Millimeter wave linear antenna arrays based on ridge dielectric and groove waveguides

Antennas based on a ridged dielectric waveguide are preferable for aperture dimensions of no more than 200 wavelengths. Further aperture increase raises the losses. For example, they are more than 1.5dB for teflon waveguides. In the radar mode of operation this reduces the the radar potential by 50%. In order to decrease the losses, it seems advisable to replace the ridge dielectric waveguide by the metal groove waveguide. The groove waveguide is remarkable as it is a structure which may be suitable for antennas operating at wavelengths up to 2 mm due to comparatively large groove dimensions. The development of the linear antenna arrays on the basis of a groove waveguide raises a number of problems concerned with the field structure investigation, loss measurements, the excitation of the fundamental mode with a high efficiency, the investigation of the interaction of the fundamental mode with periodic scatterers. The latter problem is concerned with the investigation of the efficiency of the fundamental mode cotransforming into a leaky wave for the regimes with converting and nonconverting of polarization, and with the study of the transformation of the fundamental mode into higher ones