Substrate Integrated Waveguide Cavity Filter Research Articles

Miniaturised substrate integrated waveguide cavities in dual‐band filter and diplexer design

The contribution of this study is to develop a miniaturised substrate integrated waveguide (SIW) cavity resonator with two evanescent-mode resonances. The circuit area of the developed dual-frequency SIW cavity is only 9.2% that of its conventional SIW cavity counterpart. A dual-band filter is implemented from using two miniaturised SIW cavity resonators. The two-passband frequencies can be independently controlled. Two transmission zeros are created by the two sides of each passband for enhancing the signal selectivity. A diplexer is also designed from using the proposed SIW cavities. A dual-band filter and a diplexer are built for experimental verification. Agreements between measured and simulated data are observed. To the best of the authors' knowledge, the designed dual-band filter and diplexer have achieved the best circuit area efficiency in the categories of dual-band SIW cavity filters and diplexers.

Compact high Q bandpass filter by using substrate integrated waveguide and split rings capacitive load post

A substrate integrated waveguide cavity filter is designed by loading with two split rings capacitive posts. Using these split rings posts results in high quality factor, low insertion loss (2.1 dB), very narrow bandwidth (2%) at 4.6 GHz centre frequency and compact (0.97×0.5 λ g 2 ) bandpass filter structure. The filter measured results are in good agreement with the simulation ones which prove the idea.

Two New Electric Coupling Structures for Double Folded Substrate Integrated Waveguide Cavity Filters with Transmission Zeros

Two electric coupling structures for double folded substrate integrated waveguide (DFSIW) cavity filters are presented in this article. The coupling strength can be easily tuned, and the coupling mechanism is investigated. With electric coupling realized by the proposed structures in the main path and magnetic coupling by a conventional coupling structure in the cross coupling path, an X-band cross-coupled filter is designed, which possesses a transmission zero on either side of the passband. A prototype of the filter is fabricated to validate the predicted frequency response, and the measured results agree with the simulated ones. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1815–1818, 2013

A folded substrate integrated waveguide cavity filter using novel negative coupling

AbstractThis article presents a cross‐coupled folded substrate integrated waveguide (FSIW) cavity bandpass filter. A novel type of negative coupling between FSIW cavities has been investigated and demonstrated. A prototype of four‐pole FSIW cavity bandpass filter has been designed, fabricated with multilayer standard printed circuit board process. The filter has good selectivity which is demonstrated by the measured results, indicating 7.5% bandwidth and more than 14‐dB return loss, with good agreement obtained when compared with the simulated ones. In addition, the rejection band of this filter is quite wide, implying good harmonic rejection. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 866–871, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24181

Novel substrate integrated waveguide cavity filter with defected ground structure

An open-structure eigenvalue problem of substrate integrated waveguide (SIW) cavity structures is investigated in detail by using a finite-difference frequency-domain method, and the quality (Q) factor of such SIW cavities is given. Based on the concept of a defected ground structure, a new class of SIW cavity bandpass filters are designed, fabricated, and measured around 5.8 GHz. With their fabrication on standard printed circuit boards, such filters present the advantages of high-Q factor, high power capacity, and small size. Simulated and measured results are presented and discussed to show promising performances of the proposed filters.