Posted on August 19th 2019 by Kass
On August 6, 2019, Canada’s Department of Innovation, Science, and Economic Development (ISED) released a draft of the Supplementary Procedure for Assessing Radio Frequency Exposure Compliance of Portable Devices Operating in the 60 GHz Frequency Band (57 GHz - 71 GHz). SPR-003 delineates general test methods to assess compliance with power-density exposure limits described in RSS-102 for portable devices operating in the 60 GHz frequency band.
ISED is currently seeking comment on SPR-003, Issue 1. All comments should be submitted no later than October 18, 2019. For more information, click here.
Below is a summary of the RF exposure compliance assessment approach, as detailed in SPR-003. You can find the comprehensive draft released by ISED here.
RF Exposure Compliance Assessment Approach
Preparation for the device under test (DUT)
Preparation is based on the principles described in the IEC TR 63170 and consists of the determination of:
Evaluation Surface: A 0 mm evaluation surface from the enclosure must be determined for a detachable laptop/ tablet or wearable with a transmitter operating in the 60 GHz frequency band. Each side/edge of the DUT must be evaluated unless meeting the exclusion requirement.
Test Position: A smartphone with a transmitter operating in the 60 GHz frequency band must be tested as defined in the RSS-102, where main positions are the cheek and tilt positions against virtual inner shell of modified SAM phantom. Each position of the smartphone must be evaluated unless certain positions provide conservative values compared to other required positions.
Test Frequencies: To determine the number of test frequencies, use the approach and formula in Section 6.2.4 of the IEC TR 63170.
Configuration: Use the modulation, coding scheme index, and data rate producing maximum output power as the test configuration to be assessed. The duty cycle should be based on the inherent property of transmission technology.
Computational Modelling
Computational modelling is optional and may be used to determine the configurations with the highest psPD. Details of this approach include:
A minimum of 1 configuration per array/sub array should be conducted.
All configurations yielding psPD within 3dB of RF exposure limits will be measured up to 3 configurations per channel.
All information, including electronic copies of simulation and modelling information, must be submitted.
Applicant is responsible for compliance with limits specified in RSS-102.
Applicant can elect to conduct the entire power density assessment by measuring all possible antenna configurations.
CAD Model
The DUT model used for computations must be identical to the actual device that will be assessed.
CAD files should be made available upon ISED’s request in an available format.
Objects and layers within the CAD file should be organized in a table.
Materials and dielectrics properties must be identified.
Conducting parts should be integrated into the CAD file with corresponding frequency dependent dielectrics properties when possible.
When and if a truncated model is used, it should be documented in the RF technical brief that “truncation is of negligible impact on the RF characteristics of the DUT model.”
Measurements
Test environment should be free of ambient signals; if not, background noise should be measured and removed from final measurements.
Measurement system must be capable of assessing near-field psPD on the evaluation surface; measuring E-field and/or H-field; and computing local and spatial averaged power density from measured data.
Reconstruction algorithms can be used to generate the H-field from the E-field and other field information.
Refer to Table 1 for field measurement units.
System check to ensure measurement system is operating within specifications and without component failure should be completed prior to performing power density measurements based on Annexes A and C of the IEC TR 63170.
See SPR-003 for formulas.
Routine system checks should be conducted 24 hours prior to performing power density measurements.
Test procedure and results should be documented in RF exposure technical brief.
Uncertainty Evaluation
Applicants should provide computational and measurement uncertainty budgets.
Below are the changes that have been made to the uncertainty budget table found in 7.4 of IEC/IEEE 62704-1:
Replacing the evaluation of phantom dielectrics is an evaluation of dielectric parameters of the DUT.
Impact of lossy conductors will be evaluated.
The total numerical uncertainty budget should additionally contain the uncertainty associated with field maximization technique.
In regards to the measurement uncertainty budget, the following components should be addressed in addition to the uncertainty components described in section 7.3 of the IEC TR 63170:
Uncertainty associated with the field, taking into account field probe frequency response, sensor cross coupling, field impedance dependence, readout electronics, and response time.
Uncertainty component introduced by power density scaling.
Spatial-averaging uncertainty.
RF Exposure Technical Brief This brief should encompass all information required to perform a repeated simulation. You can find a list of the required information in Annex A. Rhein Tech Laboratories, Inc. is an accredited ISED laboratory, recognized under the Canadian Requirements for Wireless Testing Laboratories. We perform tests for Canadian RF product approval and are equipped to assist with international approvals. For further questions on our services, contact us today. Sources: https://www.rabc-cccr.ca/open-consultations/ised-supplementary-procedure-spr-003-issue-1-supplementary-procedure-for-assessing-radio-frequency-exposure-compliance-of-portable-devices-operating-in-the-60-ghz-frequency-band-57-ghz-71/