Dual-Band Filter Composed of Dielectric and Waveguide Resonators with In-Band Transmission Zeros

AbstractIn this paper, a novel single-cavity triangular substrate-integrated waveguide (TSIW) dual-band filter loading a complementary triangular split ring resonator (CTSRR) is proposed, which has three transmission zeros (TZs) in the stopband in total. The dual-band response is achieved by the CTSRR and the degenerate modes of the TSIW cavity. In order to control the TZs, we propose two adjustment techniques, shift feeding technique and adding via perturbation. In addition, the CTSRR etched on the surface can produce a new TZ in the upper first-passband. Finally, a dual-band filter with three TZs is simulated, fabricated, and measured. There is a good agreement between the simulated results and measured ones.

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Compact Dual-Band Bandpass Waveguide Filter with H-Plane Inserts

Journal of Circuits System and Computers ◽

10.1142/s0218126616400156 ◽

2015 ◽

Vol 25 (03) ◽

pp. 1640015 ◽

Cited By ~ 7

Author(s):

Snežana Stefanovski ◽

Milka Potrebić ◽

Dejan Tošić ◽

Zoran Stamenković

Keyword(s):

Filter Design ◽

Ring Resonators ◽

Dual Band ◽

Filter Model ◽

Band Filter ◽

Waveguide Filter ◽

Waveguide Resonators ◽

Electromagnetic Models ◽

Compact Filter ◽

Good Agreement

A novel compact dual-band bandpass waveguide filter is presented in this paper. H-plane metal inserts with complementary split-ring resonators are implemented as resonating elements in the standard (WR-90) rectangular waveguide. Design starts from the models of the waveguide resonators with two resonant frequencies (9[Formula: see text]GHz and 11[Formula: see text]GHz) using a single flat or folded metal insert. Further, folded inserts are used for the second-order dual-band filter design. The equivalent circuits are proposed for the considered waveguide resonators and filter. A good agreement of the amplitude responses obtained for three-dimensional electromagnetic models and microwave circuits is achieved. Finally, compact dual-band bandpass waveguide filter is proposed as a novel solution using miniaturized inverters for both central frequencies. Compact filter model is further modified in order to obtain solution customized for easier fabrication. For the compact filter model, amplitude response is experimentally verified. The required filter response is preserved, as verified by a good agreement of the results obtained for the original dual-band filter and for the compact filter solutions.

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A Compact Tri-Band Bandpass Filter with High Out-of-Band Rejection

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.1209 ◽

2017 ◽

Vol 7 (4) ◽

pp. 1786-1790

Author(s):

M. Abdul-Niby ◽

M. Farhat ◽

M. Nahas ◽

Μ. Μ. Alomari

Keyword(s):

Degrees Of Freedom ◽

Bandpass Filter ◽

Wide Band ◽

Open Loop ◽

Dual Band ◽

Center Frequency ◽

Transmission Zeros ◽

Harmonic Rejection ◽

Band Filter ◽

Loop Ring

This paper presents a planar tri-band bandpass filter with high out-of-band rejection over a wide band. The filter is based on two pairs of λ/4 resonators embedded inside an open loop ring resonator without any size increase, where each pair of resonators are electromagnetically coupled to each other and the feedlines. This results in the excitations of passbands, where the first passband is generated by the open loop resonators. The second and the third passbands are excited by λ/4 resonators. The proposed technique provides sufficient degrees of freedom to control the center frequency and bandwidth of the three passbands independently. In addition, the six transmission zeros created around the passbands results in a tri-band filter with high selectivity, sharp 3 dB cut-off frequency, high isolation, low passband insertion-loss and high out-of-band harmonic rejection across an ultra-broadband frequency range up to 17 GHz. The proposed technique has the ability to switch from triple to dual band by removing one pair of the inner resonators. Design methodology and simulation results of the filter are provided.

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