Novel thin and compact H-plane SIW horn antenna

Abstract—The substrate integrated waveguide (SIW) tech-nology allows to construct several types of commonly used antennas in a planar way. However, some practical constraints limit their performances when frequencies below 20 GHz are considered. In the case of SIW horn antennas, the available substrates are much thinner than the wavelength yielding to poor matching and undesired back radiation. In this paper, an innovative structure to overcome these limitations is presented. It consists of a transition printed on the same SIW substrate, which improves both the radiation and the matching performances of conventional SIW horns. The horn shape is also further optimized by reducing its dimensions required for a given directivity. This is obtained by modifying the horn profile in order to effectively combine different TE modes. Guidelines are provided to design this type of thin and compact SIW horn antenna. They were ap-plied to manufacture a prototype in the Ku-band with a substrate thinner than. Measurement results validate the proposed concepts showing excellent performances. Index Terms—End-fire, front-to-back ratio, horn antenna, horn taper, low profile, printed transition, size reduction, substrate in-tegrated waveguide, vertical polarization. I