Periodic Reporting for period 1 - PABLO (Power Amplifier Design Through Behavioural Modelling)
Reporting period: 2019-02-01 to 2021-01-31
The 5th generation (5G) of mobile will revolutionise the world of wireless communications and is driving huge investments in research and development. Radio transceivers are the enabling technology for any mobile system and 5G will bring important changes in the way radios operate at both user terminal and base-stations. Massive antenna arrays will be adopted to increase the number of users served by a single base-station, with increased channel bandwidth and spectral efficiency with respect to previous generations.
The power amplifier (PA) is the most critical element of a high frequency transceiver for its impact on the quality of the transmitted signal (linearity) and on energy consumption. Several techniques have been successfully adopted in the past to optimize the trade-off between linearity and power efficiency; however the adoption of large arrays will deeply change the scenario.
The project PABLO will introduce the use of nonlinear behavioural modelling of high frequency transistors for the design of advanced high energy efficiency PAs, focus on 5G applications. In this way, the project looks for increasing the computation efficiency, which is necessary in the context of emerging 5G technologies.
This research program (PABLO) is framed in one of the EU2020 targets, which is the efficient use of energy, as an important issue related to the climate change and energy sustainability of the world. The expansion and increasing pervasiveness of wireless networks has significantly increased the impact of their power consumption. By delivering a method to design efficient 5G PAs, PABLO will contribute to green and economically viable 5G systems.
The power amplifier (PA) is the most critical element of a high frequency transceiver for its impact on the quality of the transmitted signal (linearity) and on energy consumption. Several techniques have been successfully adopted in the past to optimize the trade-off between linearity and power efficiency; however the adoption of large arrays will deeply change the scenario.
The project PABLO will introduce the use of nonlinear behavioural modelling of high frequency transistors for the design of advanced high energy efficiency PAs, focus on 5G applications. In this way, the project looks for increasing the computation efficiency, which is necessary in the context of emerging 5G technologies.
This research program (PABLO) is framed in one of the EU2020 targets, which is the efficient use of energy, as an important issue related to the climate change and energy sustainability of the world. The expansion and increasing pervasiveness of wireless networks has significantly increased the impact of their power consumption. By delivering a method to design efficient 5G PAs, PABLO will contribute to green and economically viable 5G systems.
Initially, the Cardiff Model has been extracted using simulations over a set of loads, covering a great part of the Smith Chart. In this case, the model was extracted including only the fundamental component, and fundamental and second harmonic at the device output. This demonstrated the importance of including the second harmonic at the output of the device in terms of accuracy (WP1). On the other hand, in cooperation with researchers from different areas (materials), a new magneto-dielectric composite has been evaluated to be used as a substrate in the design of broadband power amplifiers. This new material has shown the possibility of obtaining dielectric constants for particular concentrations of magnetite and average particle size. It means that this new material can contribute to the design of power amplifiers where the matching is complicated due to the small load magnitude (WP1), as it is the case of high-power devices. This work has been published in the Journal of Physics [1].
Next, based on previous work realized by members of the CHFE, a methodology to limit the extraction space has been adopted to optimize the measurement procedure (WP2). This consists of a simplified prediction of the power and efficiency contours. It was validated through the design of an ultra-wideband high efficiency power amplifier with a band from 0.45 to 3.4 GHz. This work was published in [2]. The results obtained compared very well with the state-of-the-art but introducing a much simpler design strategy. The designed PA can find application in flexible hardware for 5G applications, as well as in broadband radar and countermeasure systems. Using the adopted strategy, the load-pull measurements were carried out for a MMIC device at 28 GHz (WP2 and WP3). Furthermore, in order to increase the accuracy of the model related to the input matching, load-pull measurements were carried out in a different device including the second harmonic, not only at the output but also at the input. An ultra-wideband power amplifier and a Doherty Power Amplifier have been designed and simulated using both the Cardiff Model and the foundry non-linear model, which has shown a good agreement between them (WP2 and WP3). The variation of the model coefficients respect to the bias conditions has been investigated and a mathematical relation has been found, this contributes to the design of Doherty Power Amplifier, where main and peaking devices are biased differently. Besides, the intensity of the load-pull measurements was decreased up to 80%. The results of this work have been presented and published in the 2020 IEEE/MTT-S International Microwave Symposium (IMS), in Los Angeles (USA) [3].
Next, based on previous work realized by members of the CHFE, a methodology to limit the extraction space has been adopted to optimize the measurement procedure (WP2). This consists of a simplified prediction of the power and efficiency contours. It was validated through the design of an ultra-wideband high efficiency power amplifier with a band from 0.45 to 3.4 GHz. This work was published in [2]. The results obtained compared very well with the state-of-the-art but introducing a much simpler design strategy. The designed PA can find application in flexible hardware for 5G applications, as well as in broadband radar and countermeasure systems. Using the adopted strategy, the load-pull measurements were carried out for a MMIC device at 28 GHz (WP2 and WP3). Furthermore, in order to increase the accuracy of the model related to the input matching, load-pull measurements were carried out in a different device including the second harmonic, not only at the output but also at the input. An ultra-wideband power amplifier and a Doherty Power Amplifier have been designed and simulated using both the Cardiff Model and the foundry non-linear model, which has shown a good agreement between them (WP2 and WP3). The variation of the model coefficients respect to the bias conditions has been investigated and a mathematical relation has been found, this contributes to the design of Doherty Power Amplifier, where main and peaking devices are biased differently. Besides, the intensity of the load-pull measurements was decreased up to 80%. The results of this work have been presented and published in the 2020 IEEE/MTT-S International Microwave Symposium (IMS), in Los Angeles (USA) [3].
"The designed PA in [2] can find application in flexible hardware for 5G applications, as well as in broadband radar and countermeasure systems. Due to the much simpler design approach, this can be an interesting contribution for the industry. In cooperation with some of the members of the research group CHFE, for the first time the Cardiff Behavioural Model coefficients has been considered as a function of the gate bias voltage. As a result, the intensity of the load-pull measurements decreases up to 80%. This contributes to the energy and computational efficiency of the extraction methodology, which can make it attractive to academia and industry [3]. The substrate based on a magneto-dielectric composite is an interesting contribution as well, since it will allow the development of smaller circuits (Power Amplifier) and larger bandwidths. This is an interesting topic in which new investigations have been planned.
Five additional designs have been realized using novel methodologies and they can become contributions to the state-of-the-art in the short term. In this case, an ultra-wideband power amplifier was designed over the band from 3 to 20 GHz. This amplifier was designed following an innovative methodology that was able to obtain state-of-the-art results, it is much simpler than others and uses a single transistor and a small MMIC area. It makes this design very attractive to academia and industry. A paper has been submitted to one of the most important journals of this area. Additionally, two MMIC Doherty Power Amplifier was designed at 28 GHz, which is considered one of the most trialled 5G bands in the world. Both of them represents novel design methodologies that can be considered potential publications. On the 38 GHz band, a Doherty Power Amplifier has been designed and its simulation results were promising. And finally, in cooperation with members of the group, a new type of amplifier has been designed based on the Load Modulated Power Amplifier.
[1] L. A. Lara, D. L. Mancipe, Y. Pineda, J. J. Moreno, and G. Peña-Rodríguez, ―Design and characterization of a magneto-dielectric composite in high frequency with aligned magnetite powders,‖ in Journal of Physics: Conference Series, Volume 1386, 5th International Meeting for Researchers in Materials and Plasma Technology (5th IMRMPT), Cucuta, 2019.
[2] J. J. Moreno Rubio, R. Quaglia, A. Baddeley, P. J. Tasker and S. C. Cripps, ""Design of a Broadband Power Amplifier Based on Power and Efficiency Contour Estimation,"" in IEEE Microwave and Wireless Components Letters, vol. 30, no. 8.
[3] E. M. Azad, J. J. Bell, R. Quaglia, J. J. Moreno Rubio and P. J. Tasker, ""Gate Bias Incorporation into Cardiff Behavioural Modelling Formulation,"" 2020 IEEE/MTT-S International Microwave Symposium (IMS), Los Angeles, CA, USA, 2020."
Five additional designs have been realized using novel methodologies and they can become contributions to the state-of-the-art in the short term. In this case, an ultra-wideband power amplifier was designed over the band from 3 to 20 GHz. This amplifier was designed following an innovative methodology that was able to obtain state-of-the-art results, it is much simpler than others and uses a single transistor and a small MMIC area. It makes this design very attractive to academia and industry. A paper has been submitted to one of the most important journals of this area. Additionally, two MMIC Doherty Power Amplifier was designed at 28 GHz, which is considered one of the most trialled 5G bands in the world. Both of them represents novel design methodologies that can be considered potential publications. On the 38 GHz band, a Doherty Power Amplifier has been designed and its simulation results were promising. And finally, in cooperation with members of the group, a new type of amplifier has been designed based on the Load Modulated Power Amplifier.
[1] L. A. Lara, D. L. Mancipe, Y. Pineda, J. J. Moreno, and G. Peña-Rodríguez, ―Design and characterization of a magneto-dielectric composite in high frequency with aligned magnetite powders,‖ in Journal of Physics: Conference Series, Volume 1386, 5th International Meeting for Researchers in Materials and Plasma Technology (5th IMRMPT), Cucuta, 2019.
[2] J. J. Moreno Rubio, R. Quaglia, A. Baddeley, P. J. Tasker and S. C. Cripps, ""Design of a Broadband Power Amplifier Based on Power and Efficiency Contour Estimation,"" in IEEE Microwave and Wireless Components Letters, vol. 30, no. 8.
[3] E. M. Azad, J. J. Bell, R. Quaglia, J. J. Moreno Rubio and P. J. Tasker, ""Gate Bias Incorporation into Cardiff Behavioural Modelling Formulation,"" 2020 IEEE/MTT-S International Microwave Symposium (IMS), Los Angeles, CA, USA, 2020."