WSI provides testing facilities for SAR, antenna characterization, and radio frequency harmonics. SAR testing ensures product safety compliance and avoids redesigns. Antenna characterization includes impedance, radiation patterns, gain, efficiency, power, and sensitivity. Harmonics testing checks for unwanted emissions from electronics and antennas from 700 MHz to 6 GHz.

1. WSI TEST FACILITIES
SAR testing
Antenna characterization
Radio frequency harmonics

2. SAR testing
 WSI provides precompliance testing
regarding SAR (Specific Absorption Ratio)
using a DASY3 system from SPEAG
(Schmid and Partner Engineering AG)
 Tests can be performed in the frequency
range of 300 MHz to 2.5 GHz covering
radio standards such as GSM900,
DCS1800, PCS1900, UMTS, Bluetooth,
ZigBee, WiFi etc.
 This is highly useful in the early stages of
projects to avoid major redesign in terms
of mechanics and electronics. It is not
uncommon that antenna types need to be
changed, antennas need to be moved, the
product needs to be made thicker, metal
structures must be cleverly grounded or
even be removed to meet SAR
requirements.

3. Antenna characterization
 There are a number of ways
to characterize antenna
performance such as
 Antenna impedance/VSWR
(voltage standing wave ratio)
 Radiation patterns and antenna
gain
 Radiation efficiency
 TRP (total radiated power) and
TIS (total isotropic sensitivity)
 Antenna isolation to check
concurrent radio operation
 WSI provides all of these
measurements.

4. Antenna impedance and VSWR
 WSI provides measurements of
input impedance of single band
and multiband antennas.
 WSI can tune input impedance by
means of lumped component
matching, stub matching, tweaks
to the antenna radiator etc.

5. Radiation pattern and antenna gain
 WSI provides radiation
pattern measurements
including peak antenna
gain, 3 dB beamwidth,
back lobe supression etc
for both linear, dual and
circular polarized
antennas using an
anechoic chamber from
Flame & Russell. The
measurement software is
MIDAS by Orbit/FR.
 Measurements can be
made in the frequency
range of 300 MHz - 6
GHz

6. Radiation efficiency, TRP and TIS
 WSI provides active and
passive scattered field chamber
measurements
 Following items can be
measured:
 Radiation efficiency. (This
is a passive measurement
showing how the antenna
radiates on the average
over all solid angles.)
 TRP (total radiated power)
 TIS (total isotropic
sensitivity)
 TRP and TIS are highly useful
means to check that the radio
works well together with the
target antenna
 Measurements can be made in
the frequency range of 700MHz
to 6 GHz

7.  WSI provides measurements of radio
frequency harmonics in the frequency
range of 700 MHz to 6 GHz using a
semi-anechoic chamber from
Siemens Matsushita.
 This is useful in a number of ways,
e.g.
 Check harmonics that are radiated
from the PCBA since these are often
higher (!) than harmonics that can be
seen in conducted measurements.
 Check that non-ideal antenna
impedance (will never be perfectly 50
ohms over the band of interest) does
not increase the level of harmonics
 Check that semi-conductors in vicinity
of the antenna is not ”light up” by the
RF field generating harmonics
Radio frequency harmonics
 The semi-anechoic chamber is also
ideal for measurements of radiated
desense (i.e. check that there is no
internally generated interference that
is picked up by the antenna degrading
receiver sensitivity).