DASY8/6 Module mmWave V3-0 Solves the Remaining Close Near-Field Problem

SPEAG has integrated a novel equivalent source reconstruction algorithm into DASY8/6 that generates Maxwell solutions for the reactive near field from measurements. The first implementation provides accurate and simple certification of Wi-Fi 6E devices.

The previously developed plane-to-plane reconstruction algorithm, which is at the core of DASY8/6 Module mmWave V2-4, comes with two major shortcomings: it is limited (i) to distances larger than λ/5 and (ii) to planar surfaces, i.e., phones with extruded camera modules or devices like virtual reality glasses could not be evaluated easily.

Research Project “Equivalent Source Reconstruction Algorithm”

To address these shortcomings, the IT’IS Foundation and ETH Zurich, supported by SPEAG and ZMT Zurich MedTech AG, launched a research project in 2020 with the goal of developing a method to reconstruct the complete electromagnetic model of any transmitter, based only on near-field amplitude measurement data, which can be used from the surface of the device to the far-field. The result of this fruitful collaboration is the equivalent source reconstruction (ESR) algorithm. This algorithm models an unknown and inaccessible radiator as a set of distributed auxiliary sources that are optimized to reconstruct the measured near fields. As a result, the radiator inside a black box can be replaced by these equivalent sources in any radiation problem, including exposure assessment scenarios.

The novel method has been submitted for publication and in parallel SPEAG and ZMT have started to implement this method into the DASY8/6 systems and Sim4Life software.

This breakthrough will revolutionize simulations and measurements as both can now be used interchangeably in research, R&D, and certification.

Simplified Test Procedure for Wi-Fi 6E Devices

In recent months, SPEAG has accelerated the implementation of the new ESR algorithm, and DASY8/6 Module mmWave V3-0 offers its customers a simplified solution for evaluating devices with WI-FI 6E (IEEE 802.11ax in the 6 GHz band). To date, SPEAG has only been able to provide a cumbersome workaround with very limited accuracy, but testing of Wi-Fi 6E devices is now precise and easy, as demonstrated in the video.

Module mmWave V3-0 is optimized for testing Wi-Fi 6E devices operating in the U-NII-5/6/7/8 bands. With the next version, V3.2, which will be released soon, the new method will be generalized and also applicable for frequencies above 10 GHz. The simulation model of the transmitter generated by DASY8/6 can then be directly imported into Sim4Life V7.0 – more information will be made available with the release of Sim4Life V7.0 and SEMCAD V20.0 on March 1st, 2022.

Figure 1: Electric field reconstructed in Sim4Life V7.0 with the ESR algorithm at 2 mm from the device under test surface

DASY8/6 Module mmWave V3-0, together with the updated manuals, can be downloaded here. The Application Note “Demonstrating Compliance of Devices Operating between 6–10 GHz: Updated Interim Procedures (Version 4.0)” has also been updated to provide guidance on how to meet the latest FCC and ISED requirements.