Sharing ridge-based cavity microwave coupler and millimeter wave filter integrated structure

Abstract

The invention discloses a ridge-sharing child-mother type microwave cavity coupler and millimeter wave cavity filter integrated structure, particularly relates to the technical field of wireless communication, and solves the problems that in the prior art, loss is large in microwave and millimeter wave passive device integrated design, microwave and millimeter wave devices can influence each other, and the cost is low. And independent design of the two is difficult to realize. According to the technical scheme, a ridge waveguide structure is adopted, and meanwhile, a ridge sharing scheme is utilized, so that low-loss cross-function microwave and millimeter wave frequency band device integration is realized; according to the invention, integration of different devices is realized, and the devices can be independently designed and do not interfere with each other.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to an integrated structure of a cavity microwave coupler and a millimeter wave filter based on a shared ridge. Background Art

[0002] Large-scale IoT networks are characterized by massive data throughput and high data transmission rates. Today's communication systems use microwave bands, and the demand for gigabits per second is difficult to meet, so they will move upward to millimeter waves. However, due to propagation losses in the lower atmosphere, microwaves still have advantages in wide-area coverage. Therefore, the integration of microwaves and millimeter waves will inevitably become the development direction of future wireless communications. With the continuous enrichment and diversification of application scenarios, the design complexity has also increased significantly. Therefore, integrating microwave and millimeter wave devices together not only helps to reduce size, but also effectively reduce costs.

[0003] In recent years, many attempts have been made to integrate passive devices in microwave and millimeter wave bands. For example, the integration of microwave and millimeter wave bandpass filters of filters can be realized by using structural reuse methods such as mode composite transmission lines, and microwave and millimeter wave filters can be designed separately. However, the passband loss of substrate-based filters is relatively high, which hinders their practical application. Therefore, a structural common-mode composite cavity resonator was proposed, and its cavity structure ensures low loss. However, the design of its microwave band and millimeter wave band will affect each other, making it difficult to achieve independent design. These limitations not only limit the performance optimization of the filter, but also increase the design complexity and cost. The above are all for the integration of microwave and millimeter wave of the same device (filter). With the growing demand for communications, research on the integration of different types of devices is also crucial. In summary, the integration of a low-loss, independently designable cross-functional device is still a huge technical bottleneck. Summary of the invention

[0004] Therefore, the present invention solves the technical problems in the prior art that microwave and millimeter wave passive device integration design has large losses, microwave and millimeter wave devices interfere with each other, and it is difficult to achieve independent design of the two. The present invention provides a cavity microwave coupler and millimeter wave filter integrated structure based on a shared ridge, which realizes the integration of different devices, and each device can be designed independently without interfering with each other. At the same time, the broadband microwave coupler and the flexible and adjustable millimeter wave filter designed by the present invention further improve the system performance.

[0005] The inventive concept of the present invention is: based on the superior characteristics of ridge waveguides, such as low loss, wide single-mode bandwidth and high Q value, a method of mother-child ridge sharing is further proposed. Specifically, by sharing a ridge with relatively large microwaves and cleverly laying out two or more millimeter-wave devices at its bottom, the maximum utilization of space is achieved. At the same time, the ridge of the ridge waveguide is an ideal conductor, so the design inside the ridge not only has an excellent electromagnetic shielding effect, but also enables microwave millimeter-wave devices to be independently designed to meet their respective specific design goals and performance requirements, while also greatly simplifying the integration process of devices with different functions.

[0006] The present invention provides a shared ridge mother-child microwave cavity coupler and millimeter wave cavity filter integrated structure, comprising an upper microwave cavity and a lower microwave cavity; the upper microwave cavity and the lower microwave cavity are connected by a coupling hole; a first metal ridge is arranged in the upper microwave cavity, and a second metal ridge is arranged in the lower microwave cavity; a first millimeter wave cavity filter is arranged in the first metal ridge, and a second millimeter wave cavity filter is arranged in the second metal ridge. The size of the odd and even mode impedance is adjusted by adjusting the size of the coupling hole, and the required coupling degree is further obtained.

[0007] Furthermore, the first metal ridge includes a stepped ridge, and rectangular strip metal blocks are arranged on both sides of the stepped ridge. The upper microwave cavity and the lower microwave cavity serve as the basic coupler part, and the four rectangular strip metal blocks constitute the transition part. They are symmetrically placed at the four ends of the basic coupler, and the other end is connected to the SMA, such as Figure 3 As shown. In addition, after optimization, these four stripline ridge waveguide transition structures can generate a new resonance point, thereby effectively expanding the bandwidth of the coupler. The transition part and the basic coupler part form a microwave cavity coupler.

[0008] Furthermore, the step ridge is T-shaped, and the top of the step ridge is in close contact with the upper wall surface inside the upper microwave cavity.

[0009] Furthermore, the second metal ridge is formed by mirroring the first metal ridge downward with the horizontal plane of the center point of the coupling hole as a reference.

[0010] Furthermore, the first millimeter wave cavity filter includes a dumbbell-shaped millimeter wave cavity; a millimeter wave metal ridge is arranged in the dumbbell-shaped millimeter wave cavity. A dumbbell-shaped cavity is formed by digging symmetrical rectangular blocks on the side wall. The lower cutoff frequency of the filter can be adjusted by adjusting the depth of the dumbbell-shaped cavity.

[0011] Furthermore, the dumbbell-shaped millimeter wave cavity is embedded in the stepped ridge, and its top is close to the upper surface of the stepped ridge; a plurality of rectangular grooves are continuously and uniformly etched on the millimeter wave metal ridge along the length direction, and the upper surface of the millimeter wave metal ridge forms a sawtooth shape. A deceptive surface plasmon polariton (SSPP) structure, i.e., a sawtooth structure, is adopted. It has the advantages of near-field enhancement, low loss, and flexible design, and its structure has a natural low-pass characteristic. The upper cutoff frequency of the filter can be adjusted by adjusting the parameters of the SSPP.

[0012] Furthermore, cylindrical transitions are provided at both ends of the millimeter wave metal ridge for connecting ports.

[0013] Furthermore, the second millimeter wave cavity filter is formed by mirroring the first millimeter wave cavity filter downward with the horizontal plane of the center point of the coupling hole as a reference.

[0014] Furthermore, the upper microwave cavity and the lower microwave cavity have the same shape and size.

[0015] Furthermore, a port is provided at one end of the rectangular strip metal block away from the stepped ridge; the total number of ports on the strip metal block and the millimeter wave metal ridge is eight, namely, port 1 to port 8 in FIG. 1 .

[0016] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0017] 1. The present invention provides a shared ridge mother-child microwave cavity coupler and millimeter wave cavity filter integrated structure, which adopts the ridge waveguide structure and utilizes the ridge sharing solution to achieve low-loss cross-functional microwave and millimeter wave frequency band device integration. The structure is compact, and the designed devices will not affect each other, and independent design can be achieved.

[0018] 2. The present invention provides a shared ridge mother-child microwave cavity coupler and millimeter wave cavity filter integrated structure. The microwave coupler expands the bandwidth by adding a ridge waveguide stripline structure to achieve broadband coupler performance. The millimeter wave filter flexibly adjusts the bandwidth of the coupler and the upper and lower cutoff frequencies of the filter by adjusting the dumbbell-shaped cavity structure and the SSPP structure on the ridge, i.e., the sawtooth structure, further improving the performance and flexibility of the device.

[0019] 3. The present invention provides a shared ridge mother-and-child microwave cavity coupler and millimeter-wave cavity filter integrated structure, based on the superior characteristics of ridge waveguides, such as low loss, wide single-mode bandwidth and high Q value, and further proposes a mother-and-child ridge sharing method. Specifically, by sharing a ridge with relatively large microwaves and cleverly laying out two or more millimeter-wave devices at its bottom, the maximum utilization of space is achieved. At the same time, the ridge of the ridge waveguide is an ideal conductor, so the design inside the ridge not only has an excellent electromagnetic shielding effect, but also enables the millimeter wave and millimeter wave devices to be independently designed to meet their respective specific design goals and performance requirements, while also greatly simplifying the integration process of devices with different functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0021] Figure 1a It is a schematic diagram of the overall structure of the integrated structure of the mother-child type microwave cavity coupler and the millimeter wave cavity filter with a shared ridge according to the present invention;

[0022] Figure 1b It is a cross-sectional view of the integrated structure of the mother-child type microwave cavity coupler and the millimeter wave cavity filter sharing a ridge of the present invention;

[0023] Figures 2a to 2b Dimensional drawings of embodiments provided by the present invention;

[0024] Figure 3 It is a schematic diagram of the structure of the microwave coupler of the present invention;

[0025] Figure 4 This is a diagram of the S parameter simulation results of the basic coupler of the present invention;

[0026] Figure 5 The performance result diagram of the microwave coupler of the present invention, (a) is the S parameter simulation result diagram, (b) is the amplitude imbalance and the phase difference between port 1 and port 2;

[0027] Figure 6 The structural parameters of the millimeter wave filter of the present invention are given in FIG. 21 | Influence diagram, (a) is the depth of the dumbbell-shaped cavity, (b) is the depth of the SSPP;

[0028] Figure 7 This is a diagram of the S parameter simulation results of the millimeter wave filter of the present invention.

[0029] Description of reference numerals:

[0030] 101, upper microwave cavity; 102, first metal ridge; 103, coupling hole; 104, lower microwave cavity; 105, second metal ridge; 106, dumbbell-shaped millimeter wave cavity; 107, millimeter wave metal ridge; 10201, step ridge; 10202, rectangular strip metal block; 10706, first cylindrical transition; 10107, second cylindrical transition. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0032] This embodiment provides a mother-and-child microwave cavity coupler and millimeter-wave cavity filter integrated structure with a shared ridge, as shown in FIG1 , for the microwave cavity coupler, it includes an upper microwave cavity 101, a first metal ridge 102; the stepped ridge 10201 forms a T-shaped structure, and the top of the stepped ridge 10201 is in close contact with the upper wall of the upper microwave cavity 101. Two rectangular strip metal blocks 10202 of the same size are respectively located on both sides of the stepped ridge 10201. A rectangular coupling hole 103 is placed directly below the upper microwave cavity 101, and the coupling hole 103 is located at the center of the entire structure. Similarly, there is a lower microwave cavity 104 body with the same size as the upper microwave cavity 101 directly below the coupling hole 103, and the second metal ridge 105 and the second millimeter-wave cavity filter structure in the lower microwave cavity 104 body are mirrored downward with the center horizontal plane of the coupling hole 103 as the structure in the upper microwave cavity 101.

[0033] For the millimeter wave cavity filter, it is composed of a dumbbell-shaped millimeter wave cavity 106 and a millimeter wave metal ridge 107. The dumbbell-shaped millimeter wave cavity 106 is embedded in the step ridge 10201, and its top is tightly fitted on the top surface of the step ridge 10201. The surface of the millimeter wave metal ridge 107 is continuously etched with multiple rectangular grooves along its length, forming a sawtooth-like ridge. The first cylindrical transition 10706 and the second cylindrical transition 10107 are respectively provided at both ends of the millimeter wave metal ridge 107, which are used to transitionally connect the millimeter wave SMA.

[0034] like Figure 2a and Figure 2b As shown, in this embodiment, the parameters marked in the figure are: a=63, c=91.2, w ap =30,l ap =32.2,w tr =20.4,l tr =25.8,h tr =4,h rid =10.7,h o =13.5,lrid =36,h ap =2.2,andb=14.1,a m =6,a m1 =1.5,c m =30.4,c m1 =14.2,w m =1.6,b m =3.2,h m3 =2.2,h m1 =1.7,h m4 =1.7and.Unit:mm;

[0035] After adding the transition, it is clearly observed that a resonance point is added, which significantly expands the bandwidth. The final simulation results and measurement results are shown in Figure 5 , in the frequency range of 1.7GHz to 3GHz, the return loss is greater than 20.3dB, and the amplitude imbalance is less than ±0.34dB. The phase fluctuates in the range of 90±1.9°, showing excellent performance. The millimeter wave filter is composed of a dumbbell-shaped millimeter wave cavity 106 and a millimeter wave metal ridge 107. The SSPP, i.e., the sawtooth structure, on the millimeter wave metal ridge 107 has a natural low-pass characteristic, and the ridge waveguide has a high-pass characteristic. Therefore, the ridge waveguide loaded with the SSPP structure can easily achieve bandpass characteristics. In addition, this design can adjust the upper and lower cutoff frequencies by adjusting the depth of the dumbbell-shaped cavity and the depth of the SSPP, thereby realizing the design of a bandpass filter with controllable bandwidth, such as Figure 6 The final simulation results and measurement results are shown in Figure 7 The center frequency of the millimeter wave filter is 26GHz, the 3dB fractional bandwidth is 21.2% (23.2–28.7GHz), the return loss is less than -17.5dB, and the insertion loss is less than 0.2dB.

[0036] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A shared ridge mother-child microwave cavity coupler and millimeter wave cavity filter integrated structure, characterized in that: The invention comprises an upper microwave cavity (101) and a lower microwave cavity (104); the upper microwave cavity (101) and the lower microwave cavity (104) are connected via a coupling hole (103); a first metal ridge (102) is arranged in the upper microwave cavity (101), and a second metal ridge (105) is arranged in the lower microwave cavity (104); a first millimeter wave cavity filter is arranged in the first metal ridge (102), and a second millimeter wave cavity filter is arranged in the second metal ridge (105).

2. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 1, characterized in that: The first metal ridge (102) comprises a stepped ridge (10201), and rectangular strip-shaped metal blocks (10202) are arranged on both sides of the stepped ridge (10201).

3. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 2, characterized in that: The stepped ridge (10201) is a T-shaped structure, and the top of the stepped ridge (10201) is in close contact with the upper wall surface inside the upper microwave cavity (101); the rectangular strip metal blocks (10202) are arranged on both sides of the upper steps of the T-shaped structure of the stepped ridge (10201).

4. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 3 is characterized in that: The second metal ridge (105) is formed by mirroring the first metal ridge (102) downwards with the horizontal plane of the center point of the coupling hole (3) as a reference.

5. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 4, characterized in that: The first millimeter wave cavity filter comprises a dumbbell-shaped millimeter wave cavity (106); a millimeter wave metal ridge (107) is arranged in the dumbbell-shaped millimeter wave cavity (106).

6. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 5, characterized in that: The dumbbell-shaped millimeter wave cavity (106) is embedded in the stepped ridge (10201), and its top end is in close contact with the upper surface of the stepped ridge (10201); a plurality of rectangular grooves are continuously and evenly etched on the millimeter wave metal ridge (107) along the length direction, and the rectangular grooves are evenly distributed to form a sawtooth ridge.

7. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 6, characterized in that: The two ends of the millimeter wave metal ridge (107) are respectively provided with a first cylindrical transition (10706) and a second cylindrical transition (10107) for connecting ports.

8. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 7, characterized in that: The second millimeter wave cavity filter is formed by mirroring the first millimeter wave cavity filter downward with the horizontal plane of the center point of the coupling hole (3) as a reference.

9. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 8, characterized in that: The rectangular coupling hole (103) is located directly below the upper microwave cavity (101), and the coupling hole (103) is located at the center of the entire structure; directly below the coupling hole (103) there is a cavity (104) with the same size as the upper microwave cavity (101); the upper microwave cavity (101) and the lower microwave cavity (104) have the same shape and size.

10. The integrated structure of a mother-and-child microwave cavity coupler and a millimeter-wave cavity filter with a shared ridge according to claim 9, characterized in that: The rectangular strip metal block (10202) is provided with a port at one end away from the stepped ridge (10201).

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