A monolithic low noise amplifier with externally matched input port for use in liquid helium temperature region

Abstract

The present invention relates to a monolithic low-noise amplifier with externally matched input port for liquid helium temperature zone, including an input matching circuit and a wide-band monolithic low-noise amplifier circuit. The input matching circuit is cascaded with the monolithic low-noise amplifier circuit, and the input port of the monolithic amplifier circuit is matched mainly through capacitors C1, C2, inductor L1 and resistor R1 to optimize the performance of the amplifier such as noise and port return loss; the monolithic low-noise amplifier circuit includes a three-level strained high electron mobility transistor, a matching circuit and a bias circuit. By adopting the low-noise amplifier disclosed in the present invention, it can be stably used in the ultra-low temperature liquid helium temperature zone, and within the wide frequency band range of 2GHz to 15GHz, the gain is greater than 32dB and the noise temperature is less than 10K. By changing the external input matching circuit, more excellent narrowband performance can be achieved. The device has the characteristics of low noise, small size, and convenient matching, and can be applied to receiving systems in the fields of deep space exploration and radio astronomy.

Description

Technical Field

[0001] The invention relates to the technical field of microwave devices, and in particular to a single-chip low-noise amplifier with an externally matched input port for a liquid helium temperature zone. Background Art

[0002] The sensitivity of the receiver system is limited by the system noise, which is determined by the noise of the device used and the environmental background noise. In general microwave receiving systems, the requirements for noise indicators are not very high, and conventional microwave amplifiers can meet their needs. However, for systems such as radio astronomy, deep space exploration, and cryogenic physics, the background noise of the received signal is only a few K. In this case, the noise requirements of the system itself are very strict. A cooled receiving front end with an ultra-low temperature low-noise amplifier as the core must be used to minimize the noise generated by the device to maximize the performance of the receiver system.

[0003] Strained high electron mobility transistor (mHEMT) has the best noise and excellent high-frequency characteristics, and can obtain very high carrier velocity at a lower drain voltage. In addition, at ultra-low temperatures, the energy required to excite electrons due to the increase in quantum well potential energy must be higher than normal temperature. However, mHEMT technology is not affected by the carrier freeze-out effect when electrons migrate at ultra-low temperatures. In the liquid helium (about -269°C) temperature range, only a slight increase in the gate voltage is required to ensure the normal operation of the device.

[0004] Noise performance is the most concerned indicator of low noise amplifiers, which is determined by the noise impedance matching between the input circuit and the first-stage mHEMT device. The matching circuit of a conventional monolithic low noise amplifier is integrated on-chip with other circuits. When the operating frequency band drifts in the liquid helium temperature range, it cannot be debugged, and even more seriously, self-oscillation occurs. The present invention designs a monolithic low noise amplifier with external matching for the input port in the liquid helium temperature range based on the low temperature characteristics of the mHEMT device and the characteristics of the monolithic circuit. Summary of the invention

[0005] The present invention proposes a monolithic low-noise amplifier with external matching for the input port in the liquid helium temperature zone, which can meet the needs of radio astronomy, deep space exploration, low-temperature physics and other fields for broadband low-noise amplifiers. At the same time, the external matching circuit at the input end can be optimized and adjusted according to the actual frequency band used, thereby expanding the use range of the amplifier to the greatest extent.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A monolithic low-noise amplifier with externally matched input port for liquid helium temperature zone comprises an input-end matching circuit and a monolithic low-noise amplifier circuit, wherein the input-end matching circuit and the monolithic low-noise amplifier circuit are cascaded;

[0008] The input end matching circuit includes capacitor C1, capacitor C2, inductor L1, resistor R1, microstrip line TL7, microstrip line TL8 and gate bias circuit, and microstrip line TL8 and monolithic circuit PAD1 are connected by a gold wire with a diameter of 25μm and a length of 350μm to 400μm. The input port of the monolithic amplifier circuit can be matched, thereby optimizing the performance of the amplifier such as noise and port return loss, and is also conducive to optimizing and debugging the circuit performance in a liquid helium environment.

[0009] Furthermore, the monolithic low-noise amplifier circuit includes a first-stage mHEMT tube T1, a second-stage mHEMT tube T2, and a third-stage mHEMT tube T3. The gate of the first-stage mHEMT tube T1 is connected to the input-end matching circuit through PAD1, the source is grounded through microstrip lines TL1 and TL2, the drain is connected to the second-stage mHEMT tube T2 through the inter-stage matching circuit, the source of the second-stage mHEMT tube T2 is grounded through microstrip lines TL3 and TL4, the drain is connected to the third-stage mHEMT tube T3 through the inter-stage matching circuit, the gate of the third-stage mHEMT tube T3 is connected to the input-end matching circuit, the source is grounded through microstrip lines TL5 and TL6, and the drain is connected to the output port PAD2 through the output matching circuit. Among them, TL1~TL6 improve the stability of the circuit, TL7 and TL8 are microstrip transmission lines with 50Ω impedance, and the monolithic low-noise amplifier circuit adopts 130nm process. Since the room-temperature microwave performance and bias operating point of the three-level mHEMT tubes T1, T2, and T3 are quite different, an ultra-low temperature microwave probe station is used in the design to extract the scattering parameters (S parameters) and DC parameters of the mHEMT tube in the liquid helium temperature zone. At the same time, the S parameters of passive devices such as resistors, capacitors, and inductors in the liquid helium temperature zone are extracted through the test fixture, and the model circuit of the mHEMT tube and passive devices in the liquid helium temperature zone is established and applied to the simulation design of the low-noise monolithic circuit to improve the design efficiency of the monolithic amplifier.

[0010] Furthermore, the gate width of the first-stage mHEMT tube T1 is 2×100 μm, the gate width of the second-stage mHEMT tube T2 is 2×50 μm, and the gate width of the third-stage mHEMT tube T3 is 2×50 μm.

[0011] Furthermore, the gate and drain of the three-stage mHEMT tubes T1, T2, and T3 are independently powered by the bias circuit composed of B1-B6. The separate power supply of the gate and drain of the mHEMT tube is beneficial to the debugging and testing at room temperature and liquid helium temperature zone.

[0012] Furthermore, the signal input port and the signal output port can be connected to SMA or K-type coaxial connectors, or can be integrated with other microwave devices using microstrip lines to form a multifunctional ultra-low temperature microwave component.

[0013] It can be seen from the above technical scheme that the monolithic low-noise amplifier with external matching for the input port in the liquid helium temperature zone of the present invention is mainly composed of an input matching circuit and a monolithic low-noise amplifier circuit. The monolithic low-noise amplifier circuit ensures the gain, in-band flatness and noise performance of the amplifier within a wide bandwidth; the external matching circuit can match the input port of the amplifier, thereby optimizing the amplifier's noise and port return loss and other performances, and is optimized to be a narrowband low-noise amplifier operating in the liquid helium temperature zone. In summary, the present invention has the characteristics of small size and low noise temperature, and can be applied to receiving systems with extreme requirements for noise performance such as deep space exploration, radio astronomy, and low-temperature physics research. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a circuit schematic diagram of the present invention;

[0015] Figure 2 is a gain test result diagram of the present invention;

[0016] Figure 3 It is a noise temperature test result diagram of the present invention. DETAILED DESCRIPTION

[0017] 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.

[0018] This embodiment provides a monolithic low noise amplifier with an externally matched input port for use in a liquid helium temperature region, such as Figure 1 As shown, it includes an input matching circuit and a monolithic low-noise amplifier circuit, wherein the input matching circuit and the monolithic low-noise amplifier circuit are cascaded.

[0019] Specifically, the input end matching circuit includes capacitor C1, capacitor C2, inductor L1, resistor R1, microstrip line TL7, microstrip line TL8 and gate bias circuit, and microstrip line TL8 and monolithic circuit PAD1 are connected by a gold wire with a diameter of 25μm and a length of 350μm to 400μm. The input port of the monolithic amplifier circuit can be matched, thereby optimizing the performance of the amplifier such as noise and port return loss, and is also conducive to optimizing and debugging the circuit performance in a liquid helium environment.

[0020] The monolithic low-noise amplifier circuit includes a first-stage mHEMT tube T1 with a gate width of 2×100 μm, a second-stage mHEMT tube T2 with a gate width of 2×50 μm, and a third-stage mHEMT tube T3 with a gate width of 2×50 μm. The gate of the first-stage mHEMT tube T1 is connected to the input end matching circuit through PAD1, the source is grounded through microstrip lines TL1 and TL2, the drain is connected to the second-stage mHEMT tube T2 through the inter-stage matching circuit, the source of the second-stage mHEMT tube T2 is grounded through microstrip lines TL3 and TL4, the drain is connected to the third-stage mHEMT tube T3 through the inter-stage matching circuit, the gate of the third-stage mHEMT tube T3 is connected to the input end matching circuit, the source is grounded through microstrip lines TL5 and TL6, and the drain is connected to the output port PAD2 through the output matching circuit. Among them, TL1~TL6 improve the stability of the circuit, TL7 and TL8 are microstrip transmission lines with 50Ω impedance, and the monolithic low-noise amplifier circuit adopts 130nm process. Since the room-temperature microwave performance and bias operating point of the three-level mHEMT tubes T1, T2, and T3 are quite different, an ultra-low temperature microwave probe station is used in the design to extract the scattering parameters (S parameters) and DC parameters of the mHEMT tube in the liquid helium temperature zone. At the same time, the S parameters of passive devices such as resistors, capacitors, and inductors in the liquid helium temperature zone are extracted through the test fixture, and the model circuit of the mHEMT tube and passive devices in the liquid helium temperature zone is established and applied to the simulation design of the low-noise monolithic circuit to improve the design efficiency of the monolithic amplifier.

[0021] The gate and drain of the three-stage mHEMT tubes T1, T2, and T3 are independently powered by the bias circuit composed of B1-B6. The gate and drain of the mHEMT tube are powered separately, which is beneficial to the debugging and testing at room temperature and liquid helium temperature zone. When used in the liquid helium temperature zone, the drain voltage and current of the three-stage mHEMT tube are respectively: the drain voltage of T1 is 1.5V, and the current is 8mA; the drain voltage of T2 is 1.2V, and the current is 6mA; the drain voltage of T3 is 1.2V, and the current is 6mA.

[0022] The signal input port can be connected to an SMA or K-type coaxial connector, or to other microwave devices using a microstrip line. The signal output port can be bonded to an SMA or K-type coaxial connector using two gold wires with a diameter of 25 μm and a length of less than 300 μm, or to other microwave devices after being bonded to a microstrip line using the gold wires.

[0023] The models of the internal components in the monolithic low-noise amplifier with external matching for the input port in the liquid helium temperature zone provided by the embodiment of the present invention can be selected according to the actual situation. For example, the input end matching circuit capacitor element can use chip capacitors, the capacitor C1 value is 12pF, and the capacitor C2 value is 33pF; the inductor element is an air-core coil inductor, and the inductor L1 value is 39nH; the resistor element can use chip resistors, and the resistor R1 value is 20Ω; the impedance of the microstrip line TL7 and the microstrip line TL8 are both 50Ω. The monolithic low-noise amplifier circuit adopts a 130nm gallium arsenide GaAs-based process, and the standard thickness of the circuit is 100μm.

[0024] The embodiment of the present invention provides a monolithic low-noise amplifier designed for liquid helium temperature zone input port with external matching, and the working range can be 2GHz to 15GHz. During the test, the amplifier is installed in a low-temperature dewar after the instrument is calibrated, sealed, evacuated and then cooled. When the device operating temperature drops to the liquid helium temperature zone, it is kept warm for 1 hour, and the gain of the device is tested with a vector network analyzer. The measured curve is as follows: Figure 2 As shown; the noise temperature of the device is tested using a high-precision noise test platform, and the measured curve is as follows Figure 3 As shown, from Figure 2 ,3, it can be seen that the gain of the device is greater than 32dB and the noise temperature is less than 10K.

[0025] 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. A monolithic low noise amplifier with externally matched input port for use in liquid helium temperature region, characterized in that: It includes an input matching circuit and a wide-band monolithic low-noise amplifier circuit capable of operating at minus 269 degrees Celsius, wherein the input matching circuit and the wide-band monolithic low-noise amplifier circuit are cascaded; The input end matching circuit includes capacitor C1, capacitor C2, inductor L1, resistor R1, microstrip line TL7, microstrip line TL8 and gate bias circuit, and the microstrip line TL8 and the monolithic circuit PAD1 are connected by a gold wire with a diameter of 25 μm and a length of 350 μm to 400 μm; The broadband monolithic low-noise amplifier circuit comprises a first-stage mHEMT tube T1, a second-stage mHEMT tube T2, and a third-stage mHEMT tube T3. The gate of the first-stage mHEMT tube T1 is connected to the input end matching circuit through PAD1, the source is grounded through microstrip lines TL1 and TL2, the drain is connected to the second-stage mHEMT tube T2 through the inter-stage matching circuit, the source of the second-stage mHEMT tube T2 is grounded through microstrip lines TL3 and TL4, the gate of the second-stage mHEMT tube T2 is connected to the inter-stage matching circuit, the drain is connected to the third-stage mHEMT tube T3 through the inter-stage matching circuit, the gate of the third-stage mHEMT tube T3 is connected to the inter-stage matching circuit, the source is grounded through microstrip lines TL5 and TL6, and the drain is connected to the output port PAD2 through the output matching circuit; The gate width of the first-stage mHEMT tube T1 is 2×100 μm, the gate width of the second-stage mHEMT tube T2 is 2×50 μm, and the gate width of the third-stage mHEMT tube T3 is 2×50 μm; The wide-band monolithic low-noise amplifier circuit adopts a 130nm gallium arsenide GaAs-based process, and the standard thickness of the circuit is 100 μm.

2. The monolithic low noise amplifier with externally matched input port for liquid helium temperature region according to claim 1, characterized in that: The gates and drains of the mHEMT tubes T1, T2, and T3 are independently powered by bias circuits composed of B1-B6.

3. The monolithic low noise amplifier with externally matched input port for liquid helium temperature region according to claim 1, characterized in that: The capacitive elements of the input matching circuit are chip capacitors, the capacitance C1 value is 12pF, and the capacitance C2 value is 33pF; The inductor element of the input end matching circuit is an air-core coil inductor, and the inductor L1 value is 39nH; The resistance element of the input end matching circuit is a chip resistor, and the value of the resistor R1 is 20Ω; the impedance of the microstrip line TL7 and the microstrip line TL8 are both 50Ω.

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