E-plane terahertz waveguide filter based on a capacitive admittance inverter structure
Patent Information
- Application Number
- CN202522223411.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-09-15
- Estimated Expiration
- 2035-10-21
AI Technical Summary
[0006]然而到了太赫兹的高频段，加工误差成为制约高频滤波器的一个关键因素，传统的耦合结构对CNC加工提出了巨大挑战
宽频段：3dB带宽为390~438GHz，相对带宽为11.59%；
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Figure CN224759594U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of terahertz waveguide filters, and in particular to an E-plane terahertz waveguide filter based on a capacitive admittance inverter structure. Background Technology
[0002] Terahertz waves typically refer to electromagnetic waves with frequencies between 0.1 THz and 10 THz (wavelengths of 3 mm to 30 μm), situated between microwaves and infrared light, and were long referred to as the "terahertz gap." Terahertz waves possess many unique properties, such as penetrability, high bandwidth, and low photon energy. These characteristics make terahertz technology a promising candidate for applications in high-speed communication, imaging, spectral analysis, biosensing, and security detection.
[0003] In any wireless system, filters are indispensable passive components, their function being to select the desired frequency signal and suppress unwanted frequencies and interference. In the terahertz band, traditional planar structures such as microstrip lines and coplanar waveguides face a series of severe challenges, while metallic waveguides demonstrate irreplaceable advantages: 1. Extremely low transmission loss: When electromagnetic waves propagate inside a metallic waveguide, the loss mainly comes from conductor loss. In the terahertz high-frequency band, the skin depth is very small, but compared to the radiation loss and dielectric loss of a planar transmission line, the overall loss is still much lower. Low loss is one of the core performance indicators pursued by terahertz systems.
[0004] 2. High power capacity: The waveguide structure has a large internal space, which can transmit high power without being broken down, making it suitable for high-power terahertz source systems.
[0005] 3. High Q value (quality factor): The Q value of waveguide resonators is much higher than that of planar structures (such as microstrip resonators). A high Q value means that the filter has a steeper roll-off and lower passband insertion loss.
[0006] However, in the terahertz high-frequency band, machining errors become a key factor restricting high-frequency filters, and traditional coupling structures pose a huge challenge to CNC machining.
[0007] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create an E-plane terahertz waveguide filter based on a capacitive admittance inverter structure, making it more valuable for industrial applications. Utility Model Content
[0008] To solve the above-mentioned technical problems, the purpose of this utility model is to provide an E-plane terahertz waveguide filter based on a capacitive admittance inverter structure.
[0009] To achieve the above objectives, the present invention adopts the following technical solution: An E-plane terahertz waveguide filter based on a capacitive admittance inverter structure, including the filter body. The filter body contains a first capacitive admittance inverter, a second capacitive admittance inverter, a third capacitive admittance inverter, a fourth capacitive admittance inverter, and a fifth capacitive admittance inverter arranged in parallel. It also includes a first load and a second load, the first load being coupled to a first capacitive admittance inverter, and a fifth capacitive admittance inverter being coupled to the second load; The first, second, third, fourth, and fifth capacitive admittance inverters are interconnected through a coupling structure, forming a filter network containing at least one non-adjacent inter-stage coupling path, which causes the filter body to generate a quasi-elliptic response and form a transmission zero outside the high-frequency band.
[0010] As a further improvement of this utility model, the first load is an input port and the second load is an output port.
[0011] As a further improvement of this utility model, both the first load and the second load are standard WR-2.2 waveguides.
[0012] As a further improvement of this utility model, the 3dB bandwidth of the filter body is 390-438 GHz, and the relative bandwidth is 11.59%.
[0013] As a further improvement of this utility model, the widths of the first capacitive admittance inverter and the fifth capacitive admittance inverter are equal, the widths of the second capacitive admittance inverter, the third capacitive admittance inverter and the fourth capacitive admittance inverter are equal, and the width of the first capacitive admittance inverter is smaller than the width of the second capacitive admittance inverter.
[0014] As a further improvement of this utility model, the first capacitive admittance inverter, the second capacitive admittance inverter, the third capacitive admittance inverter, the fourth capacitive admittance inverter and the fifth capacitive admittance inverter are cascaded in sequence.
[0015] As a further improvement of this utility model, all the edges inside the filter body are machined with chamfers with a radius of 0.1mm.
[0016] By means of the above solution, this utility model has at least the following advantages: Wideband: 3dB bandwidth is 390~438GHz, with a relative bandwidth of 11.59%; High return loss: Return loss within the passband is better than -20dB; An additional zero is introduced at high frequencies, significantly improving out-of-band rejection. It has a compact structure and is easy to process.
[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the following are the preferred embodiments of this utility model and are described in detail with reference to the accompanying drawings. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the E-plane terahertz waveguide filter based on the capacitive admittance inverter structure of this utility model; Figure 2 yes Figure 1 Top view; Figure 3 This is a schematic diagram of the simulation results of the filter of this utility model.
[0020] The meanings of the labels in the figures are as follows.
[0021] First load S, second load L, first capacitive admittance inverter R1, second capacitive admittance inverter R2, third capacitive admittance inverter R3, fourth capacitive admittance inverter R4, fifth capacitive admittance inverter R5. Detailed Implementation
[0022] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.
[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0024] The first embodiment of this utility model: This embodiment relates to the design of an E-plane terahertz filter with a capacitive admittance inverter structure. Specifically, it is based on the coupling method of the capacitive admittance inverter. By using the capacitive admittance inverter, the fabrication difficulty of terahertz band devices is reduced, and the out-of-band selectivity of high frequencies is effectively improved, ultimately realizing a terahertz waveguide filter based on the capacitive admittance inverter structure.
[0025] like Figures 1-3 As shown, the E-plane terahertz waveguide filter based on the capacitive admittance inverter structure in this embodiment includes the filter body.
[0026] The first capacitive admittance inverter R1, the second capacitive admittance inverter R2, the third capacitive admittance inverter R3, the fourth capacitive admittance inverter R4, and the fifth capacitive admittance inverter R5 are arranged in parallel within the filter body.
[0027] It also includes a first load S and a second load L. The first load S is coupled to the first capacitive admittance inverter R1, and the fifth capacitive admittance inverter R5 is coupled to the second load L.
[0028] The first capacitive admittance inverter R1, the second capacitive admittance inverter R2, the third capacitive admittance inverter R3, the fourth capacitive admittance inverter R4, and the fifth capacitive admittance inverter R5 are interconnected through a coupling structure, forming a filter network containing at least one non-adjacent inter-stage coupling path, which causes the filter body to generate a quasi-elliptic response and form a transmission zero outside the high-frequency band.
[0029] The first load S is the input port, and the second load L is the output port. Both the first load S and the second load L are standard WR-2.2 waveguides.
[0030] The filter body has a 3dB bandwidth of 390-438 GHz and a relative bandwidth of 11.59%.
[0031] The widths of the first capacitive admittance inverter R1 and the fifth capacitive admittance inverter R5 are equal. The widths of the second capacitive admittance inverter R2, the third capacitive admittance inverter R3, and the fourth capacitive admittance inverter R4 are equal. The width of the first capacitive admittance inverter R1 is smaller than the width of the second capacitive admittance inverter R2.
[0032] The first capacitive admittance inverter R1, the second capacitive admittance inverter R2, the third capacitive admittance inverter R3, the fourth capacitive admittance inverter R4, and the fifth capacitive admittance inverter R5 are cascaded in sequence.
[0033] All the edges inside the filter body are machined with chamfers with a radius of 0.1mm.
[0034] This embodiment improves the coupling structure and ultimately realizes a high-performance terahertz filter through a capacitive admittance inverter structure. It proposes a high-performance terahertz filter scheme with a 400GHz, miniaturized structure, high return loss, high out-of-band rejection, and easy fabrication.
[0035] The second embodiment of this utility model: like Figures 1-3 As shown, the E-plane terahertz waveguide filter based on the capacitive admittance inverter structure in this embodiment includes a filter body, in which a first capacitive admittance inverter R1, a second capacitive admittance inverter R2, a third capacitive admittance inverter R3, a fourth capacitive admittance inverter R4, and a fifth capacitive admittance inverter R5 are cascaded sequentially along the signal transmission direction.
[0036] The input of the filter body is the first load S (standard WR-2.2 waveguide), and the output is the second load L (standard WR-2.2 waveguide). The first load S is coupled to the first capacitive admittance inverter R1, and the fifth capacitive admittance inverter R5 is coupled to the second load L.
[0037] Admittance inverter dimensions: The first capacitive admittance inverter R1 and the fifth capacitive admittance inverter R5 have the same width, the second capacitive admittance inverter R2, the third capacitive admittance inverter R3 and the fourth capacitive admittance inverter R4 have the same width, and the width of the first capacitive admittance inverter R1 is smaller than the width of the second capacitive admittance inverter R2 (the specific dimensions are optimized according to the filtering requirements of the 390~438GHz frequency band).
[0038] Manufacturing details: All metal edges inside the filter body are machined with a chamfer of 0.1mm radius to reduce the CNC machining accuracy requirements and reduce the impact of machining errors on filtering performance.
[0039] Material selection: The filter body is made of oxygen-free copper (aluminum alloy can also be used), and the inner surface is plated with a silver layer (or gold layer) to reduce conductor loss and improve Q value and power capacity.
[0040] A brief description of the working principle of this embodiment: After the terahertz signal enters the filter body from the first load S (input port), it is coupled with the first capacitive admittance inverter R1. The signal is transmitted in the first capacitive admittance inverter R1 and passes through the interstage structure containing adjacent and non-adjacent coupling paths, and then sequentially enters the second capacitive admittance inverter R2, the third capacitive admittance inverter R3, the fourth capacitive admittance inverter R4 and the fifth capacitive admittance inverter R5. During transmission, the capacitive admittance inverter and the coupling path work together to achieve frequency selection: signals in the 390~438GHz band pass through with low loss (forming a passband), and out-of-band signals are suppressed; the non-adjacent interstage coupling path causes the filter to produce a quasi-elliptic response, and the transmission zeros outside the high-frequency band are greatly enhanced to suppress high-frequency interference. Finally, the filtered signal is coupled from the fifth capacitive admittance inverter R5 to the second load L (output port), completing the filtered transmission of the terahertz signal.
[0041] The filter in this embodiment achieves a quasi-elliptic response for terahertz filters through a coupling structure using a capacitive admittance inverter. Compared to traditional magnetic or electric field coupling, the coupling structure implemented using a capacitive admittance inverter is easier to fabricate. Furthermore, the capacitive admittance inverter introduces a transmission zero outside the high-frequency band, significantly improving the filter's passband selectivity. To facilitate design and fabrication, the filter's chamfer radius is 0.1 mm.
[0042] The filter in this embodiment can be widely used in scenarios such as signal filtering for terahertz high-speed communication, clutter suppression for terahertz imaging, and spectrum selection for terahertz security detection. It combines high performance with ease of fabrication and has significant practical value.
[0043] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0044] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0045] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. An E-plane terahertz waveguide filter based on a capacitive admittance inverter structure, comprising a filter body, characterized in that: The filter body contains a first capacitive admittance inverter (R1), a second capacitive admittance inverter (R2), a third capacitive admittance inverter (R3), a fourth capacitive admittance inverter (R4), and a fifth capacitive admittance inverter (R5) arranged in parallel. It also includes a first load (S) and a second load (L), the first load (S) being coupled to a first capacitive admittance inverter (R1), and the fifth capacitive admittance inverter (R5) being coupled to the second load (L); The first capacitive admittance inverter (R1), the second capacitive admittance inverter (R2), the third capacitive admittance inverter (R3), the fourth capacitive admittance inverter (R4), and the fifth capacitive admittance inverter (R5) are interconnected through a coupling structure therebetween, forming a filter network containing at least one non-adjacent inter-stage coupling path, so that the filter body generates a quasi-elliptic response and forms a transmission zero outside the high-frequency band.
2. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, The first load (S) is an input port, and the second load (L) is an output port.
3. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, Both the first load (S) and the second load (L) are standard WR-2.2 waveguides.
4. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, The filter body has a 3dB bandwidth of 390-438 GHz and a relative bandwidth of 11.59%.
5. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, The widths of the first capacitive admittance inverter (R1) and the fifth capacitive admittance inverter (R5) are equal, the widths of the second capacitive admittance inverter (R2), the third capacitive admittance inverter (R3) and the fourth capacitive admittance inverter (R4) are equal, and the width of the first capacitive admittance inverter (R1) is smaller than the width of the second capacitive admittance inverter (R2).
6. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, The first capacitive admittance inverter (R1), the second capacitive admittance inverter (R2), the third capacitive admittance inverter (R3), the fourth capacitive admittance inverter (R4), and the fifth capacitive admittance inverter (R5) are cascaded in sequence.
7. The E-plane terahertz waveguide filter based on a capacitive admittance inverter structure as described in claim 1, characterized in that, The edges inside the filter body are all chamfered with a radius of 0.1 mm.