A low phase noise quadrature VCO using super-harmonic coupling technique in 65-nm CMOS technology

This paper presents a new low phase noise (PN) quadrature voltage controller oscillator (QVCO), which includes four class C LC-VCOs oscillated at 13 GHz operating frequency with 45-degree phase differences from each other. By combining the second harmonics (super-harmonic) of the LC-VCOs, the quadrature outputs with low PN at 26 GHz are generated. To assess the performance of the proposed QVCO, post-layout simulations are performed in 65-nm CMOS technology with a 0.6 V supply voltage. The post-layout results represent that the proposed circuit has 26 GHz quadrature outputs with the PN of -116.4 at 1 MHz offset frequency. Also, the proposed QVCO occupies an area of 0.366 mm(2) and consumes 10.4 mW of power. Therefore, the proposed QVCO is a good candidate for 5G applications.