Analysis and Design of a Doherty-Like RF-Input Load Modulated Balanced Amplifier

Pednekar, Prathamesh H.; Hallberg, William; Fager, Christian; Barton, Taylor W.

doi:10.1109/tmtt.2018.2869571

Cited by 73 publications

(39 citation statements)

References 31 publications

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“…Similar considerations can be made for the LMBA, which was originally proposed for telecom applications as a dual-input structure [ 5 ]. However, single-input solutions have also been proposed [ 17 ], and critically compared to the dual-input case [ 18 ]. Furthermore, in this case, the single input solution is viable, with a clear advantage in terms of simplicity, but at the cost of compromised performance.…”

Section: Introductionmentioning

confidence: 99%

Machine-Learning Assisted Optimisation of Free-Parameters of a Dual-Input Power Amplifier for Wideband Applications

Wang

Quaglia

et al. 2021

Sensors

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This paper presents an auto-tuning approach for dual-input power amplifiers using a combination of global optimisation search algorithms and adaptive linearisation in the optimisation of a multiple-input power amplifier. The objective is to exploit the extra degrees of freedom provided by dual-input topologies to enhance the power efficiency figures along wide signal bandwidths and high peak-to-average power ratio values, while being compliant with the linearity requirements. By using heuristic search global optimisation algorithms, such as the simulated annealing or the adaptive Lipschitz Optimisation, it is possible to find the best parameter configuration for PA biasing, signal calibration, and digital predistortion linearisation to help mitigating the inherent trade-off between linearity and power efficiency. Experimental results using a load-modulated balanced amplifier as device-under-test showed that after properly tuning the selected free-parameters it was possible to maximise the power efficiency when considering long-term evolution signals with different bandwidths. For example, a carrier aggregated a long-term evolution signal with up to 200 MHz instantaneous bandwidth and a peak-to-average power ratio greater than 10 dB, and was amplified with a mean output power around 33 dBm and 22.2% of mean power efficiency while meeting the in-band (error vector magnitude lower than 1%) and out-of-band (adjacent channel leakage ratio lower than −45 dBc) linearity requirements.

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Section: Introductionmentioning

confidence: 99%

Machine-Learning Assisted Optimisation of Free-Parameters of a Dual-Input Power Amplifier for Wideband Applications

Wang

Quaglia

et al. 2021

Sensors

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“…For example, the reported broadband LMBAs in [20]- [22] do not employ complete OMNs in the balanced PA. The reported RF-input LMBA in [23], sequential-LMBA (SLMBA) in [31] and phase controlled LMBA in [32] employ OMNs while the bandwidth performance and impact from the OMNs have not been analyzed in detail. In [33], the proposed Pseudo-Doherty LMBA (PD-LMBA) employs OMN for the carrier PA with similar system configuration to the SLMBA in [31] and achieves 57% fractional bandwidth with 10 dB OBO level, verified the feasibility of using OMNs in broadband LMBAlike architectures.…”

Section: Introductionmentioning

confidence: 99%

“…In [33], the proposed Pseudo-Doherty LMBA (PD-LMBA) employs OMN for the carrier PA with similar system configuration to the SLMBA in [31] and achieves 57% fractional bandwidth with 10 dB OBO level, verified the feasibility of using OMNs in broadband LMBAlike architectures. The RF-input LMBA introduced in [23] has proven that Doherty-like operation can be achieved by the LMBA with RF-input structure. It is thus interesting to explore the possibility of bandwidth enhancement in RF-input LMBA structures by using the continuous mode output matching networks (CM-OMNs) while maintaining the Doherty-like performance.…”

Section: Introductionmentioning

confidence: 99%

Broadband RF-Input Continuous-Mode Load-Modulated Balanced Power Amplifier With Input Phase Adjustment

Pang

Chu

et al. 2020

IEEE Trans. Microwave Theory Techn.

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This paper presents the theory and design methodology of broadband RF-input continuous mode load modulated balanced power amplifier (CM-LMBA) by introducing the continuous mode output matching networks in the LMBA architecture. It is illustrated that the continuous mode impedance condition can be achieved by properly adjusting the phase difference between the different PA branches in the proposed CM-LMBA during the entire load modulation process. An RF-input CM-LMBA with 1.45-2.45 GHz bandwidth using commercial GaN transistors is designed and implemented to validate the proposed architecture. The fabricated CM-LMBA attains a measured 11.2-13.4 dB gain and around 40 Watts saturated power. Power added efficiency (PAE) of 46.4-56.5% and 43.2-50.3% is achieved at 6 dB and 8 dB output power back-off throughout the designed band. When driven by a 100 MHz OFDM signal with 8 dB peak to average power ratio (PAPR), the proposed CM-LMBA achieves better than -46 dBc adjacent channel leakage ratio (ACLR) and higher than 45% average PAE after digital pre-distortion at 1.8 GHz and 2.1 GHz.

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“…In a seminal paper [4] it was shown that, (a) by varying the magnitude and phase of the injected signal, the load magnitude presented to the balanced devices could be substantially adjusted, with a full phase sweep, and (b) the control signal power (CSP) is entirely recovered at the RF output port. As such, the LMBA has been demonstrated to be a useful alternative to the Doherty, especially in broadband applications [5], [6], [7], [8], [9], [10], [11]. This paper proposes an important evolution of the LMBA; the "Orthogonal LMBA" (OLMBA), whereby the CSP buffer and main PA functions are combined in a single balanced amplifier.…”

Section: Introductionmentioning

confidence: 99%

The Orthogonal LMBA: A Novel RFPA Architecture With Broadband Reconfigurability

Collins

Quaglia

Powell

et al. 2020

IEEE Microw. Wireless Compon. Lett.

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A novel RFPA architecture, the Orthogonal Load Modulated Balanced Amplifier, or OLMBA, is described and demonstrated. Compared to the LMBA, the OLMBA displays many of the same benefits, such as active adaptive tuning using the phase and amplitude of an external control signal, but with much lower power requirements on the control signal power (CSP). As such, a useful range of active tuning can be implemented with essentially no impact on overall efficiency due to the low level of control signal. A demonstrator is described and measured, which delivers 30 W at a minimum of 50% efficiency over a 0.65-3.25 GHz bandwidth.

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Analysis and Design of a Doherty-Like RF-Input Load Modulated Balanced Amplifier

Cited by 73 publications

References 31 publications

Machine-Learning Assisted Optimisation of Free-Parameters of a Dual-Input Power Amplifier for Wideband Applications

Machine-Learning Assisted Optimisation of Free-Parameters of a Dual-Input Power Amplifier for Wideband Applications

Broadband RF-Input Continuous-Mode Load-Modulated Balanced Power Amplifier With Input Phase Adjustment

The Orthogonal LMBA: A Novel RFPA Architecture With Broadband Reconfigurability

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