Simulation Test Report

FCC ID: PD917265NG

RF Exposure Info

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FCCID_2528089

Intel® Model: 17265NGW LC, FCC ID:
PD917265NG

HP PC model HSTNN-I22C Power Density report for FCC

January 2015

Revision 2.31

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2

Document scope

Table of Contents
1 Document scope ........................................................................................................... 6
2 Background – WiGig system operation ......................................................................... 7
2.1 System block diagram ........................................................................................... 7
2.2 Beam forming ...................................................................................................... 7
2.3 Tx Duty Cycle ...................................................................................................... 7
2.4 Intel 17265NGW module in HP PC model HSTNN-I22C .............................................. 8
3 Simulation Methodology ............................................................................................... 9
3.1 Electromagnetic Simulation .................................................................................... 9
3.1.1 Tool description ................................................................................... 9
3.1.2 Solver description ................................................................................ 9
3.1.3 Evaluting near field power ..................................................................... 9
3.1.4 Power averaging ................................................................................. 10
3.1.5 Dielectric parameters .......................................................................... 10
3.2 3D Models used in the simulation .......................................................................... 11
3.2.1 RFEM housing inside Intel 17265NGW LC module .................................... 11
3.2.2 Closest distance to the body of an end user ........................................... 11
3.2.3 Metals in proximity of the RFEM ............................................................ 11
3.3 Antenna feed ...................................................................................................... 11
4 Simulation results....................................................................................................... 13
4.1 Power averaging .................................................................................................. 13
4.2 Power Density ..................................................................................................... 15
5 Validation of Simulation results .................................................................................. 16
5.1 Correlation of power density in far field .................................................................. 16
5.1.1 Far field boundary calculation ............................................................... 16
5.1.2 Lab measurements.............................................................................. 16
5.1.3 Correlation of measurements and simulation .......................................... 17
5.2 Simulating a canonical antenna design ................................................................... 20
6 Summary .................................................................................................................... 23

3

List of Figures

Figure 1 – Intel 17265NGW LC module system block diagram........................................................ 7
Figure 2 - Illustration of evaluation of near field power ................................................................. 9
Figure 3 - Example of Power Density results ...............................................................................10
Figure 4 - Example Mesh visualization of 1cm2 test plane at 2.48mm distance from RFEM ................10
Figure 5 – Simulation mesh for RFEM module .............................................................................12
Figure 6 – Maximum complex E-field and H-field over 1cm2 with 100% duty cycle at 2.48mm
distance...........................................................................................................13
Figure 7 - Power Density mesh for maximum 1cm2 test plane at 100% duty cycle and distance of
2.48mm ..........................................................................................................14
Figure 8 – HFSS Simulation results in Ch2 ..................................................................................15
Figure 9 - Comparison of Power Density simulation to lab measurements.......................................17
Figure 10 – Zoom-in on the comparison of simulation to lab measurements ...................................18
Figure 11 – Estimate EIRP of Simulation vs. lab measurements and far field boundary (Ch2) ...........19
Figure 12 - Simulation of a single Patch antenna .........................................................................20
Figure 13 – Patch Antenna Gain ................................................................................................20
Figure 14 – Simulation 3D structure ..........................................................................................21
Figure 15– Power Density of Canonical Patch Antenna .................................................................22

List of Tables
Table 1 – Acronyms 4
Table 2 - Setup parameters and measurement results, Intel Regulatory Lab...................................17
Table 3 – Gain calculation from power density per several distances..............................................21
Table 4 – Summary of simulation results for RF exposure compliance ............................................23

Table 1 – Acronyms

ABS Acrylonitrile butadiene styrene – the plastic type from which the HP model HSTNN-
I22C is built

Ant Antenna

Az Azimuth

BB Base Band

BF Beam Forming

BT Bluetooth

BW Band Width

CAD Computer Aided Design

CPU Central Processing Unit

EIRP Equivalent Isotropically Radiated Power

4

Document scope

El Elevation

EM Electro-Magnetic

GHz Giga Hertz (109 Hz)

IF Intermediate Frequency

MAC Media Access Control

mmWave Milli-Meter Wave

OTP One Time Programmable memory

PC Personal Computer

R&D Research and Development

RF Radio Frequency

RFEM Radio Front End Module

RFIC Radio Frequency Integrated Circuit

RX Receive

SKU Stock Keeping Unit, specific product model version

TPC Transmit Power Control

T/R SW Transmit / Receive Switch

TX Transmit

WiGig Wireless Gigabit Alliance – the alliance that promoted the 60GHz into 802.11ad
standard.

5

1 Document scope
This report is submitted to support the compliance to FCC rule parts §2.1093 and §15.255(g), of Intel
17265NGW LC WiGig module (FCC ID: PD917265NG), including an active antenna array, embedded
inside the HP PC model HSTNN-I22C.
Per the location of the active antenna array (a.k.a. RFEM) in the HP PC model HSTNN-I22C platform,
the distance between the antenna array to the body of an end user, at the closest contact point, will be
in the near field, and consequently accurate power density measurements are not possible.
Therefore, to obtain accurate near field power density results, we used an EM simulation that includes
the RFEM transmitter model, embedded inside the HP PC model HSTNN-I22C 3D model. These results
are documented in the following sections of this report.
To prove the validity of these results, we will show how the results of the same simulation are well
correlated, for far field distances, to lab measurements of Intel 17265NGW LC module inside the HP PC
model HSTNN-I22C platform.
The 2nd chapter provides relevant background on Intel 17265NGW LC module. The 3rd chapter describes
the simulation methodology to determine RF exposure (power density) levels. The 4th chapter includes
simulation results, and 5th chapter the correlation between simulation and lab measurements in far field.
Chapter 6 summarizes the RF-Exposure analysis.

6

Background – WiGig system operation

2 Background – WiGig system operation
2.1 System block diagram
Intel 17265NGW LC module is a solution for WiGig connectivity for various platforms. Intel 17265NGW
LC module can be embedded in conventional clamshell PC as well as modern 2 in 1 platforms (detachable
platforms, e.g., like HP PC model HSTNN-I22C).
Intel 17265NGW LC WiGig module solution is made of an M.2 module connected to an RFEM using one
IF coaxial cable.
M.2 Module: a combo board, including a Wi-Fi / BT chip as well as a WiGig BB chip, which implements
the WiGig MAC, Modem, BF algorithm, and active antenna array module control, as well as the BB + IF
stage circuitry.
RFEM: an active antenna array module, which converts between the IF signal and 60GHz signal. It also
performs the beam forming functionality. The RFEM is slave to the WiGig BB chip – all module control
and algorithms run on the BB chip.

Figure 1 – Intel 17265NGW LC module system block diagram
In typical application the RFEM is located at the top of the lid of a notebook PC, in order to improve the
RF propagation of the communication link.
Due to the detachable nature of the HP PC model HSTNN-I22C platform, both the M.2 module and the
RFEM are located inside the same section of the PC platform. The following picture shows the location
of the M.2 and RFEM module inside the HP PC model HSTNN-I22C platform with a (white) coax cable
connection between them. Please refer to figure 1 in the test setup photos document.

2.2 Beam forming
Achieving high bandwidth communication over 60GHz channels usually requires directional antenna at
the transmitter and receiver sides. In consumer electronics, fixed directional or mechanically rotated
antenna are not practical and electronically steerable antenna are usually used.
In Intel 17265NGW LC module, such electronic steerable antenna array is being used. Beam forming
protocol (defined in the IEEE 802.11ad standard) is used to find the right direction for setting both the
RX and TX antenna directions.
Due to the antenna structure the highest antenna gain is achieved when directing the antenna to the
antenna origin (Az,El)=(0,0).

2.3 Tx Duty Cycle
The WiGig protocol, as defined in IEEE 802.11ad, is packet based with time division multiplexing (TDM).
Intel 17265NGW LC module is configured to guarantee that the Tx-Duty-Cycle, defined as the ratio of

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the duration of all transmissions to the total time, is at most 70% over any 10 seconds period. This was
established by worst case analysis, as derived from full system simulation, and verified by
measurements.
The limited Tx-Duty-Cycle is established based on HW and FW implementation with ~100 ms (102.4
ms) measurement duration and 10 seconds averaging. The 70% duty cycle limitation is guaranteed
independent of user activity, and therefore it adheres to the source-based time-averaging definition in
2.1093(d)(5).

2.4 Intel 17265NGW module in HP PC model HSTNN-I22C
Intel produces several HW SKUs (variations) of Intel 17265NGW module, which target different types
of customer platform products.
HP uses Intel 17265NGW LC module inside the HP PC model HSTNN-I22C platform. This SKU is
characterized by:
1. supporting only channels 2+3
2. Reduced power emission, which translates to:
a. Maximal transmit conducted power of 6.4 dBm aggregated conducted power at the
antenna ports.
b. Maximal TX duty-cycle of 70%.

8

Simulation Methodology

3 Simulation Methodology
3.1 Electromagnetic Simulation
3.1.1 Tool description
For the EM simulation we use the commercially available ANSYS HFSS tool 2014 version. ANSYS HFSS
tool is used in industry for simulating 3-D full-wave electromagnetic fields.

3.1.2 Solver description
The HFSS simulation is done using the Finite Element Method which operates in the frequency domain.
The HFSS is based on an accurate direct solver with first order basis functions.
Time domain WiGig packets can’t be simulated in HFSS simulation due to two reasons:
1. The simulation is done in frequency domain, problematic to add time domain packets.
2. Simulation time would explode if long time domain packets (10’s-100’s uSec) would be added
to the electromagnetic solver that runs on 60GHz simulation.

3.1.3 Evaluting near field power
The simulation calculates the electric and magnetic fields in a fine mesh of points. The average power
density on a given surface is calculated as the surface integral of the Poynting vector:
1
𝑊 = Re ∫( 𝐸⃗ × 𝐻
⃗ ∗ ) ⋅ 𝑛⃗𝑑𝑆
2 𝑆
The power density is calculated in the relevant places (in front of the RFEM outside the HP PC model
HSTNN-I22C platform) on surfaces of 1cm * 1cm. For each distance, the 1cm2 with the maximum power
is chosen as the power for that distance.

Intel 17265NGW LC
module 3D model

Figure 2 - Illustration of evaluation of near field power

9

3.1.4 Power averaging
In the simulation we simulate the power density. Figure 3 below depicts an example of the the overall
power density of the RFEM at a given distance.

Figure 3 - Example of Power Density results
We integrate over the worst case (spatial and channel wise) 1cm2, and use this value. Later, in
chapter 4, we use this worst case in determining the RF exposure level.
HFSS employs the finite element method which the geometric model is automatically divided into a large
number of Tetrahedra in 3D objects or triangles in 2D objects. The value of a vector field quantity (E
field or H field) at point inside each tetrahedron/triangle is interpolated from the vertices and midpoint
of selected edges. HFSS uses iterative process in which the mesh is automatically refined in critical
regions to meet the 2% accuracy criteria (accuracy is better than 0.18 dB).
In the Intel 17265NGW LC module platform, the RFEM is located inside the platform chassis and covers.
The shortest distance between an end user holding the platform and the antenna surface of the RFEM
is 2.48mm. Therefore, the 1cm x 1cm Mesh used to calculate the power density is taken at a distance
of 2.48mm. An example of this Mesh can be seen in the figure below.

Figure 4 - Example Mesh visualization of 1cm2 test plane at 2.48mm distance from RFEM

3.1.5 Dielectric parameters
Three material types are used in the simulation:
1. The PCB that is used for the antenna module. The dielectric constant parameters that are used
for this material are: Permittivity =3.7, tanδ=0.01. The source for this coefficients is the material
manufacturer.
2. The ABS plastic that is used in the Intel 17265NGW LC module platform build, the dielectric
constants parameters for the ABS material are: Permittivity =3, tanδ=0.01. These are the
industry used parameters for ABS plastic at the 60GHz frequency bands.

10

Simulation Methodology
3. Metal (copper) that is used in the active antenna module. The metal is used for the antenna
structure, feed lines, vias etc. In addition metal is used for antenna ground plane (the same
structure in the simulation and the actual module).

3.2 3D Models used in the simulation
3.2.1 RFEM housing inside Intel 17265NGW LC module
3D Intel 17265NGW LC module CAD files are used in the EM simulation to allow correct exposure level
simulation.
Please refer to figure 2 in the test setup photos document to see RFEM placement inside the HP
HSTNN-I22C platform.

3.2.2 Closest distance to the body of an end user
The closest distance between the active antennas to the skin of an end user is when the person holding
the unit and touching the plastic grill. At this case the distance between a hand or body to the active
antenna is 2.48mm.

3.2.3 Metals in proximity of the RFEM
The closest metal to the active antenna is the WWAN antenna, the antenna is located at a lateral distance
of about 2mm from RFEM edge (~5mm from the active element) at a plane that is slightly behind the
RFEM.
Since the WWAN antenna is relatively far away and behind the WiGig antenna ground plane
(wavelength wise @ 60GHz) we don’t foresee the WWAN antenna impacting the WiGig antenna
performance, hence WWAN antenna was not included in the simulation.

3.3 Antenna feed
The EM simulation uses an accurate 3D model of the WiGig antenna. The model includes the antenna
elements as well as their feeding lines.
In the simulation, we excite the antennas at the origin of the antenna structure on the RFEM (the
antenna structure includes the vias, traces and actual antenna element). This via feed point is used as
the interface point for the simulation – and is marked in green in the above diagram. Antenna layers
are fully simulated, including all parts of the PCB and antennas: conducted traces, feeds, antenna
elements and dielectrics. The modeling (mesh resolution) is automatically defined by the simulation tool
to assure better than 2% accuracy. The picture below shows the feeding layer inside the antenna and
the selected mesh resolution.

11

Figure 5 – Simulation mesh for RFEM module

The trace loss from the Si to the antenna feed point ( including trace loss and vias) is incorporated by
the power level at the antenna feed point
In the simulation, all the antenna are excited at the same phase – hence forming a forward looking
beam (boresight direction, (Az,El)=(0,0) ). This is the direction that yields the highest antenna gain.
Note: the lab tests also use the same predefined steering (values of the phase shifters) in order to
create the forward looking beam bore sight direction, (Az,El)=(0,0), the direction with the maximum
antenna gain.
The simulation uses a fixed power feed per element, such that the aggregated conducted output power
at the antenna feed points is 6.4dBm. In addition, the simulation is conducted using 100% TX duty
cycle.

12

Simulation results

4 Simulation results
4.1 Power averaging
The figures below present the Magnitude of the complex E-field and H-field for the worst case 1cm2 test
plane located at 2.48mm from the RFEM, located inside HP PC model HSTNN-I22C.

Figure 6 – Maximum complex E-field and H-field over 1cm2 with 100% duty cycle at

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2.48mm distance
We can deduce from the figure that the resolution of the HFSS simulation at this distance is very high,
hence able to identify the 1cm2 with the worst case (highest) power density.

From the E-Field and H-Field we calculate the power density using the Poynting equation. The result is
shown in the figure below:

Figure 7 - Power Density mesh for maximum 1cm2 test plane at 100% duty cycle and
distance of 2.48mm
Figure 7 was calculated with a resolution of 0.1mm (10,000 points in 1cm 2). The HFSS resolution is
even finer.

14

Simulation results

4.2 Power Density

The following figure shows the worst case power-density (over X-Y position and channels) computed
by the simulation versus the distance from the RFEM.

Figure 8 – HFSS Simulation results in Ch2
Notes for the figure:
1. The minimal distance shown is 0.248 cm, which is the smallest possible distance to the end
user, achieved when touching the HP HSTNN-I22C Platform lid in the nearest point to the RFEM.
2. The maximal power density (spatially averaged over worst 1cm2) in the HFSS simulation is
achieved at 0.248cm, and equals to 1.06mW/cm2 over 100% duty cycle.
3. As explained in section 2.3, the Intel 17265NGW LC module is limited to Transmit at a duty
cycle of 70% over 10sec. Therefore the maximal average (spatial and time) power density over
1cm2 is 1.06 * 0.7 = 0.74mW/cm2.
4. According to HFSS simulation, the EIRP and Power-Density on Channel-3 are lower than those
of Channel-2. Here we present the results for Channel-2, which is the worst-case for RF
Exposure.

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5 Validation of Simulation results
In order to validate the accuracy of the simulation we took a few measures, presented in
this chapter:
1. Correlation of simulated power density in far-field to lab measurements
2. Simulating a simpler “canonical” antenna design
3. Comparison between simulation results and lab measurements

5.1 Correlation of power density in far field
Note – the correlation of power density in far field was done with conducted output power of 7.5dBm &
42.4% Duty cycle. Those values (both power and duty cycle) were used for both lab measurements
and simulation results. After doing UL Fremont lab tests we found that output power level and duty
cycle adjustments are needed. However Intel believes that far field correlation is agnostic to small
output power and correlation adjustments, hence the correlation can be used as is.

5.1.1 Far field boundary calculation
Far field boundary can be estimated using Fraunhofer distance equation:
Equation 2 – Far field boundary calculation
2𝑑2
FarFieldBoundary =
𝜆
In the RFEM, d (largest antenna dimension) = 19mm (counting only the antenna elements that
actually transmit).
λ (wave length) = 4.96mm for channel 2.
So the far field boundary is at distance 14.5cm from the RFEM.

5.1.2 Lab measurements
Measurements setup:
In both lab tests below, both duty cycle and beam forming direction were manually set.
The Duty cycle was set to 42% and the beam forming direction was set to boresight (azimuth &
elevation =0°)
UL Verification Services Inc.
Measurements were taken on December 17th on HP HSTNN-I22C platform with 17265NGW LC module.
Report number: 14U19637-1, Revision B.

Intel Regulatory Lab, Sophia-Antipolis, France
Measurements were taken December 11th on HP HSTNN-I22C platform with 17265NGW LC module, ,
detailed in the below pages. Please refer to figure 3 in the test setup photos document.
In this setup, an average power meter sensor was directly connected to the measuring antenna.
The power meter sensor was wrapped inside absorbing material (as shown on the picture) to avoid
reflections.

16

Validation of Simulation results

The table below concentrates the parameters used, and the measurement results:
Averaged power
Measurement Meas Avg Estimated EIRP density
Parameters: Distance (cm) Power (dBm) (dBm) (mW/cm^2)
Freq (GHz) 60.48 7.248 -20.47 18.87 0.052
Small Aperture Probe Gain (dBi) 10.29 8.248 -20.85 19.65 0.047
waveguide-to-coax Loss (dB) 0.8 9.248 -21.31 20.21 0.042
Duty Cycle (%) 41.16 10.248 -21.82 20.62 0.038
11.248 -22.35 20.92 0.033
12.248 -22.9 21.12 0.029
13.248 -23.38 21.34 0.026
14.248 -23.8 21.56 0.024
20.248 -26.67 21.79 0.012

Table 2 - Setup parameters and measurement results, Intel Regulatory Lab

5.1.3 Correlation of measurements and simulation

The figure below shows the power density comparison:

Figure 9 - Comparison of Power Density simulation to lab measurements

17

The figure on the next page shall zoom-in inside this graph.

Figure 10 – Zoom-in on the comparison of simulation to lab measurements

We see an excellent correlation in the far-field between the HFSS simulation and 2 independent lab
measurements. According to measurements, the far-field boundary is at distance of 13-15cm, in
accordance with the prediction, as can be seen in the EIRP Plot in the UL Verification Services test report.
For distances above 17cm there is a slight mismatch between the simulation and measurements, and it
is due to the inaccuracy of the simulation near its boundaries.

The figure on the next page shows the EIRP correlation between the EIRP estimate from simulation and
the lab measurements, to identify the far-field boundary.

18

Validation of Simulation results

Figure 11 – Estimate EIRP of Simulation vs. lab measurements and far field boundary (Ch2)

We see an excellent correlation in the EIRP of the simulation vs. both lab measurements, as from already
from 10cm distance, the deviation between the EIRPs is less than dB. From this we can deduce that
the far-field boundary is at distance of 12-15cm, in accordance with the prediction.

19

5.2 Simulating a canonical antenna design
A simple patch antenna with Length = 7.5mm (GND plane length), and Lambda = 4.8mm, and was
designed to work at 62.5GHz, as can be seen in the figure below.

Figure 12 - Simulation of a single Patch antenna

Figure 13 – Patch Antenna Gain
The simulated Far-Field Max Realized Gain [dBi] is 7.05[dBi], as simulated by far field simulation. The
7.05dBi gain was obtained using HFSS simulation using Far Field Gain option.
Theoretically patch antenna gives ~7-9dBi gain. The simulated patch antenna in the HFSS simulation
is not a theoretical patch, it includes several “real life” non-idealities (width, size, feeding point etc).
The 7.05 dBi Max Realized Gain is the gain obtained from HFSS simulation including those non-
idealities.

A few test planes were integrated into the simulation at different far-field distances from the patch
(shown below) for power density calculations:

20

Validation of Simulation results

Figure 14 – Simulation 3D structure

The distances between the patch and the test planes range from 24mm to 54mm.
To validate the numerical tool, the power density results at the test planes are translated into gain using
omnidirectional power propagation and compared to far field gain according to simulation (table below).
The table below summarizes the results:

Far Field 𝑃 𝑊 Power Density from Gain calculation from
𝑃𝑜𝑚𝑛𝑖 = [ ] 𝑊
Distance 4𝜋𝑅 𝑚𝑚2
2 simulation [ 2 ] power density [dBi]
𝑚𝑚

24mm 1.34e-4 6.70e-4 6.99

29mm 9.11e-5 4.61e-4 7.04

34mm 6.59e-5 3.38e-4 7.10

44mm 3.91e-5 2.03e-4 7.15

54mm 2.59e-5 1.35e-4 7.17

Table 3 – Gain calculation from power density per several distances

Where P is the simulated radiated power and R is the distance from the patch to the test plane.
The table above shows excellent correlation between the Patch antenna gain calculated from power
density, to the Far-Field Max realized gain (7.05[dBi]). This is also depicted in the figure below:

21

Figure 15– Power Density of Canonical Patch Antenna

22

Summary

6 Summary
We validated the accuracy of the HFSS simulation in several ways, including excellent correlation of
measurements in far-field performed in 2 different labs, to HFSS simulation results
In the near-field the following table summarizes the results of Intel 17265NGW LC module, embedded
in HP PC model HSTNN-I22C:

Parameter Value

Total conducted power 6.4 dBm

Maximal TX duty-cycle 70%

Maximal (spatial and time) average power 0.74 mW/cm2
density, over 1cm2 and 10 seconds

Margin from FCC requirement on maximal 1.3 dB
allowed power density (1 mW/cm2)

Table 4 – Summary of simulation results for RF exposure compliance

Therefore Intel 17265NGW LC module, embedded in HP PC model HSTNN-I22C, complies with FCC
rule parts §2.1093 and §15.255(g).

23

Document Created: 2015-01-27 12:16:54
Document Modified: 2015-01-27 12:16:54

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