A 24 GHz quadrature pulsed oscillator for short-range UWB vehicular radar applications

A new 24 GHz quadrature pulsed oscillator is presented using 0.13 μm CMOS for short-range ultra-wideband (UWB) vehicular radar. A quadrature inductor-capacitor (LC) oscillator is quickly switched on and off for a pulse repetition time (PRT) as short as 1.66 ns. The switching technique creates a large initial voltage for fast startup (0.5 ns) and locks the initial phase of the oscillations to the input clock for phase coherence. The measured output phase noise matches that of the clock signal, with a relatively low phase noise of -70 dBc/Hz and -100 dBc/Hz at 1 kHz and 1 MHz offset respectively. The integrated rms jitter from 100 Hz to 1 MHz is thus less than 720 fs. The circuit consumes a low average power of less than 1.6 mW and 13.3 mW at 50 MHz and 600 MHz pulse repetition frequencies (PRFs) respectively, or below 8 pj of energy per pulse. It occupies an active area of less than 0.17 mm².