| 1. |
- Chani Cahuana, Jessica, 1988, et al.
(författare)
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A new variant of the indirect learning architecture for the linearization of power amplifiers
- 2015
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Ingår i: 2015 European Microwave Conference (EuMIC). - 9782874870408 ; , s. 444-447
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Konferensbidrag (refereegranskat)abstract
- The indirect learning architecture (ILA) is the most commonly used technique for the identification of digital pre-distorters for power amplifiers (PA). A critical issue in ILA is the selection of the normalization gain used to synthesize the predistorter function. In this paper, we investigate the effects that the normalization gain has on the average output power and linearity of PAs. Moreover, we propose a new variant of the ILA that eliminates the need of a normalization gain inside the iterative loop. Experimental results show that the selection of the normalization gain affects the average output power and consequently the linearity performance of the linearized PA. If the normalization gain is not chosen correctly, the average output power of the linearized PA will differ from the average output power obtained before DPD. It is experimentally shown that the proposed ILA variant can maintain the same average output power before and after DPD. Consequently the proposed ILA variant simplifies the linearization process and allows proper evaluation of the DPD performance.
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| 2. |
- Prasad, Ankur, 1987, et al.
(författare)
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Symmetry based Nonlinear Model for GaN
- 2015
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Ingår i: 2015 10th European Microwave Integrated Circuits Conference (Eumic). - 9782874870408 ; , s. 85-88
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new nonlinear transistor model based on a symmetrical small-signal model far GaN HEMTs. The intrinsic symmetry reflected into the small signal equivalent circuit is used to build a new model to describe the nonlinear behavior of the device. The model consists of a new nonlinear charge expression with only 6 parameters, while the nonlinear current expression is extended front an existing model to enable validity in both the positive and negative Vis region. Therefore, it can be used for transistors in switches, resistive mixers as well as amplifiers. The model is validated with both small-signal and nonlinear measurements showing good agreements.
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| 3. |
- Singerl, Peter, et al.
(författare)
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A 2.7-GHz multi-level PWM carrier-bursting RF transmitter
- 2015
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Ingår i: European Microwave Week 2015: "Freedom Through Microwaves", EuMW 2015 - Conference Proceedings; 2015 10th European Microwave Integrated Circuits Conference Proceedings, EuMIC. - 9782874870408 ; , s. 273-276
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Konferensbidrag (refereegranskat)abstract
- Carrier-bursting is an attractive RF transmitter concept to achieve high efficiency. The power amplifier (PA) itself either operates at its peak efficiency or is turned off. Another efficiency-enhancing approach is the Doherty concept, where the main PA reaches its peak efficiency already in back-off and the peak PA contributes at high input levels to reach the desired output power. In this work, we attempt to combine the best of both concepts and derive a two-level dual-output pulse width modulator driving two PAs whose outputs are combined. We have evaluated the concept by a real-time FPGA implementation of the modulator for a 2.7GHz carrier driving two Class-AB PAs with a combined peak output power of 30W. The approach exhibits a potentially more pronounced back-off efficiency peak compared to the Doherty concept. Furthermore, the overall efficiency scales with the drain efficiency of the PAs and can thus be improved by employing Class-D or Class-F PAs.
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