development of low profile substrate integrated waveguide horn antenna with improved gain

in this paper a new low profile substrate integrated waveguide (siw) probe-fed h-plane horn antenna structure with improved gain is proposed. the proposed antenna consists of two waveguides including a rectangular and a taper one, in which both, first and third modes of the structure are simultaneously excited leading to a uniform field distribution along the radiating aperture of the antenna and in turn, its directivity is highly improved. moreover, using the coaxial probe feeding of the structure, spurious radiation due to feeding network is suppressed. the antenna structure is numerically investigated using a software package. a prototype of the structure is made by a thin substrate using tly031 substrate and it was successfully tested. a very good agreement is obtained between simulated and measured results. the measured results show 10.48 dbi gain which is 4.9 dbi higher than gain of a conventional siw horn is obtained at 27.8 ghz.