Conjugated polymers (CPs) undergo a wide range of reversible
intrinsic
property changes including electrical conductivity, electromagnetic
absorption, volume, and charge mobility upon electrochemical oxidation/reduction,
which has made them popular as ON/OFF organic-based switchable materials.
Recent studies on the insulating-to-conductive transition within CPs
have paved the way for a next generation of flexible switches that
permit the creation of “dynamic” electric circuits.
Here, we present an approach to a low-voltage, low-power electrochemically
controllable, switchable, and printable CP-based conductive element
that acts as a platform for the configuration of frequency-reconfigurable
radiative antennas. We demonstrate that the DC conductivity of a soluble
PEDOT derivative, PE2, film can be switched electrochemically
by 4 orders of magnitude across large insulating gaps up to 15 mm
within 20 s. Its integration in a DC switching element that is incorporated
along the poles of a half-wave dipole antenna structure is able to
generate an AC resonant frequency switch, and thus a radiation frequency
shift, in the microwave (i.e., 1–2 GHz) range. This type of
printable antenna fills an important need for the demand of bandwidth
that is growing beyond the crowded frequency spectrum, by relying
on the development of frequency-reconfigurable antenna systems capable
of dynamically tuning their spectral properties when desired.