This paper presents the design and characterization of a low-power 55 GHz oscillator using complementary transistors. It has the highest continuous tuning range in its frequency band reported to date. The tuning range is 27.4 % and 30.8 % for supply voltages 0.8 V and 1.4 V, respectively. Its core and buffers consume in average 3 mW and 8 mW power, respectively, from a supply voltage of 1.2 V. The peak DC-to-RF efficiency is about 6 % for supply voltages above 1 V. The circuit was manufactured on a 22 nm FD-SOI CMOS technology, and requires a total silicon area of 0.012 mm²,.