A three dimensional array for smart antenna applications

This study investigates in a first part optimal three dimensional antennas for adaptive applications. As already known, spherical arrays provide wide scan coverage with low grating lobe levels. The choice of the antenna element distribution on the spherical surface is governed by the desire to maintain constant power to the mobile being tracked. Therefore, we will choose a uniform spherical distribution. We calculate this uniform distribution for a set of antennas on a sphere. Based on formulas of spherical trigonometry, we show the only five possible exact uniform distributions. Because the number of possible uniform spherical distributions is limited, the number of elements that can be placed uniformly on a spherical surface is also limited to 20. In a second part, one uniform spherical distribution, the cubical or hexahedral configuration, is simulated and realised. After the optimisation of the cube size, the coupling is investigated