Higher Mode Discrimination in a Rectangular Patch: New Insight Leading to Improved Design With Consistently Low Cross-Polar Radiations

Discrimination of a higher order TM
₀₂
mode in a rectangular patch by minimally tampering its boundary condition has been addressed based on some insightful studies. The magnetic wall across each nonradiating edge has been transformed into a composite boundary and unlike the earlier designs, this mechanism has been successfully demonstrated in eliminating the cross-polarized (XP) fields without causing any harm to the primary resonance. The signature of modal discrimination has been experimentally evidenced in the X-band by reducing the H-plane XP level consistently over the full range of elevation angle varying over 15-18 dB. Such “full-elevation” feature is highly significant from practical aspect and not commonly achievable in the other known methods. The proposed technique is directly integratable with a practical system without imposing any constraint on its deployment platform.