This work presents a 28GHz reflection type transmission-line (TL) based phase shifter. The proposed architecture employs a completely passive approach to double the phase shift achievable using a TL when compared to conventional architectures. The phase shifter, along with a preceding low noise amplifier and buffer, is implemented in a 65nm CMOS process. The fabricated chip achieves a measured phase resolution of 11.25° at 28GHz, with an rms error of 3° and a total phase shift of 180°. The insertion loss of the phase shifter alone is 17dB. The active area of the entire phase shifter, including LNA and buffer is 0.41mm2. © 2004-2012 IEEE.