Probe compensation in thick microstrip patches

In thick microstrip patches, probe inductance prevents matching of the patch impedance to the input connector. The probe inductance can be tuned out with a capacitive gap. To maintain simplified construction the gap is here etched on the patch surface. Bandwidths equal to or greater than that theoretically predicted are realised. Use of a single probe-compensated feed results in radiation pattern distortion, high crosspolarisation and low efficiency due both to higher-order modes and surface-wave generation. Two-probe feeding is used here to overcome these problems and to give a wide-band antenna with good radiation pattern control and high efficiency.