Design of an input multiplexer using dual-band planar filters

The design of an input quadriplexer is presented. It is based on a novel topology of ring-based dual-band filters. Two 2nd-order dual-band filters are implemented in microstrip technology and measured. These filters are then set in parallel to form the final IMUX dedicated to telecommunications standards: GSM (1.8 GHz), UMTS (2.1 GHz), Wi-Fi (2.45 GHz) and Wi-Max (2.9 GHz). The proposed concepts are validated by measurement results.