| Summary: | Travelling wave parametric amplifiers (TWPAs) made from highly nonlinear reactive superconducting thin films
have been demonstrated to be a viable technology for various quantum applications, including fundamental
physics experiments such as astronomy and axion dark matter searches, as well as commercial applications
like quantum computational and communication systems. In this paper, we present the design of a kinetic
inductance TWPA comprising a patterned titanium nitride film that can operate at 0.3 K to demonstrate the
feasibility of operation closer to 1 K temperature, paving the way to achieve even higher bath temperature
operation. We discuss in detail the design of our TWPA, along with the predicted gain-bandwidth product and
other characteristics. We perform the preliminary experimental investigation of the thin film properties and
compare that with the simulated results. We found that there are several discrepancies between the measured
and the predicted behaviour of the thin film. We attribute these differences to the fact that the fabricated thin
film has a different gap voltage, resistivity and thickness to what we expected. With a new set of estimated
parameters, we successfully reproduce the measured transmission profile. We further show that by utilising
bridges to ensure equipotential grounds for the CPW lines, we managed to reduce the rippling effect and achieve
higher gain with broader bandwidth. We expect that our TWPA can achieve higher than 20 dB gain from
approximately 0–8 GHz.
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