Speaker
Description
In recent years, millimeter-wave bands have been increasingly utilized in wireless communication technologies, and the exploitation of even higher frequency bands is anticipated in the future. IEC/IEEE are actively cooperating in advancing discussions towards the international standardization of compliance assessment methods for absorbed power density (APD), which serves as the basic restriction in international guidelines. Our research group has proposed the inverse source method (ISM) for APD evaluation. We have been investigating absorbed power density measurement methods using a planar scanning near-field measurement system with ISM post-processing, and evaluation is being performed in three target center frequencies namely 28, 40, and 60 GHz using a single measurement system. In this study, we investigated the key measurement parameters (measurement area, phantom size, spatial resolution, and necessary measurement distances) of our proposed method at 28 GHz, 40 GHz, and 60 GHz frequency bands. Through our measurements at 28, 40, and 60 GHz, we have discovered that the standard gain horn antenna presents the most significant measurement challenges among the tested DUTs even when using continuous wave (CW) signals. This difficulty arises from its narrow and highly directive beam characteristics, which make it particularly sensitive to position of the reference antenna. A detailed uncertainty evaluation of the APD measurement system at 28, 40, and 60 GHz is currently underway and will be reported in future work. This evaluation will provide the measurement system's accuracy and reliability across different frequency bands.
