RF Exposure Info

FCC ID: PYFAR400US

RF Exposure Info

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FCCID_451905

Document 8096-MPE, Rev. 0 RF Exposure Test Report June 2004
FCC ID: PYFAR400US Washington Laboratories, Ltd

Maximum Permissible Exposure Test Report

for

FCC ID: PYFAR400US
1.0 Introduction

This report has been prepared on behalf of Matrics, Inc. FHSS RFID Device to show compliance
with the RF exposure requirements as defined in FCC §1.1307.

1.1 Requirements

Three different categories of transmitters are defined by the FCC in OET Bulletin 65. These
categories are fixed installation, mobile, and portable and are defined as follows:

Fixed Installations: fixed location means that the device, including its antenna, is
physically secured at a permanent location and is not able to be easily moved to another
location. Additionally, distance to humans from the antenna is maintained to at least 2
meters.

Mobile Devices: a mobile device is defined as a transmitting device designed to be used
in other than fixed locations and to be generally used in such a way that a separation
distance of at least 20 centimeters is normally maintained between the transmitter's
radiating structures and the body of the user or nearby persons. Transmitters designed to
be used by consumers or workers that can be easily re-located, such as a wireless modem
operating in a laptop computer, are considered mobile devices if they meet the 20
centimeter separation requirement. The FCC rules for evaluating mobile devices for RF
compliance are found in 47 CFR §2.1091.

Portable Devices: a portable device is defined as a transmitting device designed to be
used so that the radiating structure(s) of the device is/are within 20 centimeters of the
body of the user. Portable device requirements are found in Section 2.1093 of the FCC's
Rules (47 CFR§2.1093).

For this test report the Matrics RFID device with 6dBi antenna is considered a fixed installation
as it is used for the purpose of reading tags.

The FCC also categorizes the use of the device as based upon the user’s awareness and ability to
exercise control over his or her exposure. The two categories defined are Occupational/
Controlled Exposure and General Population/Uncontrolled Exposure. These two categories are
defined as follows:

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Document 8096-MPE, Rev. 0 RF Exposure Test Report June 2004
FCC ID: PYFAR400US Washington Laboratories, Ltd

Occupational/Controlled Exposure: In general, occupational/controlled exposure limits
are applicable to situations in which persons are exposed as a consequence of their
employment, who have been made fully aware of the potential for exposure and can
exercise control over their exposure. This exposure category is also applicable when the
exposure is of a transient nature due to incidental passage through a location where the
exposure levels may be higher than the general population/uncontrolled limits, but the
exposed person is fully aware of the potential for exposure and can exercise control over
his or her exposure by leaving the area or by some other appropriate means. Awareness
of the potential for RF exposure in a workplace or similar environment can be provided
through specific training as part of a RF safety program. If appropriate, warning signs
and labels can also be used to establish such awareness by providing prominent
information on the risk of potential exposure and instructions on methods to minimize
such exposure risks.

General Population/Uncontrolled Exposure: The general population / uncontrolled
exposure limits are applicable to situations in which the general public may be exposed
or in which persons who are exposed as a consequence of their employment may not be
made fully aware of the potential for exposure or cannot exercise control over their
exposure. Members of the general public would come under this category when
exposure is not employment-related; for example, in the case of a wireless transmitter
that exposes persons in its vicinity. Warning labels placed on low-power consumer
devices such as cellular telephones are not considered sufficient to allow the device to be
considered under the occupational/controlled category, and the general
population/uncontrolled exposure limits apply to these devices.

Since there are no warnings or training associated with this unit and it can be used by anyone,
the Matrics RFID device is evaluated to the General Population/Uncontrolled Exposure limits.

1.2 Radio Frequency Radiation Exposure Evaluation

The highest RF output power of the unit was measured at 30dBm at 915 MHz. According to
§1.1310 of the FCC rules, the power density limit for General Population/Uncontrolled Exposure
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at 915 MHz is 0.610mW/cm . The MPE is calculated to show the required separation distance
that must be maintained during installation to maintain compliance with the power density limit.
The following formula was used to calculate the Power Density:
PG
S=
4πR 2
Where:
S = Power Density
P = Output Power at the Antenna Terminals
G = Gain of Transmit Antenna (linear gain)
R = Distance from Transmitting Antenna
To solve for the minimum mounting distance required:

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Document 8096-MPE, Rev. 0 RF Exposure Test Report June 2004
FCC ID: PYFAR400US Washington Laboratories, Ltd

PG
R=
4πS

For this device, the calculation is as follows:
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S = 0.610 mW/cm
P = Output Power = 1000 mW
G = Worst Case Gain = 6dBi = INVLOG(6/10) = 4

(1000) × (4)
R= = 23 cm (Based on continuous transmission)
4 × π × 0.61

Based on the above calculation the Matrics AR 400 Reader antenna must be mounted such that it
provides a minimum separation distance of 23 cm. The User’s Manual addresses the mounting
location in the instructions for mounting the reader.

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Document Created: 2004-06-18 14:04:57
Document Modified: 2004-06-18 14:04:57

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