New DASY Software Feature: Improved Precision for Capacitive Coupled Sources Ahead of Standardization

Since the publication of the IEC 62209-2 standard in 2010, thinner and flatter devices with distributed electrically short antennas and/or feeding networks close to the surface, i.e., just below the cover, have been developed. Concomitant new regulatory requirements demand compliance testing of these devices at a separation distance closer than 5 mm to the outside surface of the phantom shell. Especially in cases where the device is in direct contact with the phantom, the induced fields may be very localized, particularly if the radiofrequency (RF) coupling mechanism is predominately of a capacitive nature. The specific absorption rate (SAR) is not only localized in the plane parallel to the phantom surface but also decays very steeply normal to surface. To ensure the same uncertainty for these devices as for all other sources inducing more distributed SAR patterns, measurements on a sufficiently fine grid are crucial. Since the minimal grid requirements of current standards are, however, not sufficiently defined to address this problem, the IEC 62209-2 standardization group recently submitted an amendment addressing this topic, publication of which is expected later this year.

Thanks to a new integrated feature in cDASY6 and DASY52, SPEAG customers already today have the possibility to quickly and precisely identify cases in which the applied grid is not sufficient and additional measurements points are needed. After the amendment is officially approved, the system will add these points automatically to future measurements without any user intervention. The measurement time for compliance demonstration of standard devices is only increased minimally (<1%) due to SPEAG’s smart implementation.

A study performed by our research partner, the IT’IS Foundation, demonstrates the increased precision by evaluating the VPIFA antennas defined in the IEC PAS 63151. The user guidelines of the new DASY-feature are provided in the Application Note “SAR Testing at Close Distances to the Phantom”.

For further information, please contact us at info@speag.swiss.