KIDs detector noise test circuit based on active quadrature mixer and test method thereof

Abstract

The invention provides a KIDs detector noise test circuit based on an active quadrature mixer and a test method thereof. The test circuit is characterized in that the test circuit comprises a frequency synthesis source, a directional coupler, a KIDs detector readout circuit module, an adjustable phase shifter, an active mixing circuit module, a filter circuit module, a data acquisition card, a control computer and the like. The test circuit takes a broadband Gilbert double-balance active quadrature mixer circuit structure as a core module, can complete noise test work on KIDs detector chips, and has excellent amplitude / phase balance degree and port isolation degree. The parasitic direct current bias voltage generated by a frequency output port is weak, the measurement is accurate, the mixer does not need to be separately calibrated, the measurement process is simplified, and the power level of the frequency synthesis source is reduced at the same time.

Description

technical field [0001] The invention relates to a KIDs detector noise test circuit and a test method based on an active quadrature mixer, belonging to the field of terahertz / optical technology research. Background technique [0002] Superconducting dynamic inductance detectors (Kinetic Inductance Detectors, KIDs) are a new type of low-temperature high-sensitivity detectors, which can be used for target imaging observations from millimeter wave to terahertz, optical / ultraviolet, X-ray, and γ frequency bands. The core circuit of the KIDs detector is mainly composed of a photon signal receiver and a microwave resonator. According to the working principle of KIDs, when an external radio frequency signal irradiates the KIDs detector, the superconducting Cooper pair rupture occurs after the receiver receives photon energy. , will lead to changes in the dynamic resistance and dynamic inductance of the microwave resonator, thus causing changes in the characteristics (Q factor, ampli...

AI Technical Summary

Problems solved by technology

However, the two quadrature IF output terminals of passive quadrature mixers generally have amplitude and phase imbalances, and the specific values ​​change with frequency, which makes the calibration of quadrature mixers a complicated and demanding task. high process

In addition, microwave passive quadrature mixers require large LO excitation levels

On the one hand, this puts forward higher requirements on the output power level of the frequency synthesis source. On the other hand, it also causes a large parasitic DC bias voltage at the output terminal of the intermediate frequency, which limits the multiple of DC amplification and the dynamics of the analog-to-digital conversion sampling circuit. scope

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