Reconfigurable high frequency class S power amplifier demonstrator

Abstract

-This paper presents an end-to-end high frequency class S power amplifier. A description of the full testbench and some important points on generation of RF outputs from FPGA devices and current mode class D design are given. Experimental measurements are provided for the prototype PA consisting of a signal generator, analog to digital converter, driver circuit, current mode class D switching stage and bandpass filter. Theory and experimentally measured results for this prototype are presented for a multi tone signal centred at 930 MHz and with a total output power of 24.7dBm.

FPGA SerDes Capability as Switch mode PA Modulator

“…Class-S power amplifiers, outlined in Figure 1, are a combination of a switch mode power amplifier (Class-D), driven by either a pulse width modulator [1] or a sigma delta modulator (SDM) [2]. Pulse width modulators can provide lower in band and out of band noise floors compared to SDM, however it requires analogue implementation to achieve this, resulting in a costly, dedicated design.…”