Abstract—Based on a new open-stub loaded open-loop resonator and step impedance cells, a low insertion losses dual band microstrip filter is designed to create two passbands at almost 2.4 GHz (exactly at 2.35GHz) and almost 5.7 GHz (exactly at 5.68GHz) for Multimode Wireless LANs application. The insertion losses at the 2.4GHz and 5.7GHz are 0.35 dB and 0.25 dB respectively. Also two width fractional bandwidths in its first and second bands are obtained. Several step impedance cells are used in loops and tapped line feed structures to obtain a novel dual band bandpass filter with compact size. The input impedance of the proposed resonator is calculated. The effect of the microstrip stubs and their impedances and impedances on the resonance frequencies is obtained using the input impedance of the proposed resonator.

Index Terms—Dual band bandpass filter, step impedance cells, compact size, low insertion loss.

The authors are with the Department of Electrical and Electronics Engineering, Shiraz University of Technology, Shiraz, Iran (e-mail: salehi@sutech.ac.ir, abiri@ sutech.ac.ir, Leila_noori62@yahoo.com).

 

Cite:M. R. Salehi, E. Abiri, and L. Noori, "Design of a Microstrip Dual-Band Bandpass Filter with Compact Size and Tunable Resonance Frequencies for WLAN Applications," International Journal of Computer and Electrical Engineering vol. 6, no.3, pp. 248-251, 2014.