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This paper presents a gain-boosting technique for two-port N-path band-pass filters (BPFs) based on the principle of discrete-time parametric amplification in MOS devices. The proposed technique also acts as a noise figure (NF) reduction technique due to the low-noise amplification before the output commutation. Analytical expressions for gain, NF, and input impedance of the proposed parametrically gain-boosted N-path BPF are derived using linear periodically time-variant (LPTV) network analysis and have been verified through simulations. The measurement results of a pseudo-differential eight-path BPF, implemented in a 180 nm CMOS technology, are presented. The center frequency of the implemented filter is tunable from 0.05 GHz to 0.4 GHz with a Q varying from 4 to 18. The gain of the filter is programmable with the input common-mode voltage. At 0.4 GHz, the filter achieves a variable gain of 2–8 dB over the input common-mode range of 0.55 V to 0.85 V. At every tuned frequency, the filter has a peak gain ≥8 dB, NF < 4.1 dB, and in-band third-order intercept power (IB-IIP3) >0 dBm. It is also shown in simulations that the proposed gain-boosting technique reduced the NF of the filter by >2.2 dB while consuming a dynamic power in the range of 3.8-31 mW per filter. [ABSTRACT FROM AUTHOR]

In this paper, a technique for the synthesis of lumped element multi-band matching networks is proposed using frequency transformations. The proposed technique has been generalized for n-bands using 1\mapsto n frequency transformations. The effect of the transformations on the bandwidth of the matching network and the effect of inductor losses on the transducer loss of the matching network are analyzed. A strategy to improve the efficiency of the matching networks in the presence of lossy components has been proposed. Applications of the proposed synthesis technique in the development and design of new multi-band LNA/PA architectures are discussed in detail with the help of design examples. In one of the design examples, the circuit has been prototyped and measured results are presented. [ABSTRACT FROM PUBLISHER]