A 8x1 Sprout-Shaped Antenna Array with Low Sidelobe Level of -25 dB

Abstract

This paper proposes a 8 x 1 sprout-shaped antenna array with low sidelobe level (SLL) for outdoor point to point applications. The array has the dimensions of 165 mm x 195 mm x 1.575 mm and is designed on Rogers RT/Duroid 5870tm with the thickness of 1.575 mm and permittivity of 2.33. In order to achieve low SLL, Chebyshev distribution weights corresponding to SLL preset at -30 dB has been applied to design the feed of the array. Unequal T-junction dividers has been used to ensure that the output powers are proportional to the Chebyshev amplitude distribution. A reflector has been added to the back of the antenna to improve the directivity. The simulated results show that the proposed array can work at 4.95 GHz with the bandwidth of 185 MHz. Moreover, it can provide the gain up to 12.9 dBi and SLL suppressed to -25 dB. A prototype has also been fabricated and measured. A good agreement between simulation and measurement has been obtained. It is proved that the array can be a good candidate for point to point communications.