Dual Band Filter Design for GSM Bands Using Frequency Mapping and Real Frequency Technique

Abstract

In this study, dual band frequency mapping is incorporated with Real Frequency Technique to design a dual band filter for GSM900 and GSM1800/UMTS bands. The proposed real frequency design technique (RFT) involves a parametric representation of input impedance of filter and the use of a dual band (DB) frequency mapping. A direct DB frequency mapping from low pass proto-type network is utilized along with the design and optimization of a low pass prototype network. Microstrip implementation of the designed filter and measurement results of the design are presented.