Dr Timothy Pelham

Dr Timothy Pelham

Research Fellow

Publications

Rapid Virtual Prototyping for Cubesat Scale Deployable Reflector Antennas

Published in 2025 URSI International Symposium on Electromagnetic Theory (EMTS), 2025

An open source approach to rapid virtual prototyping of parabolic reflector antennas is proposed. The impact of focal distance, illuminator offset from focal spot, and platform scattering are examined for an antenna to be mounted to an 8U CubeSat chassis with a constant arc length for the parabolic reflector. A total of 30 parametric variations were simulated and antenna patterns predicted in 16 minutes. The selected parabolic reflector was prototyped and measured on platform, with a correlation of 0.59 between the predicted and measured antenna patterns, with maximum total directivity of 20.6dBi and 17.6dBi respectively.

Recommended citation: Pelham, T., & Austin, A. C. M. (2025). Rapid Virtual Prototyping for Cubesat Scale Deployable Reflector Antennas. In 2025 URSI International Symposium on Electromagnetic Theory (EMTS) (URSI International Symposium on Electromagnetic Theory). Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.46620/URSIEMTS25/YXDS2743 https://research-information.bris.ac.uk/admin/files/454482977/EMTS_Paper_Virtual_Prototyping.pdf

A Scalable open-source electromagnetics model for Wireless power transfer and Space-Based Solar Power

Published in 2025 URSI International Symposium on Electromagnetic Theory (EMTS), 2025

Space-based solar power has been proposed as early as the 1960s as a source of reliable and clean energy. Due to reductions in the cost of orbital access it has received renewed interest in recent years. A practical challenge to the deployment of these systems is the requirement for ultra-large scale antenna arrays for wireless power transfer at scale, with proposed GW scale systems with antenna array diameters on the order of 2km, with billions of antenna elements. In this paper a development of the Rayleigh-Sommerfeld Diffraction Integral is introduced together with CUDA accelerated ray tracing for flexible modelling. A simplified parallel antenna array model is introduced at 10GHz demonstrating the effectiveness of different beamforming algorithms, together with preliminary results of a larger array scenario for wireless power transfer over 5.9km to a receiving array in a 5km square map tile.

Recommended citation: Pelham, T., & Fearon, T. C. (2025). A Scalable open-source electromagnetics model for Wireless power transfer and Space-Based Solar Power. In 2025 URSI International Symposium on Electromagnetic Theory (EMTS) (URSI International Symposium on Electromagnetic Theory). Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.46620/URSIEMTS25/NKLW8291 https://research-information.bris.ac.uk/files/454482912/EMTS_Paper.pdf

Robust Deployable Reflectors for Antennas on Cubesats

Published in 42nd ESA Antenna Workshop, 2024

A deployable corner reflector antenna for an 8U CubeSat operating at 1.5 GHz is proposed. The impact of reflector size, position, and opening angle is analysed using simulations for a monopole feed antenna. A fixed (non-deployable) prototype mounted on a 8U CubeSat chassis was found to improve the directivity from 3.7 dBi to 8.6 dBi when the reflectors were included, with good agreement between the simulated and measured radiation patterns.

Recommended citation: Austin, A. C. M., Pelham, T., Hilton, G., & Beach, M. A. (2024). Robust Deployable Reflectors for Antennas on Cubesats. Paper presented at 42nd ESA Antenna Workshop., Noordwijk, Netherlands. https://research-information.bris.ac.uk/en/publications/robust-deployable-reflectors-for-antennas-on-cubesats

Mechanical Vibrations on a Deployable Nanosatellite Antenna: SAR Performance Analysis

Published in 2024 18th European Conference on Antennas and Propagation (EuCAP), 2024

The mechanical vibrations of a high-strain glass-fibre composite deployable X-band synthetic aperture radar (SAR) antenna structure are investigated using a finite element method. The antenna is approximately 2 m×0.3 m , and exhibits natural frequencies at 2.8 Hz and 7.6 Hz. The radiation patterns for a reflectarray formed from the structure are calculated using a ray-tracing approach for the nominal and mechanically deformed cases. The mechanically deformed antenna pattern is defocused, and a SAR system model shows this reduces the signal-to-noise ratio of a point scattering target by approximately 6 dB.

Recommended citation: Austin, A. C. M., Pelham, T., Mencarelli, S., Tresoldi, A., Dabboor, M., & Neve, M. (2024). Mechanical Vibrations on a Deployable Nanosatellite Antenna: SAR Performance Analysis. In 2024 18th European Conference on Antennas and Propagation (EuCAP) Article 10501343 (Proceedings of the European Conference on Antennas and Propagation). Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.23919/EuCAP60739.2024.10501343 https://research-information.bris.ac.uk/admin/files/435189420/EuCAP2024_template.pdf

LyceanEM: GigaScale Electromagnetics for Beamforming and System Planning

Published in 2024 18th European Conference on Antennas and Propagation (EuCAP), 2024

Gigascale antenna arrays (3 to 4 orders of magnitude more elements than the largest ever built) are a critical component of proposed space-based solar power (SBSP) systems. The transmitting antenna arrays in orbit are expected to be up to 3 km2 , while the receiving arrays on Earth have been proposed at up to 77 km2 . There are many challenges and risks in the design, modelling, operation and deployment of the gigascale antenna arrays in the SBSP system. This paper highlights these challenges and risks, reviews existing solutions and proposes novel approaches.

Recommended citation: T. Pelham, X. Chen, B. Collins, C. Parini and A. Brown, "An Overview of Gigascale Antenna Arrays and Electromagnetics for Space Based Solar Power," 2024 18th European Conference on Antennas and Propagation (EuCAP), Glasgow, United Kingdom, 2024, pp. 1-4, doi: 10.23919/EuCAP60739.2024.10501466. https://ieeexplore-ieee-org.bris.idm.oclc.org/document/10501466

LyceanEM: GigaScale Electromagnetics for Beamforming and System Planning

Published in International Conference on Energy from Space, 2024

Global Navigation Satellite System (GNSS) data has become a stable of modern life, whether delivered through a smartphone, vehicle, or as part of an industrial dataset. The expectation of reliable position and time information, irrespective of the environment, becomes challenging in tunnels and canyons with significant multipath, whether natural or urban. An initial look at an open dataset of LIDAR, Computer Vision, and GNSS data is presented, combined with a channel model produced from this dataset, comparing the expected and measured line of sight and multipath contributions from GPS sources while moving around Bristol, from unobstructed surroundings to deep natural and urban canyons.

Recommended citation: Pelham, T., Kudera, S. M. & Fearon, T. C. LyceanEM: GigaScale Electromagnetics for Beamforming and System Planning. International Conference on Energy from Space, London, United Kingdom, 19th April 2024. https://research-information.bris.ac.uk/en/publications/lyceanem-gigascale-electromagnetics-for-beamforming-and-system-pl

Open Spatial Dataset for GNSS and Autonomous Navigation

Published in Operating in the Future Electromagnetic Environment Symposium, 2024

Global Navigation Satellite System (GNSS) data has become a stable of modern life, whether delivered through a smartphone, vehicle, or as part of an industrial dataset. The expectation of reliable position and time information, irrespective of the environment, becomes challenging in tunnels and canyons with significant multipath, whether natural or urban. An initial look at an open dataset of LIDAR, Computer Vision, and GNSS data is presented, combined with a channel model produced from this dataset, comparing the expected and measured line of sight and multipath contributions from GPS sources while moving around Bristol, from unobstructed surroundings to deep natural and urban canyons.

Recommended citation: Timothy Pelham, Y Chen, S Liu, et al. Open Spatial Dataset for GNSS and Autonomous Navigation. TechRxiv. April 01, 2024. DOI: 10.36227/techrxiv.171198164.47035045/v1 https://www.techrxiv.org/users/690214/articles/737375-open-spatial-dataset-for-gnss-and-autonomous-navigation?commit=c669274e86b5ccb6e5ec356c5c3cab58a046b518

Spatial Modelling for GPS Replication in Natural and Urban Canyons

Published in Operating in the Future Electromagnetic Environment Symposium, 2023

Global Navigation Satellite System (GNSS) data has become a stable of modern life, whether delivered through a smartphone, vehicle, or as part of an industrial dataset. The expectation of reliable position and time information, irrespective of the environment, becomes challenging in tunnels and canyons with significant multipath, whether natural or urban. An initial look at an open dataset of LIDAR, Computer Vision, and GNSS data is presented, combined with a channel model produced from this dataset, comparing the expected and measured line of sight and multipath contributions from GPS sources while moving around Bristol, from unobstructed surroundings to deep natural and urban canyons.

Recommended citation: Pelham, T. G., (2023). Spatial Modelling for GPS Replication in Natural and Urban Canyons. Operating in the Future Electromagnetic Environment Symposium - 2023

Spatial Fingerprinting for Future Self Securing Networks

Published in Operating in the Future Electromagnetic Environment Symposium, 2023

The electromagnetic environment represents a consistently open RF attack surface. Spatial fingerprinting is proposed as a fusion of spatial intelligence, onboard electromagnetic modelling and machine learning to allow nodes within a network to identify and localise transmitters in their locality . This capability forms the basis of reciprocal trust networks between nodes in a node work, enabling self securing behaviour, and the identification and localisation of unauthorised transmitters attempting to penetrate the network. This process is demonstrated using modelled and measured data of LoRa network packets with an Anechoic Chamber, allowing for complete modelling of the scattering environment within the spatial intelligence node, and localisation of the transmitters.

Recommended citation: Pelham, T. G., (2023). Spatial Fingerprinting for Future Self Securing Networks. Operating in the Future Electromagnetic Environment Symposium - 2023

LyceanEM: A python package for virtual prototyping of antenna arrays, time and frequency domain channel modelling

Published in The Journal of Open Source Software, 2023

Demonstration of the workflow for rapid antenna array design and analysis using LyceanEM

Recommended citation: Pelham, T. G., (2023). LyceanEM: A python package for virtual prototyping of antenna arrays, time and frequency domain channel modelling. Journal of Open Source Software, 8(86), 5234 https://joss.theoj.org/papers/10.21105/joss.05234#

Spatial Intelligence through combined sensing, using computer vision and on board electromagnetics modelling to enhance signals intelligence and situational awareness

Published in Military Sensing Symposium, 2023

As the cost of antenna arrays continues to decrease, there is an emerging opportunity for the combination of flexible electromagnetics models, modular and distributed antenna array design, and computer vision to provide enhancements to the situational awareness of platform operators. Combining computer vision, efficient electromagnetics modelling and radio channel measurements can provide a consistent understanding of the local environment for improved signals intelligence and situational awareness using commercial off the shelf (COTS) mobile AI modules.

Recommended citation: Pelham, T. G., (2023). Spatial Intelligence through combined sensing, using computer vision and on board electromagnetics modelling to enhance signals intelligence and situational awareness. Military Sensing Symposium - 2023

Royal Academy of Engineering Research Forum

Published in Royal Academy of Engineering Research Forum 2022, London, 2022

Vision to Radio, Computer Vision based Spatial Modelling for future Networks

Recommended citation: T. G. Pelham

Reflector Analysis for Novel OTA Test Method

Published in 15th European Conference on Antennas and Propagation, 2021

This paper is part of a new series on over the air test (OTA) techniques at 26GHz.

Recommended citation: A. L. Freire, T. G. Pelham, G. Hilton, M. Beach

Experimental evaluation of 3D printed spiral phase plates for enabling an orbital angular momentum multiplexed radio system

Published in Royal Society Open Science, 2019

This paper is about evaluating 3D printed spiral phase plates for generating orbital angular momentum modes

Recommended citation: Allen B., Pelham T., Wu Y., Drysdale T., Isakov D., Gamlath C., Stevens C. J., Hilton G., Beach M. A. and Grant P. S. (2019) "Experimental evaluation of 3D printed spiral phase plates for enabling an orbital angular momentum multiplexed radio system" Royal Society Open Science https://royalsocietypublishing.org/doi/10.1098/rsos.191419

Polarimetric Diffuse Scattering Channel Measurements at 26 GHz and 60 GHz

Published in Annual International Symposium on Personal, Indoor and Mobile Radio Communications, 2018

This paper covers polarimetric multiband measurements of urban multipath propagation

Recommended citation: A. L. Freire, T. Pelham, D. Kong, L. Sayer, V. Sgardoni, F. Tila, E. Mellios, M. Beach, A. Nix, G. Steinböck, "Polarimetric Diffuse Scattering Channel Measurements at 26 GHz and 60 GHz," 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Bologna, 2018, pp. 210-214, doi: 10.1109/PIMRC.2018.8581035.

Non-intrusive characterization of 60GHz antenna array, using packet measurements

Published in European Conference on Antennas and Propagation, 2018

This paper is introduces a convenient method for characterization of integrated antenna arrays using packed measurements

Recommended citation: T. G. Pelham, D. Reyes, M. Beach, E. Mellios and M. Rumney, "Non-intrusive characterization of 60GHz antenna array, using packet measurements," 12th European Conference on Antennas and Propagation (EuCAP 2018), London, 2018, pp. 1-3, doi: 10.1049/cp.2018.1045.

Link performance evaluation for mm-Wave systems

Published in European Conference on Networks and Communications (EuCNC), 2017

This paper is about modelling antenna elements within a reconfigurable conformal framework.

Recommended citation: V. Kalokidou, T. Pelham, M. Beach, P. Legg and A. Lunness, &quotLink performance evaluation for mm-Wave systems ", 2017 European Conference on Networks and Communications (EuCNC), Oulu, 2017, pp. 1-5, doi: 10.1109/EuCNC.2017.7980712.

Predicting Conformal Aperture Gain From 3-D Aperture and Platform Models

Published in IEEE Antennas and Wireless Propagation Letters, 2016

This paper is about predicting the on platform performance envelope for conformal antenna arrays

Recommended citation: T. Pelham, G. Hilton, E. Mellios and R. Lewis, "Predicting Conformal Aperture Gain From 3-D Aperture and Platform Models" IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 700-703, 2017, doi: 10.1109/LAWP.2016.2600403 .

Conformal antenna array modelling, FDTD predictions and measurements for Dual Circular Patch in Variable Geometry Conformal Antenna Array Test Rig

Published in 10th European Conference on Antennas and Propagation, 2016

This paper is about modelling antenna elements within a reconfigurable conformal framework.

Recommended citation: T. G. Pelham, G. Hilton, E. Mellios, C. Railton and R. Lewis, "Conformal antenna array modelling, FDTD predictions and measurements for Dual Circular Patch in Variable Geometry Conformal Antenna Array Test Rig, " 2016 10th European Conference on Antennas and Propagation (EuCAP), Davos, 2016, pp. 1-4, doi: 10.1109/EuCAP.2016.7481683.

Predicting conformal aperture directivity for arbitrary curved surfaces

Published in Wideband and Multi-Band Antennas and Arrays for Civil, Security and Military Applications, 2015

This paper investigates an extension of Hannans equation for the maximum achievable directivity of a planar aperture

Recommended citation: T. Pelham, G. Hilton, E. Mellios and R. Lewis, "Predicting conformal aperture directivity for arbitrary curved surfaces," Wideband and Multi-Band Antennas and Arrays for Civil, Security & Military Applications, London, 2015, pp. 1-3, doi: 10.1049/ic.2015.0147.

FDTD model performance analysis for a Cavity Slot Antenna array in a variable geometry conformal test rig

Published in IEEE International Symposium on Antennas and Propagation, 2015

This paper is about modelling antenna elements within a reconfigurable conformal framework, with reference to measurements of the same

Recommended citation: T. G. Pelham, G. Hilton, C. Railton and R. Lewis, "FDTD model performance analysis for a Cavity Slot Antenna array in a variable geometry conformal test rig," 2015 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, Vancouver, BC, 2015, pp. 1836-1837, doi: 10.1109/APS.2015.7305307.

Variable Geometry Conformal Antenna Array for Element Comparison

Published in Vehicular Technology Conference, 2015

This paper is about modelling antenna elements within a reconfigurable conformal framework.

Recommended citation: T. G. Pelham, G. Hilton, R. Lewis and C. Railton, "Variable Geometry Conformal Antenna Array for Element Comparison," 2015 IEEE 81st Vehicular Technology Conference (VTC Spring), Glasgow, 2015, pp. 1-5, doi: 10.1109/VTCSpring.2015.7146157. http://lyceanem.github.io/files/07146157.pdf

Simulation of d(7Be,t)6Be with Fresco, and investigation of resonant states of 6Be

Published in Annual Meeting of the Division of Nuclear Physics, 2008

This paper is about modelling antenna elements within a reconfigurable conformal framework.

Recommended citation: T. G. Pelham, "Simulation of d(7Be,t)6Be with Fresco, and investigation of resonant states of 6Be " 2008 Annual Meeting of the Division of Nuclear Physics, http://meetings.aps.org/link/BAPS.2008.DNP.DA.78