ANALYSIS OF DGS FILTERS USING 𝝅-CIRCUIT MODEL

Abstract

The design and analysis of two defected ground structures (DGS)-based filtershave been proposed in this article. The first is a multifrequency bandstop filter(BSF) which utilizes a semi-H defect in the ground plane. This structure is thenprototyped on a Rogers 4350B substrate of overall size 45 mm×15 mm withan external SMD capacitors employed to control the resonance of the circuit forthe stopband frequencies of 433, 700, and 915 MHz. An equivalent𝜋-circuit ismodified to validate this multiband filter. The second filter is a combination of aBSF and bandpass filter in one structure. The filter operating with a controllablepassband and stopband frequency is fabricated on Rogers 4350B lossy substrate.Two SMD capacitors are loaded in the filter structure to control the passbandand stopband frequencies of the filter with a structure size of 20 mm x 20 mm.Finally, the equivalent circuit from the BSF is modified further to encompass thebandpass and bandstop frequency response of the proposed work