A high Q value wide frequency range tunable superconducting wave trap

Abstract

The application relates to a high-Q-value wide-frequency-range tunable superconducting wave trap, which comprises a wave trap circuit; the wave trap circuit comprises a main transmission line and a superconducting resonator; the superconducting resonator is loaded with a superconducting interdigital capacitor and at least two variable capacitance tubes. The tunable superconducting wave trap can solve the defects in the prior art, by means of parallel loading of multiple variable capacitance tubes and adoption of a superconducting interdigital capacitor as a direct-current capacitor, the tuning range of the wave trap can be increased, the Q value of the overall circuit can be improved, and the performance of the tunable wave trap is improved.

Description

Technical Field

[0001] This invention relates to the field of microwave radio frequency communication technology, and specifically to a high-Q wide-frequency tunable superconducting notch filter. Background Technology

[0002] A tunable superconducting notch filter is a superconducting microwave device whose center frequency or bandwidth can be changed drastically. Tunable superconducting notch filters, made using superconducting films, not only offer advantages such as high sensitivity, strong anti-interference capability, and small size and weight, but also significantly reduce system size and increase system stability when replacing switched notch filter arrays with tunable superconducting notch filters. Furthermore, because their frequency can be continuously varied, they increase the receiver's frequency band coverage and enhance compatibility.

[0003] Existing tunable superconducting notch filters are generally implemented by loading a gallium arsenide varactor diode onto the resonator. Furthermore, to increase the tuning range of the notch filter and prevent short circuits in the resonator, a DC blocking capacitor is typically added to the resonator. However, because the gallium arsenide varactor diode and the DC blocking capacitor have low Q values, the overall circuit Q value is also low. Summary of the Invention

[0004] The purpose of this invention is to provide a high-Q wide-frequency-domain tunable superconducting notch filter. This tunable superconducting notch filter can overcome the shortcomings of the prior art. By loading multiple varactor tubes in parallel and using superconducting interdigitated capacitors as DC blocking capacitors, not only can the tuning range of the notch filter be increased, but the Q value of the overall circuit can also be improved, thereby improving the performance of the tunable notch filter.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-Q wide-frequency-domain tunable superconducting notch filter includes a notch filter circuit; the notch filter circuit includes a main transmission line and a superconducting resonator; the superconducting resonator is loaded with a superconducting interdigitated capacitor and at least two varactor diodes.

[0007] Furthermore, the high-Q wide-frequency-domain tunable superconducting notch filter also includes a notch filter cavity; the notch filter circuit is installed in the notch filter cavity; the notch filter cavity is provided with an input connector and an output connector.

[0008] Furthermore, the main transmission line has an input terminal and an output terminal at its two ends respectively; the input terminal is connected to the input connector; and the output terminal is connected to the output connector.

[0009] Furthermore, the varactor tube is connected in parallel on the superconducting resonator.

[0010] Furthermore, the main transmission line, the superconducting resonator, and the superconducting interdigitated capacitor are all in microstrip form, and all three are made of superconducting materials.

[0011] Furthermore, the varactor tube is a gallium arsenide varactor tube.

[0012] Furthermore, both the input connector and the output connector are any one or more combinations of SMA, N, and DIN.

[0013] Furthermore, the superconducting resonator includes a positive terminal, a negative terminal, a first current-limiting resistor, and a second current-limiting resistor; the positive terminal is connected to one end of the superconducting interdigitated capacitor via the first current-limiting resistor, and the other end of the superconducting interdigitated capacitor is connected to the negative terminal via the second current-limiting resistor; one end of the varactor is connected to the node between the first current-limiting resistor and the superconducting interdigitated capacitor, and the other end of the varactor is connected to the node between the second current-limiting resistor and the superconducting interdigitated capacitor; all the varactors are connected in parallel.

[0014] Furthermore, the notch filter cavity is provided with a through-hole capacitor; the positive power terminal and the negative power terminal are respectively connected to the power supply through a through-hole capacitor.

[0015] Furthermore, the main transmission line includes several first transmission sections arranged in parallel and several second transmission sections connecting the several first transmission sections into a line.

[0016] Furthermore, the number of superconducting resonators is one or more; the superconducting resonators are located between two adjacent first transmission sections.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] (1) This invention provides a high-Q superconducting notch filter that achieves a center frequency jump over a wide frequency range. By loading two or more gallium arsenide varactor diodes onto the resonator, the Q value of the circuit can be effectively improved. This invention can filter out interference signals generated in the signal path during the operation of a microwave communication system.

[0019] (2) The tunable superconducting notch filter of the present invention uses a superconducting interdigitated capacitor as a DC blocking capacitor, which can not only increase the tuning range of the notch filter, but also improve the Q value of the overall circuit, thus better improving the performance of the notch filter and related systems. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the high-Q wide-frequency-domain tunable superconducting notch filter in this invention;

[0021] Figure 2 This is a schematic diagram of the notch filter cavity in this invention.

[0022] in:

[0023] 1. Input terminal, 2. Output terminal, 3. Main transmission line, 4. Superconducting resonator, 5. Superconducting interdigitated capacitor, 6. Varactor tube, 7. Negative power-on terminal, 8. Current-limiting resistor II, 9. Notch filter circuit, 10. Input connector, 11. Output connector, 12. Feedthrough capacitor, 13. Notch filter cavity, 14. Positive power-on terminal, 15. Current-limiting resistor I, 16. First transmission section, 17. Second transmission section. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings:

[0025] like Figure 1 and Figure 2 The diagram illustrates a high-Q, wide-frequency-domain tunable superconducting notch filter, comprising a notch filter circuit 9 and a notch filter cavity 13. The notch filter circuit 9 is installed within the notch filter cavity 13; the notch filter cavity 13 is provided with an input connector 10 and an output connector 11. The notch filter cavity 13 serves as magnetic shielding for the superconducting circuit, facilitating cooling and connection to other devices.

[0026] like Figure 1 As shown, the notch filter circuit 9 includes a main transmission line 3 and a superconducting resonator 4; the superconducting resonator 4 is loaded with a superconducting interdigitated capacitor 5 and at least two varactor diodes 6. The superconducting interdigitated capacitor 5 serves as a DC blocking capacitor. The varactor diodes 6 are the tuning elements of the adjustable notch filter, and are loaded by welding or bonding. The superconducting resonator 4 loaded with the superconducting interdigitated capacitor 5 forms the main functional circuit of the notch filter. Loading two or more varactor diodes in parallel on the superconducting resonator, while using superconducting interdigitated capacitors as DC blocking capacitors, can effectively improve the Q value and tuning range of the overall circuit. When the loading voltage of the varactor diodes 6 is changed, the resonant frequency of the resonator can be changed, thereby realizing the tunability of the notch filter frequency band of the circuit.

[0027] Furthermore, the main transmission line 3 is provided with an input terminal 1 and an output terminal 2 at its two ends respectively; the input terminal 1 is welded to the input connector 10; and the output terminal 2 is welded to the output connector 11.

[0028] Furthermore, the varactor tube 6 is connected in parallel on the superconducting resonator 4.

[0029] Furthermore, the main transmission line 3, the superconducting resonator 4, and the superconducting interdigitated capacitor 5 are all in microstrip form, and all three are made of superconducting materials, preferably YBCO. The superconducting microstrip circuit facilitates the assembly of varactor diodes.

[0030] Furthermore, the varactor 6 is a gallium arsenide varactor.

[0031] Furthermore, the input connector 10 and the output connector 11 are any one or more combinations of SMA, N, and DIN.

[0032] Furthermore, the superconducting resonator 4 includes a positive terminal 14, a negative terminal 7, a first current-limiting resistor 15, and a second current-limiting resistor 8. The positive terminal 14 is connected to one end of the superconducting intercalation capacitor 5 via the first current-limiting resistor 15, and the other end of the superconducting intercalation capacitor 5 is connected to the negative terminal 7 via the second current-limiting resistor 8. One end of the varactor tube 6 is connected to the node between the first current-limiting resistor 15 and the superconducting intercalation capacitor 5, and the other end of the varactor tube 6 is connected to the node between the second current-limiting resistor 8 and the superconducting intercalation capacitor 5. All the varactor tubes 6 are connected in parallel. The first current-limiting resistor 15 and the second current-limiting resistor 8 are used to limit the current of the external power supply to prevent the current from exceeding the threshold of the varactor tube 6.

[0033] Furthermore, the notch filter cavity 13 is equipped with a feedthrough capacitor 12; the positive terminal 14 and the negative terminal 7 are respectively connected to the power supply through a feedthrough capacitor 12. The external power supply applies voltage to the varactor tube through the feedthrough capacitor and the power supply terminal, which is used to adjust the capacitance value of the varactor tube. The external power supply is conveniently powered through the feedthrough capacitor.

[0034] Furthermore, the main transmission line 3 includes a plurality of first transmission sections 16 arranged in parallel and a plurality of second transmission sections 17 connecting the plurality of first transmission sections 16 into a line.

[0035] Furthermore, the number of superconducting resonators 4 is one or more; the superconducting resonators 4 are located between two adjacent first transmission sections 16.

[0036] The working principle of this invention is as follows:

[0037] The capacitance of a varactor diode changes with the applied voltage. When a varactor diode is applied to a resonator, the resonator's frequency also changes with the applied voltage, thus altering the notch filter's frequency band and enabling tunability. Applying two or more varactor diodes in parallel enhances the energy storage efficiency of the resonant circuit over one cycle, thereby increasing the Q value. Superconducting interdigitated capacitors have extremely low microwave losses, reducing the energy dissipation constraints required for energy storage and further improving the circuit's Q value. Furthermore, DC blocking capacitors increase the change in the resonant frequency of the resonator for the same voltage change, thus expanding the notch filter's tuning range.

[0038] The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-Q, wide-frequency-domain tunable superconducting notch filter, characterized in that, The system includes a notch filter circuit; the notch filter circuit includes a main transmission line and a superconducting resonator; the superconducting resonator is loaded with a superconducting interdigitated capacitor and at least two varactor diodes; the varactor diodes are connected in parallel on the superconducting resonator; the varactor diodes are gallium arsenide varactor diodes; the superconducting resonator includes a positive terminal, a negative terminal, a first current-limiting resistor, and a second current-limiting resistor; the positive terminal is connected to one end of the superconducting interdigitated capacitor via the first current-limiting resistor, and the other end of the superconducting interdigitated capacitor is connected to the negative terminal via the second current-limiting resistor; one end of each varactor diode is connected to the node between the first current-limiting resistor and the superconducting interdigitated capacitor, and the other end of each varactor diode is connected to the node between the second current-limiting resistor and the superconducting interdigitated capacitor; all the varactor diodes are connected in parallel.

2. The high-Q wide-frequency-domain tunable superconducting notch filter according to claim 1, characterized in that, It also includes a notch filter cavity; the notch filter circuit is installed in the notch filter cavity; the notch filter cavity is provided with an input connector and an output connector.

3. A high-Q wide-frequency-domain tunable superconducting notch filter according to claim 2, characterized in that, The main transmission line has an input terminal and an output terminal at its two ends respectively; the input terminal is connected to the input connector; and the output terminal is connected to the output connector.

4. A high-Q wide-frequency-domain tunable superconducting notch filter according to claim 1, characterized in that, The main transmission line, the superconducting resonator, and the superconducting interdigitated capacitor are all in microstrip form, and all three are made of superconducting materials.

5. A high-Q wide-frequency-domain tunable superconducting notch filter according to claim 2, characterized in that, Both the input connector and the output connector are combinations of any one or more of SMA, N, and DIN.

6. A high-Q wideband tunable superconducting notch filter according to claim 1, characterized in that, The notch filter cavity is equipped with a through-hole capacitor; the positive and negative power terminals are respectively connected to the power supply through a through-hole capacitor.

7. A high-Q wide-frequency-domain tunable superconducting notch filter according to claim 1, characterized in that, The main transmission line includes several first transmission sections arranged in parallel and several second transmission sections that connect the several first transmission sections into a line.

8. A high-Q wide-frequency-domain tunable superconducting notch filter according to claim 7, characterized in that, The number of superconducting resonators is one or more; the superconducting resonators are located between two adjacent first transmission sections.

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