A compact L-band multi-channel superconducting filter receiver front-end assembly

Abstract

The present application relates to the technical field of microwave circuit, especially to a compact L-band multi-path superconducting filter receiving front-end component, which is composed of a low-pass filter, a limiter, a first radio frequency switch, a straight-through radio frequency cable, a superconducting band-pass filter group, a second radio frequency switch, a low-noise amplification circuit and a digital control attenuator, and forms the compact L-band multi-path superconducting filter receiving front-end component through the connection relationship among them, realizes the combination of normal-temperature devices and superconducting filter components, improves the power capacity of the filter, and ensures the normal work of the receiving link under the failure condition of low-temperature environment.

Description

A compact L-band multi-channel superconducting filter receiver front-end assembly Technical Field

[0001] This invention relates to the field of microwave circuit technology, and in particular to a compact L-band multi-channel superconducting filter receiver front-end assembly. Background Technology

[0002] The in-band insertion loss of the filter and the noise figure of the low-noise amplifier determine the overall noise figure of the RF receiver front-end, while the out-of-band rejection performance of the filter determines its out-of-band rejection performance. Existing RF receiver front-ends typically use coaxial cavity filters, whose surface resistance introduces insertion loss within the passband. To ensure out-of-band isolation performance, a relatively high number of filter stages is required. However, as the number of filter stages increases, the in-band insertion loss increases dramatically, necessitating a trade-off that limits the overall performance of the receiver front-end.

[0003] The development of high-temperature superconducting technology has provided a practical and effective method for developing high-performance filters. However, the power capacity of superconducting filters, as well as the requirements and guarantees for low-temperature operation, have limited their development. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a compact L-band multi-channel superconducting filter receiver front-end assembly, which combines room temperature devices and superconducting filter components to improve the power capacity of the filter, while ensuring that the receiver link can still work normally under the condition of failure in low temperature environment.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A compact L-band multi-channel superconducting filter receiver front-end assembly includes a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator.

[0007] The low-pass filter is electrically connected to one end of the first RF switch via a limiter; the other end of the first RF switch is electrically connected to one end of the second RF switch via a straight-through RF cable; the other end of the first RF switch is electrically connected to one end of the second RF switch via a superconducting bandpass filter bank; and the other end of the second RF switch is electrically connected to a digitally controlled attenuator via a low-noise amplifier circuit.

[0008] Furthermore, the low-noise amplifier circuit is positioned close to the superconducting bandpass filter bank.

[0009] Furthermore, both the first and second RF switches are single-pole eight-throw coaxial switches.

[0010] Furthermore, the superconducting filter in the superconducting bandpass filter bank adopts an asymmetric variable-pitch double-helix resonant cavity, and the input and output of the superconducting filter adopt variable impedance feed lines.

[0011] The beneficial effects of this invention are as follows:

[0012] This invention provides a compact L-band multi-channel superconducting filter receiver front-end assembly, comprising a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator. These components are interconnected to form the compact L-band multi-channel superconducting filter receiver front-end assembly, achieving a combination of room-temperature devices and superconducting filter components. This improves the power capacity of the filter while ensuring the receiver link continues to function normally even under conditions of low-temperature failure. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the structure of a compact L-band multi-channel superconducting filter receiver front-end component according to the present invention;

[0014] Figure 2 is a schematic diagram of the filter layout of the present invention;

[0015] Figure 3 is a measured curve of the performance of a single filter in a compact L-band multi-channel superconducting filter receiver front-end component of the present invention.

[0016] Label Explanation:

[0017] 1. Low-pass filter; 2. Limiter; 3. First RF switch; 4. Straight-through RF cable; 5. Superconducting bandpass filter bank; 6. Second RF switch; 7. Low-noise amplifier circuit; 8. Digitally controlled attenuator. Detailed Implementation

[0018] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0019] Please refer to Figures 1 to 3. The present invention provides a compact L-band multi-channel superconducting filter receiver front-end assembly, including a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator.

[0020] The low-pass filter is electrically connected to one end of the first RF switch via a limiter; the other end of the first RF switch is electrically connected to one end of the second RF switch via a straight-through RF cable; the other end of the first RF switch is electrically connected to one end of the second RF switch via a superconducting bandpass filter bank; and the other end of the second RF switch is electrically connected to a digitally controlled attenuator via a low-noise amplifier circuit.

[0021] As can be seen from the above description, the beneficial effects of the present invention are as follows:

[0022] This invention provides a compact L-band multi-channel superconducting filter receiver front-end assembly, comprising a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator. These components are interconnected to form the compact L-band multi-channel superconducting filter receiver front-end assembly, achieving a combination of room-temperature devices and superconducting filter components. This improves the power capacity of the filter while ensuring the receiver link continues to function normally even under conditions of low-temperature failure.

[0023] Furthermore, the low-noise amplifier circuit is positioned close to the superconducting bandpass filter bank.

[0024] As can be seen from the above description, placing the low-noise amplifier circuit close to the superconducting bandpass filter bank can effectively reduce the noise figure of the entire receiving link and improve the receiving sensitivity.

[0025] Furthermore, both the first and second RF switches are single-pole eight-throw coaxial switches.

[0026] Furthermore, the superconducting filter in the superconducting bandpass filter bank adopts an asymmetric variable-pitch double-helix resonant cavity, and the input and output of the superconducting filter adopt variable impedance feed lines.

[0027] As shown in Figures 1 to 3, Embodiment 1 of the present invention is as follows:

[0028] The present invention provides a compact L-band multi-channel superconducting filter receiver front-end assembly, comprising a low-pass filter 1, a limiter 2, a first radio frequency switch 3, a straight-through radio frequency cable 4, a superconducting bandpass filter bank 5, a second radio frequency switch 6, a low-noise amplifier circuit 7, and a digitally controlled attenuator 8.

[0029] The low-pass filter 1 is electrically connected to one end of the first RF switch 3 via the limiter 2; the other end of the first RF switch 3 is electrically connected to one end of the second RF switch 6 via the through RF cable 4; the other end of the first RF switch 3 is electrically connected to one end of the second RF switch 6 via the superconducting bandpass filter group 5; the other end of the second RF switch 6 is electrically connected to the digitally controlled attenuator 8 via the low-noise amplifier circuit 7.

[0030] In this embodiment, the low-pass filter 1 is used to suppress parasitic passband signals of the superconducting bandpass filter bank, thereby suppressing far-end interference signals. The limiter 2 protects the superconducting filter; the entire circuit can withstand a 1.0kW pulse wave, with the power reaching the superconducting filter not exceeding 13dBm. Both the first RF switch 3 and the second RF switch 6 are single-pole eight-throw coaxial switches with a FAILSAFE mode. In the no-power-supply mode, the switch keeps the first channel closed, designed as a straight-through channel. This design ensures that even if the refrigerator fails and the superconducting filter cannot enter the superconducting state, the back-end receiving path can still function normally. The remaining seven paths of the RF switches are connected to the superconducting filter, and the filtering channels are selected and controlled by the main control unit. The low-noise amplifier circuit 7 is integrated near the superconducting filter, effectively reducing the noise figure of the entire receiving link and improving receiving sensitivity. The use of the digitally controlled attenuator 8 makes the gain of the entire receiving front-end circuit controllable to adapt to different gain requirements of the back-end circuit. The superconducting filter uses an asymmetric variable-pitch double-helix resonant cavity, and the input and output adopt variable impedance feed lines. The filter layout is shown in Figure 2.

[0031] It should be noted that the low-pass filter, limiter, first RF switch, through RF cable, second RF switch, low-noise amplifier circuit and digitally controlled attenuator mentioned above are all existing products. This technical solution combines the above products and connects them to form a brand-new compact L-band multi-channel superconducting filter receiver front-end component.

[0032] Figure 3 shows the measured performance curves of a single filter. By adjusting the positions of the resonant units and feed lines, this design achieved coverage of the 960-1215 GHz frequency band using seven filters. The size of a single filter is less than 26 mm × 10 mm, achieving miniaturization while ensuring high out-of-band rejection. Only eight resonant units were used, achieving 70 dB rejection at a distance of 20 MHz from the sideband. Each resonant unit consists of two coils arranged in opposite directions. The eight resonant units are arranged in a line with spacing between them. The spacing between adjacent resonant units gradually widens towards the center, while the spacing between the two middle resonant units gradually narrows, thus improving the high out-of-band rejection.

[0033] In summary, the present invention provides a compact L-band multi-channel superconducting filter receiver front-end assembly, which consists of a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator. These components are interconnected to form the compact L-band multi-channel superconducting filter receiver front-end assembly, achieving a combination of room-temperature devices and superconducting filter components. This improves the power capacity of the filter and ensures that the receiver link can still function normally even under conditions of failure in low-temperature environments.

[0034] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A compact L-band multi-channel superconducting filter receiver front-end assembly, characterized in that, The system includes a low-pass filter, a limiter, a first RF switch, a through RF cable, a superconducting bandpass filter bank, a second RF switch, a low-noise amplifier circuit, and a digitally controlled attenuator. The low-pass filter is electrically connected to one end of the first RF switch via the limiter. The other end of the first RF switch is electrically connected to one end of the second RF switch via the through RF cable, and the other end of the first RF switch is also electrically connected to one end of the second RF switch via the superconducting bandpass filter bank. The other end of the second RF switch is electrically connected to the digitally controlled attenuator via the low-noise amplifier circuit. Both the first and second RF switches are single-pole eight-throw coaxial switches. The superconducting filter in the superconducting bandpass filter bank uses an asymmetric variable-pitch double-helix resonant cavity, and the input and output of the superconducting filter use variable impedance feed lines.

2. The compact L-band multi-channel superconducting filter receiver front-end assembly according to claim 1, characterized in that, The low-noise amplifier circuit is positioned close to the superconducting bandpass filter bank.

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