Error analysis of tiled overlapped subarrays

In designing large phased arrays, it is common to design and construct a basic building block, or tile, and use duplicate tiles to build the final array. This method is important in both contiguous and overlapped subarrays. In stripline technology, the tile consists of a subarray of several elements on the top layer followed by the beamformer on the lower layers. Line bends, impedance transformers, and mutual coupling between adjacent lines can cause errors in the amplitude and phase distribution to the individual radiating elements. These errors can lead to other errors in phased arrays such as sidelobe levels and directivity. This paper presents a review of array theory as applied to both contiguous and overlapped subarrays. It also presents a method to help array designers differentiate between errors within the tile and others caused by crossovers between tiles.