Design of Dual Ultra–Wideband Band–Pass Filter Using Stepped Impedance Resonator λg/4 Short Stubs and T–Shaped Band-Stop Filter

Portable wireless communication systems are increasingly in demand small sizes for human convenience. In systems, the performance, size, and unit cost very important. A band−pass filter is important to sharp cut–off frequency characteristics, selectivity systems. The has three types of techniques transmission−zero method, stub−loaded resonator, stepped impedance resonator cut−off characteristic, adjustable bandwidth, excellent response characteristics. To obtain these ratio length a stub mainly adjusted. It also utilizes multi–mode technique increase bandwidth. However, it analyzed that problem reducing size device still remains. solve problems, paper applied control results bandwidth control, reduction through folded structure. Dual−band was secured by integrating T−shaped band−stop filter. designed band–pass center frequencies 243 GHz 7.49 GHz, insertion loss proposed 0.102 dB 0.103 dB. Additionally, return 19.13 19.96 dB, respectively. 120% 105%, 0.0708 λg × 0.0533 λg. good skirt phenomenon, low loss, dual−band