Design of Metamaterial Based High Pass Filter Using CSRR at Cut Off Frequency 0.9 Ghz

In this work, highly selective filters based on periodic arrays of electrically small resonators are pointed out. The highpass filters are implemented in microstrip technology by etching complementary split ring resonators (CSRRs), in the ground plane, and series capacitive gaps, or interdigital capacitors, in the signal strip. The structure exhibits a composite right/left handed (CRLH) behavior and, by properly tuning the geometry of the elements, a high pass response with a sharp transition band is obtained. Introduction: By the design of high pass filters, it was demonstrated that this filter response can be achieved in microstrip lines periodic-loaded with CSRRs and series gaps. To do so, it is necessary to balance the line, that is, to achieve a continuous transition between the left handed band (due to the presence of the loading elements) and the right handed band (that appears at higher frequencies, where the line parameters are dominant). One key aspect of this composite right/left handed (CRLH) lines is that they exhibit a transmission zero to the left of the left handed band. Thus, high frequency selectivity can be achieved, as has been reported previously. One of the objectives of this paper is to demonstrate that by using complementary split ring resonators (CSRRs), further levels of minimization in these high pass filters can be achieved. The second objective is to point out that by properly modifying the topology of the CSRR, we can obtain an open resonator, the open complementary split ring resonator (OCSRR), which is very useful for the implementation of highly selective low pass filters in microstrip technology. Compact High Pass Filters Based On CSRRS: The typical unit cell topology and circuit model of these filters is depicted in Fig. 1. L is the line inductance; the CSRR is modeled by the resonant tank formed by Lc and Cc, and Cg and C (The coupling capacitance), are given by the line capacitance, CL, the fringing capacitance of the gap, Cf, and the series capacitance of the gap Cs Fig 1.Equivalent Circuit