Ultra‐wideband bandpass filter using hybrid microstrip‐defected‐ground structure

Abstract

A novel ultra‐wideband (UWB) bandpass filter (BPF) with a fractional bandwidth (FBW) of about 110% is presented using the hybrid microstrip‐defected‐ground structure (DGS). The proposed filter was designed using a combination of hybrid microstrip‐defected‐ground structure lowpass filter (LPF) with typical quarter‐wavelength short‐circuited stubs highpass filter (HPF), followed by an optimization for tuning in‐band performance. The high selectivity LPF using hybrid microstrip and four backside slots on ground plane is equivalent to a typical 9‐ploe stepped‐impedance LPF. The proposed LPF is employed to attenuate the upper stopband and etching on the ground plane with four rectangular slots provides attenuation pole to suppress the second spurious harmonic. Four shunt quarter‐wavelength short‐circuited stubs are used to realize the lower stopband for an optimum distributed HPF. The design was successfully realized in theory and verified by full‐wave EM simulation of the full layout and the experiment. The proposed filter had a good performance, including an ultra‐wideband bandpass (3.1–10.6 GHz), low insertion loss, sharp rejection, and a group delay of about 0.12 ns over the most center band. The filter also demonstrated an UWB reject band from 11.4 GHz to more than 19 GHz at −30 dB. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3085–3089, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23875

Defected ground structure based wideband microstrip low‐pass filter for wireless communication

“…A novel ultra wideband bandpass filter based on DGS with the fractional bandwidth of 110% is presented in literature [8]. Bandpass filter is designed with the use of low-pass and high pass filter.…”

“…Generally circularly polarized nature can be obtained with single or multiple feeds for a limited band of frequencies. Research reported on CP DRA with simple configuration and less space on feed substrate shows less axial ratio bandwidth [5][6][7][8][9][10][11]. Wide band CP operation therefore requires either dual feed network [12,13] or some special configuration [14-16].…”

UWB Bandpass Filter Based on Ring Resonator

“…Another type of UWB BPF was developed, based on a stub‐loaded multiple‐mode resonator, so that several resonant modes within the UWB passband could be obtained by placing three open‐ended stubs at appropriate positions and adjusting their lengths . A novel UWB BPF with compact size and improved upper stopband performance was also realized using a multiple‐mode resonator . It was discovered that a stepped‐impedance stub‐loaded resonator provides more freedom with regard to adjusting the resonant frequencies and also enables the creation of two transmission zeros at the lower and upper ends of the passband .…”

Design of Plasmonic Comb-Like Filters Using Loop-Based Resonators

“…This MMR has compact size and improved upper stopband performance. A novel UWB BPF with compact size and improved upper stopband performance was also realized using a MMR [7,8]. The resonators proposed in [9] offer the advantages of more degrees of freedom for adjusting the resonant frequencies and two transmission zeros at both the lower and upper ends of the passband.…”