Over-the-Air Characterization of a Steerable Sub-THz Si Lens and On-Chip Antenna System

Sub-terahertz (THz) frequencies have the potential to realize the extremely high data rates envisioned for upcoming sixth generation (6G) wireless communications. Moving to this range causes several technological and practical challenges for measurements and testing. This work presents a characterization technique for over-the-air (OTA) testing of a sub-THz lens and on-chip antenna system operating at the WR3.4 frequency band (220-330 GHz). The measurement approach uses a narrowband modulated transmission signal fed through a narrowband frequency extender to produce the highest power for long detection range. At the receiver (Rx) side, the output of the on-chip antenna is connected to a power detector. The detector downconverts the signal to the kHz-range modulation frequency, and the resulting response provides information on the antenna response. The use of a low-noise amplifier (LNA) between the antenna and detector to boost sensitivity and enable longer detection ranges is also considered. Several key parameters have been studied in simulations and measurements, and the general agreement between the results is good. The proposed measurement technique is a viable candidate for testing integrated on-chip antennas, especially in situation where the antenna or system layout is challenging for alternative experimental approaches.