Evolution of microstrip components for mobile communication systems

This paper present the development of advanced components to minimize the size and improve the reliability and performance of transceivers of mobile systems. In particular, multiport hybrid networks based on the Butler matrix concept and an innovating type of phase-shifters, able to provide a very accurate phase equalization over a wide frequency band, are shown. The technology used is the thick film microstrip and the applications are the antennas of cellular DCS 1800 (ground mobile), in view of the integration of ground and satellite communication equipment. A Butler matrix can advantageously be used as a key element of multiport power amplifiers (MPA´s) and as a transmit combining network in place of other solutions employing filters or couplers. Prototypes of these components, designed using Libra software (by Eesof) to operate over the 1.7-1.9 GHz band, were manufactured on Rogers RT6006 and RT5880 Duroid substrates. It is to be noticed that the microstrip technology used for DCS applications at 1.8 GHz can easily be transferred to satellite mobile systems at 1.6 GHz and to cellular based PCN (2-2.5 GHz Band)