This letter presents a highly integrated 1-bit 90 degrees phase shifter based on high-pass/low-pass structure for 60 GHz beam-forming applications using a standard 65 nm CMOS process. In order to overcome the limitation of the conventional low-pass only phase shifter, the combination of high-pass/low-pass network was utilized as a 1-bit phase shifter. By integrating a high pass network into the low-pass network with low loss single-pole single throw (SPST) switches that adapt a resistive body floating technique, the proposed phase shifter achieves average 5 dB IL and less than +/- 0.18 dB of insertion loss flatness and 1 dB rms amplitude error over the whole band in a small chip area of 0.16 mm(2) including pads.