Evaluation of Radar Cross-Section and Half Power Beamwidth of LCM-Printed Al2O3 Reflectors at Sub-THz Frequencies

Dielectric corner reflectors (CRs) have recently attracted attention in millimetre-wave frequencies due to the potential of combining them with 3D printing techniques for their manufacturing and integration within existing systems, as well as presenting a broader half power beamwidth (HPBW) than metallic CRs. In this paper, the monostatic radar cross-section (RCS) and HPBW of three fully dielectric reflectors are measured at sub-THz frequencies, specifically between 220 GHz to 330 GHz. The structures are printed in Al
2
O
3
via lithography-based ceramic manufacturing (LCM). From the three reflectors evaluated, namely a cube, a CR, and a filled corner reflector (FCR), it is found that the cube presents the narrower HPBW, of 2°. The measured HPBW for the CR is similar to its metallic counterparts, of 34°. Finally, the FCR presents an enhanced HPBW of 70°. The aperture edge for the cube is 13 mm, for the CR is 20.60 mm and for the FCR is 22 mm. The maximum measured RCS for the three structures is of −10.0 dBsqm, −13.1 dBsqm and −7.8 dBsqm, respectively. The results verify the potential of FCR as a broad angle reflector for applications at sub-THz frequencies.