Gain enhancement of waveguide slot antennas using quasi-TEM mode in rectangular waveguide

In this paper, First the structure of a rectangular waveguide with a longitudinal slot is presented to show the quasi-TEM wave with uniform distribution in the waveguide width. This Quasi-TEM wave improves the aperture field illumination of the slot and enhances the efficiency in this kind of antennas. Finally, by simulation a slot antenna is excited by a quasi-TEM wave. The results indicate the high efficiency of this antenna.