New Equivalent Circuit Analysis and Synthesis for Broadband Composite Right/Left-Handed Transmission Line Metamaterials

摘要

This paper proposes a new equivalent circuit analysis and synthesis method for the broadband composite right/left-handed transmission line (CRLH TL) and Dual-CRLH (DCRLH) TL metamaterials. In order to consider magnitude and phase of S-parameter of the CRLH/DCRLH TL element simultaneously, a pseudo-inverse technique is first implemented to extract the primary equivalent circuit. By using the filter synthesis technique, the retrieval primary equivalent circuit is further transformed to a typical band-pass/bandstop filter circuit as the secondary equivalent circuit. With two-step retrieval procedure, the response of the secondary equivalent circuit can more accurately agree with that of CRLH/DCRLH TL unit cell, compared with the sole use of the pseudo-inverse technique or the filter synthesis technique. Based on the equivalent circuit models, the topological structure and parameters of CRLH/DCRLH TL can be effectively synthesized for a given center frequency and bandwidth. Numerical results are given to demonstrate good performance of the proposed analysis and synthesis methods.