Near Field Shaping

Microwave Bessel-beam launchers, exciting the fundamental resonant cavity mode, require extremely thin substrates if scaled at millimeter waves. This leads to unbearable level of losses and to mechanical issues.

I have worked to the development of a Bessel-beam launcher based on a moderately thick cavity, operating with higher-order resonances. Closed-form expressions are obtained for the design of the structure starting from an analytic modeling of the relevant layered geometry.

At microwaves, a radial line slot array antenna has been designed, built and measured, focusing the normal component of the electric field in the near field with reduced side lobe levels and defined beamwidth.

The automatic design procedure is linked to the in-house Method of Moment I have developed at IETR. The position and the length of each slot can be varied in order to meet the aperture field corresponding to the required field mask on a reference plane.