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Dr James J W Bell
Lecturer - Teaching and Research
- BellJJ1@cardiff.ac.uk
- +44 29208 79378
- Queen's Buildings - South Building, Room S1.03, 5 The Parade, Newport Road, Cardiff, CF24 3AA
- Available for postgraduate supervision
Overview
James Bell is the year-1 tutor for the Electrical and Electronic Engineering and Integrated Engineering degree programs at Cardiff University. He received the bachelor’s and Ph.D. degrees from Cardiff University in 2009 and 2013 respectively. He has worked in the Centre for High Frequency Engineering here at Cardiff University, where he has been involved with the development of nonlinear measurement systems, the "Cardiff Model" and high-efficiency power amplifier design. He is currently a lecturer and year-1 tutor in the School of Engineering at Cardiff University and remains a member of the Centre for High Frequency Engineering. He continues his work in the areas of behavioural modelling, RF and millimeter-wave measurement systems, and broadband power amplifier design.
Publication
2023
- Tian, M., Bell, J., Azad, E., Quaglia, R. and Tasker, P. 2023. A novel Cardiff model coefficients extraction process based on artificial neural network. Presented at: 2023 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless ApplicationsED, MAY BE LINKED, Las Vegas, NV, USA, 22-25 January 20232023 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications. IEEE, (10.1109/PAWR56957.2023.10046221)
2022
- Azad, E. M., Quaglia, R., Chadhary, K., Bell, J. J. and Tasker, P. J. 2022. Cardiff model utilization for predicting the response of multiple-input power amplifiers. Presented at: Mediterrannean Microwave Symposium (MMS), Pizzo Calabro, Italy, 9-13 May 2022Proceedings of Microwave Mediterranean Symposium (MMS). IEEE, (10.1109/MMS55062.2022.9825516)
- Azad, E. M., Bell, J. J., Quaglia, R., Moreno Rubio, J. J. and Tasker, P. J. 2022. New formulation of Cardiff behavioral model including DC bias voltage dependence. IEEE Microwave and Wireless Components Letters 32(6), pp. 607-610. (10.1109/LMWC.2022.3140653)
- Azad, E. M., Quaglia, R., Bell, J. J., Chaudhry, K., Nghiem, A., Sulaksono, K. and Tasker, P. J. 2022. Load-pull data analysis of a GaN on SiC HEMT targeting multi bias Doherty design. Presented at: International Workshop on Integrated Nonlinear Microwave and Millimeterwave Circuits, INMMIC, Cardiff, UK, 7-8 April 2022Proceedings of the 2022 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits. IEEE, (10.1109/INMMiC54248.2022.9762106)
- Baddeley, A., Azad, E., Quaglia, R., Bell, J. and Tasker, P. 2022. Gate bias voltage dependence of Cardiff admittance model in Ka-band GaAs pHEMTs. Presented at: IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR), Las Vegas, NV, USA, 16-19 January 20222022 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR). IEEE pp. 8-10., (10.1109/PAWR53092.2022.9719858)
- Azad, E. M., Quaglia, R., Bell, J. J., Chaudhry, K. and Tasker, P. J. 2022. DC-dependent Cardiff model from modulated supply and load-pull data. Presented at: 2022 Asia-Pacific Microwave Conference (APMC), Yokohama, Japan, 29 November 2022 - 02 December 2022Proceedings of 2022 Asia-Pacific Microwave Conference (APMC). IEEE pp. 181-183., (10.23919/APMC55665.2022.9999796)
2021
- Alimohammadi, Y. et al. 2021. Incorporating gate-lag effects into the Cardiff Behavioural Model. Presented at: 50th European Microwave Conference (EuMC 2020), Utrecht, Netherlands, 12-14 January 20212020 50th European Microwave Conference (EuMC). IEEE pp. 684-687., (10.23919/EuMC48046.2021.9338185)
2020
- Azad, E. M., Bell, J. J., Quaglia, R., Moreno Rubio, J. J. and Tasker, P. J. 2020. Gate bias incorporation into Cardiff behavioural modelling formulation. Presented at: IEEE/MTT-S International Microwave Symposium (IMS 2020), Los Angeles, CA, USA, 4-6 August 20202020 IEEE/MTT-S International Microwave Symposium (IMS). IEEE pp. 420-423., (10.1109/IMS30576.2020.9223817)
- Alimohammadi, Y. et al. 2020. Pulse profiling active load pull measurements. Presented at: IEEE/MTT-S International Microwave Symposium (IMS 2020), Los Angeles, CA, USA, 4-6 August 20202020 IEEE/MTT-S International Microwave Symposium (IMS). IEEE pp. 759-762., (10.1109/IMS30576.2020.9223989)
2019
- Syed Anera, S. M. H. et al. 2019. High-efficiency broadband PA design based on continuous Class-F mode with compression. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019MTT-S International Microwave Symposium (IMS). IEEE pp. 698-701., (10.1109/MWSYM.2019.8700767)
- Al-Rawachy, A., Husseini, T., Benedikt, J., Bell, J. and Tasker, P. 2019. Behavioural model extraction using novel multitone active load-pull. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019MTT-S International Microwave Symposium (IMS). IEEE pp. 196-199., (10.1109/MWSYM.2019.8700779)
- Husseini, T., Al-Rawachy, A., Benedikt, J., Bell, J. and Tasker, P. 2019. Global behavioural model generation using coefficients interpolation. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019. pp. -.
2018
- Husseini, T., Al-Rawachy, A., Anera, S. S., Bell, J., Tasker, P. and Benedikt, J. 2018. On the effective modeling of the test-set non-linearity. Presented at: 2018 91st ARFTG Microwave Measurement Conference (ARFTG), Philadelphia, PA, USA, 15 June 20182018 91st ARFTG Microwave Measurement Conference (ARFTG). IEEE, (10.1109/ARFTG.2018.8423832)
- Bogusz, A., Costello, Z., Quaglia, R., Bell, J., Lees, J., Tasker, P. and Cripps, S. 2018. Power and efficiency continuous modes in saturated GaN HEMT devices. Presented at: Inmmic 2018, Brive-La-Gaillarde, France, 5- 6 July 2018.
2017
- Quaglia, R., Bell, J. J. and Cripps, S. 2017. New general formulation and experimental verification of harmonic clipping contours in high-frequency power devices. IEEE Transactions on Microwave Theory and Techniques 65(10), pp. 3903-3909. (10.1109/TMTT.2017.2687900)
2014
- Bell, J. J. 2014. Input Harmonic and Mixing Behavioural Model Analysis. PhD Thesis, Cardiff University.
- Koh, M., Bell, J. J., Williams, D., Patterson, A., Lees, J., Root, D. E. and Tasker, P. J. 2014. Frequency scalable large signal transistor behavioral model based on admittance domain formulation. Presented at: International Microwave Symposium, Tampa, Florida, 1-6 June 20142014 IEEE MTT-S International Microwave Symposium (IMS). Picastaway, NJ: IEEE pp. 1-3., (10.1109/MWSYM.2014.6848287)
2013
- Koh, M., Bell, J. J., Williams, D., Patterson, A., Wohlmuth, W., Lees, J. and Tasker, P. J. 2013. X-band MMIC scalable large signal model based on unit cell behavioral data model and passive embedding network. Presented at: International Microwave Symposium, Seattle, WA, 2-7 June 20132013 IEEE MTT-S International Microwave Symposium Digest (IMS). Picastaway, NJ: IEEE pp. 1-4., (10.1109/MWSYM.2013.6697424)
- Aldoumani, A., Tasker, P. J., Saini, R. S., Bell, J. J., Williams, T. and Lees, J. 2013. Operation and calibration of VNA-based large signal RF I-V waveform measurements system without using a harmonic phase reference standard. Presented at: ARFTG Microwave Measurement Conference (ARFTG), Seattle, WA, 7-7 June 20132013 81st ARFTG Microwave Measurement Conference (ARFTG). Picastaway, NJ: IEEE pp. 1-4., (10.1109/ARFTG.2013.6579055)
2011
- Bell, J. J., Saini, R., Woodington, S. P., Lees, J., Benedikt, J., Cripps, S. C. and Tasker, P. J. 2011. Behavioral model analysis using simultaneous active fundamental load-pull and harmonic source-pull measurements at X-band. Presented at: 2011 IEEE/MTT-S International Microwave Symposium, Baltimore, MD, USA, 5-10 June 2011Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International. New York: IEEE pp. 982-986., (10.1109/MWSYM.2011.5972803)
- Powell, J. R. et al. 2011. GaAs X-band high efficiency (65%) broadband (30%) amplifier MMIC based on the Class B to Class J continuum. Presented at: 2011 IEEE/MTT-S International Microwave Symposium, Baltimore, MD, USA, 5-10 June 2011 Presented at Seigel, P. et al. eds.2011 IEEE/MTT-S International Microwave Symposium - MTT 2011. New York: IEEE pp. 355., (10.1109/MWSYM.2011.5973350)
- Saini, R. et al. 2011. High speed non-linear device characterization and uniformity investigations at X-band frequencies exploiting behavioral models. Presented at: 2011 77th ARFTG Microwave Measurement Conference (ARFTG), Baltimore, MD, USA, 10 June 2011Design and Measurement of Microwave Systems - Proceedings of the 2011 77th ARFTG Microwave Measurement Conference (ARFTG). Los Alamitos, CA: IEEE, (10.1109/ARFTG77.2011.6034552)
- Saini, R., Bell, J. J., Williams, T., Lees, J., Benedikt, J. and Tasker, P. J. 2011. Interpolation and extrapolation capabilities of non-linear behavioural models. Presented at: 2011 78th ARFTG Microwave Measurement Symposium (ARFTG), Tempe, AZ, USA, 1-2 December 2011Proceedings of the 2011 78th ARFTG Microwave Measurement Symposium (ARFTG) - High Power RF Measurement Techniques. Los Alamitos, CA: IEEE, (10.1109/ARFTG78.2011.6183865)
Articles
- Azad, E. M., Bell, J. J., Quaglia, R., Moreno Rubio, J. J. and Tasker, P. J. 2022. New formulation of Cardiff behavioral model including DC bias voltage dependence. IEEE Microwave and Wireless Components Letters 32(6), pp. 607-610. (10.1109/LMWC.2022.3140653)
- Quaglia, R., Bell, J. J. and Cripps, S. 2017. New general formulation and experimental verification of harmonic clipping contours in high-frequency power devices. IEEE Transactions on Microwave Theory and Techniques 65(10), pp. 3903-3909. (10.1109/TMTT.2017.2687900)
Conferences
- Tian, M., Bell, J., Azad, E., Quaglia, R. and Tasker, P. 2023. A novel Cardiff model coefficients extraction process based on artificial neural network. Presented at: 2023 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless ApplicationsED, MAY BE LINKED, Las Vegas, NV, USA, 22-25 January 20232023 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications. IEEE, (10.1109/PAWR56957.2023.10046221)
- Azad, E. M., Quaglia, R., Chadhary, K., Bell, J. J. and Tasker, P. J. 2022. Cardiff model utilization for predicting the response of multiple-input power amplifiers. Presented at: Mediterrannean Microwave Symposium (MMS), Pizzo Calabro, Italy, 9-13 May 2022Proceedings of Microwave Mediterranean Symposium (MMS). IEEE, (10.1109/MMS55062.2022.9825516)
- Azad, E. M., Quaglia, R., Bell, J. J., Chaudhry, K., Nghiem, A., Sulaksono, K. and Tasker, P. J. 2022. Load-pull data analysis of a GaN on SiC HEMT targeting multi bias Doherty design. Presented at: International Workshop on Integrated Nonlinear Microwave and Millimeterwave Circuits, INMMIC, Cardiff, UK, 7-8 April 2022Proceedings of the 2022 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits. IEEE, (10.1109/INMMiC54248.2022.9762106)
- Baddeley, A., Azad, E., Quaglia, R., Bell, J. and Tasker, P. 2022. Gate bias voltage dependence of Cardiff admittance model in Ka-band GaAs pHEMTs. Presented at: IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR), Las Vegas, NV, USA, 16-19 January 20222022 IEEE Topical Conference on RF/Microwave Power Amplifiers for Radio and Wireless Applications (PAWR). IEEE pp. 8-10., (10.1109/PAWR53092.2022.9719858)
- Azad, E. M., Quaglia, R., Bell, J. J., Chaudhry, K. and Tasker, P. J. 2022. DC-dependent Cardiff model from modulated supply and load-pull data. Presented at: 2022 Asia-Pacific Microwave Conference (APMC), Yokohama, Japan, 29 November 2022 - 02 December 2022Proceedings of 2022 Asia-Pacific Microwave Conference (APMC). IEEE pp. 181-183., (10.23919/APMC55665.2022.9999796)
- Alimohammadi, Y. et al. 2021. Incorporating gate-lag effects into the Cardiff Behavioural Model. Presented at: 50th European Microwave Conference (EuMC 2020), Utrecht, Netherlands, 12-14 January 20212020 50th European Microwave Conference (EuMC). IEEE pp. 684-687., (10.23919/EuMC48046.2021.9338185)
- Azad, E. M., Bell, J. J., Quaglia, R., Moreno Rubio, J. J. and Tasker, P. J. 2020. Gate bias incorporation into Cardiff behavioural modelling formulation. Presented at: IEEE/MTT-S International Microwave Symposium (IMS 2020), Los Angeles, CA, USA, 4-6 August 20202020 IEEE/MTT-S International Microwave Symposium (IMS). IEEE pp. 420-423., (10.1109/IMS30576.2020.9223817)
- Alimohammadi, Y. et al. 2020. Pulse profiling active load pull measurements. Presented at: IEEE/MTT-S International Microwave Symposium (IMS 2020), Los Angeles, CA, USA, 4-6 August 20202020 IEEE/MTT-S International Microwave Symposium (IMS). IEEE pp. 759-762., (10.1109/IMS30576.2020.9223989)
- Syed Anera, S. M. H. et al. 2019. High-efficiency broadband PA design based on continuous Class-F mode with compression. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019MTT-S International Microwave Symposium (IMS). IEEE pp. 698-701., (10.1109/MWSYM.2019.8700767)
- Al-Rawachy, A., Husseini, T., Benedikt, J., Bell, J. and Tasker, P. 2019. Behavioural model extraction using novel multitone active load-pull. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019MTT-S International Microwave Symposium (IMS). IEEE pp. 196-199., (10.1109/MWSYM.2019.8700779)
- Husseini, T., Al-Rawachy, A., Benedikt, J., Bell, J. and Tasker, P. 2019. Global behavioural model generation using coefficients interpolation. Presented at: 2019 IEEE MTT-S International Microwave Symposium, IMS 2019, Boston, USA, 2 -7 June 2019. pp. -.
- Husseini, T., Al-Rawachy, A., Anera, S. S., Bell, J., Tasker, P. and Benedikt, J. 2018. On the effective modeling of the test-set non-linearity. Presented at: 2018 91st ARFTG Microwave Measurement Conference (ARFTG), Philadelphia, PA, USA, 15 June 20182018 91st ARFTG Microwave Measurement Conference (ARFTG). IEEE, (10.1109/ARFTG.2018.8423832)
- Bogusz, A., Costello, Z., Quaglia, R., Bell, J., Lees, J., Tasker, P. and Cripps, S. 2018. Power and efficiency continuous modes in saturated GaN HEMT devices. Presented at: Inmmic 2018, Brive-La-Gaillarde, France, 5- 6 July 2018.
- Koh, M., Bell, J. J., Williams, D., Patterson, A., Lees, J., Root, D. E. and Tasker, P. J. 2014. Frequency scalable large signal transistor behavioral model based on admittance domain formulation. Presented at: International Microwave Symposium, Tampa, Florida, 1-6 June 20142014 IEEE MTT-S International Microwave Symposium (IMS). Picastaway, NJ: IEEE pp. 1-3., (10.1109/MWSYM.2014.6848287)
- Koh, M., Bell, J. J., Williams, D., Patterson, A., Wohlmuth, W., Lees, J. and Tasker, P. J. 2013. X-band MMIC scalable large signal model based on unit cell behavioral data model and passive embedding network. Presented at: International Microwave Symposium, Seattle, WA, 2-7 June 20132013 IEEE MTT-S International Microwave Symposium Digest (IMS). Picastaway, NJ: IEEE pp. 1-4., (10.1109/MWSYM.2013.6697424)
- Aldoumani, A., Tasker, P. J., Saini, R. S., Bell, J. J., Williams, T. and Lees, J. 2013. Operation and calibration of VNA-based large signal RF I-V waveform measurements system without using a harmonic phase reference standard. Presented at: ARFTG Microwave Measurement Conference (ARFTG), Seattle, WA, 7-7 June 20132013 81st ARFTG Microwave Measurement Conference (ARFTG). Picastaway, NJ: IEEE pp. 1-4., (10.1109/ARFTG.2013.6579055)
- Bell, J. J., Saini, R., Woodington, S. P., Lees, J., Benedikt, J., Cripps, S. C. and Tasker, P. J. 2011. Behavioral model analysis using simultaneous active fundamental load-pull and harmonic source-pull measurements at X-band. Presented at: 2011 IEEE/MTT-S International Microwave Symposium, Baltimore, MD, USA, 5-10 June 2011Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International. New York: IEEE pp. 982-986., (10.1109/MWSYM.2011.5972803)
- Powell, J. R. et al. 2011. GaAs X-band high efficiency (65%) broadband (30%) amplifier MMIC based on the Class B to Class J continuum. Presented at: 2011 IEEE/MTT-S International Microwave Symposium, Baltimore, MD, USA, 5-10 June 2011 Presented at Seigel, P. et al. eds.2011 IEEE/MTT-S International Microwave Symposium - MTT 2011. New York: IEEE pp. 355., (10.1109/MWSYM.2011.5973350)
- Saini, R. et al. 2011. High speed non-linear device characterization and uniformity investigations at X-band frequencies exploiting behavioral models. Presented at: 2011 77th ARFTG Microwave Measurement Conference (ARFTG), Baltimore, MD, USA, 10 June 2011Design and Measurement of Microwave Systems - Proceedings of the 2011 77th ARFTG Microwave Measurement Conference (ARFTG). Los Alamitos, CA: IEEE, (10.1109/ARFTG77.2011.6034552)
- Saini, R., Bell, J. J., Williams, T., Lees, J., Benedikt, J. and Tasker, P. J. 2011. Interpolation and extrapolation capabilities of non-linear behavioural models. Presented at: 2011 78th ARFTG Microwave Measurement Symposium (ARFTG), Tempe, AZ, USA, 1-2 December 2011Proceedings of the 2011 78th ARFTG Microwave Measurement Symposium (ARFTG) - High Power RF Measurement Techniques. Los Alamitos, CA: IEEE, (10.1109/ARFTG78.2011.6183865)
Thesis
- Bell, J. J. 2014. Input Harmonic and Mixing Behavioural Model Analysis. PhD Thesis, Cardiff University.
Research
James' research interests include, but are not limited to, behavioural modelling, intelligent measurement systems, and power amplifier design. He is currently working on robust automated load-pull measurement systems; augmenting the 'Cardiff Behavioural Model' framework for measurement system control and robust CAD models for PA design; and the practical application of 'Clipping Contours' for the design of linear or linearisable PAs. James works closely with international industry and academics, as his research impacts both sectors.
Teaching
Year-1 Tutor
EN1072 Laboratory (Module Leader)
EN1079 Professional Engineering (Module Leader)
EN1092 Professional Engineering (Module Leader)
EN3818 Analogue and Digital Communications Systems (Module Contributor)
EN4110 Mechatronics (Space Drone Project)
Biography
Professional memberships
Member of the IEEE
Supervisions
Supervised Areas
- Active device modelling
- Machine learning RF and mm-wave measurement and modelling solutions
- Intelligent load-pull measurement systems
- Power amplifier theory and design
Current supervision
Derek Kozel
Research student