Fundamental W-band InP DHBT-based VCOs with low phase noise and wide tuning range

In this paper, fundamental W-band voltage controlled oscillators (VCOs) featurring low phase noise and wide tuning range are reported. These monolithically integrated circuits (ICs) are fabricated using an InP/InGaAs DHBT technology, exhibiting cut-off frequency values of more than 250 GHz for both f(T) and f(max). The VCOs in differential topology consist of an oscillator core according to the negative resistance type and an ac-coupled output buffer. A first VCO version features operation frequencies ranging between 88 GHz and 100 GHz. Within this tuning range, phase noise values down to -90 dBc/Hz have been achieved at 1 MHz offset frequency, while single-ended output power values up to +4 dBm were measured, resulting in a total signal power of +7 dBm. A second VCO version shows operation frequencies between 101 GHz and 109 GHz. Within this frequency operation interval, phase noise values down to -88 dBc/Hz have been achieved at 1 MHz offset frequency, while a single-ended output power up to +2 dBm was measured, i.e. a total available signal power of +5 dBm.