Integrated conformal four-beam antenna array with wide angular coverage fed by compact 4×4 Butler matrix

The paper presents the design of an integrated conformal four-beam antenna array. The goal was to design an integrated conformal multibeam antenna array that is capable to generate four independent beams which ensure wide angular coverage. Moreover, it was desirable that the designed multibeam conformal antenna featured sidelobe level comparable to a four-beam planar antenna array. To achieve that, a relatively small radius of the antenna array has been selected, and the phase compensation technique, in which additional phase delays introduced in outer channels compensate the curvature of the antenna structure, has been applied. A fully integrated four-beam conformal multibeam antenna array designed in a multilayer microstrip technology has been manufactured and measured, in which a compact 4×4 Butler matrix, additional phase shifters and a compensated multilayer crossover have been integrated constituting its feeding network.