Digital Radio Broadcasting Frequency Chebyshev CLF and HPF Designs Using ROGER 4003C

Abstract

The development of the frequency bands in microwave range filter play an important role in many RF or microwave applications. Filters are two port networks used to control the frequency response in an RF or microwave system by allowing transmission at frequencies within the passband, and attenuation within stopband of the filter. This research project consists of the elementary principle of microwave theory, the elementary knowledge of microwave filter design as well as fabrication and performance evaluation of Chebychev bandpass filters. The purpose of the research project is to compare the characteristic performance of different microstrip filter designs i.e coupled line (CLF) and hair pin filters (HPF). The designs were fabricated on the same type of material i.e FR4. Insertion loss method has been used in the design to produce the parallel coupled quarter wavelength resonator filters. The compatible filter in this project was able to filter out the required frequency for Digital Radio Broadcasting in the range of 1.452 GHz to 1.492 GHz. The designs were implemented using Microwave Office 2003 (V6.01) simulation software. The two filter designs were fabricated based on the Chebychev filter. The Chebyshev response is more selective than the Butterworth response at the expense of the insertion loss and greater group delay. The filters were tested using Advantest R3767CG Network Analyser. The entire filter designs and the performance of the substrate were evaluated. It was found that the HPF has better performance compared with CLF design in terms of bandwidth, matching impedance and quality factor.