A fully integrated 2-channel Ka-band True Time Delay (TTD) phase shifter with 12ps continuous changing delay time has been realized in a 0.25µm SiGe:C BiCMOS technology. A delay variation cancellation technique is proposed, resulting in less than 0.8ps delay variation over a 20-40GHz frequency span, meanwhile maintaining a constant input impedance. In the high (low) power mode, the measured input 1dB compression point and input IP3 are +9.7dBm (+3.6dBm) and +18dBm (+13dBm) at 30GHz with an averaged power consumption per channel of 145mW (33mW) for the same TTD performance. The size of the core phase shifter is less than 0.1mm2