Abstract-This paper presents an analysis of outphasing class-E Power Amplifiers (OEPAs), using load-pull analyses of single class-E PAs. This analysis is subsequently used to rotate and shift power contours and rotate the efficiency contours to improve the efficiency of OEPAs at deep power back-off, to improve the Output Power Dynamic Range (OPDR) and to reduce switch voltage stress. To validate the theory a 65nm CMOS prototype, using a pcb transmission-line based power combiner was implemented. The OEPA provides +20.1dBm output power from VDD=1.25V at 1.8GHz with more than 65% Drain Efficiency (DE) and 60% Power Added Efficiency (PAE). The presented technique enables more than 49dB OPDR and 37% DE and 22% PAE at 12dB back-off with reduced switch voltage stress.

Class-E RF Power Amplifiers (PAs) are very power efficient under nominal operating conditions. Due to incorporating two tuned tanks, the dependency on the load impedance is however relatively large, resulting in e.g. load dependent output power, power efficiency, peak voltages and peak (and average) currents which can lead to reliability issues. This paper presents load-pull analyses for class-E RF power amplifiers from a mathematical perspective, with analyses and discussions of the effects of the most common non-idealities of class-E PAs: the limited loaded quality factor (Q loaded) of the series filter, switch on-resistance, limited quality factor of the dc-feed inductor, loadmismatch dependent switch conduction loss and the limited negative voltage excursions (due to e.g. the reverse conduction of the switch transistor for negative voltage excursions). The theoretical findings are backed up by extensive circuit simulations and loadpull measurements of a class-E power amplifier implemented in 65 nm CMOS technology. The PA provides 18.1 dBm output power and 72% efficiency at 1.4 GHz under nominal operating condition employing an off-chip matching network.

Highly efficient switch-mode Class-E power amplifiers (PAs) are sensitive to load impedance variations. For voltage standing wave ratios (VSWRs) up to 10:1, the peak switch voltage and average switch current can increase by a factor 1.7 and 2.5, respectively, with respect to the nominal load condition, thereby imposing serious reliability risks. This work introduces a technique to self-protect/self-heal Class-E PAs against the effects of load variations, with only a minor impact on output power and efficiency. To validate the proposed technique, load-pull measurements are conducted on a Class-E PA implemented in a standard 65nm CMOS technology, employing an off-chip matching network, augmented with a fully automated self-protective/self-healing control loop. Under nominal operating conditions, the PA provides 17.5dBm output power into 50Ω from a 1.2V supply with 67% efficiency when all the losses of the matching network are included. It is shown that the proposed self-protective PA can reduce its peak switch voltage to below the value allowed by the technology for all load mismatch conditions with VSWR up to 19:1 while output power and efficiency are not considerably affected. Furthermore, a PA with an average current safety factor of 2.5 can reliably handle VSWRs up to 19:1.

-This paper presents an outphasing class E PA (OEPA) in a 65nm CMOS technology, using a pcb transmission-line based power combiner. The OEPA can provide +20dBm output power from VDD=1.25V at 1.4GHz with 61% drain efficiency (DE) and 58% power added efficiency (PAE). We introduced a technique to rotate and shift power and efficiency contours of the two branch PAs that enables more than 44dB output power dynamic range, reduces switch voltage stresses compared to conventional OEPAs and enables 41% DE and 24% PAE at 12.5dB back-off.

Research objectives Moral distress is a common phenomenon among nurses and can negatively affect their mental health and quality of the care. This study aimed to determine the effect of professional ethics workshop with virtual follow-up on the moral distress of nurses. Methods This experimental study was performed on 50 nurses in Ghaem Hospital, Mashhad, Iran. The intervention group received 8-hour professional ethics workshop and 4 weeks follow-up through social network. The moral distress was evaluated through the Moral Distress Scale-Revised at the beginning of the study, two weeks after the workshop and at the end of follow-up. Data were analyzed using SPSS21 by descriptive and statistical analysis.This study approved by Mashhad university Medical Ethics Committee and publishing ethics were also observed. Results The changes in the mean value of the frequency of moral distress in the intervention group was not significant, while these changes were significant in the control group ( p < 0.001, df = 2, f = 26.41) and had an upward trend. About intensity changes in the intervention group were significant ( p < 0.01, df = 2, f = 8.52) and had a downward trend, while it was not significant in the control group. Changes in the mean value of level of moral distress in the intervention group were not significant, while these changes were significant in the control group ( p < 0.01, df = 1, f = 16.8). The mean value of moral distress level decreased in the intervention and increased in control group. Conclusion The level of moral distress was increased in the control group due to increase in its frequency. This could be due to awareness of nurses regarding the concept of moral distress which caused them to pay more attention to this issue. Professional ethics workshop did not have effect on the frequency of moral distress, while it reduced the intensity and level of moral distress. Moreover, follow-up through social network reduced the frequency, intensity and the level of moral distress among nurses.