High-gain and high-isolation millimeter wave double-balance passive subharmonic mixer

Abstract

The invention discloses a high-gain and high-isolation millimeter wave double-balance passive subharmonic mixer. The passive subharmonic mixer comprises an active balun radio-frequency input stage, apassive balun local oscillator input stage, a passive subharmonic mixing stage and a transimpedance output stage. Radio-frequency signals amplified by an active balun and local oscillator differentialsignals generated by a passive balun are subjected to subharmonic mixing, and intermediate-frequency signals are output through a transimpedance amplifier. In the mixing stage, local oscillator signals are injected from the source of a transistor, and radio-frequency signals are injected from the grid of the transistor, so that the conversion gain is increased. In the active balun, a cross coupling tube is added on the basis of a cascade differential pair structure to improve the amplitude and phase consistency. In the transimpedance amplifier, a cross coupling structure is utilized to increase the gain, decrease the input and output impedance, improve the input current amplification capability and the output drive capability and further increase the conversion gain. The passive subharmonic mixer has the advantages of being high in conversion gain, high in port isolation and the like, and is suitable for the application scenarios of mixing with single-ended input and differential output.

Description

technical field [0001] The invention relates to a passive mixer, specifically a high-gain and high-isolation millimeter-wave double-balanced passive subharmonic mixer, which can be used for mixing the front-end radio frequency signals of Ka-band integrated receivers, and belongs to microwave radio frequency receivers technology field. Background technique [0002] The sub-harmonic mixer uses the second harmonic of the local oscillator signal to mix with the RF signal. The frequency of the local oscillator signal is only half of the frequency of the local oscillator signal of the fundamental mixer, which greatly reduces the design of the local oscillator signal source. Difficulty and cost, so it is more suitable for microwave frequency band. Active subharmonic mixers are based on traditional Gilbert units, but put forward special requirements for local oscillator signals, requiring four-phase quadrature local oscillator signals or other more complex structures. In contrast, ...

AI Technical Summary

Problems solved by technology

Baluns are divided into passive baluns and active baluns: passive baluns have the advantages of good symmetry and simple structure, but there is a natural 3dB loss; active baluns can provide a certain gain and are compact in size, but due to Parasitic effects of active devices, limiting the increase in operating frequency

Common active baluns include common source-cascode structure, common source-common drain structure, differential pair structure, etc., but these structures need to carefully design circuit parameters according to the operating frequency to achieve output signal amplitude and phase consistency, and As the frequency increases, the amplitude and phase imbalance due to parasitic effects become more obvious

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