Solving Power Amplifier Design Challenges Towards Development of JCAS Transmitter

Joint Communication and Sensing (JCAS) systems aim to unify radar and communication functionalities and a single RF front-end could play a key role in reducing hardware duplication and improving spectral reuse, leading to faster deployment. However, these two functions impose fundamentally different requirements on the transmitter, particularly on the power amplifier (PA). Radar operation typically demands high saturated output power and efficiency near compression in today’s systems, while communication systems of today require high linearity, low distortion, and compliance with stringent error-vector magnitude and adjacent-channel leakage specifications under high peak-to-average power ratio waveforms. Navigating these challenges, this paper proposes a practical transmitter architecture that enables reconfigurability through multi-mode PA design, tunable matching networks, and adaptive biasing. The architecture supports both switching and simultaneous operating modes, ensuring that radar and communication performance targets are met without duplicating hardware in heterogeneous systems and diverse application scenarios. A combination of bias control methodologies and tunable matching networks is used to realize bandwidth adaptation, frequency band switching, and power-level adjustment. These controls help enable rapid and stable transitions between operating states for the power amplifiers. With realistic simulation results in state of the art silicon-based technology, this paper validates an implementation methodology, emphasizing PA-centric solutions to meet diverse transmitter requirements for communication and radar scenarios.