Circuit simulation and design of integrated RF filter for vehicle-based W-CDMA mobile communications system

This paper presents the results of circuit simulation and design of a car-based antenna integrated RF filter structure for 3G wideband code-division multiple access (W-CDMA) mobile phone communication system. Printed-on-thin film microstrip filter layout has been optimized to miniaturize the filter dimensions and to provide seamless integration with the feed line of a printed-on-glass antenna element. Side-coupled bandpass filter structure has been optimized to meet strict passband/stopband specification as well as to minimize the total loss of the filter circuit. The dependence of the filter transmission characteristics on the material properties of the thin film has also been numerically investigated.