Multiconductor Transmission Line Model for an Antenna With High-Impedance Ground Plane

We present a circuit model for an antenna above a 2-D high-impedance surface (HIS) ground plane with an arbitrary number of rows. Multiconductor transmission lines model coupling in the joint antenna and HIS structure. Discontinuities are modeled as circuit elements using closed-form expressions. One 2-D electromagnetic simulation is used to extract the per-unit-length capacitance parameters of the multiconductor transmission line structure. Input impedance predicted by the transmission line model agrees with full-wave simulations from low frequencies to above the second series resonance of the structure. The rms error in predicted S
₁₁
of two example structures with respect to HFSS simulation is reduced by a factor of more than 2.5 compared to our previous work.