A COMPACT TUNABLE DUAL-STOP-BAND FILTER BASED ON DMS AND DGS

In this paper, a compact tunable dual-stop-band fllter is proposed. The proposed fllter is based on the combination of double H-shaped defected ground structure (HDGS) and E-shaped defected microstrip structure (EDMS). The loaded HDGS/EDMS varactor diode is introduced to realize the tunable dual-stop-band fllter. The equivalent-circuit models and theoretical analysis of the proposed structure are presented; also its performance evaluation is compared with traditional structure. The proposed fllter has the characteristic of two independently adjustable stopbands and wide tuning range. EDMS also shows size reduction up to 38% compared with the T- shaped defected microstrip structure. The measured performance of the tunable dual-stop-band fllter agrees well with the simulation results.