Development of millimetre-wave metamaterial-based focal planes arrays for Cosmic Microwave Background experiments and satellite missions (astronomy)
Measurements of the polarisation states of the Cosmic Microwave Background (CMB) is currently one of the hottest topics in Cosmology. In particular, the detection of the associated primordial B-modes is the present challenge in this field. The signals we are after are extremely weak and this require instrumentation with extraordinary sensitivity and exquisite control of the systematic effects introduced by the instrument itself. High sensitivity can be achieved by using hundreds or thousands of detectors which implies very compact and dense arrays of pixels/antennas coupled to detectors. This is a huge step in technology development when comparing these numbers with those of the latest successful CMB satellite mission Planck, which had just e few tens of pixels based on traditional massive
corrugated horns. This field is in very rapid evolution and new solutions have been recently adopted in ground based experiments hosting hundreds of detectors based on ‘lens-let’ arrays. However, these small and very-curved lenses are not easy to manufacture and require specifically designed antireflection coatings to work efficiently.
Another important requirement of these instruments is the control of the systematic effects. Any tiny modification of the incoming signal going through the optical system, from the telescope mirrors down to the detectors, needs to be quantified in details. These additional spurious signals need to be isolated and removed in order to avoid mixing them with the cosmological signals which we want to detect. Designing instrumentation controlling the systematics effects requires deep understanding of the physics behind the behaviour of each single component. Sometimes, due to the uncertainty in the knowledge of some of the parameters, the experimental characterisation is
the only way to determine these effects.
In this project we propose to develop compact and high performance focal plane arrays based on metamaterials. The Astronomy Instrumentation Group (AIG) is world-leading in the design and production quasi-optical devices based on metamaterials, specifically using the ‘mesh-filters’ technology. We have recently developed flat ‘mesh-lenses’ able to accurately mimic the behaviour of the thicker classical dielectric lenses. These lenses can be also ’miniaturised’ and used in front of compact array of detectors. The mesh-lens array can be a simple flat device which includes all the single lenses and which does not require additional anti-reflection coatings.
The modelling and the design of these devices will be carried out by using electromagnetic finite element analysis software such as Ansoft HFSS. The devices will be manufactured and tested within the AIG cleanrooms and laboratories. The electromagnetic characterisation will be carried out by using a Vector Network Analyser.
The PhD research project will consist of:
- Finite-element analysis electromagnetic modelling (Ansys HFSS)
- Design of novel focal plane metamaterial components
- Optimisations for large and compact arrays
- Following the clean-room device manufacture
- Device testing with Vector Network Analyser
- Analysis and interpretation of the data
This project is available to students applying for funded PhD studentships and may be altered or withdrawn.
Studentships will be awarded to successful applicants from all applications received. Applicants must satisfy RCUK residency rules for the full studentship.
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FTE Category A staff submitted: 19.50
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