Compact microstrip bandpass filter based on concentric ring resonators

In this dissertation, a new dual mode microstrip bandpass filter has been presented for the requirements of modern wireless communication systems. The filter has been constructed from double concentrated square loop resonators; each resonator is based on applying step impedance resonator generator on each side of closed resonator. The proposed bandpass filters have been designed using a substrate with a dielectric constant of 10.8 and thickness of 1.27mm at 2.43GHz and 5.75 GHz resonant frequencies.These filters have compact size and narrow band response which are the requirements of mobile wireless communication systems. The performance of suggested filters have been analyzed using Microwave office software package and Sonnet simulator, which are widely adopted in microwave research and industry. The output results showed that this filter possesses very good frequency responses and high selectivity as well as blocked 2nd harmonic in out of band regions. Keywords: Microstrip Bandpass Filter, Narrow Bandpass Filter, Compact Filters, Double Ring Concentric Resonators, Step Impedance Resonator (SIR).