Dec 20, 2022

DASY8/6 Module mmWave V3.2: Equivalent Source Generalized Reconstruction

Equivalent source reconstruction has proven to be THE solution for evaluating power density in the highly reactive near field, i.e., at distances as close as λ/25. Regulators have recognized this and recently approved the new method. With Module mmWave V3.2, SPEAG has further generalized the equivalent source reconstruction method to expand its scope of application.

The equivalent source reconstruction (ESR) method for reconstructing a set of auxiliary sources in the radiating antenna is a rather old idea. However, here – for the first time – ESR is based on field measurements in the close reactive near field, which preserves the characteristics of the purely reactive components that would be lost in measurements at greater distances. We have rigorously validated Module mmWave V3.2 for evaluation of power density (PD) at distances as close as λ/25 to the device under test (DUT), i.e., 2 mm at 6 GHz.

Reconstructed E-field at 2 mm of a 10 GHz pyramidal horn loaded with a slot array


In recent months, we have further generalized the implementation of ESR in DASY8/6 Module mmWave, automated the grid selection, and verified the quality of the conversions. These improvements mean that V3.2 is now robust for measurements at frequencies up to 110 GHz and can be used by operators with no intrinsic knowledge of the method. 

ESR Approved by Regulators

During the October 2022 Telecommunication Certified Body (TCB) Council Workshop, the US Federal Communications Commission (FCC) confirmed that the ESR method is approved for assessment of the PD of mobile devices operating in the 6 – 8.5 GHz frequency range.

FCC procedures for PD evaluations in the 6-8.5GHz frequency range


SPEAG will continue to collaborate closely with national regulators to further extend the validity range of the ESR method. In the next release, we will add incident PD evaluations conformal to the device surface and further reduce the reconstruction time.

New 6.5 GHz Verification Source

At the request of customers and regulators, we have also developed the new RP6500V1 coaxial-fed rectangular patch verification source operated at 6.5 GHz for system checking of PD and absorbed power density (APD) systems in the Wi-Fi 6 GHz bands. The validation results are available in this report. The RP6500V1 will become available to our DASY customers in March 2023 for on-site validation of the PD / APD setups. 

Reconstructed E-field at 2 mm for the new RP6500V1 patch array antenna

The DASY8/6 Module mmWave V3.2 software installer and manual are available for download on our website.

If you have any suggestions or would like to receive further information, please contact us at

Kind regards,

Your DASY Team