![Ehsan Azad](https://profiles-cardiff.imgix.net/attachments/3492?w=200&h=200&auto=format&crop=faces&fit=crop&q=90")
Dr Ehsan Azad
Research student
- AzadEM@cardiff.ac.uk
- Queen's Buildings - Central Building, Room Room C/3.10, 5 The Parade, Newport Road, Cardiff, CF24 3AA
Overview
I am a PhD research student at the Centre for High Frequency Engineering (CHFE), School of Engineering; under the supervision of Dr. Roberto Quaglia, Dr. James J. Bell, and Prof. Paul J. Tasker.
My research addresses the problems encountered in the field of non-linear RF and microwave power amplifier design. My research activities include design, modelling and characterisation of non-linear RF and microwave transistors and power amplifier circuits.
I have published several peer-reviewed scientific papers.
My peers and I participated in two High Efficiency Power Amplifier (HEPA) student design competitions. Our team won second place in the 2022 RWW/ARFTG MTT-S HEPA Student Design Competition, Las Vegas, USA; and the third place award in the 2021 IMS HEPA Student Design.
Publication
2023
- Yuan, T., Quaglia, R., Chaudhry, K., Azad, E., Powell, J. R. and Cripps, S. C. 2023. Output signal re-injection in load modulated balanced amplifiers for RF bandwidth improvement. IEEE Microwave and Wireless Components Letters 33(10), pp. 1458-1461. (10.1109/LMWT.2023.3305812)
- Ghozati, S. U., Quaglia, R., Azad, E., Powell, J., Tasker, P. and Cripps, S. 2023. Load pull-driven behavioral modelling of microwave switches for the design of tunable reflective terminations. Presented at: EuMW 2024: European Microwave Week 2023, 19 - 21 September 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)
- Azad, E. 2023. Efficiency improvement in base station power amplifiers. PhD Thesis, Cardiff University.
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)
Articles
- Yuan, T., Quaglia, R., Chaudhry, K., Azad, E., Powell, J. R. and Cripps, S. C. 2023. Output signal re-injection in load modulated balanced amplifiers for RF bandwidth improvement. IEEE Microwave and Wireless Components Letters 33(10), pp. 1458-1461. (10.1109/LMWT.2023.3305812)
- 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)
Conferences
- Ghozati, S. U., Quaglia, R., Azad, E., Powell, J., Tasker, P. and Cripps, S. 2023. Load pull-driven behavioral modelling of microwave switches for the design of tunable reflective terminations. Presented at: EuMW 2024: European Microwave Week 2023, 19 - 21 September 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)
- 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)
Thesis
- Azad, E. 2023. Efficiency improvement in base station power amplifiers. PhD Thesis, Cardiff University.
Research
My PhD research project is in collaboration with Ampleon Netherlands B.V to design highly efficient power amplifiers capable of working at multiple DC supply voltages. The design is based on the state of the art Gallium Nitride (GaN) high electron mobility transistor (HEMT) devices for sub-6 GHz 5G base stations.
The Cardiff nonlinear behavioural model is a critical element in the design process as it allows us to directly use the nonlinear load-pull measurement data within the CAD simulator environment. Hence; increasing the chance of "first pass" successful design.
We have developed a new mathematical formulation for the Cardiff model which is capable to predict the device behaviour at various DC supply voltages. The result of this achievement has been published in several peer-reviewed scientific papers.
Thesis
Efficiency Improvement in Base Station Power Amplifiers
Teaching
I have more than 250 hours of experience as a lab demonstrator and teaching assistant in both undergraduate and postgraduate ectrical and electronic enginieering Modules. The modules which I have participated in are listed as below:
- MSc: Microwave and Millimetre-Wave Integrated Circuit Design and Technology.
- MSc: RF circuit design & CAD.
- Year one: Electrical and electronic engineering lab.
- Year one: Analogue and digital communication systems.
- Year one: Matlab surgery.
- Year one: Electrical and Electronic Engineering 1.
