Analysis and Design A Dual-Band Self-Oscillating Mixer

A self-oscillating mixer that employs both the fundamental and harmonic signals generated by the oscillator subcircuit in the mixing process is experimentally demonstrated. The resulting circuit is a dual-band down-converting mixer that can operate in C-band, or in X-band. The oscillator uses active superharmonic coupling to enforce the quadrature relationship of the fundamental outputs. Either the fundamental outputs of the oscillator or the second harmonic oscillator output signals that exists at the common mode nodes are connected to the mixer via a set of complementary switches. The mixer achieves a conversion gain between 9–11.5 dB in both frequency bands. Output third-order intercept point for C-band and X–band operation are 10.42 and 8.33 dBm, respectively. The circuit was designed and simulated in 0.18- CMOS technology by ADS2008.