Quarter-Wavelength Stepped-Impedance Resonator Filter With Mixed Electric and Magnetic Coupling

• Published in: IEEE microwave and wireless components letters Vol. 24; no. 2; pp. 90 - 92
• Main Authors: Zhu, Fang, Hong, Wei, Chen, Ji-Xin, Wu, Ke
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2014; Institute of Electrical and Electronics Engineers
• Subjects: Adjustment; Applied sciences; Bandpass filter (BPF); Circuit properties; Conduction; Couplings; Electric filters; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Frequency filters; Joining; Magnetic resonance; Magnetic separation; Microstrip; Microwave filters; Microwaves; mixed-coupling; Oscillators, resonators, synthetizers; Resonator filters; Resonators; Simulation; Stability; stepped-impedance resonator (SIR); transmission zero (TZ); Second order; Resonator; Stepped impedance device; transmission zero (TZ); Third order; Non linear filter; Spacing; Transmission zero; Bandpass filter (BPF); Magnetic coupling; Band pass filter; stepped-impedance resonator (SIR); mixed-coupling
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2013.2290225

This letter proposes a new type of microstrip quarter-wavelength stepped-impedance resonator (SIR) filter with controllable mixed electric and magnetic coupling. A conducting pin and an open gap between two coupled SIRs are jointly used to create the mixed coupling, and the electric and magnetic coupling can be separately controlled by adjusting the spacing between the gap and the position of the conducting pin. Based on the proposed structure, a second-order filter and a third-order filter are designed and fabricated. Good agreement between the measured and simulated data is obtained.