Design and development of a radial line slot array antenna of arbitrary polarisation

A unified design of a single layer Radial Line Slot Array (RLSA) antenna of arbitrary polarisation is presented. It addresses such tasks as the electromagnetic modelling of the feed, modelling of the radiating surface, prototyping of the feed and the radiating surface, and near- and far-field testing of the developed prototype. A circularly polarised RLSA (CP RLSA) antenna inherently features a high return loss. In contrast, a standard linearly polarised RLSA (LP RLSA) antenna suffers from poor return loss. The addition of reflection cancelling slots and tilting the main beam from the broadside direction is considered as the means for improving the return loss performance of the LP RLSA. While allowing for beam tilting, beam broadening and beam shaping is considered. The developed antennas are tested in terms of return loss, uniformity of aperture illumination, gain and radiation pattern. Iterative refinements are performed when the prototype does not meet the assumed performance specifications.