Equivalent circuits for an electrically thick square patch directly fed by a coaxial probe or by a microstrip line
The authors present lumped-element equivalent circuits for two specific square patches on an electrically thick (0.05 λ0) substrate. The equivalent circuits were derived from experimental data and could be useful in the verification of theoretical techniques. For the particular geometry studied the probe fed patch requires sidelengths approximately 6% shorter than the microstrip fed patch, for the same resonant frequency. The microstrip-fed patch has a sharper resonance and approximately half the bandwidth of the probe-fed patch. Presumably the probe introduces more losses than the microstrip, thus damping the patch resonance.