An SISL Sequentially Rotated Feeding Circularly Polarized Stacked Patch Antenna Array

A substrate integrated suspended line (SISL) circularly polarized stacked patch antenna and array is proposed. The stacked patch is introduced to achieve impedance matching and circular polarization. A windmill slot is etched on the driven patch to generate resonant frequencies of 5.05 and 5.3 GHz. Another resonant frequency of 6.5 GHz also exists due to the slot and driven patch. The proposed antenna is based on five dielectric layers, among which two layers are hollowed. On the basis of the measured results of the antenna element, the fractional impedance bandwidth of 28.3% from 4.8 to 6.38 GHz and 3 dB axial ratio (AR) bandwidth from 5.29 to 6.02 GHz are obtained. In addition, the antenna gain is larger than 8 dBic. A sequential rotation feeding network with 90° phase difference between each output port is presented to feed the antenna array with four elements. For the proposed antenna array, the measured results agree well with the simulated results. In the impedance bandwidth from 5.03 to 6.16 GHz and 3 dB AR bandwidth from 5.13 to 6.2 GHz, the antenna peak gain ranges from 12 to 13.8 dBic.