Dual band bandpass filter based on substrate integrated waveguide loaded with mushroom resonators

Abstract

This article presents a dual band bandpass filter by loading two cascaded mushroom resonators inside the cavity of a rectangular substrate integrated waveguide (SIW). The passbands are generated by exciting TE101 and TE201 modes of dual mushroom structures loaded inside SIW cavity. The fundamental mode, that is, TE101 of the entire filter structure is utilized to create the first passband and the next higher order mode, that is, TE201 of the filter structure is employed for the generation of second passband. Due to the incorporation of mushroom resonators into SIW, which are composite right/left handed transmission lines, the anticipated frequency response represents highly selective passbands with three transmission zeros (TZs) and an improved out‐of‐band response beyond the second passband. The effects of some structural parameters of the filter on the control over coupling parameters (k101 and k201) and quality factor (Q) are studied. This modified SIW based dual bandpass filter is fabricated and measured to verify two passbands centered at 2.25 and 4.1 GHz with 12.9% and 10.8% fractional bandwidth (FBW) and minimum insertion loss of 0.86 dB and 1.6 dB, respectively. Mobile satellite communications, weather radar systems and Wi‐Fi technology are the actual fields where such bandpass filters can be thoroughly applied.

Dual band bandpass filter based on semi‐circular mushroom loaded substrate integrated waveguide

“…The specifications for the first passband are; CF of 2.24 GHz, 3 dB FBW of 13% and return loss of 15 dB and that for the second passband are; CF of 4.35 GHz, 3 dB FBW of 6.2% and return loss of 15 dB. The optimization procedure for the synthesis of bandpass filter described in 13 is employed here and the coupling elements as design parameters are found using the relations shown in Equation ) and Equation ), where M ij is the coupling matrix element between the i th and the j th resonator, f 0 is the center frequency, BW is the 3 dB bandwidth and k ij is the coupling coefficient calculated using the lower and higher resonating frequencies f 1 and f 2 respectively. The coupling elements can be found as shown in Equation ) and Equation ), where superscripts I and II denote the first and the second passbands controlled by TM 101 and TM 201 modes respectively.…”

“…The specifications for the first passband are; CF of 2.24 GHz, 3 dB FBW of 13% and return loss of 15 dB and that for the second passband are; CF of 4.35 GHz, 3 dB FBW of 6.2% and return loss of 15 dB. The optimization procedure for the synthesis of bandpass filter described in 13 is employed here and the coupling elements as design parameters are found using the relations shown in Equation 5and Equation 6,…”

“…This paper presents a dual band bandpass filter based on circular SIW cavity loaded with two cascaded semi‐circular mushroom resonators (ScMRs), having high selectivity in the frequency response with four TZs and undergoes less insertion loss in both passbands compared to the referred works. In general a mushroom resonator having a metal patch and a ground plane shorted by a metallic via through a dielectric substrate is quite helpful in implementing highly selective bandpass filters 11‐13 . In this paper, unique structures of ScMRs are cascaded and loaded into the cavity of circular SIW to achieve highly selective dual passbands with less insertion loss.…”

“…In general a mushroom resonator having a metal patch and a ground plane shorted by a metallic via through a dielectric substrate is quite helpful in implementing highly selective bandpass filters. [11][12][13] In this paper, unique structures of ScMRs are cascaded and loaded into the cavity of circular SIW to achieve highly selective dual passbands with less insertion loss. first and second passbands of the proposed bandpass filter are generated by exciting TM 101 and TM 201 modes respectively of the mushroom resonator loaded circular SIW cavity.…”

Artificial Neural Network Based Siw Bandpass Filter Design Using Complementary Split Ring Resonators

“…An SIW bandpass filter, modelled on a double layer dielectric substrate consisting of metallic via holes in order to realize the classical H-plane filter has been proposed [12]. Two cascaded mushroom resonators have been modelled on the SIW cavity that works as a dual band bandpass filter has been presented [13]. On the waveguide top metal layer, a number of cross-slot patterns have been modelled to act as dual mode SIW filters [14].…”