RF exposure calculation

FCC ID: KA2DWL3200APA1

RF Exposure Info

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FCCID_511533

FCC ID: KA2DWL3200APA1




                     RF EXPOSURE REPORT

                     REPORT NO.: SA931214H02
                      MODEL NO.: DWL-3200AP


                     ACCORDING: FCC Guidelines for Human Exposure
                                IEEE C95.1


                      APPLICANT:   D-LINK Corporation

                       ADDRESS:    No.8, Li-shing Road VII, Science-based
                                   Industrial Park, Hsinchu, Taiwan.




                      ISSUED BY: Advance Data Technology Corporation

                LAB LOCATION: No. 81-1, Lu Liao Keng, 9 Ling, Wu Lung
                              Tsuen, Chiung Lin Hsiang, Hsin Chu Hsien,
                              Taiwan, R.O.C.




ADT No.: 931214H02                   1


FCC ID: KA2DWL3200APA1




                        RF Exposure Measurement
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




ADT No.: 931214H02                      2


FCC ID: KA2DWL3200APA1




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


Pd is the limit of MPE, 1 mW/cm2. 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 is a stand alone radio device. So under normal use condition, it is easy to be re-
located in the place where at least 20 cm 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.




ADT No.: 931214H02                      3


FCC ID: KA2DWL3200APA1




6 Test Results

6.1 Antenna Gain
    Antenna No.      The maximum Gain      Cable lose (dB)
         3                7.61 dBi                0
         5                5.89 dBi                0
         9                12.0 dBi              3.2
        10                 5.0 dBi                0

6.2 Output Power Into Antenna & RF Exposure value at distance 20cm:

 For Part 802.11b:
 Antenna 3
                  Channel                                           Limit of
                               Output Power to   Power Density
   Channel       Frequency                                       Power Density
                               Antenna (mW)        (mW/cm2)
                   (MHz)                                           (mW/cm2)
      1             2412         90.1571138      0.103449675          1.0
      6             2437         162.181010      0.186092611          1.0
      11            2462         86.8960429      0.099707799          1.0

 Antenna 5
                  Channel                                           Limit of
                               Output Power to   Power Density
   Channel       Frequency                                       Power Density
                               Antenna (mW)        (mW/cm2)
                   (MHz)                                           (mW/cm2)
      1             2412         90.1571138      0.069619216          1.0
      6             2437         162.181010      0.125235983          1.0
      11            2462         86.8960429      0.067101021          1.0

 Antenna 9
                  Channel                                           Limit of
                               Output Power to   Power Density
   Channel       Frequency                                       Power Density
                               Antenna (mW)        (mW/cm2)
                   (MHz)                                           (mW/cm2)
      1             2412         90.1571138      0.136059581          1.0
      6             2437         162.181010      0.244753623          1.0
      11            2462         86.8960429      0.131138173          1.0

 Antenna 10
                  Channel                                           Limit of
                               Output Power to   Power Density
   Channel       Frequency                                       Power Density
                               Antenna (mW)        (mW/cm2)
                   (MHz)                                           (mW/cm2)
      1             2412         90.1571138      0.056719074          1.0
      6             2437         162.181010      0.102030292          1.0
      11            2462         86.8960429      0.054667489          1.0



ADT No.: 931214H02                  4


FCC ID: KA2DWL3200APA1




 For Part 802.11g:
 Antenna 3
                  Channel                                         Limit of
                             Output Power to   Power Density
   Channel       Frequency                                     Power Density
                             Antenna (mW)        (mW/cm2)
                   (MHz)                                         (mW/cm2)
      1             2412       63.095734        0.0723984           1.0
      6             2437       199.52623        0.2289439           1.0
     11             2462       63.095734        0.0723984           1.0
   Turbo 6          2437       60.255959         0.06914            1.0

 Antenna 5
                  Channel                                         Limit of
                             Output Power to   Power Density
   Channel       Frequency                                     Power Density
                             Antenna (mW)        (mW/cm2)
                   (MHz)                                         (mW/cm2)
      1             2412       63.095734        0.0487225           1.0
      6             2437       199.52623        0.1540739           1.0
     11             2462       63.095734        0.0487225           1.0
   Turbo 6          2437       60.255959        0.0465296           1.0

 Antenna 9
                  Channel                                         Limit of
                             Output Power to   Power Density
   Channel       Frequency                                     Power Density
                             Antenna (mW)        (mW/cm2)
                   (MHz)                                         (mW/cm2)
      1             2412       63.095734        0.0952202           1.0
      6             2437       199.52623        0.3011127           1.0
     11             2462       63.095734        0.0952202           1.0
   Turbo 6          2437       60.255959        0.0909346           1.0

 Antenna 10
                  Channel                                         Limit of
                             Output Power to   Power Density
   Channel       Frequency                                     Power Density
                             Antenna (mW)        (mW/cm2)
                   (MHz)                                         (mW/cm2)
      1             2412       63.095734        0.0396944           1.0
      6             2437       199.52623        0.1255247           1.0
     11             2462       63.095734        0.0396944           1.0
   Turbo 6          2437       60.255959        0.0379078           1.0




ADT No.: 931214H02                5



Document Created: 2005-01-25 15:54:23
Document Modified: 2005-01-25 15:54:23

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