Development of microstrip-coupled Lumped-Element Kinetic Inductance Detectors for astronomy

Hornsby, Amber ORCID: https://orcid.org/0000-0002-9998-1720 2020. Development of microstrip-coupled Lumped-Element Kinetic Inductance Detectors for astronomy. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Lumped-element Kinetic Inductance Detectors (LEKIDs) are superconducting Inductor-Capacitor (LC) resonators that have been utilised in large-format arrays of detectors for millimetre-wave astronomy. LEKIDs are highly multiplex-able by design and have been demonstrated to reach the photon-noise limit required for astronomy. However, coupling such structures directly to low loss superconducting transmission lines and filtering structures has proved challenging. The research presented in this thesis is aimed at developing techniques for coupling a LEKID to an antenna structure and microwave transmission line, which would be compatible with existing device architecture used in existing Cosmic Microwave Background (CMB) experiments. Several important developments towards realising large arrays of multi-chroic, polarisation-sensitive pixels suitable for future Cosmic Microwave Background experiments are presented in this thesis. These include coupling a Kinetic Inductance Detector (KID) to an antenna and microstrip, which is made possible by the separated inductor and capacitor architecture of a LEKID. The results presented in this thesis demonstrate that a dielectric can be deposited over the inductor only, to form a coupling microstrip structure, while leaving the LEKID relatively immune to the noise created by the typically noisy dielectrics. The section of microstrip between the antenna and KID can then be utilised to introduce on-chip filtering structures which limit the band of frequencies reaching the detector. Initial measurements of single-colour prototype devices suggest the current devices are susceptible to stray light, an issue that needs to be considered in future design iterations. However, the overall results presented in this thesis still represent an important step towards realising large arrays of multi-chroic, polarisation-sensitive detectors required for future studies of the CMB.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Uncontrolled Keywords:	Kinetic Inductance Detectors, Resonators, Cosmic Microwave Background, On-chip filters
Funders:	Cardiff University, College of Physical Sciences, STFC
Date of First Compliant Deposit:	4 May 2021
Last Modified:	09 Nov 2022 10:52
URI:	https://orca.cardiff.ac.uk/id/eprint/140909

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