Linearly-polarized radial-line slot-dipole array antenna without canceling elements

The basic structure of a RLSA consists of a set of slots placed on the upper face of a simple parallel plate waveguide. Such guide is fed at its centre, typically by a coaxial probe. The suitable arrangement of slots provides the desired radiation pattern and polarization. However, while the circularly-polarized RLSA (CP-RLSA) has been successfully developed and it is commercially available, its equivalent with linear polarization (LP-RLSA) presents a tricky inherent drawback. The standard arrangement distributes the slots in concentric rings spaced half wavelength, in order to produce linear polarization and broadside radiation.