MUTUAL COUPLING COMPENSATION IN SMALL PLANAR ARRAY ANTENNAS

Far-field pattern synthesis of small antenna arrays is a nontrivial pr oblem. Typically radiation patterns are required to exhibit low sidelo be levels, whilst maintaining the ability to scan the main beam in spa ce. Mutual coupling is a pertinent problem when the number of antenna elements is small, often precluding the use of conventional tapering a lgorithms. In this paper a technique previously employed to compensate for mutual coupling in linear arrays is extended to include small pla nar antenna arrays. The method consists of the calculation of the coup ling coefficients between the array elements, which are then formed in to a matrix and used to compensate for the effects of mutual coupling. It is then shown that this method is not suitable for all planar arra y configurations and a new technique is developed which allows the cal culation of coupling matrices for these element configurations. Measur ed data from a small planar antenna array is presented, with the outli ned methods employed to produce low sidelobe sum and difference beams.