Symmetrical Load Modulated Balanced Power Amplifier With Asymmetrical Output Coupling for Load Modulation Continuum

Broadband Sequential Load Modulated Balanced Amplifier With Extended Design Space Using Second Harmonic Manipulation

“…This leads the PAE to be much lower than DE reported above. To directly use this PA prototype in a real system, a large driver amplifier would be required to keep the system efficiency [39]. Besides the tradeoff in gain versus frequency versus bandwidth [40], the low gain is a general issue for the SLMBA-based architectures [33], [34], [37], [38], [39].…”

“…To directly use this PA prototype in a real system, a large driver amplifier would be required to keep the system efficiency [39]. Besides the tradeoff in gain versus frequency versus bandwidth [40], the low gain is a general issue for the SLMBA-based architectures [33], [34], [37], [38], [39]. At least half of the input power is steered to drive large peaking BA and wasted at OBO level.…”

“…In theory, the bandwidth of both the LMBA and SLMBA configurations is only constrained by the bandwidth of the input and output quadrature couplers [26], [33], [34], [38], [39]. However, in practice, the active devices of CA and BA cells require proper source/load fundamental or harmonic impedance tuning to achieve high efficiency with broadband operation [32], [35], [36], [37], [40], [41], [42], [43], [44], [45], [46].…”

Load-Modulated Balanced Amplifier: From First Invention to Recent Development

“…In the light of this, two different asymmetrical architectures were proposed to mitigate this impact while maintaining wideband performance as shown in Figure 15. By introducing asymmetrical couplers [21] or asymmetrical Aux. currents behavior [22], different LM ratio can be established for the CSP PA, which means the main output current can still continue to increase when the Aux.…”

The MTT-S Technical Coordinating and Future Directions Committee: Promoting Our Technical Communities-2022

“…This trend is expected to continue in the future, with compact load-modulated PAs being used in massive MIMO (mMIMO) applications. Other load-modulated architectures, such as the distributed efficient PA (DEPA) [77] and the load-modulated balanced amplifier (LMBA) [78], can be used to extend the bandwidth of operation with good back-off efficiency at the price of increased size and complexity. Conversely, loadmodulated PAs are not widely found in mid-to-low-power transmitters, mainly because of degraded linearity metrics, where high-performance DPD is not feasible.…”