Accurate CAD model for computation of input impedance of equilateral triangular patch antenna on suspended and composite substrates

A set of closed form expressions based on cavity model are proposed to investigate the effect of composite and suspended substrate on the input impedance of an equilateral triangular patch antenna (ETPA). The proposed model has been validated employing standard commercial software (HFSS). A comparison of theoretical values for input impedance of an ETPA with that obtained by simulation (HFSS) reveals close proximity with each other for wide range of permittivity and thickness of composite and suspended substrate. Also the computed value of input impedances of ETPA on single substrate is compared with the measured values available in literature. The comparison result is found to be in close agreement with the available experimental results compared to other models available in literature.