A new current mirror based all-pass, tunable phase shifter architecture is proposed in 0.18 um CMOS, after a brief introduction on phase shifter applications, and comparison between different implementation methods. In the new current-mode approach the cut-off frequency of transistor is the operational limit of the proposed phase-shifter architecture and power consumption for this design is 80 microwatts. Simulations are carried out in HSpice and cover a frequency range from 1 MHz to 50 GHz.