Millimeter-Wave Receiver With Non-Uniform Time-Approximation Filter

This article presents a non-uniform (NU) time-approximation filter (TAF) technique for a wireless receiver (RX) to reject unwanted blockers. The proposed NU TAF leverages the alias-spreading property of NU sampling (NUS) and a TAF that approximates a finite impulse response (FIR) filter response in the time domain, achieving an overall flexible filter response with a higher attenuation factor. The filter response can be readily reconfigured by changing the NU sequence and/or the TAF waveform without adjusting the passive component value. In addition, a quad-switch gated integrator is proposed to significantly reduce the power consumption by sharing the current among the
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cells. Detailed theoretical analysis on NU-TAF operation and RX implementation considering circuit non-idealities are provided to explore the design tradeoffs of the proposed techniques. A proof-of-concept millimeter-wave RX is implemented in the 28-nm CMOS process. Thanks to the NU TAF, the RX prototype achieves >45-dB blocker rejection with a 33.7-GHz carrier frequency. The EVM measures −30.9 dB using a 100-MSymbol/s 64-QAM signal in the presence of a 10-dBc out-of-band (OOB) blocker.