This paper presents an 11-15GHz MMIC multifunction chip (MFC) with phase and amplitude control. The chip is based on the common-leg structure and comprises a phase shifter (PS), attenuator (ATT), T/R switch, gain compensation amplifiers (AMPs), driver stage AMPs and parallel control circuits. In the 11-15GHz bandwidth, measurements show that the gain and saturation power (Psat) are higher than 21.5dB and 26.5dBm, while the efficiency is more than 30% in TX mode. In RX mode, the small signal gain is more than 10.2dB, the NF is less than 9.8dB, and output 1dB power (OP1dB) is more than 8.5dBm. The measured minimum RMS phase and amplitude errors are 1.7° and 0.45dB, respectively.