Wideband SIW horn antenna loaded with offset double-sided parallel-strip lines

A novel substrate integrated waveguide (SIW) horn antenna loaded with offset double-sided parallel-strip lines (DSPSL) is proposed in this paper. The mismatch between horn aperture and free space leads to narrow impedance bandwidth when the substrate thickness is much smaller than the wavelength. The offset DSPSL placed in front of the horn aperture acts as an impedance transformer so as to improve the radiation performance effectively. Simulated results show that a 21% impedance bandwidth is obtained, with a low profile less than λ₀/10.