DESIGN OF COPLANAR WAVEGUIDE ULTRAWIDEBAND BANDPASS FILTER USING STUB-LOADED RESONATOR WITH NOTCHED BAND

摘要

In the present research, a novel compact ultrawideband (UWB) bandpass filter on coplanar waveguide (CPW) is examined and implemented. Pairs of three stepped-impedance open stubs are connected in shunt to a uniform high-impedance line to form a multiplemode resonator (MMR). The physical dimension of the stepped-impedance stubs is regulated to allocate the first four resonant modes of the MMR within UWB passband (3.1-10.6 GHz).Thus, through etching a complementary split ring resonator on the CPW feed line, the narrow notched band having admissible rejection level is made. Subsequent to obtaining the optimization parameters from the electromagnetic fullwave simulation, the intended filter is fabricated. The level of agreement between the measured and the simulation results was excellent. The advantages of the proposed filter include compaction (0.55λ), flat group delay with maximum 0.17 ns variation in the passband, low insertion loss, and good return loss as well as improved upper stopband.