Design and measured performance of cylindrical microstrip patch antenna arrays for SDMA-applications

This paper demonstrates the high flexibility and performance of conformal microstrip patch arrays and their advantageous use in SDMA applications. A fast, mathematically simple and robust algorithm for the pattern synthesis of cylindrical patch antenna arrays is described. It is based on the least mean square (LMS) method and hence does not need any non-linear optimisation technique. The involved integrals can be replaced by rapidly converging infinite sums, using the properties of the Fourier series expansion. The described pattern synthesis algorithm allows a fast and efficient evaluation of all the array excitation coefficients, which are necessary to generate the required beams for the SFIR or SDMA operation of base stations for mobile communication systems as well as for indoor WLAN systems. As a design example the measured and calculated performance of a conformal 16x4 element cylindrical microstrip patch phased array is shown. Excellent agreement between predicted and measured radiation patterns is achieved.