5376

5036

كارشناسي ارشد

الكترونيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1389

نه،94ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

سعيد صدري

ابوالقاسم زيدآبادي نژاد

18/5/89

امير برجي، اصغر غلامي

مهندسي برق و كامپيوتر

ID5036

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Design and Fabrication of a New Microstrip Ultra Wideband Bandpass Filter Using 3 4 Wavelength Stepped Impedance Resonators Maryam Jouzdani m jouzdani@ec iut ac ir Date of Submission 2010 05 1 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Saeed Sadri sadri@cc iut ac ir Abstract Since Federal Communications commission FCC of the USA released the microwave frequencies from 3 1 GHz to 10 6 GHz for commercial radio systems in February 2002 the ultra wideband UWB radio has been paid attention as one of the future high speed wireless communication system A UWB bandpass filter is one of the key components for the UWB system to control the spectrum of the UWB signals In the development of an UWB bandpass filter the main difficulties one may face come from the ultra wideband about 110 percent fractional bandwidth as FCC s mask and the hard requirements for out band performance In this thesis a compact ultra wideband UWB bandpass filter composed of two parallel coupled stepped impedance resonators SIRs is proposed The SIR resonators are tapped with open stubs to create two transmission zeros at both edges of the rejection bands providing a very sharp transition band The genetic algorithm is used to determine the physical dimensions of the filter Using Ansoft HFSS EM simulator the fitness values are calculated during the algorithm The interaction between MATLAB and Ansof HFSS is done through functions that create visual basic script The optimized bandpass filter shows a quasi elliptic function response and a fractional bandwidth of about 110 from 3 1GHz to 10 6GHz Simulated results of the filter indicate low insertion loss and a flat group delay within the passband and a very sharp attenuation at the stopband edges better than 120dB GHz Finally the resultant UWB bandpass filter is fabricated and measured to provide an experimental demonstration of its actual UWB passband and skirt performances Good agreements between the measurement and simulation results are achieved and demonstrated Keywords bandpass filter Ultra wideband resonator insertion loss microstrip

سعيد صدري

ابوالقاسم زيدآبادي نژاد

امير برجي، اصغر غلامي