Operation of kinetic-inductance travelling wave parametric amplifiers at millimetre wavelengths

Abstract

It is expected that the operation of microwave Kinetic Inductance Travelling Wave Parametric Amplifiers (KITWPAs) can be extended to the millimetre (mm) and the sub-mm wavelength range as long as the frequency is below the gap frequency of the superconducting film. This paper presents possible mm-wave designs for KITWPAs based on microstrip transmission lines. Our device is designed based on the BCS (Bardeen-Cooper-Schrieffer) model which successfully reproduces the measured transmission profile, gain, bandwidth, and nonlinear response of a fabricated KITWPA operating in the Ka-band, and includes the millimetre-wave dielectric loss determined by fitting the quality factor of a W- band microstrip resonator. We suggest a layout for a KITWPA operating near 220 GHz that can be fabricated using the same superconducting properties as the Ka-band device and can be coupled to a waveguide system. We conclude the paper by extending the 220 GHz design to higher frequency regimes approaching 1 THz.

Non-degenerate-pump four-wave mixing kinetic inductance travelling-wave parametric amplifiers

“…With the placement of = f 6.148 GHz pumps on the leading edges of the first and second stopbands, respectively, we show that the pump harmonics and their cross-terms would fall into the subsequent stopbands at higher frequencies. The |S 21 | spectrum presented here has been simulated using the realistic modelling technique described in [24], which has been shown to accurately predict the measured performance of KITWPAs when the surface resistance of the superconducting film is calibrated to be close to negligible compared to the BCS prediction [28] at cryogenic temperature. Figure 5 .…”