Abstract: The Si-base technology can help SOC (system-on-chip) to achieve smaller size, lower cost and low power consumption. In this paper, a fully integrated K-band CMOS receiver front-end was designed based on TSMC 90nm CMOS technology. The receiver front-end consisted of a 2-stage differential cascode low noise amplifier (LNA) and a double balanced Gilbert cell down-conversion mixer. The RF input, LO input and between the LNA and mixer were matched with on-chip transformer Balun. Measurement results show that, when RF is at 23.2GHz, the conversion gain can reach 27.6dB, the noise figure just is 3.8dB, and a high isolation can be got. The receiver chip consumes 35mW with a 1.2V power supply, and only occupies a chip area of 1.45×0.60mm<sup<2</sup<.