طراحی و ساخت یک فیلتر پایین¬گذر مایکرواستریپی با پهنای باند قطع وسیع و فرکانس قطع در باندهای S و L به کمک تشدید کننده¬های اصلاح شده

In this thesis, novel types of microstrip lowpass filters are designed, optimized and fabricated for microwave applications. For the first type a new design of microwave low¬pass filter (LPF) using novel structure by stepped impedance stubs in Telescopic-shaped resonator has been presented. The designed filter has specifications such as very sharp cut-off, ultra wide stopband, and low insertion loss in passband, in addition to its compact size. The lowpass filter has cut-off frequency of 1.38 GHz. The transition band is 0.12 for 1.38 GHz to 1.50 GHz and with attenuation levels of -3 dB and -20 dB, respectively. Maximum insertion loss in about 80% of passband region is 0.1 dB. The measured and simulated results indicate ultra wide stopband from 1.38 GHz to 22.5 GHz with the attenuation level better than -20 dB. Simulated and measurement results are close. This filter achieved remarkable figure of merit, 171622.