End-correction network of a coaxial probe for microstrip patch antennas

A simple end-correction network for the constant current probe model of probe-fed microstrip patch antennas is derived. The parameters of the network are solved asymptotically and verified by the numerical solution of the integral equation formulation. Based on the analysis of a problem concerning a coaxial-fed microstrip patch, it is concluded that: (1) TEM (transverse electromagnetic) aperture field approximation can provide an accurate result to the input admittance, and there is no need to introduce a specific correction network for most applications; and (2) Constant current probe is valid only when both k₁ h≪1 and a/h≪1 are satisfied. An end-correction network consists of a series inductance and a shunt capacitance should be used in other ranges or for higher accuracy