Wifi Module Connector Types; Wifi Antenna Placement; Antenna Placement - Intel Quark SoC X1000 Design Manual

Wireless Modules and Antenna Design Guidelines—Intel
22.2.4

WiFi Module Connector Types

As WiFi modules are mounted on the platform, connectors plugging into them will add
to the total z-height. OEM's can select connectors of low z-heights to keep the total z-
height down. There are miniature coaxial RF connectors available in the market today
with z-heights of the order of 2.5 mm to 1.4 mm.
22.2.5

WiFi Antenna Placement

SoC systems are more likely to use metal enclosures for manufacturing reasons. In
addition, antenna clearances will be much lesser than on conventional Thin and Light
designs due to tighter z-height budgets. Both factors will create significant challenges
in ensuring signal quality and reception comparable to a laptop with a plastic chassis
and larger z-height budgets. System designers will have to strike a compromise
between signal quality and cost while integrating antennas into the system.
The antenna should be placed as close to the module as possible to reduce losses in the
board and/or cables, which can affect performance (throughput/range) directly. It is
also important to ensure that the antenna is not covered by or in close proximity to the
user's body and/or metallic body worn accessories. This is for two reasons; detuning of
the antenna and high Specific Absorption Ratio (SAR) numbers. In addition the antenna
should be kept away from noisy circuits and components such as the processor,
memory, display (unshielded) etc. Minimum distances need to be maintained from
metal parts depending on the type of antenna used.
The design must incorporate non conducting surfaces around the antenna for WiFi
connectivity.
Maximizing the distance between the antenna and body to beyond the limit used for
modular approval will allow for a reduction in test cases. This is best achieved by
placing the antenna as close to the A-surface as possible.
Antenna performance is severely degraded if it is enclosed by metal or in close
proximity to metal. Studies indicate that acceptable gains are possible with antenna
separations of 5-mm to 10-mm from metal enclosures.
22.2.6

Antenna Placement

When there is a metal surface surrounding the antenna, it is recommended to have
plastic sections or insert molded plastic in the metal panel to maintain WiFi
connectivity. Other options include cutouts and also placing antennas on the sides of
the motherboard enclosure. In this case, care should be taken to ensure EMI from
adjacent IO connectors does not interfere with the antenna reception.
The following placement options may be considered for closed lid operation:
1. Base mounted WLAN antennas: Incorporating 3G antennas in the same area
will likely require additional components to achieve a compliant solution. Platform
noise pickup from base mounted antennas needs to be measured before
committing to a particular location as there is a higher risk of impact from platform
noise with the use of base mounted antennas.
2. Slot antennas cut into the chassis: Slots can be cut into the surface of the
antenna, near the apex of the lid and the cutout can be covered with plastic inserts.
Such an antenna would be integrated into the chassis and special care must be
given to the feeding mechanism, especially when materials not amenable to
soldering such as aluminum are used. There are no discrete antennas with this
solution. Multiple antenna SKUs will imply multiple chassis SKUs, so this option will
need to be considered very early in the design cycle.
June 2014
Order Number: 330258-002US
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Quark™ SoC X1000
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Intel Quark™ SoC X1000
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