A low-noise ultrawideband CMOS mixer circuit for the down conversion of a K-band signal is presented. A bleeding path g(m)-boosting technique is proposed, which reduces the effect of noise sources of the proposed mixer. The measurement results show that the minimum noise figure is 3.61 dB at 24 GHz when consuming 2.6 mW at a 1.5-V supply voltage. The results also show a conversion gain of 9.15 dB, a P-1 dB of -13 dBm, and an isolation of a local oscillator port to a radio frequency port of -40 dB. The circuit was fabricated using 0.13-mu m CMOS technology with a chip area of 0.68 x 1.07 mm(2).