Modelling and analysis of radiation effects for one-dimensional metamaterial-based transmission lines

Radiation effects due to the inclusion of a series capacitor and a shunt inductor in a unit cell for the right/left-handed transmission line (RLH-TL) are analysed and modelled using transmission line theory. The radiation rate per unit cell is derived and used as a key parameter for analysing and synthesising one-dimensional (1-D) metamaterial-based transmission lines (MTM-TL or RLH-TL). Various methods of extracting parameters related with radiation (or loss in general) from electromagnetic (EM) simulations (or measurements) are also provided. The S-parameters for 1-D periodic structures with a different number of unit cells are compared and analysed in various aspects based on EM and circuit simulations considering radiation effects, leading to close agreement. Some of the meta-structures are fabricated and measured for comparison with circuit/EM-simulated data. The presented modelling and analysis of 1-D MTM-TL considering radiation effects has drastically narrowed the gap between the characteristics based on circuit simulations (usually assumed lossless) and those based on EM simulations and measurements.