Double-Lorentz Transmission Line Metamaterial and its Application to Tri-Band Devices

A double-Lorentz (DL) transmission line (TL) metamaterial is proposed for the first time. Both effective material parameters mu_eff and epsiv_eff of the corresponding line exhibit a Lorentz-type dispersion, hence the proposed terminology double-Lorentz. This type of TL presents the interest of being intrinsically tri-band, while the previously reported composite right/left-handed TL metamaterial is only dual-band. The DL TL theory is fully derived and demonstrated experimentally by a microstrip implementation. The tri-band property of the DL TL is illustrated by the design of a tri-band lambda/4 impedance transformer and a systematic design procedure is described.