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have the processor physically
separated from the RF components,
making a quadrature correction
algorithm very difficult to implement
across frequency, temperature, and
bandwidth.
Integrated transceivers
provide SWaP solution
Integrating the ZIF architecture into a
monolithic transceiver device provides
the path forward for next-generation
systems. By having the analog and
RF signal chain on a single piece of
silicon, process variation will be kept
to a minimum. In addition, DSPblocks
can be incorporated into the
transceiver, removing the boundary
between the quadrature calibration
algorithm and the signal chain. This
approach provides both unparalleled
improvements in SWaP and can also
Figure 3: Zero-IF image cancellation.
Figure 4: AD9361 and AD9371 block diagrams.
match the super-het architecture for
performance specifications.
Analog Devices offers two transceivers
aimed at use in the defense and
aerospace markets: the AD9361 and
AD9371 (Figure 4). These devices
integrate the RF, analog, and digital
signal chain onto a single CMOS
device and include digital processing
to run quadrature and carrier leakage
correction in real time across all
process, frequency, and temperature
variations. The AD9361 focuses on
medium performance specifications
and very low power, such as UAV
data links, handheld and man-pack
communication systems, and small-
form-factor SIGINT. The AD9371,
optimized for very high performance
specifications and medium power, has
an integrated ARM microprocessor for
refined calibration control, as well as an
observation receiver for power amplifier
(PA) linearization and a sniffer receiver
for white-spacedetection. These
features mean that communication
platforms using wideband waveforms,
or occupying noncontiguous spectrum,
can now be implemented in a much
smaller form factor. The high dynamic
range and wide bandwidth enables
SIGINT, EW, and phased-array radar
operation in locations with highly
congested RF spectrum.
The next generation is now
One hundred years of device
optimization had allowed the super-
het to achieve greater and greater
performance, in continually smaller
and lower-power platforms. Those
improvements are beginning to
slow, as physical limitations become
real. Next-generation aerospace
and defense platforms will demand
a new approach to RF design, one
where several square inches of an
existing platform is integrated into
a single device. In these devices
the boundary between software and
hardware is blurred, allowing for
greater optimization and integration
and where decreased SWaP no longer
means decreased performance.
David Brown is an RF system applications
engineer with Analog Devices, Inc., in
Greensboro, North Carolina. He joined
Analog Devices in 2015 and focuses primarily
on defense and aerospace applications.
David graduated from NC State University
in 2014 with a bachelor’s degree in electrical
engineering.
Wyatt Taylor is a senior RF systems engineer
with Analog Devices, Inc., in Greensboro,
North Carolina. He is focused on defense and
aerospace radio applications, with a particular
emphasis on integrated RF transceivers, small-
form-factor microwave design, and software-
defined radio (SDR). Formerly, Wyatt was an
RF design engineer at Thales Communications
Inc., and Digital Receiver Technology, Inc., in
the Maryland area. Wyatt received his MSEE
and BSEE from Virginia Tech.
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