The paper discusses the possibility of generating a pseudo-Bessel beam, with a propagation distance of several hundreds of wavelengths in microwave and millimeter frequency band, by using a radial line slot array (RLSA). A specific application for non-contact microwave detection of buried mines has been considered as test case. The design benefits of a holographic approach to assure the required aperture field distribution and makes use of an ad hoc optimization tool to control the antenna slot layout. The predicted and measured antenna behaviors show that high efficiency and polarization purity can be obtained by such a compact and flat antenna, achieving at the same time both manufacturing and setup simplicity.

To detect buried objects at a not well-defined distance of several meters from the radar system it is preferable to maintain the beam confined in a small spot of a few centimeters for a wide range. To this purpose a pseudo-Bessel beam having a propagation distance of several hundreds of wavelengths can be suitably used. This paper shows how this beam can be conveniently obtained in the microwave band by using a Radial Line Slot Array (RLSA). To assure the required aperture field distribution, the antenna design has been achieved by making use of a holographic approach and by employing an ad hoc optimization tool that provides directly the final antenna slot layout. Simulated and measured antenna characteristics show that high efficiency and polarization purity can be obtained by such a flat antenna, also achieving both manufacturing and setup simplicity.

No abstract