RF Exposure Calculation

FCC ID: H8NWLL4030

RF Exposure Info

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FCCID_498371

FCC ID: H8NWLL4030 RF EXPOSURE REPORT REPORT NO.: SA920624R02D MODEL NO.: WLL4030 ACCORDING: FCC Guidelines for Human Exposure IEEE C95.1 APPLICANT: ASKEY COMPUTER CORP. ADDRESS: 10F, NO.119, CHIENKANG RD., CHUNG-HO, TAIPEI TAIWAN R.O.C. ISSUED BY: Advance Data Technology Corporation LAB ADDRESS: No. 47, 14th Ling, Chia Pau Tsuen, Lin Kou Hsiang 244, Taipei Hsien, Taiwan, R.O.C. TEST LOCATION: No. 19, Hwa Ya 2n d Rd., Wen Hwa Tsuen, Kwei Shan Hsiang, Taoyuan Hsien 333, Taiwan, R.O.C. Report No: SA920624R02D 1

FCC ID: H8NWLL4030 RF Exposure Measurement (Mobile Device) 1. Introduction In this document, we try to prove the safety of radiation harmfulness to the human body for our product. The limit for Maximum Permissible Exposure (MPE) specified in FCC 1.1310 is followed. The Gain of the antenna used in this product is measured in a Fully Anechoic Chamber (FAC) calibrated for antenna measurement in ADT, and also the maximum total power input to the antenna is measured. Through the Friis transmission formula and the maximum gain of the antenna, we can calculate the distance, away from the product, where the limit of MPE is reached. Although the Friis transmission formula is a far field assumption, the calculated result of that is an over-prediction for near field power density. We will take that as the worst case to specify the safety range. 2. RF Exposure Limit According to FCC 1.1310: The criteria listed in the following table shall be used to evaluate the environmental impact of human exposure to radio-frequency (RF) radiation as specified in 1.1307(b) LIMITS FOR MAXIMUM PERMISSIBLE EXPOSURE (MPE) Frequency Electric Field Magnetic Field Power Density Average Time Range Strength (V/m) Strength (A/m) (mW/cm2) (minutes) (MHz) (A)Limits For Occupational / Control Exposures 300-1500 … … F/300 6 1500-100,000 … … 5 6 (B)Limits For General Population / Uncontrolled Exposure 300-1500 … … F/1500 6 1500-100,000 … … 1.0 30 F = Frequency in MHz Report No: SA920624R02D 2

FCC ID: H8NWLL4030 3. Friis Formula Friis transmission formula : Pd = (Pout*G) / (4*pi*r2) where Pd = power density in mW/cm2 Pout = output power to antenna in mW G = gain of antenna in linear scale Pi = 3.1416 R = distance between observation point and center of the radiator in cm If we know the maximum Gain of the antenna and the total power input to the antenna, through the calculation, we will know the MPE value at distance 20cm. Ref. : David K. Cheng, Field and Wave Electromagnetics, Second Edition, Page 640, Eq. (11-133). 4 EUT Operating condition The software provided by Manufacturer enabled the EUT to transmit and receive data at lowest, middle and highest channel individually. 5. Classification This device is not fixed inside the host equipment, it is connected with host through wire. So it is easy to be re-located in the place where at least 20cm far away from the body of the user. Warning statement to the user for keeping at least 20cm or more separation distance with the antenna should be included in users manual. So, this device is classified as Mobile Device. Report No: SA920624R02D 3

FCC ID: H8NWLL4030 6 Test Results 6.1 Antenna Gain The maximum Gain measured in Fully Anechoic Chamber are 0.69dBi or 1.172 (numeric) for 2.4GHz, 4.91dBi or 3.097 (numeric) for 5.0GHz. 6.2 Output Power Into Antenna & RF Exposure at Distance 20cm: For 2.4GHz: Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2 ) (MHz) (mW/cm2 ) 1 2412 40.664 0.009 1.0 6 2437 40.272 0.009 1.0 11 2462 40.272 0.009 1.0 For 5GHz Channel Limit of Output Power to Power Density Channel Frequency Power Density Antenna (mW) (mW/cm2 ) (MHz) (mW/cm2 ) 1 5180 32.509 0.020 1.0 4 5240 32.885 0.020 1.0 5 5260 41.976 0.026 1.0 8 5320 41.400 0.026 1.0 9 5745 65.163 0.040 1.0 12 2805 65.163 0.040 1.0 Note: Both of the 2.4GHz and 5GHz bands can not transmit simultaneously, the maximum power density value is 0.009mW/cm 2 (for 2.4GHz), and 0.040mW/cm 2 (for 5GHz) which is less than the 1mW/cm 2 limit. Report No: SA920624R02D 4


Document Created: 2004-12-17 09:22:07
Document Modified: 2004-12-17 09:22:07
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