Application and modeling of GaN FET in 1MHz large signal bandwidth power supply for radio frequency power amplifier

In this paper, implementation and testing of non- commercial GaN HEMT in a simple buck converter for envelope amplifier in ET and EER transmission techn iques has been done. Comparing to the prototypes with commercially available EPC1014 and 1015 GaN HEMTs, experimentally demonstrated power supply provided better thermal management and increased the switching frequency up to 25MHz. 64QAM signal with 1MHz of large signal bandw idth and 10.5dB of Peak to Average Power Ratio was gener ated, using the switching frequency of 20MHz. The obtaine defficiency was 38% including the driving circuit an d the total losses breakdown showed that switching power losses in the HEMT are the dominant ones. In addition to this, some basic physical modeling has been done, in order to provide an insight on the correlation between the electrical characteristics of the GaN HEMT and physical design parameters. This is the first step in the optimization of the HEMT design for this particular application

Towards a full implementation of collaborative care plan. OR Informing National Health Policy

Today, UK healthcare strategy managers face a challenge in developing and implementing an efficient care process in line with preserving a steady care evidence-based practice. This would be possible through the monitoring of time schedule and reduction of unnecessary variability with respect to clinical performances, consequently, to achieve the required quality of service at a contained cost. For this purpose the development of a model requires a firm rational basis to provide clear direction. Therefore, it is necessary to provide a systematic assessment for planning and coordinating healthcare services through which patients needs have to be achieved. This study aims to cover the healthcare process for particular conditions, e.g., COPD, Diabetes, Chronicle Heart Disease etc, modelling together the interaction of all components of Hounslow healthcare system, hence, to track patient flow across the system using spatio-temporal models and to evaluate the variations in length of stay and referral activities from the standardised pathways. Furthermore, we intend to derive indexes to inform the reshaping and the delivery of healthcare system

Ga2O3 Schottky rectifiers with 1 ampere forward current, 650 V reverse breakdown and 26.5 MW.cm-2 figure-of-merit

A key goal for Ga2O3 rectifiers is to achieve high forward currents and high reverse breakdown voltages. Field-plated β-Ga2O3 Schottky rectifiers with area 0.01 cm2, fabricated on 10 μm thick, lightly-doped drift regions (1.33 x 1016 cm-3) on heavily-doped (3.6 x 1018 cm-3) substrates, exhibited forward current density of 100A.cm-2 at 2.1 V, with absolute current of 1 A at this voltage and a reverse breakdown voltage (VB) of 650V. The on-resistance (RON) was 1.58 x 10-2 Ω.cm2, producing a figure of merit (VB2/RON) of 26.5 MW.cm-2. The Schottky barrier height of the Ni was 1.04 eV, with an ideality factor of 1.02. The on/off ratio was in the range 3.3 x 106 - 5.7 x 109 for reverse biases between 5 and 100V. The reverse recovery time was ∼30 ns for switching from +2V to -5V. The results show the capability of β-Ga2O3 rectifiers to achieve exceptional performance in both forward and reverse bias conditions