1.8‐dB insertion‐loss planar UWB CMOS bandpass filter with suspended inductors

Abstract

AbstractThis article demonstrates a low insertion‐loss ultra‐wideband (UWB) CMOS bandpass filter (BP‐filter). Low insertion‐loss was achieved by adopting microstrip‐line (MSL) with optimized ground‐plane pattern as the needed small‐inductance inductors. In addition, to reduce the substrate loss of the large‐inductance spiral inductors, the underneath silicon was removed with the CMOS‐compatible backside inductively coupled plasma deep trench technology. This filter achieved insertion‐loss (1/S21) lower than 3 dB over the frequency range of 4.3–11.2 GHz, stop‐band rejection better than 25 dB over the frequency range of 0–2.3 and 17.4–36.8 GHz, and input return loss (S11) better than −10 dB over the frequency range of 3.1–15.8 GHz. The minimum insertion‐loss was 1.8 dB at 7 GHz. To our knowledge, this is the best result ever reported for a CMOS BP‐filter with operation frequencies higher than 3 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2946–2948, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24806