Broadband Lens-Integrated CMOS Camera-Type THz Compact Antenna Test Range

This article presents the concept of a lens-integrated CMOS camera-type terahertz (THz) compact antenna test range (CATR) to determine the far-field characteristics of transmitters (TX), including the radiation pattern, directivity, half-power beam-width (HPBW), and radiation power. For concept validation, the frequency-dependent far-field radiation pattern of a 0.6-1.1 THz TX equipped with a 23.7-28.2 dBi standard gain horn antenna was measured using THz CATR. Directivity, HPBW, and radiation power have been extracted from THz CATR measurements. The first two parameters are compared with values obtained from calculations, full-wave simulations, and reference measurements performed at a conventional far-field range. In contrast, the third parameter is compared with a reference measurement performed with an absolute power meter. The following performance was achieved employing super-resolution imaging. Frequency-dependent directivity and HPBW were determined within a root mean square (RMS) accuracy of 0.85 dB and 1.16^\circ, respectively, related to reference measurements performed at the conventional far-field range. The frequency-dependent radiation power was determined within an RMS accuracy of 0.7 µW related to reference measurements with the absolute power meter. Camera-related limitations concerning the THz CATR application are discussed in detail, such as field-of-view limitations, angular resolution limits, scan loss, pixel-to-pixel variation, signal-to-noise ratio limitations, and the interaction between TX and camera lens.