SIW sext‐band bandpass filter based on split‐type triple‐band symmetrical frequency responses

Abstract

Substrate‐integrated waveguide (SIW) sext‐band bandpass filter (BPF) composed of two dual‐mode cavities coupled with multiple single‐mode ones is synthesized and designed for the first time by combining split‐type triple‐band symmetrical frequency responses for two virtual wide passbands dominated by TE101 and TE201 modes in SIW rectangular cavities. By applying our previously proposed dual‐mode frequency and coupling controlling techniques, the center frequencies and fractional bandwidths of the two virtual passbands can be allocated flexibly. An experimental prototype with the two virtual wide bands centered at 11.993 and 14.336 GHz is synthesized, designed, fabricated, and tested to demonstrate and validate the collaborative design concept, showing excellent agreement between the measured and simulation results.

Semi‐circular mushroom resonator loaded substrate integrated waveguide cavity based compact triple‐band bandpass filter with high selectivity

“…The proposed filter shows high selectivity with six TZs compared to 5,7–9,11,13 and has relatively less insertion loss at all three passbands compared to 7,8,10,13,14 . Comparatively wider FBWs at lower operating frequencies are achieved at all three passbands in the proposed filter with respect to other referred works having higher operating frequencies 5,7–10,13,14 . The occupied volume of the proposed triple bandpass filter is calculated in terms of the guided wavelength (λ g ) of the propagating wave inside the dielectric medium used to implement the filter, corresponding to the CF of the first passband of the proposed triple bandpass filter.…”

“…The substrate integrated waveguide (SIW), while acting as a transmission structure carries the advantageous features of both planar transmission line and bulky metallic waveguide 1–3 . Due to the ability to operate at multiple frequencies with high quality factor, low insertion loss, high selectivity, structural compactness, easy integration and miniaturization in microwave communications systems, SIW‐based multiple bandpass filters have been adequately proposed by various researchers 4–14 . Triple passbands are implemented by employing multiple SIW cavities cascaded together resulting a bulky size with center frequencies (CFs) being dependent on the cavity dimensions 4,5 .…”

“…Due to the ability to operate at multiple frequencies with high quality factor, low insertion loss, high selectivity, structural compactness, easy integration and miniaturization in microwave communications systems, SIW‐based multiple bandpass filters have been adequately proposed by various researchers 4–14 . Triple passbands are implemented by employing multiple SIW cavities cascaded together resulting a bulky size with center frequencies (CFs) being dependent on the cavity dimensions 4,5 . Inverter coupled resonators based on SIW cavity are used to implement triple bandpass filter with symmetric frequency response but with single TZs each at the lower and upper stopbands resulting in poor selectivity 6 .…”

Q‐band dual‐mode substrate integrated waveguide filter and diplexer with circular cavity

“…Each structure can generate two transmission zeros, which can be located on the lower or upper side of the passband or on both sides of the passband respectively. Therefore, all the elliptic responses and asymmetric responses in [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] are covered, and the asymmetric responses proposed above are even better due to more transmission zeros. The simulation circumstance is composed of Ansoft HFSS and 0.254-mm TLY-5 (ε r = 2.2 and t g δ = 0.0009).…”

“…18,21,22 However, they still have some issues, such as broken cavity integrity, 17,18,21,22 insufficient transmission zeros, 16,18,21,22 transmission zeros that cannot be transferred 16,17,[20][21][22][23] design and processing difficulties 17,19 and relatively lower transmission frequency. [16][17][18][19][20][21][22] As compared, traditional rectangular cavity [24][25][26][27][28][29][30][31][32] has relatively lower Q-factor and the position of the feeding line is limited by its structure, so it can only translate along the four sides of the rectangle. In the circular cavity, the feeding line can rotate at any angle around the circular cavity.…”