104 I-CONNECT007 MAGAZINE I AUGUST 2026
the traditional sense, it shares the same underlying
principle: a flat-fabricated sheet that folds into a
functional 3D structure. Later iterations have moved
toward true rigid-flex PCB approaches as commer-
cial fabrication capabilities have improved.
The weight savings are dramatic. A wire harness
connecting a dozen sensors to a central processor
in a robot this small might weigh more than the
motors themselves. By routing all interconnects
through the PCB substrate, which must exist in
the design anyway, that parasitic mass disappears
entirely. The board does double duty as conductor
and structure.
Rigid-flex Exoskeletons
Turning the PCB into an exoskeleton also solves
a connector reliability problem that plagues small
robots. At insect scale, vibration, impact, and the
repeated flexion of locomotion quickly fatigue sol-
dered wire connections. When the traces are em-
bedded in a continuous substrate, there are no
separate connections to fail; the signal path and the
structural member are one.
Current research applications include search-
and-rescue micro-robots designed to navigate
rubble fields, environmental monitoring robots that
can be deployed by the thousands to map contami-
nated sites, and medical micro-robots intended for
minimally invasive diagnostics. Each demands the
smallest possible size-to-capability ratio, and each
benefits from the structural electronics approach.
Fabrication challenges are significant. The tight
bend radii required by folded rigid-flex designs
push the limits of standard PCB materials. Imped-
ance continuity through flex folds requires careful
trace geometry and via placement, and the thermal
management constraints of sealing active compo-
nents into a structural element with no airflow
require creative heat-spreading solutions.
Summary
As fabrication tolerances shrink and flex materi-
als improve, the insect-scale structural electronics
robot will become an increasingly standard platform.
The rigid-flex PCB that is simultaneously a skeleton,
nervous system, and muscle interface may prove to
be one of the most consequential engineering in-
novations in small-scale robotics. I-CONNECT007
Anaya Vardya is president and CEO of American
Standard Circuits; co-author of The Printed Circuit
Designer's Guide to… Funda-
mentals of RF/Microwave
PCBs and Flex and Rigid-
Flex Fundamentals. He
is the author of Thermal
Management: A Fabri-
cator's Perspective, The
Printed Circuit Designer's
Guide to DFM Essen-
tials, and The Companion
Guide to Flex and Rigid-Flex Fundamentals.
Visit I-007eBooks.com to download these and
other free, educational titles.
