J4 ›› 2014, Vol. 41 ›› Issue (1): 53-56.doi: 10.3969/j.issn.1001-2400.2014.01.010

• Original Articles • Previous Articles     Next Articles

Novel dual-mode square loop microstrip bandpass filter

SUN Shoujia;WU Bian;LIANG Changhong   

  1. (Science and Technology on Antenna and Microwave Lab., Xidian Univ., Xi'an  710071, China)
  • Received:2012-10-20 Online:2014-02-20 Published:2014-04-02
  • Contact: SUN Shoujia E-mail:sunshoujia@gmail.com

Abstract:

This paper presents a novel dual-mode square loop resonator with a compact size. Firstly, the odd-even-mode method is utilized to analyze the resonant property of the proposed resonator since its structure is symmetrical, and the passband center frequency can be easily tuned by changing the lengths of a pair of loaded open-ended stubs. Secondly, source-load coupling is introduced to produce a new transmission zero and improve the passband selectivity. Finally, a microstrip dual-mode bandpass filter (BPF) centering at 1.95GHz with a 3dB fractional bandwidth (FBW) of 37.7% is designed and fabricated. The measured and simulated results in good agreement are presented.

Key words: dual-mode resonator, bandpass filter, source-load coupling