Comparison of calculations and measurements of an electronically scanned circular array

A circular array is modeled using two independent moment method codes. The array utilizes closely spaced high-gain end-fire elements to maximize the volumetric efficiency of an ellipsoidal enclosure, while minimizing the number of elements requiring control. An initial element was designed with an optimizer based upon the NEC4 engine; however, the use of moderately thick wires, wire-wire spacings of approximately one diameter, and non-trivial feeds required a wire/plate code for accurate element performance prediction. At the same time, efficient modeling of the entire array required a second code with a discrete body-of-revolution (DBOR) capability. Both electromagnetic codes were used in conjunction to arrive at a complete array design. With the exception of the highest frequency, where balun difficulties were plainly evident, correlation between predicted and measured results are very good.