We present the successful operation of the first dielectric elastomer actuator (DEA) driven tunable millimeter-wave
phase shifter. The development of dynamically reconfigurable microwave/millimeter-wave (MW/MMW) antenna
devices is becoming a prime need in the field of telecommunications and sensing. The real time updating of antenna
characteristics such as coverage or operation frequency is particularly desired. However, in many circumstances
currently available technologies suffer from high EM losses, increased complexity and cost. Conversely, reconfigurable
devices based on DEAs offer low complexity, low electromagnetic (EM) losses and analogue operation. Our tunable
phase shifter consists of metallic strips suspended a fixed distance above a coplanar waveguide (CPW) by planar DEAs.
The planar actuators displace the metallic strips (10 mm in length) in-plane by 500 μm, modifying the EM field
distribution, resulting in the desired phase shift. The demanding spacing (50 ±5 μm between CPW and metallic strips)
and parallel alignment criteria required for optimal device operation are successfully met in our device design and
validated using bespoke methods. Our current device, approximately 60 mm x 60 mm in planar dimensions, meets the
displacement requirements and we observe a considerable phase shift (~95° at 25 GHz) closely matching numerical
simulations. Moreover, our device achieves state of the art performance in terms of phase shift per EM loss ~235°/dB
(35 GHz), significantly out performing other phase shifter technologies, such as MMIC phase shifters.