Sectoral Horn and Patch Array Antenna Design for a 76–81 GHz High-Resolution Tomographic Radar

Nondestructive testing is employed in a wide range of industrial applications for quality control and process optimization. Recently, tomographic millimeter-wave radar has been investigated for highly demanding scenarios such as imaging of gas distributions. In such systems, application specific antenna design is crucial to ensure a sufficient number of signal paths between the sensors while at the same time reducing unwanted reflections. This paper describes the design of both a sectoral horn and a patch array antenna producing a fan-shaped beam in the frequency range of 76-81 GHz. Prototypes are realized utilizing innovative additive manufacturing techniques and characterized in a semi-anechoic chamber. The impact of mounting the antennas behind quartz glass is investigated in both simulation and measurement. Finally, the antenna performance is compared with commercial standard gain horn antennas in a tomographic radar setup demonstrating a significant improvement in the quality of the reconstructed permittivity distribution.