Probe radiation cancellation in wideband probe-fed microstrip arrays

The dual probe-fed patch technique, which is used to suppress unwanted probe radiation in wideband probe-fed microstrip patches, is extended for the case of a balanced two-patch sub-array. To demonstrate this technique, two S-band microstrip arrays were fabricated: with and without the balanced two-patch sub-arrays. The balanced array showed a reduction in the cross-polarisation peak level by nearly 10 dB. The unwanted radiation is effectively suppressed (20 dB cross-polarisation isolation) over a bandwidth of greater than 6.3%