Reconfigurable and Tunable S Shaped Split Ring Resonators and Application in Band Notched UWB Antennas
This paper proposes a compact reconfigurable (bandstop/bandpass) and frequency tunable structure based on S shaped split ring resonators (S SRRs) It is known that an S SRR coupled to a coplanar waveguide (CPW) provides a stopband in the transmission characteristic of the line. It is shown here that this behavior of the S SRR can be switched between fundamental resonance and second harmonic response by introduction of a p i n diode in the center segment of the S SRR. Alternatively, if the S SRR is loaded with a varactor diode instead of a switch, the frequency of the stopband can be continuously tuned from the S SRRs fundamental resonance frequency to its second harmonic. Furthermore, it is shown that if a pair of shunt p i n diodes are introduced across the slots of the host CPW, the structure can be reconfigured from a bandstop to a bandpass structure. Thus, the proposed resonator structure can be used as the building block of reconfigurable (bandstop/bandpass) filters with tunable operating frequency. Finally, to demonstrate a practical application of the proposed structure, an ultrawideband antenna with a tunable band notch is designed and experimentally validated.
IEEE Transactions on Antennas and Propagation