Double-Conversion, Noise-Cancelling Receivers Using Modulated LNTAs and Double-Layer Passive Mixers for Concurrent Signal Reception With Tuned RF Interface

A double-conversion, noise-cancelling receiver architecture is presented that consists of a double-layer mixer-first branch and two quadrature-modulated LNTA branches. The two layers of passive mixing in the mixer-first branch up-convert the low-pass, baseband impedance and create concurrent, narrowband impedance matching at (F _LO ±F _IF ), as well as concurrently receive signals around these two RF carriers while rejecting spurious responses without using any IF filters. To improve the noise performance, quadrature-modulated LNTA branches are incorporated to allow frequency-translational, noise cancellation for better receiver sensitivity. Double conversion is achieved in the LNTA branches by periodically varying the LNTA transconductance and current-mode, passive mixing. A generalized, linear time-varying (LTV) analysis of the receiver is presented and verified with behavioral-model simulation results.