Design of 3-D Printed Wideband THz Spatial Power Dividers Based on Two-Stage Phase Optimization Method for Heterodyne Detector Array Applications

• Published in: IEEE transactions on microwave theory and techniques 2024-12, p.1-14
• Main Authors: Zhai, Zhen Jun, Lin, Feng, Chan, Ka Fai, Sun, Hou Jun, Wu, Geng-Bo
• Format: Article
• Language: English
• Subjects: Heterodyne detector array; spatial power divider (SPD); terahertz (THz); transmitarray (TA); wideband
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2024.3507173

This article presents a 3-dimensional (3-D) printed wideband M \times M terahertz (THz) spatial power divider (SPD) based on the two-stage phase optimization method. It consists of a feed source and two cascading transmitarrays (TAs), providing independent manipulation of amplitude and phase for M \times M focuses. To generate the electric field distribution with equal amplitude and phase for M \times M focuses with a small separation, a two-stage phase optimization method is proposed to tune the phases of TAs. The electric field distribution on the target plane with M \times M focuses remains constant within a wide bandwidth by using the height-varying dielectric TA element with a linear phase shift. Two 270-GHz 3-D printed 2 \times 2 and 4 \times 4 THz SPDs with a focus separation of 2.2 mm are designed and fabricated. For the 2 \times 2 and 4 \times 4 THz SPDs, the measured amplitude and phase imbalances are in the range of 0.2-0.7 dB and 6 ^{\circ} -10 ^{\circ} within 230-320 GHz for the former and 1-1.6 dB and 9 ^{\circ} -17 ^{\circ}