Design of planar wideband surface-wave excited substrate integrated waveguide horn antenna loaded with metamaterials

In this paper, a wideband planar substrate integrated waveguide (SIW) horn antenna based on surface wave excitation through loading metamaterials is designed. Strong coupling effect is realized between the employed bilayer metamaterial unit with the top layer as a pi-shaped-slotted patch while the bottom layer as the complementary cross-shaped-slotted patch. The equivalent permittivity of the extended substrate in front of the planar horn aperture can be effectively reduced to unity and impedance mismatching for conventional planar SIW horn antenna can be reduced in a wide bandwidth. Results indicate that the working frequency of the antenna is 12.3-15.8 GHz with the relative impedance bandwidth of 24.6%.