A 44 GHz Quadrature Traveling Wave Oscillator

This paper presents a technique for quadrature phase generation in an LC oscillator by sharing a single turn inductor between a pair of oscillators. This special structure of the inductor cancels the magnetic flux within the loop, and thereby allows placement of other components beneath it. A Vernier-scale based capacitor-DAC is implemented to achieve fine frequency tuning. The circuit is implemented on a 65 nm CMOS technology. The oscillator exhibits a fine tuning range of 43-44 GHz in silicon and has a phase noise of -76 dBc/Hz at a 1 MHz offset. Core power consumption is 15 mA from a supply of 1.6 V. An integrated Image Band Rejection (IBR) mixer is implemented to measure the quadrature accuracy. This results simulated quadrature mismatch of 3.5°.