Microstrip Stop-band RF Filter at Microwave Frequencies Using CLLs Elements

In this paper, the design and performance characteristics of microstrip quad-band RF filter at microwave frequencies are reported. The stop-bands filter with four rejected bands (GSM, UMTS, WIFI and LTE) consists of a micro-strip line coupled to four capacitively loaded loops elements (CLLs) used as rejecting elements. Simulation results in terms of S11, S21 parameters and surface currents are presented and discussed. In the proposed topology, the number of rejected frequencies band is determined by the number of CLLs. This RF filter is geometrically simple and had a compact size. This proposed structure is considered as a promising solution which can be implemented in the front-end RF receivers to make them suitable for UWB wireless systems.