Implementation of left handed transmission lines based on waveguide TM modes

Abstract In this article, a novel left‐handed (LH) waveguide transmission line with good filtering performance is proposed and implemented below the TM mode cutoff frequency. TM11 mode is employed and transmitted inside the waveguide. The LH passband is achieved by TM mode cutoff operation and complementary split‐ring resonator (CSRR) loading, which are able to provide negative μ and ε, respectively. It constitutes the main novelty here with the rectangular waveguide TM mode and CSRR to realize the LH characteristics, which has not been done before. Based on this passband, two bandpass filters with high‐selectivity are designed and fabricated. The measured results are in agreement with the simulated data. It shows a good LH passband below the cut‐off frequency and TM11 mode propagation is also detected at higher frequency above the cutoff.