New SAR test requirements for computers with antennas built into displays in IC certification

      In January 2011, Industry Canada revised its RF exposure standard "RSS-102". The biggest change is that a new supplementary test procedure document (SPR)-001 needs to be referenced in SAR testing. SFR-001 is mainly a supplementary document for the SAR evaluation test requirements and methods for the body model of laptop computers (Laptop mode 1/Tablet mode 2) with antennas built into the display. The specific contents are as follows:

      The following definition is given for Specific Absorption Rate (SAR) assessment in "Industry Canada's RSS-102 - Radio Frequency (RF) Exposure Compliance of Radio Communication Apparatus (All Frequency Bands) Issue 4, published in March 2010": Specific absorption rate (SAR) assessment is a method of assessing SAR levels using a device that uses physical measurements and mathematical calculations. If the device is actually used at a distance of less than or equal to 20 cm from the user, then a SAR assessment is necessary.

      Laptops with antennas built into the display (Laptop Mode 1/Tablet Mode 2) are sometimes less than or equal to 20 cm away from the user, so they need to undergo a SAR evaluation test. In addition, this document specifically mentions that it is not enough to simply state in the instruction manual that the user should be at least 20 cm away from the device.

      The following are the test steps specifically for laptops with antennas built into the display:

      Unless the corners of the notebook (including the built-in antenna) do not meet the requirements of the flat model, such as the antenna is on the base of the notebook, the Canadian Industry Department (IC) requires that all sides of the notebook with the antenna built into the display need to face the flat model for SAR evaluation testing. In addition, the minimum distance model of the device cannot be less than 25 mm, which is used to simulate the distance between the user and the device. If the distance of 25 mm is already a "worst" test mode, then there is no need to add other test modes.

      i) If the built-in antenna is on the back of the laptop monitor, then the back needs to face the flat model and the test should be conducted at a distance of no less than 25mm;
      ii) If the antenna is placed on the edge of the monitor, then this edge needs to face the flat model and the test
      should be conducted at a distance of no less than 25mm; iii) If the antenna is placed at the corner of the monitor, both sides of the corner and the back need to face the flat model and the test should be conducted at a distance of no less than 25mm;

      For user test requirements, please refer to FCC KDB 447498 and KDB 616217 (SAR test level of host):

      1) SAR testing is based on a single module level;
      2) SAR testing is based on a typical host;
      3) SAR testing is based on a special host;

      Applicants are required to include a brief description of the various test modes in RF Exposure.

      If the laptop's RF output power meets the power level requirements in RSS-102 Section 2.5.1, then all transmitter SAR evaluation tests for users can be exempted. At the same time, if the EUT complies with RSS-102 Section 2.5.1, the applicant needs to provide a signed declaration of compliance (see Annex C on RSS-102). This declaration of compliance needs to include a calculation process of how the transmitter output power is obtained. If the EUT does not meet the corresponding exemption limit, then it needs to undergo a full SAR evaluation test. It is particularly important to emphasize that the above exemption evaluation does not mean that it does not need to comply with the RSS-102 directive.

 

      Note: 1. Laptop mode is defined as the operating mode in which the display is opened vertically and the screen is facing the keyboard when in use
          . 2. Tablet mode refers to a laptop computer with a changeable screen. It is defined as an operating mode in which the display can be folded on the keyboard and the screen is facing upward. Its screen can be switched between vertical and horizontal orientations, and during normal use, the position of the screen changes so that it can become closer to the user.