An LO Frequency Tripler with Phase Shifter and Detector in 28nm FD-SOI CMOS for 28-GHz Transceivers

This paper presents an LO frequency multiplier and phase shifter for the 28-GHz band, implemented in 28nm FD-SOI CMOS technology. The phase control is introduced in an injection-locked oscillator, followed by an injection-locked frequency tripler. The phase of the output signal is compared with that of the input signal using a phase detector based on third harmonic mixing, enabling automatic phase tuning using low frequency detector outputs. Additionally, the phase detector can be used to detect locking of the oscillators, supporting automatic frequency tuning. A 24-30GHz sliding-IF receiver is also implemented to test the LO circuitry. Simulations show that the phase shifter achieves >360° tuning range over the full 24-30GHz span, with a gain variation of 0.11 dB or less, and that the phase detector has an rms phase error of <2.5°. The entire chip, including pads, measures 1080µm x 1080µm and consumes 27–29 mW from a 1 V supply.