CORA
Cork Open Research Archive (CORA) is UCC’s Open Access institutional repository which enables UCC researchers to make their research outputs freely available and accessible.
UCC Research Communities
Recent Submissions
Design techniques for compact and multi-functional differential and reflection-type RF-MEMS enabled phase shifters
(University College Cork, 2026-05-28) Guo, Zehan; Psychogiou, Dimitra; Analog Devices
Future wireless systems (i.e., 6G) will integrate terrestrial and non-terrestrial networks (NTNs) to deliver global connectivity. Their deployment requires high capacity, adaptable NTN links supported by advanced antenna arrays capable of dynamic beam reconfiguration to address long propagation distances and mobility. Conventional beamsteering relies on numerous phase shifters within large antenna arrays, leading to complex, bulky, and costly implementations. New design strategies are therefore needed to meet modern system requirements.
This dissertation investigates RF and electromagnetic design methodologies for the realization of differential power divider-based phase shifters and reflection type phase shifters (RTPSs) using RF-switched bandpass filter-based reflective loads. They are enabled by commercially-available RF microelectromechanical system (RF-MEMS) switches with reduced system size, weight, power, and cost (SWaP-C) through multilayer printed-circuit-board (PCB) implementations. Specifically, this thesis lays the foundations for: i) differential phase shifters that simultaneously provide phase shifting and power division functionalities to support multiple antenna elements through a single RF component, ii) RTPSs capable of directing beams from different frequency channels toward distinct directions through definable phase-frequency profiles, iii) commercially-available RF-MEMS enabled X-band design techniques compatible with multilayer RF PCB substrates.
Key experimental demonstrations of this work include i) a single phase shifter enabling beamsteering of four- or eight-element arrays in two or four distinct directions, eliminating the need for per-element phase shifters and additional power dividers, ii) an RTPS with definable phase-frequency profile, allowing multi-channel simultaneous beamsteering and eliminating the need for energy hungry and costly digital beamforming techniques in mobile user tracking and inter-beam hand-off applications, iii) validated operation at 7.5–9.16 GHz, representing the highest demonstrated frequency range for phase shifters based on commercially-available RF-MEMS technologies.
Illumination light manipulation and engineering for sensitive detection
(University College Cork, 2025-09-29) Ma, Hui; Andersson-Engels, Stefan; Konugolu, Sanathana; Gautam, Rekha; Research Ireland
Biophotonic diagnostics provide noninvasive access to structural and biochemical information, yet their performance is often limited by uncontrolled light delivery, depth-dependent signal loss, and a lack of physiological standardisation. This thesis builds on the hypothesis that diagnostic accuracy can be significantly improved by engineering illumination to actively direct photon transport rather than treating it as a static constraint. A series of illumination strategies are therefore developed across multiple platforms, progressing from fundamental beam control to application-specific sensing systems.
The thesis begins by establishing a framework for structured illumination through multimode optical fibres using the transmission matrix (TM). A real-valued intensity transmission matrix (RVITM) approach is implemented to generate controlled circular symmetric output patterns such as rings and combinations of rings without interferometric detection using a 16 x 16 Hadamard calibration basis. The generated patterns, including rings of tunable radius and
composite double ring profiles, remain stable under fibre bending, demonstrating robustness against mode scrambling and providing a compact, axicon free route to programmable beam shaping at the fibre tip.
To address the need for spatially uniform illumination in quantitative imaging, a Kohler integrator based laser microscope incorporating dual microlens arrays (500 um pitch, 13.8 mm focal length) is developed to homogenise excitation across the sample plane, achieving a coefficient of variation (CV) of approximately 1.2 to 1.5% across the field of view. This system is applied to upconversion nanoparticle (UCNP) assisted biomarker imaging for semi-quantitative assessment of HER2 expression (scoring levels 0 to 3+) in breast cancer tissues. The UCNP labelled samples achieved a signal to background ratio of 40, representing a 25 fold improvement over conventional 3,3'-diaminobenzidine (DAB) chromogenic staining (ratio of 1.6), demonstrating substantially enhanced contrast and quantification accuracy in widefield cancer diagnostics.
For subsurface biochemical detection, tailored illumination is applied in Raman spectroscopy. A dual wavelength inverse spatially offset Raman spectroscopy (DWiSORS) system is implemented using axicon based ring illumination with excitation at 730 nm and 830 nm, enabling simultaneous access to the fingerprint (393 to 2195 cm-1) and high wavenumber (2043 to 3846 cm-1) spectral regions. A novel enhancement to noise ratio (ENR) metric is introduced to determine the optimal spatial offset for subsurface probing, yielding patient specific optimal offsets in the range of 5 to 9 mm. Validated through Monte Carlo simulations and two layer tissue mimicking phantom measurements, the system demonstrates sensitive detection of bone mineral and hydration markers at depths of up to 14 mm through overlying soft tissue, with in vivo measurements performed on ten healthy volunteers.
Finally, to enable calibration of optical sensing systems under physiologically relevant conditions, a light guided solid dynamic phantom is constructed. By integrating a polymer optical fibre (3\,mm diameter) with a liquid crystal display modulator, the phantom reproduces wavelength specific pulsatile absorption changes across four wavelengths (455, 530, 660, and 940\,nm). The system accurately simulates photoplethysmography (PPG) signals across a range of heart rates (80 to 120 bpm) and oxygen saturation levels (SpO2: 86 to 100 %), providing a controllable and reproducible platform for pulse oximeter calibration and validation that outperforms conventional liquid blood based phantoms in stability, response time, and spatial controllability.
Across the different systems, analytical modelling frameworks are used to guide illumination strategy and interpret photon transport behaviour. In the Raman studies, these are further supported by Monte Carlo simulations to quantify depth sensitivity and validate experimental trends. Together, this work establishes illumination as a powerful design parameter for enhancing sensitivity, selectivity, and reliability in biophotonic diagnostics, paving the way for future platforms where light delivery is adaptively matched to the sensing target.
Bede, the Matthean Great Commission, and the Church’s universal mission
(Australian and New Zealand Association for Medieval and Early Modern Studies, 2026) Quigley, Emily
The Matthew Great Commission, in which Christ instructed the apostles to evangelise all peoples, has had importance across Christian history, but particularly resounded in the Insular world. Through exploring Bede's engagement with three core themes of Matthew 28. 19–20—the instruction to 'teach all peoples', baptism, and Christ's continued presence—this article argues that the pericope was central to Bede's vision of the Church's universal mission and his wider agenda of ecclesiastical reform. Amid concerns about spiritual complacency within his contemporary society, Bede used the Matthew commission as a framework for the ideal practice and sustainment of the faith.
In fitness and in health: women’s safe navigation of fitness on social media
(University College Cork, 2025-02-27) Peelo Dennehy, Doireann; Morrissey, Kellie; Foley, Sarah; McCarthy, John; Science Foundation Ireland
The proliferation of online fitness content in recent years has increased the availability and accessibility of health and fitness information. Emerging research identifies concerns associated with using social media for fitness, including negative impacts on health and mental health, which are reportedly worse for women. Despite these concerns, digital fitness is one of the largest niches on social media and has garnered attention in the field of HCI.
Against this backdrop, this thesis explores women’s safe navigation of social media for fitness. This PhD details users’ engagement with fitness content across platforms, focusing on their perceived safe navigation. These findings can help us support users’ active and critical cross-platform use for fitness on social media.
Across three studies, this work explores women’s use of social media for fitness, paying particular attention to their perspectives on online safety. Firstly, this thesis details a systematic review that contributes to our understanding of women’s use of social media for fitness by identifying their multifaceted and cross-platform engagement. Then, through in-depth interviews and surveys, this work describes competent and caring users and identifies their capability to navigate digital fitness safely and their expressed concern for younger users. Finally, through a series of exploratory workshops, this thesis investigates the development of this capability and, in response to their concerns, attempts to translate it into a game-based intervention.
Findings indicate the contextual and relational nature of navigating digital fitness. This implies that safe use requires an understanding of the fitness space, for example, that content is highly curated by creators, and a knowledge of the intricacies of nutrition and exercise. The relational nature of navigation describes how participants make sense of content and others online, relying heavily on other members of their communities, friends, and family. By drawing on their lived experience, education and relationships, users have learned to safely navigate fitness on social media over time. Users also report making and learning from mistakes, as they recognise the potential harms associated with fitness content and empathise with users who may be susceptible to these harms. This thesis explores how these learned competencies may be developed into an intervention. Focusing on the community learning users describe, the findings are translated into a cooperative game-based intervention for improving fitness-related digital literacies to promote the relational aspect of learning.
This thesis contributes to the field of HCI by accounting for women’s safe use of digital fitness. It provides further evidence of the context-specific nature of digital literacy and sheds light on the potential for context-specific digital literacy interventions to promote online safety. Therefore, this thesis helps those researching and designing for safe social media use to make informed decisions towards safer, more empowered social media use.
In conclusion, this PhD contributes to our evolving understanding of the complexities of fitness digital literacies. It underscores the importance of supporting situated learning and facilitating interpersonal learning for complex topics. It also positions games as a suitable intervention for this learning by encouraging collaboration, which is key to relational sensemaking. Moving forward, this research calls for the recognition of, and design for, the relational and context-dependent nature of digital literacy to promote safe and agentic online fitness experiences.
Remote powering and signalling using photovoltaic power converter and reflective electroabsorption modulator
(University College Cork, 2026-01-06) Baskaran, Meena; Corbett, Brian; Roycroft, Brendan
Power-over-fiber (POF) technology is emerging as a promising alternative to conventional electrical power delivery. In remote access networks, photovoltaic power converter (PPC) and modulators are key components for enabling both power and data transfer over fiber. A POF link offers immunity to electromagnetic interference while providing reliable, high-resolution data transmission. These advantages make it particularly well-suited for integration into minimally invasive surgical endoscopes, where precise, real-time diagnostics are essential. As POF advances toward on-chip integration, careful modulator design becomes critical to complement PPC performance and maximize overall system efficiency.
In this work, we investigated remote powering techniques and designed a reflective surface-normal electroabsorption modulator (SNEAM) specifically for integration into distal-end imaging surgical endoscopy tool, enabling both power delivery and high-speed data transmission. The SNEAM design is based on the Quantum Confined Stark Effect (QCSE), offering high modulation depth, low power consumption, and a compact footprint. For remote powering, we explored two optical coupling methods, laser to laser edge coupling and second surface normal coupling to GaAs based PPC. We demonstrated laser to laser edge coupling using commercially available laser sources as efficient PV absorbers. By coupling a 1427 nm pump laser to a 1540 nm single-junction receiver laser, an efficiency of 33% was achieved with an open circuit voltage Voc of 0.83 V. With an 850 nm pump laser coupled to a 905 nm triple junction receiver laser, we observed efficiency of 32.7% with Voc of 3.5 V.
In the second method, the multi-segment GaAs based PPC was illuminated under surface normal incidence using Gaussian and annular beam profiles delivered through a double-clad fiber. A Gaussian illumination of 850 nm on 350 μm diameter with 4 junction PPC results in 50% efficiency and Voc of 4.56 V at 10.7 W/cm2 illumination. For higher illumination on 4 junctions PPC, the annular beam illumination holds a maximum efficiency of 47.3% and Voc of 4.76 V at 52.5 W/cm2 illumination. We present comparative studies on Gaussian and annular beam illumination for compact design strategies and future improvement scope.
The SNEAM device in the 1560 nm operation were designed and fabricated. The device was successfully transfer printed onto a targeted reflection surface to enable reflection of modulated data using the EAM device. The SNEAM device with 30 μm active diameter and overall dimensions of 80 μm × 87 μm was tested for DC and AC characterization. The DC testing shows an extinction ratio of 6 dB between bias voltages of -2 V to -7 V. The data modulation over a single mode fiber were demonstrated at 1 Gbps with a driving voltage of 6 V. The device exhibits a 3 dB electro-optic bandwidth of 9 GHz at a bias voltage of -5 V.
Future work will focus on the hybrid integration of PPCs and the SNEAM device onto a single chip, packaged with multi-core fiber that supports both channels for power and data transmission. The design will target a compact 1 mm footprint optimized for distal-end imaging surgical tools, thereby advancing the development of miniaturized, high performance diagnostic systems.