Experimentally validated of defected microstrip structure to realize band stop filter based on capacitively loaded loop resonators

A metamaterial (MTM) based filter with multiple band rejection characteristics is presented in this paper. By etching out two U shaped slots of different length from signal line, band notch characteristics at 5.8 GHz and 8.4 GHz are obtained. However by incorporating a pair of capacitive loaded loop (CLL) on either side of signal line, two more notches are obtained at 3.4 GHz and 6.9 GHz to avoid possible interference with few existing licence band. The prototype of the proposed micro strip band rejected filter is fabricated on RT-Duroid substrate of relative permittivity 2.2 and height of 0.787 mm. The electromagnetic full wave simulation results agree well with the measured result to validate the proposed idea. Simple design, compact size, good linearity and easy integration with other circuit like filtering antenna could be an attractive option in wireless environment.