IEEE Transactions on Antennas and Propagation   2016 年 PP 卷 99 期

2016

A new structure of horizontally polarized antenna array is presented for azimuthal omnidirectional coverage. The proposed antenna array is engineered by breaking the fringing field symmetry along the typical parallel strip-lines, which is implemented by loading field-block structures alternatively and periodically. In physics, the blocking structures constrain the fringing fields inside, producing a series of rectangular open cavities operating at the TM1n0 (n=0.5) mode. Counterintuitively, these asymmetric open cavities are able to generate an omnidirectional radiation pattern in the E-plane with horizontal polarization, similar to the linear magnetic current array. In order to verify the design strategy, a five-unit center-fed cascaded cavity array is fabricated and tested. The measured bandwidth is 120 MHz (5.83 to 5.95 GHz) with reflection coefficient lower than -10 dB. The horizontally polarized omnidirectional pattern at 5.9 GHz provides a gain variation of 1.94 dB ranging from 6.7 to 8.64 dBi.