Ultralow-temperature noise source assembly

Abstract

An ultra-low temperature noise source assembly 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 is realized by a noise diode D1 and a peripheral circuit and generates continuous microwave white noise signals; the matching circuit is realized by a chip capacitor, a microstrip line and a thin-film resistor, and is used for controlling the output amplitude of a noise signal and matching the impedance of the noise source circuit and the switch gating circuit; and the switch gating circuit is realized by PIN diodes D1 and D2 and a peripheral circuit, and the output state of the noise signal is determined by controlling theinput level as required. By adopting the noise source assembly disclosed by the invention, the frequency coverage is 1GHz-10GHz, the over-noise ratio is greater than 25dB, the flatness is less than + / -1.5 dB, and the noise source assembly can stably work in a temperature zone of 10K-77K. The invention has the characteristics of stable noise output, high switching speed, low working temperature andthe like, and is used for measuring the noise temperature of the low-temperature low-noise amplifier.

Description

technical field [0001] The invention relates to the technical field of microwave devices, in particular to an ultra-low temperature noise source assembly. Background technique [0002] With HEMT devices as the core components, microwave amplifiers working in the temperature range of 10K and 77K (-253°C, -196°C) have excellent performance in terms of noise temperature, gain, reliability, etc., and there have been many reports in recent years . Due to the extremely low noise characteristics of the low-temperature low-noise amplifier, it can greatly reduce the noise introduced by the front end of the receiver and improve the sensitivity of the receiver system. It has been successfully used in deep space exploration, radio astronomy, wireless communication and other fields. [0003] Generally, the noise temperature is used to measure the additional noise introduced by the low-temperature low-noise amplifier (LNA). The noise temperature of the applied low-temperature devices fro...

AI Technical Summary

Problems solved by technology

[0003] Generally, the noise temperature is used to measure the additional noise introduced by the low-temperature low-noise amplifier (LNA). The noise temperature of the applied low-temperature devices from the L-band to the X-band is only about 4K to 8K, while the noise temperature of the conventional noise measurement method The uncertainty of the medium noise source is ±0.10dB (about ±7K), and the uneven temperature of the RF cable and adapter connecting the low-temperature low-noise amplifier to the external environment will also introduce errors; under the same super-noise ratio error , when the physical temperature of the noise source is closer to the noise temperature of the amplifier, the test result is more accurate

Images