A dual-band bandpass filter using single unit cell of complementary split ring resonator with third harmonic reduction

A Filter block has been highly attention due to it's highly importance in wireless communication systems. High harmonic level normally companies with the performance of the filter block. The use of both low-pass or band-stop filter and the step-impedance lines methods to reduce the spurious characteristics of the filter are not a practical solutions since that adds more complexity and large in size. On the other hand, multiband components are preferable in most modern wireless system applications. In this paper, a single unit cell of a complementary split ring resonator designed on the ground plane of the conventional five pole bandpass filter has been proposed and considered as more practical method to excite the second bandpass frequency band and to solve the important filter problem in terms of third order harmonic characteristic suppression (3fo). The final structure has been simulated using the CST Microwave Studio. The simulated result for the proposed construction was extracted and displayed together with the measured result of the conventional five pole prototype structure. The outputs showed good agreement between them also return loss enhancement is very clear through the combination between the complementary split ring resonators and band pass filter. Other advantages no complexity adds, and low in effective cost.