No abstract

Abstract-A lossless multi-way outphasing and power combining system for microwave power amplification is presented. The architecture addresses one of the primary drawbacks of Chireix outphasing; namely, the sub-optimal loading conditions for the branch power amplifiers. In the proposed system, four saturated power amplifiers interact through a lossless power combining network to produce nearly resistive load modulation over a 10:1 range of output powers. This work focuses on two microstrip-based power combiner implementations: a hybrid microstrip/discrete implementation using a combination of microstrip transmission line sections with discrete shunt elements, and an all-microstrip implementation incorporating open-circuited radial stubs. We demonstrate and compare these techniques in a 2.14 GHz power amplifier system. With the allmicrostrip implementation, the system demonstrates a peak CW drain efficiency of 70% and drain efficiency of over 60% over a 6.5-dB outphasing output power range with a peak power of over 100 W. We demonstrate W-CDMA modulation with 55.6% average modulated efficiency at 14.1 W average output power for a 9.15-dB peak to average power ratio (PAPR) signal. The performance of this all-microstrip system is compared to that of the proposed hybrid microstrip/discrete version and a previously reported implementation in discrete lumped-element form.Index Terms-base stations, outphasing, power amplifier (PA), wideband code division multiple access (W-CDMA), Chireix, LINC, load modulation.

No abstract

Abstract-Microwave-to-dc rectification is valuable in many applications including rf energy recovery, dc-dc conversion, and wireless power transfer. In such applications, it is desired for the microwave rectifier system to provide a constant rf input impedance. Consequently, variation in rectifier input impedance over varying incident power levels can hurt system performance. To address this challenge, we introduce multi-way transmissionline resistance compression networks (TLRCNs) for maintaining near-constant input impedance in rf-to-dc rectifier systems. A development of TLRCNs is presented, along with their application to rf-to-dc conversion and wireless power transfer. We derive analytical expressions for the behavior of TLRCNs, and describe two design methodologies applicable to both single and multi-stage implementations. A 2.45-GHz 4-way TLRCN network is implemented and applied to create a 4-Watt resistancecompressed rectifier system that has narrow-range resistive input characteristics over a 10-dB power range. It is demonstrated to improve the impedance match to mostly-resistive but variable input impedance class-E rectifiers over a 10-dB power range. The resulting TLRCN plus rectifier system has >50% rf-to-dc conversion efficiency over a >10-dB input power range at 2.45 GHz (peak efficiency 70%), and SWR <1.1 over a 7.7-dB range, despite a non-negligible reactive component in the rectifier loads.

No abstract