Miniaturized Bandpass Filters With Double-Folded Substrate Integrated Waveguide Resonators in LTCC

• Published in: IEEE transactions on microwave theory and techniques Vol. 57; no. 7; pp. 1774 - 1782
• Main Authors: CHIEN, Hung-Yi, SHEN, Tze-Min, HUANG, Ting-Yi, WANG, Wei-Hsin, WU, Ruey-Beei
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2009; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Band pass filters; Bandpass filter; Bandpass filters; cavity; Ceramics; Circuit properties; Coupling circuits; coupling coefficient; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Exact sciences and technology; Flexibility; folded waveguide resonator; Frequency filters; Frequency measurement; Holes; Integrated circuit technology; low-temperature co-fired ceramic (LTCC); Materials; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; miniaturized filter; Nonhomogeneous media; Planar waveguides; Resonator filters; Resonators; Size reduction; Stripline; Tellurium; Waveguides; Stack filter; Suspended structure; U shape; Chebyshev filter; Strip line; Microwave; Flexibility; V band; coupling coefficient; Millimetric wave; Bandpass filter; Transmission line; Cavity; Band pass filter; Frequency response; low-temperature co-fired ceramic (LTCC); Low temperature; Electroceramics; Waveguide resonator; miniaturized filter; Substrate integration; Multiple layer; Compact design; folded waveguide resonator; Waveguide; L shape; Simulation; Ka band; Miniaturization; Comparative study; Planar technology
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2009.2022591

This paper proposes miniaturized bandpass filters with double-folded substrate integrated waveguide (SIW) resonators using multilayer low-temperature co-fired ceramic (LTCC) technology. Formed by inserting a metal plate with two orthogonal slots into the cavity, the double-folded SIW resonator is used for the circuit size reduction with its footprint about a quarter of the conventional TE 101 mode. With LTCC technology, there is more flexibility to organize the cavities of filters because of the 3-D arrangement. The vertically stacked cavities are coupled by ldquoLrdquo- or ldquoUrdquo-shaped slots, and if arranged horizontally, by an inductive window on the common sidewall or a suspended stripline between the cavities. Through experimental measurements and simulations at both the Ka - V -bands, it has been demonstrated that the proposed filter has compact sizes and good frequency responses. The area of the fully stacked Chebyshev filter has 88% size reduction in comparison with a three-pole planar waveguide filter, while the vertically stacked quasi-elliptic filter has 74% size reduction in comparison with a four-pole planar waveguide filter.