Novel Broadband Bandpass Filters Using Y-Shaped Dual-Mode Microstrip Resonators

• Published in: IEEE microwave and wireless components letters Vol. 19; no. 9; pp. 548 - 550
• Main Authors: Song, Kaijun, Xue, Quan
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.09.2009; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Band pass filters; Bandpass filter (BPF); Bandpass filters; Bandwidth; Broadband; Circuit properties; Couplings; dual mode; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Feeds; Filtering theory; Frequency filters; Group delay; Insertion loss; microstrip; Microstrip filters; Microstrip resonators; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Noise levels; Oscillators, resonators, synthetizers; Resonance; Resonant frequency; Resonators; Simulation; Y-shaped resonator; Performance evaluation; Microstrip filters; Multivariable control; Return loss; dual mode; Parallel architectures; Microstrip resonator; Y shape; Bandpass filter (BPF); Mode filter; microstrip; Wide band; Resonance frequency; broadband; Insertion loss; Band pass filter; Y-shaped resonator; Group delay
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2009.2027058

A Y-shaped dual-mode microstrip bandpass filter (BPF) with input-output cross-coupling is presented. The characteristic of the Y-shaped dual-mode resonator has been investigated. The resonance frequencies of the degenerate modes can be adjusted easily to satisfy the bandwidth of the BPF. A parallel-coupling feed structure with a cross coupling has been used to generate two transmission zeros at the lower and upper stopband, which can improve the out-of-band performance. A broadband dual-mode microstrip BPF has been designed, fabricated, and measured. The simulated and measured results are in agreement generally. Within the 3.1 to 5.4 GHz bandwidth, the measured insertion loss, return loss and group delay variation are below 0.5 dB, above 15 dB, and below 0.2 ns, respectively.