SiGe Push–Push VCO for Low-Power C-Band FMCW High-Resolution Radar Applications

In this letter, we present a low-complexity push–push voltage-controlled oscillator (VCO) that achieves over 17% highly linear MHz/V tunable bandwidth. Unlike traditional VCOs, the proposed design does not require dedicated voltage-sensitive reactance components such as varactors or other transistors. The frequency is controlled with the bias voltage of the SiGe transistors which are placed in push–push configuration. The VCO is implemented using discrete components, and occupies 81 mm
$^{2}$
on PCB. The measured phase noise @1 MHz is −103 dBc/Hz, the average power consumption is 18 mW, the RF output power is −1 dBm, and the supply voltage is 3.3 V. The tuning range is 5.15–6.15 GHz, and the figure of merit with tuning (FoMT) at center frequency is −170. The large tunable bandwidth is obtained without using voltages greater than the supply voltage. The linearity and tuning bandwidth are evaluated by implementing the design in a low-power C-band frequency modulated continuous wave (FMCW) imaging radar.