A subharmonically injected LC delay line oscillator for 17-GHz quadrature LO generation

An injection-locked delay line oscillator multiplies a 5-6-GHz input by 3 to generate I/Q LO signals for 17-GHz wireless networking applications. I/Q errors caused by asymmetric injection are minimized by symmetric injection via a passive polyphase prefilter. Passive delay lines set the measured free-running frequency of the LC ring oscillator to 16.24 GHz. The measured locking range for a 0 dBm (50 Ω) input is 14.6-17.86 GHz. Input-to-output phase noise degradation is negligible, and I/Q amplitude and phase errors are <0.17 dB and <2°, respectively. Power consumption of the 1.2×1.4 mm² 0.2 μm SiGe BiCMOS testchip (excluding buffers) is 22 mW at 2.2 V.