Design and experimental results of a spherical antenna array for a conformal array demonstrator

The present paper describes the development of a spherical antenna array with 95x3 antenna elements, a diameter of 300 mm and an opening angle of 112 deg. Since the number of antenna elements on a planar or curved antenna aperture required for high directivity and two-dimensional beam steering can easily become very large, especially if an element spacing around half the free space wave length is required, the antenna elements are arranged in sub-arrays, each carrying 3 circularly polarized patch antennas at a centre frequency of f = 9.5 GHz and a phase corrected feed network on a common substrate. The sub-array is suited for easy integration into antenna arrays with double curved aperture and can be seen as a trade-off between antenna gain vs. beam granularity. Experimental results on antenna matching and radiated far field patterns as well as measured beam forming results will be presented