Microstrip Low-Pass Filters by Using DGS with Folded T-Shaped Arms

In this paper, two novel Low-Pass Filters (LPFs) using Defected Ground Structure (DGS) slot with a pair of folded T-shaped arms are presented. The resonant frequency of the slot can be easily controlled by changing the folded T-shaped dimensions, without changing the area taken by the structure. Using this slot, two quasi-elliptic LPFs were designed, fabricated, and tested. The experimental results show good agreement with simulation results and demonstrate that excellent stop-band performance could be obtained through the proposed LPF. The filter has a cut-off frequency of about 2.4 GHz.