Compact DGS quad band filter for multiservice wireless communication systems using stub loaded stepped impedance resonators Abstract   This paper presents a compact dualmode quad band microstrip bandpass (BPF) and low pass (LPF) filter by using a stubloaded steppedimpedance resonator (SIR) and a shortcircuited stubloaded uniform impedance resonator. Also, ring SIR geometry is introduced to miniature the size of this filter while maintaining excellent performance. The use of a stub resonator at the central point of the ring SIR can generate two resonant modes in two pass bands. For demonstration purposes, a quadband filter for the applications of the WLANWiMAXWLANUWB at 1.73.86.9110.10, Worldwide Interoperability for Microwave Access at 3.8xc2xa0GHz and wireless local area networks at 6.91xc2xa0GHz and 10.10xc2xa0GHz is designed, and fabricated.

A Compact Triple Passband Bandpass Filter Using Stub Load  Uniform impedance Resonators In this paper, a compact triple passband bandpass filter (BPF) using stub load  uniform impedance resonators (SLUIRs) is proposed. The resonators can provide the multipath propagation to enhance the filter performance and compact circuit size. The multipath SLUIRs is designed to have two resonant paths at 2.4, 3.5 and 5.2GHz for WLAN and 5G. The resonant frequencies can be easily controlled by tuning the length of the uniform impedance resonators. The proposed triple passband filter is showing a simple configuration, an effective design method and small circuit size. The measured results are in good agreement with the fullwave electromagnetic simulation results.