Abstract: A single-chip fully-integrated SiGe BiCMOS Power Amplifier (PA) is presented for the C-Band phased Array Radar T/R module based on 0.13 μm SiGe BiCMOS process. The structure of the presented PA is single stage, single-end and Cascode, working in Class AB. The bias circuits and impedance match circuits are all integrated on a single chip. The total area of the chip is 1.4 mm*0.8 mm (include Pad). Test results show that in band of 4-6 GHz, this PA gets the small-signal gain S₂₁ of more than18 dB, the input return loss S₁₁ of less than -10 dB. At the center frequency of 5 GHz, the PA has an output 1 dB compression point of 18.6 dBm and a PAE of 26%.The maximum output power is 23.8 dBm. The maximum PAE is 39.2%.This single stage PA achieve high gain and PAE.