Analysis and Design of a 60 GHz Fully-Differential Frequency Doubler in 130 nm SiGe BiCMOS

This paper presents a fully-differential frequency doubler integrated in 130 nm SiGe BiCMOS technology. To obtain a differential output signal, the conventional push-push topology is extended. The benefits of this approach are investigated with non-linear circuit analysis and discussed. While both the conventional push-push doubler and the Gilbert-cell doubler only suppress the odd harmonics, the extended topology enables the further suppression of the fourth harmonic. The circuit requires a set of phase-shifted versions of the input signal, which are generated on-chip with a polyphase filter. The proposed approach is validated with measurements of the fabricated circuit: an output power of −4 dBm at the 1 dB compression point with a −3 dB output bandwidth of 10 GHz from 55.6 GHz to 65.6 GHz is reported. With a low power consumption of 23.5 mW, a conversion gain of −15 dB and a fundamental suppression of 42 dB are achieved around the center frequency. A method to improve the conversion gain is discussed in the conclusion.