A study for rotational symmetry of the aperture field on Spiral Array radial line slot antenna

We calculated the azimuthal deviations varying slot parameters of Spiral Array RLSAs. The inner/outer termination angles of the slot array have little influence on the azimuthal distributions. The element spacing in the circumferential direction has a significant impact on the azimuthal distributions. When the element spacing in the circumferential direction is 0.58λg, the deviations are minimized to 4.5dB and 32deg. As above, the azimuthal deviations are determined not by local parameters but by global parameters.