A COMPACT COMPOSITE BROAD STOP-BAND ELLIPTIC-FUNCTION LOW-PASS FILTER FOR ULTRA WIDE-BAND APPLICATIONS USING INTERDIGITAL CAPACITORS

A COMPACT COMPOSITE BROAD STOP-BAND ELLIPTIC-FUNCTION LOW-PASS FILTER FOR ULTRA WIDE-BAND APPLICATIONS USING INTERDIGITAL CAPAC-ITORSM. NosratiFaculty of EngineeringDepartment of Electrical EngineeringIlam Azad UniversityIlam, IranT. FarajiFaculty of EngineeringDepartment of Electrical EngineeringKermanshah Azad UniversityKermanshah, IranZ. AtlasbafFaculty of EngineeringDepartment of Electrical EngineeringTarbiat Modares UniversityTehran, IranAbstract—A compact composite ultra wide-band elliptic-functionlow-pass filter is introduced by combining in cascade a microstripstepped-impedance resonator using interdigital capacitor and anadmittance inverter. A triple cascade low-pass filter is designed,analyzed and tested with this technique accompanied by its equivalentcircuit model. This composition acts similar to a composite filter withdesired attenuation and matching properties in order to obtain widebandwidth and broad stop-band. The proposed low-pass filter featuresthe sharpness of cut off frequency, low insertion loss, enhancement ofbandwidth up to X-band frequencies and very compact size.