Wideband Series-Fed Microstrip Patch Antenna Array With Flat Gain Based on Magnetic Current Feeding Technology

A series-fed microstrip patch antenna array with broad bandwidth and flat gain based on magnetic current feeding structure is presented in this letter. By appropriately blocking the microstrip line, a radiation mode of the microstrip structure is generated, which is equivalent to the magnetic current array. Also, the magnetic current is used to excite the sides-shorted microstrip patch antennas via coupling slots. The broad operation bandwidth of the series-fed array is achieved by merging the fundamental mode generated from the sides-shorted microstrip patch antenna element and the additional radiation mode from the microstrip feeding structure. Moreover, dual radiators are employed in the design to ensure that the gain remains flat. Based on the proposed idea, a 6-element linear array with a center feed is implemented and tested. The results indicate that a wide impedance bandwidth of 9.11–11.84 GHz (26.1%) and a 1 dB gain bandwidth of 9.1–11.5 GHz (23.3%) is achieved, with a maximum gain of 13.95 dBi.