Duty-Cycle Linearization Technique for Microwave and RF Transmitters

The exponential growth of the mobile and wireless applications is continuing unabated so that more and more demands are being placed on the available spectrum. This has stimulated the utilization of complex modulation techniques such as QAM, as well as spread spectrum system. Preserving the required severe linearity constraints using the conventional methods, however, deteriorates the overall power efficiency [1]. Reconciliation of the power-added efficiency and the spectral bandwidth efficiency has been addressed by using the Duty-Cycle principle with a high efficient Switching amplifier. In this paper, it will be discussed the Duty-Cycle modulation technique as a new transmitter configuration for broadband communication systems and non-constant envelope RF signals. The configuration developed comprises a comparator, a class S amplifier and two linear elements. The primary linear element is considered to be the required class S amplifier’s matching network although the auxiliary filter is supposed to regulate the system’s resonation frequency. The simulation results emphasis the broadband linearization and power-efficiency features of the "Duty-Cycle Modulation" technique.