In this letter, a microstrip Stepped Impedance Resonator (SIR) bandpass filter (BPF) based on Composite Right/LEft-Handed (CRLH) transmission lines is presented for the first time. Supported by theory, full-wave simulations and measurements, operational principle of the filter is explained and results are analysed. Also, comparison is made between this filter and its conventional right-handed (RH) counterpart. For the same centre frequency, fractional bandwidth and stop-band attenuation, the CRLH SIR BPF presented here proves to surpass its conventional counterpart in terms of size, being about 80% smaller, without degradation of performance. The CRLH SIR BPF is also significantly more controllable in its dimensions and response due to the fact that more elementary parameters are available in CRLH configuration.
- Left-handed - (LH), quater-wavelength, microstrip bandpass filter, stepped impedance resonator (SIR)