Rapid Spectrum Sweeping Scanner Exploiting Mixer Harmonics for Cognitive Radio Applications

A sequential sweeping receiver with fast switching time has been recently shown to be much more effective at spectrum scanning for cognitive radio applications than a compressed sensing receiver under similar hardware constraints. This paper presents a design of such rapid spectrum sweeping scanner. The design leverages the harmonics of hard-switching current-driven passive mixer to sense an arbitrary subband in the spectrum and downconvert it to baseband without the need for a wide-range tunable local oscillator (LO). The design operates as a frequency multiplexer with fast transient switching. The proposed scanner is designed and simulated in 65nm CMOS technology and achieves 4.8-dB minimum noise Figure and total power consumption of 38 mW from 1V supply voltage. The switching time to select a frequency bin is approximately three time constants of the corresponding frequency bin bandwidth.