Evaluation Engineering - Cover2

TESTING 5G MMWAVE
DEVICES OVER THE AIR
5G NR networks are currently in the rollout. 5G is the
first cellular technology operating at the new cmWave
and mmWave spectrum (frequency range 2 or FR2).
It uses advanced antenna technologies with a higher
number of antennas for beamforming, which is compensating for the increased path loss at FR2. However,
advanced antennas are integrated units, with transceiver frontends combined with the antenna array and
without traditional RF output ports. The lack of physical
connectors makes over-the-air (OTA) testing the default
end-user device testing environment in FR2 which necessitates chambers and positioning systems to also
cover dynamic beam steering scenarios.
Generally, all OTA measurements shall be executed
under far field (FF) conditions where the electromagnetic waves have become planar. With high frequencies, this can lead to big FF distances according to
the Fraunhofer equation, requiring large shielded
chambers. Even a 15 cm smartphone transmitting at
43.5 GHz would need a testing distance of 6.5 m due to
this. To ensure plane waves, either the distance of the
DUT from the transmitting or receiving antenna has to
be large enough, or the far field conditions have to be
created artificially in a smaller distance by converting
near field (NF) into FF, which is also referred to as indirect far field (IFF).

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transform a spherical wave front from the DUT or feed
antenna into a planar wave front it is known as a compact antenna test range (CATR). This reduces the required chamber size as well as the complexity and cost
of the test setup.
Rohde & Schwarz has several OTA solutions for mobile
device testing that make use of such a CATR setup.
These include the R&S®ATS800B benchtop antenna
test system, the R&S®ATS800R rack solution and the
R&S®ATS1800C 5G NR mmWave test chamber. All
these solutions feature the high precision CATR reflector to generate a big usable measurement area (the so
called quiet zone QZ) in a very compact setup and a
wide frequency range.
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The eBook '5G New Radio - Fundamentals,
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Using an anechoic chamber for radiation shielding and
a positioning system for the DUT together with a hardware transformation of the propagating waves makes
up an IFF system. If a parabolic reflector is used to

CATR antenna test
systems are convenient
and accurate solutions
for testing 5G mmWave
antennas, modules and
devices in a compact
setup.

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