Lossless multi-way power combining and outphasing for radio frequency power amplifiers

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 102-106).For applications requiring the use of power amplifiers (PAs) operating at high frequencies and power levels, it is often preferable to construct multiple low power PAs and combine their output powers to form a high-power PA. Moreover, such PAs must often be able to provide dynamic control of their output power over a wide range, and maintain high efficiency across their operating range. This research work describes a new power combining and outphasing system that provides both high efficiency and dynamic output power control. The introduced system combines power from four or more PAs, and overcomes the loss and reactive loading problems of previous outphasing systems. It provides ideally lossless power combining, along with nearly-resistive loading of the individual power amplifiers over a very wide output power range. The theoretical fundamentals underlying the behavior and operation of this new combining system are thoroughly developed. Additionally, a straight-forward combiner design methodology is provided. The prototype design of a 27.12 MHz, four-way power combining and outphasing system is presented, implemented, and its performance is experimentally validated over a 1OW-1OOW (10:1) output power range.by Alexander S. Jurkov.S.M

Techniques for efficient radio frequency power conversion

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 293-304).A diverse range of radio-frequency (RF) power applications demand RF power generation systems that allow for dynamic output power control while having the capability to efficiently deliver power into a varying load. While some of these existing and emerging applications are characterized with narrowband or single-frequency operation, others require operation over a range of frequencies. In such applications, the system architecture typically comprises an RF power amplifier (PA) or inverter along with a tunable impedance matching network (TMN). Electronically-controlled TMNs offer substantial benefits when it comes to the implementability of such highly reconfigurable and adaptive RF systems as they allow for proper impedance termination of the PA or inverter over the operating load and frequency range. This work explores the design of TMNs based on a solid-state technique that allows for faster and more accurate impedance matching compared to traditional approaches. The performance and design of such TMNs is demonstrated for plasma driving applications at 13.56 MHz. In addition, this work proposes techniques for designing switched-mode RF inverters that can operate efficiently over a wide load impedance range. These techniques are applied to the design of class E and class [Phi]2 inverter prototypes at 27.12 MHz, and their ability to handle large load modulation while maintaining high operating efficiency is demonstrated. The techniques presented in this work can be further applied to the integration of an RF power amplifier/inverter and a TMN into a single multi-transistor architecture capable of efficiently operating across frequency and load variation while providing dynamic output power control.by Alexander Jurkov.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc

Tunable Matching Networks Based on Phase-Switched Impedance Modulation1

The ability to provide accurate, rapid, and dynamically controlled impedance matching offers significant advantages to a wide range of present and emerging radio-frequency (RF) power applications. This article develops a new type of tunable matching network (TMN) that enables a combination of much faster and more accurate impedance matching than is available with conventional techniques and is suitable for use at high power levels. This implementation is based on a narrow-band technique, termed here phase-switched impedance modulation (PSIM), which entails the switching of passive elements at the RF operating frequency, effectively modulating their impedances. The proposed approach provides absorption of device parasitics and zero-voltage switching (ZVS) of the active devices, and we introduce control techniques that enable ZVS operation to be maintained across operating conditions. A prototype PSIM-based TMN is developed that provides a 50-Ω match over a load impedance range suitable for inductively coupled plasma processes. The prototype TMN operates at frequencies centered around 13.56 MHz at input RF power levels of up to 200 W

Multi-Inverter Discrete Backoff: A High-Efficiency, Wide-Range RF Power Generation Architecture

Industrial radio frequency (rf) power applications, such as plasma generation, require high-frequency rf power over a wide dynamic power range and across variable load impedances. It is desired in these applications to maintain high efficiency and fast dynamic response. This paper introduces a scalable power amplifier (PA) architecture and control approach suitable for such applications. This approach, which we refer to as Multi-Inverter Discrete Backoff (MIDB), losslessly combines the outputs of paralleled switched-mode PAs, and modulates the number of active PAs to provide discrete steps in rf output voltage. It further employs outphasing among sub-groups of PAs for rapid and continuous output power control over a wide range. In doing so, the architecture can maintain high efficiency and fast rf power control across a very wide backoff range. A device selection and loss optimization method for MIDB architectures is discussed for plasma generation applications. We address the use of GaN FET-based, ZVS class-D PA units, and consider dynamic R[subscript ds],on effects and C[subscript oss] losses typical of GaN FETs