JED - April 2016 - 25

Other EMS Applications

it lowers your thermal load, and your
IR signature, etc." The NEXT program is
currently winding down, although work
is continuing in 2016 using 2015 funds.

In addition to pushing the boundaries of power and frequency, DARPA has
also been addressing the challenges
associated with high-voltage power
switching through the Microscale Power
Conversion (MPC) program.
Green points out that power switching is an extremely important requirement especially for communications
and EW applications. It is also becoming
important in radar applications, as well,
because of the increased complexity of
the waveforms being transmitted, which
drives dynamic power loading of the RF
amplifier. "What this means is that as
you go up in power levels, you're changing the efficiency at which it operates,
and what the MPC program is all about
is leveraging fundamental GaN technology, optimizing the devices for power
switching, so that we can create power
supplies that can dynamically supply
just the amount of power that the RF
power amplifier needs at any moment in
time. This is kind of the GaN story. We're
pushing the frequency, and we're pushing the power switching, to create the
fundamental building blocks to handle
high frequency, high efficiency, and
high-complexity waveforms."
The power-supply switching frequencies being sought are in the gigahertz
range. As explained by Green, "The reason that it's important for the transistor to switch at these rates, is that it
defines the envelope bandwidth that
you can modulate your carrier signal at.
We want to take advantage of the advances in high frequency GaN switching
technology to do it over a dramatically

broader bandwidth. So you can think
about it as, instead of having a single
channel that you might be able to deliver for these complex waveforms, now
we're talking about 10s of channels
Thus far, the program has been able
to demonstrate a 10W amplifier with 500
MHz of envelope bandwidth at X band
(8-12 GHz), and Green says they are currently working on developing a transition path to best apply the technology
to DOD systems.

DAHI Foundry
The Diverse Accessible Heterogeneous
Integration (DAHI) program reflects
DARPA's strategy to leverage its ongoing investment and accomplishments in
advanced GaN and InP technologies and
tie them to commercial capabilities. The
program is developing transistor-scale
heterogeneous integration processes to
combine advanced compound semiconductor devices, as well as other emerging
materials and devices, with high-density
silicon CMOS technology.
DAHI's Compound Semiconductor
Materials on Silicon (COSMOS) effort
has already demonstrated a number of
unique approaches to the heterogeneous
integration of InP heterojunction bipolar transistors (HBTs) with deep submicron Si CMOS that allow designers to
combine complex signal processing and
self-correction architectures with highperformance compound semiconductor
electronics to achieve dramatic performance improvements in bandwidth, dynamic range and power consumption.
The ultimate goal, however, is to migrate and integrate these advancements
onto commercially supplied silicon
CMOS, to create a foundry flow where
designers are able to design new capabilities at the transistor level, realizing

The Journal of Electronic Defense | April 2016

In addition to being able to operate
at higher frequencies, NEXT technology
can also enable much more efficient
circuits operating at lower frequencies.
For example, Green says that by leveraging the scale advantages provided by
the devices, they've been able to realize circuits operating at, for instance,
Ka band (around 32 GHz) with significantly higher efficiencies than what is
available in conventional technologies.
"For small amplifiers, we've seen up to
10 percentage points in efficiency improvement, which is enabling because



JED - April 2016

Table of Contents for the Digital Edition of JED - April 2016

The View From Here
Conferences Calendar
Courses Calendar
From the President
The Monitor
World Report
DARPA Profile: Advanced Materials
Mission Profile: Non-Kinetic Thinking Creates New Possibilities for Air and Missile Defense
Threat Monitor
EW 101
AOC News
Index of Advertisers
JED Quick Look
JED - April 2016 - cover1
JED - April 2016 - cover2
JED - April 2016 - 3
JED - April 2016 - 4
JED - April 2016 - 5
JED - April 2016 - The View From Here
JED - April 2016 - 7
JED - April 2016 - Conferences Calendar
JED - April 2016 - 9
JED - April 2016 - Courses Calendar
JED - April 2016 - 11
JED - April 2016 - From the President
JED - April 2016 - 13
JED - April 2016 - 14
JED - April 2016 - The Monitor
JED - April 2016 - 16
JED - April 2016 - 17
JED - April 2016 - 18
JED - April 2016 - 19
JED - April 2016 - 20
JED - April 2016 - 21
JED - April 2016 - 22
JED - April 2016 - World Report
JED - April 2016 - DARPA Profile: Advanced Materials
JED - April 2016 - 25
JED - April 2016 - 26
JED - April 2016 - 27
JED - April 2016 - Mission Profile: Non-Kinetic Thinking Creates New Possibilities for Air and Missile Defense
JED - April 2016 - 29
JED - April 2016 - 30
JED - April 2016 - 31
JED - April 2016 - 32
JED - April 2016 - 33
JED - April 2016 - 34
JED - April 2016 - Threat Monitor
JED - April 2016 - 36
JED - April 2016 - EW 101
JED - April 2016 - 38
JED - April 2016 - AOC News
JED - April 2016 - 40
JED - April 2016 - Index of Advertisers
JED - April 2016 - JED Quick Look
JED - April 2016 - cover3
JED - April 2016 - cover4