Factors affecting the performance of linear arrays

The primary problem in the design of antenna-arrays is the satisfaction of the requirements of side-lobe level and beamwidth. An additional major consideration which has only recently received an analytical treatment1 is the problem of the deterioration of the beamwidth and side-lobe level arising from the variations in the excitation of each element. These variations are due primarily to the inaccuracies inherent in the manufacturing processes used to produce the array. The first problem has been discussed in great detail by many authors,2 and it will be the purpose of this paper to analyze the second problem. The analysis is formulated in general for a symmetrically excited broadside array and then, as a specific example, is applied to a linear shunt slot array which uses a Dolph-Tchebyscheff3 distribution for the element excitations. This distribution optimizes the relationship between beam width and side-lobe level. However, the method of analysis is general and may be applied to any linear array of radiators with arbitrary excitation, if the total mutual coupling between individual radiators may be neglected and no cross correlation exists between the inaccuracies of any two sources. Consideration will be given to these fundamental assumptions to show that the general method will yield useful results for slot arrays.