A Compact Impedance Measurement Solution for Systems Operating in Load Varying Scenarios

Goncalves, Cristiano F.; Barradas, Filipe M.; Nunes, Luís C.; Cabral, Pedro M.; Pedro, José C.

doi:10.1109/access.2021.3063915

Cited by 4 publications

(1 citation statement)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is composed of the DPA output stage, a medium power two-channel driver, an adaptive input splitting predriver stage, and also an impedance measurement circuit. The impedance measurement stage was already extensively described and presented in [19].…”

Section: System Architecture and Static Experimental Validationmentioning

confidence: 99%

Quasi-Load Insensitive Doherty PA Using Supply Voltage and Input Excitation Adaptation

Goncalves¹,

Barradas

Nunes

et al. 2022

IEEE Trans. Microwave Theory Techn.

Self Cite

View full text Add to dashboard Cite

This article presents a quasi-load insensitive (QLI) Doherty power amplifier (DPA). The proposed theory makes the amplifier load insensitive in terms of output power, while its efficiency is slightly degraded for complex loads. The load insensitiveness is achieved by dynamically changing the supply voltages (V DD ) and the input power splitting for both the carrier and peaking transistors. The optimal, load-dependent, V DD values are theoretically derived from back-off (BO) and full power conditions using load line theory. The optimal input excitation signals for the carrier and peaking devices are also derived for these variable V DD conditions. A 3.6-GHz QLI DPA was designed, and a complete system, composed of the DPA output stage, a two-channel medium power driver, an adaptive input driving stage, and a load sensing system, was implemented. The laboratory measurements have been performed for loads distributed inside a 2.0 maximum voltage standing wave ratio (VSWR) circle and show an output power variation between 43.8 and 42.6 dBm and a BO efficiency between 50% and 35%. Under modulated signal excitation, for the worst case loads, the peak output power capability of the DPA is improved from 41.7 to 43.1 dBm, and the average efficiency is increased from 32.6% to 43%. Index Terms-Doherty power amplifier (DPA), load insensitivity, power amplifier (PA), supply voltage modulation. I. INTRODUCTIONP OWER amplifiers (PAs) are used for various applications, and their performance has a considerable impact on the overall system operation. Normally, PAs are designed to operate with a fixed output load. However, they can be forced to operate under varying load conditions due to various causes and in different scenarios, such as microwave cooking [1], plasma heating in, e.g., plasma-enhanced chemical vapor deposition (PECVD) processes [2], or in the charging of particle accelerators cavities [3]. In telecommunication applications, the PA output load can also change due to moving objects on the antenna proximity, e.g., the hand effect [4], or also Manuscript

show abstract

Section: System Architecture and Static Experimental Validationmentioning

confidence: 99%