturing, the turning connection formed by the connection of the E-plane waveguide channel 1 and the H-plane waveguide channel 2 can be chamfered according to process requirements, and the chamfer radius is 0.01B1 to B1.

[0024] Working principle: When electromagnetic waves enter the transition cavity from the E-plane waveguide: Electric field redirection: The width and length of the transition cavity adjust the phase delay of the electromagnetic waves, causing the electric field direction to gradually rotate from perpendicular to the wide side to parallel to the wide side.

[0025] Mode matching: The height compensates for the size difference between the two ends of the waveguide, ensuring the continuity of the electromagnetic field distribution and suppressing the generation of higher-order modes.

[0026] Impedance matching: Optimize the waveguide characteristic impedance by the size range of the transition cavity: Adjusting W and L of the transition cavity can improve the impedance mismatch problem between the two sides of the waveguide, thereby reducing the reflection loss.

[0027] Figure 5 is the simulation result of the transmission loss of the waveguide transmission line for E-H plane conversion in the embodiment proposed by the present invention. It can be seen from the figure that within the working frequency band of 76 - 79 GHz, the transmission loss is less than 0.1 dB.

[0028] Figure 6 is the simulation result of the reflection coefficient of the waveguide transmission line for E-H plane conversion in the embodiment proposed by the present invention. It can be seen from the figure that within the working frequency band of 76 - 79 GHz, the reflection coefficient is less than -20 dB, and at the center frequency point of 77.5 GHz, the reflection coefficient can reach -48 dB.

[0029] The present invention provides a waveguide transmission line for E-H plane conversion. By innovatively using a transition cavity for impedance matching and mode conversion, it can change the polarization direction of electromagnetic waves by 90°, and has the advantages of small volume, simple structure, easy processing and system integration, high transmission coefficient and low return loss. This design can adapt to rectangular waveguides of various sizes, and the tuning process is convenient and fast.

[0030] As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A waveguide transmission line for E-plane to H-plane conversion, characterized in that Comprising: E-plane waveguide channel (1); H-plane waveguide channel (2) and transition cavity (3); The E-plane waveguide channel (1), H-plane waveguide channel (2) and transition cavity (3) are interconnected; A through cavity with a right-angle turn formed by the E-plane waveguide channel (1), transition cavity (3) and H-plane waveguide channel (2).

2. The waveguide transmission line for E-plane to H-plane conversion according to claim 1, characterized in that, The E-plane waveguide channel (1), H-plane waveguide channel (2) and transition cavity (3) jointly form a continuous electromagnetic wave transmission path for the polarization direction conversion from the E-plane to the H-plane.

3. The waveguide transmission line for E-plane to H-plane conversion according to claim 1, wherein The wide-side length of the E-plane waveguide channel (1) is A1, the narrow-side length is B1, the wide-side length of the H-plane waveguide channel (2) is A2, the narrow-side length is B2, the width of the transition cavity (3) is W, the length is L, and the height is A1 - B2.

4. The waveguide transmission line for E-plane to H-plane conversion according to claim 3, wherein The value range of the width W of the transition cavity (3) is [0.5B1, B1].

5. The waveguide transmission line for E-plane to H-plane conversion according to claim 4, wherein The value range of the length L of the transition cavity (3) is [0.2A2, 0.5A2].

6. The waveguide transmission line for E-plane to H-plane conversion according to claim 1, characterized in that, The upper surface of the transition cavity (3) is in the same plane as the lower surface of the H-plane waveguide channel (2), and the lower surface of the transition cavity (3) is in the same plane as the lower surface of the E-plane waveguide channel (1).

7. The waveguide transmission line for E-plane to H-plane conversion according to claim 1, wherein The turning connection formed by the connection of the E-plane waveguide channel (1) and the H-plane waveguide channel (2) is chamfered, and the chamfer radius is 0.01B1 to B1.

8. The waveguide transmission line for E-plane to H-plane conversion according to claim 1, characterized in that, The upper surface (11) of the E-plane waveguide channel (1) and the upper surface (21) of the H-plane waveguide channel (2) are in the same plane.

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