Semi-Distributed Approach to Dual-Composite Right/Left-Handed Transmission Lines and Their Application to Bandstop Filters

In this letter, an innovative approach for realization of artificial transmission lines featuring a dual-composite right/left-handed character is presented. The circuits utilize a novel semi-distributed unit cell which is composed of sections of conventional transmission lines and a lumped capacitor. Such an approach allows for efficient modeling and convenient translation of model parameters (characteristic impedance and electrical length of transmission lines) into physical realization. Moreover, a single-layer microstrip realization is possible, making the unit cell attractive in practical applications. The proposed concept has been experimentally verified by the design and measurements of an exemplary transmission line section, and discussed in a context of possible applications in bandstop filters.