This paper presents a compact and low power consumption three-stage differential low noise amplifier (LNA) with a 10 dB differential mode gain at 25.8 GHz by using transformer feedback technique in standard 0.18-μ;;;;;;;;m CMOS technology. The input 1-dB compression point and the input third-order intercept point are -17.8 dBm and -5 dBm, respectively. The measured noise figure at 25.8 GHz is only 4.84 dB. The minimum input return and output return losses over a 3-dB bandwidth of 22.8-26.8 GHz are 11 dB and 7 dB, respectively. The overall power consumption is less than 25.6 mW. This three-stage differential LNA only occupies a 0.63 × 0.88 mm2 in area.