Prototype for an Optimized Drive Signal Control System for a 2.5 GHz Doherty Power Amplifier

An Optimized Control System for the Independent Control of the Inputs of the Doherty Power Amplifier

“…After integrating the control system with the DPA, the obtained estimated theoretical output is 28.1 dBm for a maximum attenuation of 31.5 dB, where for a minimum attenuation of 15 dB, the output is 40.2 dBm for a fixed input of 19 dBm. The VA, VPS, and drive amplifier were selected following the link-budget analysis discussed in our preliminary work [34] along with the corresponding model/manufacturer details, which can be found in the same. The power splitter, 20 dB directional coupler, and power combiner are fabricated on an FR4 substrate (ε r = 4.3), which are incorporated into the overall control system.…”

“…The power ratio design methodology is employed to determine the shunt resistor's value, in conjunction with the dimensions (width and length) of the transmission lines. A comprehensive explanation of the procedure for computing line impedance and shunt resistance in the context of the Wilkinson power splitter along with the corresponding width and length can be found in our previously published research [34].…”

“…To control the expanse, as shown in Figure 4b, a directional coupler with a coupling factor C = 20 is designed, which allows for maintaining a thorough connection in the circuit using Port 1 and Port 2, where the measuring instruments can be connected through Port 4, which is the 20 dB coupled port. The detailed design of the used 20 dB directional coupler is discussed in our prior published work [34]. To determine the dimensions of the microstrip coupled line for a frequency of 2.5 GHz, we employ Keysight's Advanced Design System (ADS) Linecalc tool.…”

“…First is the initial case in which only the main amplifier is operating in the Class AB operation and the peak amplifier acts as an open circuit with infinite impedance, whereas the second case presents the impedances when the main amplifier saturates and the peak amplifier starts conducting at a high input power and sharing equal loads. The Doherty power combiner is designed and simulated using Keysight's Advanced Design System (ADS) [34]. The substrate material considered is FR4 with a thickness of 1.2 mm, and copper with a thickness of 0.2 mm is chosen as the conductor material due to its high conductivity.…”