A new LC series element for compact bandpass filter design

A new LC series element based on a modified version of the split rings resonator introduced in [1] is proposed. Owing to its small electrical size, the new open split ring resonator (OSRR) is a very attractive element for compact bandpass filter design. As an example, we have designed and fabricated a filter to produce a bandpass around the resonance frequency of the employed OSRRs. The filter bandwidth is controlled by the length of the transmission lines connecting the OSRRs. Sharp and deep out-of-band rejection is achieved by cascading several OSRRs. Circuit theory and electromagnetic based simulations reasonably agree with experiments.