Design of a band‐selective filter for UWB applications and its characteristic when combined with band‐notched antennas

Abstract

AbstractA compact microstrip band‐selective filter for ultra‐wideband (3.1–10.6 GHz) radio system is proposed. The filter combines an optimum pseudo‐bandpass filter and a coupled resonator bandstop filter on both sides of the meandered 50‐Ω microstrip line. Three coupled resonators are modified to have S‐shape to miniaturize the filter. The measured results show that the filter has wide passband of 146.7% (2.1–10.15 GHz) with low insertion loss and the stop‐band of 7.42% (5.29–5.85 GHz) for 3‐dB bandwidth. The measured group delay variation is less than 0.7 ns within the passband except the stop band. Finally, the filter is combined with band‐notched antennas and then received power levels of the antennas with and without the filter are also examined at the notch frequency. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 98–101, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23019