No abstract

No abstract

A novel sixteenth-mode substrate integrated waveguide (SMSIW) bandpass filter loaded with complementary split-ring resonator (CSRR) is proposed. The filter size is reduced by introducing the SMSIW circular cavity loaded with CSRR. The SMSIW occupies only 6.25% of the conventional substrate integrated waveguide with same resonant frequency. Further miniaturisation is achieved by loading the SMSIW circular cavities with CSRRs. The designed filter is centred at 2.45 GHz with a bandwidth of 8.2%. The measured minimum insertion loss is 0.9 dB and passband return loss is below 10 dB. Good agreement is achieved between simulated and measured results.

A compact ultra wideband bandpass filter (BPF) with sharp rejection and wide upper stopband is proposed in this letter. The proposed bandpass filter is constructed using modified U-shaped multimode resonator (MMR). The U-shaped MMR is loaded with two open stubs on the symmetrical locations. This proposed resonator has five resonant modes, out of which two are odd modes and the remaining are even modes. These modes are present in the UWB band and are used to realize the wideband passband of the filter. By optimizing the dimensions of the stubs, the five resonant modes of the resonator can be brought into the desired passband. This bandpass filter with fractional bandwidth better than 110% is simulated, fabricated, and measured. The measured impedance bandwidth of filter is from 3.75 to 13.75 GHz with an insertion loss of 2 dB and return loss better than 11 dB. The simulated and measured results show a good agreement. The group delay variation is less than 0.25 ns. A wide stopband bandwidth with 16 dB attenuation is up to 19 GHz is obtained in the proposed filter.

This article presents a compact sixteenth‐mode substrate integrated waveguide (SMSIW) bandpass filter operating at fundamental mode TM01. The filter size is reduced by introducing SMSIW circular cavity. It occupies only 6.25% of the conventional substrate integrated waveguide (SIW) circular cavity with same resonant frequency. The higher‐order mode TM02 of the circular cavity is suppressed by etching two slots on the ground plane to improve out‐of‐band performance. Measured results show that an out‐of‐band rejection better than 18 dB is obtained from 2.5 GHz to 8 GHz. The in‐band and out‐of‐band performance obtained from simulation and measurement are presented and they are in good agreement. The filter exhibits good stopband performance and compact size.