Unit cell models for right/left-handed transmission lines (RLH-TL)

Two types of unit cell models having left-handedness (LH) are presented and compared with each other. A 1D right/left-handed transmission line (RLH-TL) has lumped series capacitors (C) and parallel inductors (L) to obtain LH with conventional TL (RH-TL). One of the unit cells is asymmetric and the other is symmetric. In the latter case, we can obtain the L, C, length of RH-TL that make |S₂₁| =1 at a desired passband center radian frequency ω_p and also make a desired phase shift over a unit cell possible. The periodic RLH-TLs are analyzed with increasing numbers of units for varied lengths of the unit cells. The provided simple and essential expressions are shown to significantly facilitate the design of RLH-TL for a given specification.