Adjustable negative resistance structure-based multimode multi-channel mixer

Abstract

The invention provides an adjustable negative resistance structure-based multimode multi-channel mixer, which comprises a radio frequency input circuit, an adjustable negative resistance circuit, a digital control capacitor array circuit and a double-balanced differential structure circuit, wherein two input ports of the radio frequency input circuit are connected with radio frequency signals RF+ and RF-, and an output port of the radio frequency input circuit is directly connected with ports RFout+ and RFout-; the negative resistance size of the adjustable negative resistance circuit is controlled by two levels Vctrll and Vctrl, and an output end of the adjustable negative resistance circuit is connected with the RFout+ and the RFout-; an input port of the digital control capacitor array circuit is controlled by a digital signal, and two output ports of the digital control capacitor array circuit are connected with the RFout+ and the RFout-; and radio frequency current signals are input into the double-balanced differential structure circuit through the RFout+ and the RFout-, and are mixed with local oscillation signals LO+ and LO- to output intermediate-frequency signals IF+ and IF- to be then input into a rear-end module. By the adjustable negative resistance circuit, the equivalent parallel resistance of a capacitor array is eliminated, a noise coefficient is reduced, the gain of an active mixer is improved, the working frequency of the mixer can be controlled by a digital end, and the requirements of a broadband multi-channel system are met.

Description

Technical field [0001] The invention belongs to the technical field of radio frequency integrated circuits, and specifically relates to a multi-mode multi-channel mixer based on an adjustable negative resistance structure. The circuit can be applied to a multi-mode multi-channel broadband communication system working at 1-5 GHz. Background technique [0002] The working principle of the radio frequency transmitter is to load the signal on the high frequency carrier, and send the signal to the radio frequency receiver through the antenna to realize information transmission. For radio frequency systems, the function of the mixer is to achieve frequency conversion. The mixer is functionally divided into an up mixer and a down mixer. The up-mixer converts the intermediate frequency signal to the radio frequency signal and is mainly used in the transmitter. The down mixer converts the radio frequency signal to the intermediate frequency signal, and is mainly used in the receiver. [...

AI Technical Summary

Problems solved by technology

The disadvantage of this kind of mixer is that the adjustable frequency band range is small, it needs a large capacitive load to increase the layout area, the isolation from adjacent channels is poor, and the noise performance is not good

[0005] Therefore, a mixer with better noise performance, higher conversion gain, wider operating frequency band and better isolation is needed. At present, no similar mixer has been found at home and abroad.

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