A ridge waveguide coupler integrating tight and weak coupling in one

Abstract

This invention provides an integrated ridge waveguide coupler combining tight and weak coupling, relating to the field of wireless communication technology. The ridge waveguide introduces a metal ridge within a rectangular waveguide, resulting in distinct electromagnetic fields between the ridge and its wide walls, with a strong electromagnetic field between the ridge and the wide walls, and a weak electromagnetic field on either side of the ridge. Utilizing this characteristic of varying electromagnetic field strength in different regions of the ridge waveguide, coupling holes are created in different areas of the wide walls to construct an integrated device with both tight and weak coupling functions, where strong mutual interference between the tight and weak couplings does not occur. This application innovatively integrates the traditionally separately designed, manufactured, and cascaded tight and weak couplers into a single stacked ridge waveguide structure. By creating coupling holes on different common wide walls to achieve coupling with different characteristics, connection losses are significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to a ridge waveguide coupler that integrates tight and weak coupling. Background Technology

[0002] In the context of the evolution from 5G to 6G, more stringent requirements have been placed on directional couplers, a type of passive radio frequency device, such as compact size, high power capacity, low loss, and wide bandwidth. Currently, couplers based on traditional rectangular waveguides suffer from bottlenecks due to the characteristics of rectangular waveguides, including limited bandwidth and excessive size. Ridge waveguides, by introducing a longitudinally protruding "ridge" structure, can significantly reduce the cutoff frequency of the dominant mode, thereby achieving miniaturization of the structure at the same operating frequency. This is crucial for highly integrated base stations and terminal equipment. Ridge waveguide structures have a wider single-mode operating bandwidth, enabling them to easily meet the wider spectrum requirements of future wireless communication systems. Tight couplers are mainly implemented using large-aperture coupling. Weak couplers are implemented by adjusting the size of the aperture to adjust the performance of the weak coupling and achieve low-fluctuation coupling.

[0003] However, all these technical approaches design and manufacture tight and weak couplers as independent devices. Cascading these independent devices in a system inevitably introduces excessive insertion loss and results in a large size.

[0004] Therefore, integrating tightly coupled and loosely coupled functions into one system is the way to overcome the above-mentioned defects and meet the dual development requirements of next-generation communication systems for high performance and high integration. Summary of the Invention

[0005] Therefore, this invention provides a ridge waveguide coupler that integrates tight and weak coupling to solve the technical problems of large system size, high insertion loss, and insufficient integration caused by designing, manufacturing, and cascading the tight and weak couplers as independent devices in existing ridge waveguide couplers. The ridge waveguide coupler that integrates tight and weak coupling in this invention combines the two functions into one, while retaining the inherent advantages of ridge waveguides such as wide bandwidth, miniaturization, and low loss, and reducing the additional losses introduced by cascading, thereby achieving high performance and high integration of the device in a compact size.

[0006] The present invention provides a ridge waveguide coupler that integrates tight and weak coupling, the structure of which includes: cavity one, cavity two and cavity three arranged vertically; cavity one, cavity two and cavity three are respectively provided with a weakly coupled sub-waveguide, a main waveguide and a tightly coupled sub-waveguide.

[0007] Furthermore, cavity one and cavity two are connected via a weak coupling hole. Cavity two and cavity three are connected via a tight coupling hole.

[0008] Furthermore, the weakly coupled sub-waveguide includes a main ridge and transition ridges extending from both ends of the main ridge; the upper surface of the main ridge is flush with the upper surface of the transition ridge.

[0009] Furthermore, the tightly coupled sub-waveguide includes a second main ridge and transition ridges extending from both ends of the second main ridge; the upper surface of the second main ridge has an upwardly extending protrusion; by changing the electric and magnetic field distribution of the coupler through the protrusion, the odd and even mode impedances of the coupler are adjusted to a preset target value, thereby achieving the required coupling degree of 3 dB. Specifically, by adjusting the geometric dimensions (height and width) of the protrusion, the impedances of the odd and even modes can be changed synergistically, thereby achieving the effect of adjusting the coupling degree; the following formula is used to express the correspondence between odd and even mode impedances and coupling degree. ;

[0010] C-coupling degree, Z e and Z o These are the odd-mode impedance and the even-mode impedance, respectively.

[0011] Furthermore, the main waveguide structure is consistent with the tightly coupled sub-waveguide structure, and the center point of its tightly coupled hole is vertically symmetrical with that of the tightly coupled sub-waveguide structure.

[0012] Furthermore, each of the three cavities is provided with a transition shaft at both ends that connects to the weakly coupled sub-waveguide, the main waveguide, and the tightly coupled sub-waveguide, respectively.

[0013] Furthermore, a total of six weak coupling holes are provided, which are divided into three groups and arranged parallel to each other along the Z-axis between cavity one and cavity two.

[0014] Furthermore, the lower surface of the weakly coupled sub-waveguide is attached to the bottom wall of the cavity; the upper surface of the main waveguide and the lower surface of the tightly coupled sub-waveguide are attached to the top wall of the cavity and the bottom wall of the cavity, respectively.

[0015] The present invention has the following advantages over the prior art:

[0016] 1. The ridge waveguide of this invention introduces a metal ridge into a rectangular waveguide, resulting in different electromagnetic fields on each ridge. The electromagnetic field is strong between the ridge and the wide wall of the ridge waveguide, and weak in the regions on both sides of the ridge. Utilizing the characteristic of different electromagnetic field strengths in different regions of the ridge waveguide, coupling holes are opened in different regions of the wide wall of the ridge waveguide to construct an integrated device with tight coupling and weak coupling functions, wherein there is no strong mutual interference between the tight and weak couplings.

[0017] 2. This invention features an integrated structure, innovatively integrating tight couplers and weak couplers—traditionally requiring independent design, manufacturing, and cascading—into a single stacked ridge waveguide structure. By opening coupling apertures on different common wide walls to achieve coupling with different characteristics, connection losses are significantly reduced. Because the two different coupling aperture regions are distinct, tight coupling and weak coupling can be independently designed and optimized. In weak coupling, by combining the reduction of coupling aperture size with local adjustments to ridge waveguide geometry (such as ridge height), high stability and low fluctuations in weak coupling output over a wide bandwidth are achieved.

[0018] 3. This invention integrates 3 dB and 40 dB couplers. The integrated coupler operates within a frequency range of 1.7 GHz to 3 GHz (relative fractional bandwidth: 55.3%) with a return loss greater than 20.3 dB, an amplitude imbalance of less than ±0.34 dB in the 3 dB coupling section, and phase fluctuations within 90 ± 1.9°. Insertion loss is less than 0.1 dB. The coupling ripple in the 40 dB coupling section is less than ±0.5 dB, and isolation is greater than 50 dB. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall main structure of the present invention.

[0021] Figure 2 This is a schematic diagram of the overall three-dimensional structure of the present invention.

[0022] Figure 3 The diagram shows the mutual influence of the integrated couplers of this invention: (a) the effect of weak coupling on tight coupling, and (b) the effect of tight coupling on weak coupling.

[0023] Figure 4 The simulation results of this invention are shown in the diagrams: (a) S-parameters, and (b) phase difference.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Cavity 2; 2. Cavity 3; 3. Cavity 1; 4. Main Ridge 1; 5. Main Ridge 2; 6. Transition Ridge 2; 7. Transition Ridge 1; 8. Tight Coupling Aperture; 9. Weak Coupling Aperture; 10. Main Waveguide. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides a ridge waveguide coupler that integrates tight and weak coupling, and its structure is as follows: Figures 1 to 2 As shown, ridge waveguide 3, ridge waveguide 1, and ridge waveguide 2 are stacked sequentially, representing the weakly coupled sub-waveguide, main waveguide 10, and tightly coupled sub-waveguide, respectively. The cavities of ridge waveguide 3, ridge waveguide 1, and ridge waveguide 2 are cavity 1 (3), cavity 2 (1), and cavity 3 (2), respectively. Their common wide wall is connected by tightly coupled holes 8 and weakly coupled holes 9 to achieve different couplings. To smoothly transition to SMA, transition ridge 2 (6) and transition ridge 1 (7) are added on both sides of the ridge for better matching. The outer surface of the ridge waveguide cavity needs to be clad with aluminum alloy, and the structures of main ridge 1 (4), main ridge 2 (5), transition ridge 2 (6), and transition ridge 1 (7) are also made of aluminum alloy. Cavities 2 (1), 3 (2), and 3 (3) are air, as are the coupling holes, which can be achieved by etching the same shape into the aluminum alloy.

[0029] This structure employs a three-layer stacked ridge waveguide architecture: a main waveguide, a tightly coupled sub-waveguide, and a weakly coupled sub-waveguide. The three single-ridge waveguide structures are connected by wide walls. Tight coupling is achieved by etching large rectangular holes on the wide walls of the main waveguide and the tightly coupled sub-waveguide, while weak coupling is achieved by etching three consecutive pairs of long slots on the main waveguide and the weakly coupled sub-waveguide. The two types of coupling holes are placed in different positions based on the electromagnetic field distribution of the ridge waveguides. The large rectangular hole is located on the wide wall directly below the ridge of the main waveguide where the electromagnetic field is concentrated (tight coupling hole 8), while the continuous long slots are located on the upper wide walls on both sides of the ridge of the main waveguide where the electromagnetic field is slightly weaker (weak coupling holes 9). The large coupling holes allow the electromagnetic field energy in the main waveguide to efficiently and directly couple to the sub-waveguide through the wide walls. By adjusting the size and spacing of the holes, the coupling strength can be precisely controlled to meet power distribution / combining requirements. The continuous long slots achieve a stable and relatively low coupling strength (40 dB). This design ensures flat coupling across a wide frequency band, making it suitable for signal sampling and monitoring.

[0030] Electromagnetic waves are input from the main waveguide. When the signal is transmitted to the large, strongly coupled aperture, most of the energy is directly coupled to the tightly coupled sub-waveguide through the aperture, forming the main output of the coupled port and realizing the power distribution function. A small portion of the energy on both sides of the ridge is coupled to the weakly coupled sub-waveguide. Due to the weakening of the electromagnetic field on both sides caused by the insertion of the ridge structure, only a small portion of the energy is coupled to the weakly coupled sub-waveguide through the aforementioned aperture, forming a weakly coupled signal used for monitoring. The through signal in the main waveguide and the coupled signal in the sub-waveguide are ultimately output from different output terminals. The entire energy coupling process is completed in a device with a stack of ridge waveguides, thereby minimizing losses; the port is formed by a transition axis, such as... Figure 2 In the diagram, port 1 is the input terminal, receiving electromagnetic waves; port 2 is the through terminal, receiving the remaining output energy from the main waveguide; port 3 is the tightly coupled coupling terminal, receiving the energy output from the tightly coupled portion; port 4 is the tightly coupled isolation terminal, from which very little energy is output, ensuring high directivity of the tightly coupled connection; port 5 is the weakly coupled coupling terminal, receiving the energy output from the weakly coupled portion; and port 6 is the weakly coupled isolation terminal, from which very little energy is output, ensuring high directivity of the weakly coupled connection.

[0031] Example 2

[0032] Based on Example 1, this embodiment simulates a ridge waveguide coupler that integrates tight and weak coupling using the following parameters.

[0033] Parameters involved: a = 63, c = 91.2, b = 14.1, w t = 28, w t1 = 8.2, w s = 30, w a = 5, h2 = 13.5, h1 = 10.7, h t2 = 4.2, t a = 2, l2 = 58.4, l t2 = 18.7, l a = 19.5, t s = 2.2,h t1 = 4, l s = 32.2, l t1 = 25.8.and. Unit: mm.

[0034] Figure 3 (a) represents a comparison of the performance parameters of a separately designed tight coupler with those of an integrated architecture. It is noteworthy that the performance of the tight coupler remains unchanged between its independent design and integrated configuration. For the weak coupler portion, such as... Figure 3(b) A small deviation of approximately 1.7 dB was observed between its standalone weak coupler and the integrated weak coupler. However, this is acceptable for the design given the inherent sensitivity of weak coupling. Furthermore, targeted parameter sweeps were conducted on key design parameters (e.g., l) a w a and x a Fine-tuning can effectively compensate for this deviation, thereby achieving the desired performance in the final integrated coupler. Figure 3 This indicates that the integrated structure has good independence and minimal mutual influence between the two components.

[0035] like Figure 4 As shown, the center frequency is 2.35 GHz, and the FBW is 55.3% (1.7-3 GHz). Within this range, the tight coupling return loss (S... 11 The isolation (S) is better than 21.3 dB. 41 It is better than 21.3 dB. Its amplitude imbalance (|S 21 -S 31 |) Better than ±0.34 dB. For the weakly coupled portion, the coupling fluctuation is better than ±0.5 dB. Its directivity is better than 10 dB. Meanwhile... Figure 4 As shown in (b), the phase difference between port 2 and port 3 is within the range of 88.1°-91.8°, and the phase is stable.

[0036] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A ridge waveguide coupler integrating tight and weak coupling, characterized in that, include: Cavity 1 (3), Cavity 2 (1) and Cavity 3 (2) are arranged vertically; Cavity 1 (3), Cavity 2 (1) and Cavity 3 (2) are respectively provided with weakly coupled sub-waveguide, main waveguide (10) and tightly coupled sub-waveguide.

2. The ridge waveguide coupler integrating tight and weak coupling as described in claim 1, characterized in that, The cavity one (3) and the cavity two (1) are connected by a weak coupling hole (9).

3. The ridge waveguide coupler integrating tight and weak coupling as described in claim 2, characterized in that, The second cavity (1) and the third cavity (2) are connected by a tight coupling hole (8).

4. The ridge waveguide coupler integrating tight and weak coupling as described in claim 3, characterized in that, The weakly coupled sub-waveguide includes a main ridge (4) and a transition ridge (7) extending from both ends of the main ridge (4); the upper surface of the main ridge (4) is flush with the upper surface of the transition ridge (7).

5. The ridge waveguide coupler integrating tight and weak coupling as described in claim 4, characterized in that, The tightly coupled subwaveguide includes a main ridge (5) and transition ridges (6) extending from both ends of the main ridge (5); the upper surface of the main ridge (5) is provided with an upwardly extending protrusion.

6. The ridge waveguide coupler integrating tight and weak coupling as described in claim 5, characterized in that, The main waveguide (10) structure is consistent with the tightly coupled sub-waveguide structure, and it is symmetrical about the tightly coupled sub-waveguide structure along the center point of the tightly coupled hole (8).

7. The ridge waveguide coupler integrating tight and weak coupling as described in claim 6, characterized in that, The first cavity (3), the second cavity (1), and the third cavity (2) are each provided with a transition shaft that connects to the weakly coupled sub-waveguide, the main waveguide (10), and the tightly coupled sub-waveguide, respectively.

8. The ridge waveguide coupler integrating tight and weak coupling as described in claim 7, characterized in that, There are six weak coupling holes (9) in total, which are divided into three groups and arranged in parallel along the Z-axis between cavity one (3) and cavity two (1).

9. The ridge waveguide coupler integrating tight and weak coupling as described in claim 8, characterized in that, The lower surface of the weakly coupled subwaveguide is attached to the bottom wall of cavity 1 (3).

10. The ridge waveguide coupler integrating tight and weak coupling as described in claim 9, characterized in that, The upper surface of the main waveguide (10) and the lower surface of the tightly coupled sub-waveguide are respectively attached to the top wall of cavity two (1) and the bottom wall of cavity three (2).

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