cSAR3D V4.0 marks a major advancement for vector measurement-based array measurement systems: the newly integrated "X10 Combiner", a novel algorithm developed by the IT'IS Foundation that reliably combines multiple randomly shifted individual measurements onto a high-resolution grid, eliminates the physical limitation of the sensor density of fixed arrays by virtually increasing the spatial sampling resolution. As a result, the frequency range of cSAR3D has been extended to 10 GHz and the uncertainty has been reduced to 30% for any source. The timing is perfect as the Federal Communications Commission (FCC) and other regulators have recently opened unlicensed spectrum above 6 GHz and the soon-to-be-published IEC/IEEE Standard 62209-1528 includes SAR measurement procedures up to 10 GHz.
The key new features of cSAR3D V4.0 are:
The user video nicely illustrates these new features and how easy they are to use.
The spatial combining algorithm, called the X10 Combiner, is easy to use and does not require any new equipment. The software guides the user to make multiple measurements with the device at random positions on the cSAR3D Flat. It then automatically determines the shift in the device position from the specific absorption rate (SAR) distribution and uses these shifts to reconstruct the 3D pattern using these high-density measurement points. Thus, the physical resolution can be overcome, allowing measurement of devices having very sharp SAR distributions.
SPEAG extended the frequency range of DASY6 last year to include the 6 – 10 GHz frequency range and has now done the same for the cSAR3D Flat. This meets the emerging needs of wireless device manufacturers to test Wi-Fi and 5G devices in this frequency range.
No change is needed to the cSAR3D hardware. The miniature sensors inside the phantom have good sensitivity and are electrically small at 10 GHz. The tissue-equivalent medium is already compatible with the requirements for dielectric parameters up to 10 GHz. The only requirement is that the cSAR3D Flat or Quad is re-calibrated to include the 6 – 10 GHz frequency range. Note that SPEAG is now accredited to ISO/IEC 17025 for calibration of cSAR3D Flat and Quad at all frequencies in the 650 MHz – 10 GHz range.
cSAR3D V4.0 leads to a significant accuracy improvement for very localized SAR distributions. The full IEC 62209-3 validation (264 test conditions) has been performed on the cSAR3D Flat using the X10 Combiner as well as single measurements. Additional validation tests have been performed in the 6 – 10 GHz frequency range using the X10 Combiner. The results show that all combined values are within +/-1 dB of the target values indicating that the measurement uncertainty when using the X10 Combiner is less than 30% for any source.
Another novelty is that cSAR3D V4.0 also assesses and displays the absorbed power density (also known as epithelial power density in IEEE C95.1) averaged over an area of either 1 cm2 or 4 cm2. These dosimetric limits have been defined by ICNIRP (2020) and IEEE C95.1 (2019) in the frequency range above 6 GHz. It is expected that these new basic restrictions will soon be adopted by regulators.
SPEAG has also improved the measurement speed. The assessment time is now 2.6 s including acquisition, evaluation of 3D field reconstruction, calculation of uncertainty, and graphical output of the results. This also improves throughput for quality assurance testing in factory environments. Wireless device manufacturers have implemented cSAR3D for factory sampling due to its speed and automation features.
cSAR3D V4.0, together with the manual, are available for download here.