An ultra-low temperature noise source component

Abstract

An ultra-low temperature noise source component includes a noise source circuit for generating a noise signal, a matching circuit for impedance matching and amplitude adjustment, and a switch gating circuit for determining the output state of a signal. The noise source circuit is implemented by a noise diode D1 and a peripheral circuit to generate a continuous microwave white noise signal; the matching circuit is implemented by a chip capacitor, a microstrip line, and a thin film resistor to control the output amplitude of the noise signal and match the impedance of the noise source circuit and the switch gating circuit; the switch gating circuit is implemented by PIN diodes D1, D2, and a peripheral circuit to control the input level as needed to determine the output state of the noise signal. By adopting the noise source component disclosed in the present invention, the frequency covers 1GHz to 10GHz, the super-noise ratio is greater than 25dB, the flatness is less than ±1.5dB, and it can stably work in the temperature range of 10K to 77K. The present invention has the characteristics of stable noise output, fast switching speed, low operating temperature, etc., and is used for measuring the noise temperature of a low-temperature low-noise amplifier.

Description

Technical Field

[0001] The invention relates to the technical field of microwave devices, and in particular to an ultra-low temperature noise source component. Background Art

[0002] Microwave amplifiers with HEMT devices as core components have excellent performance in noise temperature, gain, reliability, etc. through refrigeration, which has been reported in recent years. Since low-temperature low-noise amplifiers have extremely low noise characteristics, they can greatly reduce the noise introduced by the front end of the receiver and improve the sensitivity of the receiver system. They have been successfully applied to deep space exploration, radio astronomy, wireless communications and other fields.

[0003] In general, noise temperature is used to measure the additional noise introduced by the cryogenic low noise amplifier (LNA). The noise temperature of the applied cryogenic devices from L-band to X-band is only about 4K to 8K, while the uncertainty of the noise source in the conventional noise measurement method is ±0.10dB (about ±7K), and the uneven temperature of the RF cable and adapter connecting the cryogenic low noise amplifier to the external environment will also introduce errors; under the same ultra-noise ratio error, the closer the physical temperature of the noise source is to the amplifier noise temperature, the more accurate the test result. According to the above analysis, the noise source needs to work together with the cryogenic amplifier under test in an ultra-low temperature state to accurately measure the noise temperature of the cryogenic low noise amplifier. Summary of the invention

[0004] The invention provides an ultra-low temperature noise source component, which can quickly and accurately measure the noise temperature of a microwave-band low-temperature low-noise amplifier.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An ultra-low temperature noise source component comprises a noise source circuit for generating a noise signal, a matching circuit for impedance matching and amplitude adjustment, and a switch gating circuit for determining a signal output state, wherein the noise source circuit, the matching circuit and the gating switch circuit are sequentially connected in series;

[0007] The noise source circuit includes a DC power supply port P1, capacitors C1-C4, inductors L1 and L2, resistors R1 and R2, and a noise diode D1; wherein the DC power supply port P1, resistor R1, inductor L1, resistor R2, inductor L2 and noise diode D1 are connected in series in sequence, one end of capacitor C1 is grounded and the other end is connected to the common end of resistor R1 and inductor L1, one end of capacitor C2 is grounded and the other end is connected to the common end of resistor R2 and inductor L2, one end of capacitor C3 is grounded and the other end is welded to the cathode of noise diode D1; the anode of noise diode D1 is bonded to the matching circuit through gold wire. Capacitors C1-C4, inductors L1 and L2, resistors R1 and R2 form a low-pass filter network to eliminate the influence of DC power supply port P1 on microwave noise signals and match the output impedance of noise diode D1; the output end of noise diode D1 is connected to capacitor C4 to isolate DC and microwave signals. When debugging the circuit, due to the discreteness of the noise diode device, the resistance value of the resistor R1 can be appropriately adjusted to control the operating current of the noise diode D1 to be around 8mA.

[0008] The matching circuit is further composed of capacitors C4 and C5, microstrip lines TL1 and TL2, and resistors R4-R6; wherein capacitor C4, microstrip line TL1, resistor R4, microstrip line TL1 and capacitor C5 are connected in sequence, one end of resistor R5 is grounded and the other end is connected to the common end of microstrip line TL1 and resistor R4, and one end of resistor R6 is grounded and the other end is connected to the common end of resistor R4 and microstrip line TL2. Microstrip lines TL1 and TL2 are high impedance lines, and resistors R4-R6 are used to adjust the output amplitude of the noise signal and improve the port reflection of the noise source circuit and the switch gating circuit.

[0009] Further, the switch gating circuit includes a control port P2, a signal output port P3, capacitors C6 and C7, an inductor L3, a resistor R3, and PIN diodes D2 and D3; wherein the cathodes of the PIN diodes D2 and D3 are connected to the ground in parallel, and the anodes are connected to the capacitor C7 and the signal output port P3 in sequence; the control port P2, the resistor R3 and the inductor L3 are connected in sequence, one end of the capacitor C6 is grounded and the other end is connected to the common end of the resistor R3 and the inductor L3, and the RLC filtering network composed of the capacitor C5, the inductor L3 and the resistor R3 isolates the P2 DC signal and the transmitted high-frequency signal, and forms a switch gating circuit output matching network with the capacitors C6 and C7.

[0010] It can be seen from the above technical scheme that an ultra-low temperature noise source component of the present invention is mainly composed of a noise source circuit, a matching circuit and a switch gating circuit. The noise source circuit is implemented by a noise diode D1 and a peripheral circuit to generate a continuous microwave white noise signal; the matching circuit is implemented by a thin film resistor, which is used to control the output amplitude of the noise signal and match the impedance of the noise source circuit and the switch gating circuit; the switch gating circuit is implemented by PIN diodes D1, D2 and peripheral circuits, and determines the output state of the noise signal according to the input level. By measuring the microwave parameters of the components at low temperatures, the designed noise source circuit and switch gating circuit can work stably in an ultra-low temperature environment. By adopting the noise source component disclosed in the present invention, the frequency covers 1GHz~10GHz, the super-noise ratio is greater than 25dB, the flatness is less than ±1.5dB, and it can work stably in the temperature range of 10K to 77K.

[0011] In summary, the present invention has the characteristics of stable noise output, fast switching speed, low operating temperature, etc., and can accurately measure the noise temperature of a low-temperature low-noise amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a circuit schematic diagram of the present invention;

[0013] Figure 2 is a graph of super noise ratio test results of the present invention;

[0014] Figure 3 It is a schematic diagram of the use state of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0016] This embodiment provides an ultra-low temperature noise source component, such as Figure 1 As shown, it includes a noise source circuit for generating a noise signal, a matching circuit for impedance matching and amplitude adjustment, and a switch gating circuit for determining a signal output state. The noise source circuit, the matching circuit, and the gating switch circuit are sequentially connected in series.

[0017] Specifically, the noise source circuit includes a DC power supply port P1, capacitors C1-C4, inductors L1, L2, resistors R1, R2, and a noise diode D1; wherein the DC power supply port P1, resistor R1, inductor L1, resistor R2, inductor L2, and noise diode D1 are connected in series in sequence, one end of capacitor C1 is grounded and the other end is connected to the common end of resistor R1 and inductor L1, one end of capacitor C2 is grounded and the other end is connected to the common end of resistor R2 and inductor L2, one end of capacitor C3 is grounded and the other end is welded to the cathode of noise diode D1; the anode of noise diode D1 is bonded to the matching circuit through gold wire. Capacitors C1-C4, inductors L1, L2, resistors R1, R2 form a low-pass filter network to eliminate the influence of DC power supply port P1 on microwave noise signals and match the output impedance of noise diode D1; the output end of noise diode D1 is connected to capacitor C4 to isolate DC and microwave signals. When debugging the circuit, due to the discreteness of the noise diode device, the resistance value of the resistor R1 can be appropriately adjusted to control the operating current of the noise diode D1 to be around 8mA.

[0018] The matching circuit is composed of capacitors C4 and C5, microstrip lines TL1 and TL2, and resistors R4-R6; wherein capacitor C4, microstrip line TL1, resistor R4, microstrip line TL1 and capacitor C5 are connected in sequence, one end of resistor R5 is grounded and the other end is connected to the common end of microstrip line TL1 and resistor R4, and one end of resistor R6 is grounded and the other end is connected to the common end of resistor R4 and microstrip line TL2. Microstrip lines TL1 and TL2 are high impedance lines, and resistors R4-R6 are used to adjust the output amplitude of the noise signal and improve the port reflection of the noise source circuit and the switch gating circuit.

[0019] The switch gating circuit includes a control port P2, a signal output port P3, capacitors C6 and C7, an inductor L3, a resistor R3, and PIN diodes D2 and D3; wherein the cathodes of the PIN diodes D2 and D3 are connected to the ground in parallel, and the anodes are connected to the capacitor C7 and the signal output port P3 in sequence; the control port P2, the resistor R3 and the inductor L3 are connected in sequence, and one end of the capacitor C6 is connected to the ground and the other end is connected to the common end of the resistor R3 and the inductor L3. The RLC filter network composed of the capacitor C5, the inductor L3 and the resistor R3 isolates the P2 DC signal and the transmitted high-frequency signal, and forms a switch gating circuit output matching network with the capacitors C6 and C7.

[0020] This embodiment can change the signal output state of the component by changing the voltage of the switch selection circuit P2 port. When P2 is -5V, the component outputs a noise signal. When P2 is 0V, the component has no output signal. The switching speed is less than 10 milliseconds.

[0021] In this embodiment, component simulation design is implemented based on the ultra-low temperature S parameters of the noise diode D1 and the PIN diodes D2 and D3 measured by a low-temperature probe station, thereby eliminating the changes in device performance caused by temperature changes and improving the design efficiency of the components.

[0022] The operating temperature range of the component in this embodiment is 10K to 77K, the physical temperature of the component is monitored in real time by an ultra-low temperature sensor, and a stable working environment is provided by a refrigeration system.

[0023] The models of internal components in an ultra-low temperature noise source component provided by an embodiment of the present invention can be selected according to actual conditions. For example, the capacitor element of the noise source circuit can be a chip capacitor, with a capacitor C1 value of 0.1μF, a capacitor C2 value of 330pF, a capacitor C3 value of 100pF, and a capacitor C4 value of 22pF; the inductor element is an air-core coil inductor, with an inductor L1 value of 47nH, an inductor L2 value of 12nH or a microstrip line with a width of 0.2mm and a length of 15mm; the resistor element can be a 0402 packaged chip resistor, with a resistor R1 value of 1.5kΩ and a resistor R2 value of 300Ω; the noise diode D1 adopts GaAs technology, with a normal operating current of 8-12mA and an upper limit of the operating frequency of 18GHz. When the upper limit of the operating frequency is exceeded, the impedance will become negative, thereby generating self-oscillation; the supply voltage of the P1 port is +28V.

[0024] Exemplarily, the impedances of the microstrip lines TL1 and TL2 of the matching circuit are 75Ω and 90 ohms respectively, the resistor elements are 0402 thin film resistors, the resistor R4 value is 18Ω, and the resistors R5 and R6 values ​​are both 300Ω, which can improve the port return loss of the noise source circuit and the switch gating circuit by 10dB.

[0025] Exemplarily, the capacitor element of the gating switch circuit can be a chip capacitor, the capacitor C5 value is 39pF, the capacitors C6 and C7 values ​​are 22pF; the inductor element is an air-core coil inductor, the inductor L3 value is 22nH; the resistor element can be a 0402 package chip resistor, the resistor R3 value is 100Ω; the PIN diodes D2 and D3 adopt InGaAs technology, and the normal operating current is 10mA.

[0026] The ultra-low temperature noise source component provided in the embodiment of the present invention is designed to have an operating frequency range of 1 GHz to 10 GHz. The measured curve of the excess noise ratio (ENR) in an ultra-low temperature environment is as follows: Figure 2 As shown, from Figure 2 It can be seen that the component's super-noise ratio is greater than 25dB and the flatness is less than ±1.5dB.

[0027] A schematic diagram of the use of an ultra-low temperature noise source component provided by an embodiment of the present invention is shown in FIG. Figure 3 As shown, the components and the amplifier under test are placed on a cold plate, and the circulating helium compressor and cold head provide cooling for the cold plate to keep its temperature between 10K and 77K. Figure 3Connect to power the component, input the noise signal generated by the component into the input port of the cryogenic amplifier according to the test requirements by controlling the P2 port of the component, measure the power level of the output port of the cryogenic amplifier with a spectrum analyzer, divide the two power values ​​to get the Y factor, and determine the noise temperature of the cryogenic amplifier based on the known physical temperature of the noise source and the excess noise ratio.

[0028] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-low temperature noise source component, characterized in that: It includes a noise source circuit for generating a noise signal, a matching circuit for impedance matching and amplitude adjustment, and a switch gating circuit for determining a signal output state; the noise source circuit, the matching circuit and the gating switch circuit are connected in series in sequence; The noise source circuit includes a DC power supply port P1, capacitors C1-C3, inductors L1 and L2, resistors R1 and R2, and a noise diode D1; wherein the DC power supply port P1, resistor R1, inductor L1, resistor R2, inductor L2 and noise diode D1 are sequentially connected in series, one end of capacitor C1 is grounded, the other end of capacitor C1 is connected to the common end of resistor R1 and inductor L1, one end of capacitor C2 is grounded, the other end of capacitor C2 is connected to the common end of resistor R2 and inductor L2, one end of capacitor C3 is grounded, and the other end of capacitor C3 is welded to the cathode of noise diode D1; the anode of noise diode D1 is bonded to the matching circuit through gold wire; The impedances of the microstrip lines TL1 and TL2 of the matching circuit are 75Ω and 90 ohms respectively, the resistance elements are 0402 thin film resistors, the value of the resistor R4 is 18Ω, and the values ​​of the resistors R5 and R6 are both 300Ω; The noise diode D1 adopts GaAs technology, with a normal operating current of 8-12mA and an upper limit of operating frequency of 18GHz. When the upper limit of the operating frequency is exceeded, the impedance will become negative, thereby generating self-oscillation; the supply voltage of the P1 port is +28V.

2. The ultra-low temperature noise source assembly according to claim 1, characterized in that: The matching circuit is composed of capacitors C4, C5, microstrip lines TL1, TL2, and resistors R4-R6; wherein capacitor C4, microstrip line TL1, resistor R4, microstrip line TL2 and capacitor C5 are connected in sequence, one end of resistor R5 is grounded and the other end is connected to the common end of microstrip line TL1 and resistor R4, and one end of resistor R6 is grounded and the other end is connected to the common end of resistor R4 and microstrip line TL2.

3. The ultra-low temperature noise source assembly according to claim 2, characterized in that: The switch gating circuit includes a control port P2, a signal output port P3, capacitors C6 and C7, an inductor L3, a resistor R3, and PIN diodes D2 and D3; wherein the cathodes of the PIN diodes D2 and D3 are connected to the ground in parallel, and the anodes are connected to the capacitor C7 and the signal output port P3 in sequence; the control port P2, the resistor R3 and one end of the inductor L3 are connected in sequence, and the other end of the inductor L3 is connected to the common end of the anodes of the diodes D2 and D3, and one end of the capacitor C6 is grounded and the other end is connected to the common end of the resistor R3 and the inductor L3.

4. The ultra-low temperature noise source assembly according to claim 3, characterized in that: The capacitance elements of the noise source circuit are chip capacitors, the capacitance C1 value is 0.1 μF, the capacitance C2 value is 330 pF, the capacitance C3 value is 100 pF, and the capacitance C4 value is 22 pF; The inductance element of the noise source circuit is an air-core coil inductance, the inductance L1 value is 47nH, the inductance L2 value is 12nH or a microstrip line with a width of 0.2mm and a length of 15mm; The resistance element of the noise source circuit is a chip resistor with a 0402 package, the value of the resistor R1 is 1.5 kΩ, and the value of the resistor R2 is 300 Ω.

5. The ultra-low temperature noise source assembly according to claim 1, characterized in that: The capacitance element of the gate switch circuit is a chip capacitor, the capacitance C5 value is 39pF, and the capacitance C6 and C7 values ​​are 22pF; The inductance element of the gate switch circuit is an air-core coil inductance, and the inductance L3 value is 22nH; The resistance element of the gate switch circuit is a chip resistor of 0402 package, and the value of the resistor R3 is 100Ω; PIN diodes D2 and D3 are made of InGaAs technology and have a normal operating current of 10mA.

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