Design and analysis of a low-noise saw-less receiver front-end resistant to strong out-of-band blocker

Design and analysis of a SAW-less front-end resistant to strong out-of-band blocker is presented which utilizes a main-path containing an LNA along with a 12.5% mixer and a baseband amplifier. Also, it employs an auxiliary-path using a 12.5% mixer and a baseband amplifier. Multiple N-path filtering technique is employed to improve the NF and gain of the front-end in the presence of strong out-of-band blocker. The linearity of LNA, enhanced by series resistors in the LNA inputs, is analyzed by Volterra series analysis. Using noise cancellation technique on this structure relaxes the concern of series resistor noise contribution. Furthermore, new analyses are given for N-path-switching clock non-idealities, considering overlap and its effect on input matching. Analysis and simulation results, using 0.18 µm CMOS technology, show about 6 and 5 dB improvement in LNA IIP3 and front-end NF, respectively, when series resistor is added to the LNA and the auxiliary-path is ON.