Design of a substrate integrated waveguide H plane Horn antenna on a PTFE substrate for automotive radar application

Short range radar sensors for automotive radar applications are operating in the frequency range of 22GHz to 29 GHz band in the United States. UWB sensors in the frequency domain of 24 GHz based on GaAs technology are already established in the automotive radar market. Recently automotive radar sensors based on SiGe technology chipset have also been reported in this frequency band. Thus our effort is to design a substrate integrated waveguide (SIW) based H plane Horn antenna on a PTFE substrate, with an end-fire beam, which would be better suited for automotive radar applications. Rectangular dielectric loaded substrate integrated waveguide (SIW) H-plane sectoral horn antennas, operating at various frequencies in the range of 21 GHz to 28 GHz have been fabricated and tested. These antennas have been simulated and fabricated on a substrate of thickness 3.2mm and the dielectric material used is PolyTetraFluoroEthylene (PTFE). The SIW H plane horn antenna with dielectric loading resulted in improved gain and beamwidth. The length of the H Plane sectoral horn antenna was reduced further after optimizing the dielectric loading which resulted in further increase of gain and also narrow beam widths in the E- plane and H- plane. The results from the simulation and those from the measurement which are in good agreement are presented in the paper. The antenna prototypes that have been fabricated are not only compact but also low cost and they can be integrated with the high speed digital technology required for all the other subsystems of the automotive radar on the same PTFE substrate.