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Tunable selective receiver front end with impedance transformation filtering
Author(s) -
Qazi Fahad,
Duong QuocTai,
Dąbrowski Jerzy
Publication year - 2016
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.2125
Subject(s) - noise figure , low noise amplifier , electronic engineering , noise (video) , rf front end , cmos , amplifier , filter (signal processing) , electrical engineering , acoustics , engineering , radio frequency , computer science , physics , artificial intelligence , image (mathematics)
Summary A highly selective impedance transformation filtering technique suitable for tunable selective RF receivers is presented in this paper. To achieve blocker rejection comparable with surface acoustic wave (SAW) filters, we use a two‐stage architecture based on a low‐noise transconductance amplifier (LNTA). The filter rejection is captured by a linear periodically varying model that includes band limitation by the LNTA output impedance and the related parasitic capacitances of the impedance transformation circuit. This model is also used to estimate ‘back folding’ by interferers placed at harmonic frequencies. Discussed is also the effect of thermal noise folding and phase noise on the circuit noise figure. As a proof of concept, a chip design of a tunable RF front end using 65 nm complementary metal‐oxide‐semiconductor (CMOS) technology is presented. In measurements, the circuit achieves blocker rejection competitive to SAW filters with noise figure 3.2–5.2 dB, out of band IIP3 > +17 dBm, and blocker P 1dB > +5 dBm over frequency range of 0.5–3 GHz. Copyright © 2015 John Wiley & Sons, Ltd.