Large-signal (L-S) characterization of double-drift region (DDR) impact avalanche transit time (IMPATT) devices based on silicon designed to operate at different millimeter-wave (mm-wave) and terahertz (THz) frequencies up to 0.5 THz is carried out in this paper using an L-S simulation method developed by the authors based on non-sinusoidal voltage excitation (NSVE) model. L-S simulation results show that the device is capable of delivering peak RF power of 657.64 mW with 8.25% conversion efficiency at 94 GHz for 50% voltage modulation; whereas RF power output and efficiency reduce to 89.61 mW and 2.22% respectively at 0.5 THz for same voltage modulation. Effect of parasitic series resistance on the L-S properties of DDR Si IMPATTs is also investigated, which shows that the decrease in RF power output and conversion efficiency of the device due to series resistance is more pronounced at higher frequencies especially at the THz regime. The NSVE L-S simulation results are compared with well established double-iterative field maximum (DEFM) small-signal (S-S) simulation results and finally both are compared with the experimental results. The comparative study shows that the proposed NSVE L-S simulation results are in closer agreement with experimental results as compared to those of DEFM S-S simulation.

The authors have carried out the large-signal characterization of silicon-based double-drift region (DDR) impact avalanche transit time (IMPATT) devices designed to operate up to 0.5 THz using a large-signal simulation method developed by the authors based on non-sinusoidal voltage excitation. The effect of band-to-band tunneling as well as parasitic series resistance on the large-signal properties of DDR Si IMPATTs have also been studied at different mm-wave and THz frequencies. Large-signal simulation results show that DDR Si IMPATT is capable of delivering peak RF power of 633.69 mW with 7.95% conversion efficiency at 94 GHz for 50% voltage modulation, whereas peak RF power output and efficiency fall to 81.08 mW and 2.01% respectively at 0.5 THz for same voltage modulation. The simulation results are compared with the experimental results and are found to be in close agreement.

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The paper presents a real time modelling of self-reliant isolated grid comprising both governable and ungovernable sources. The frequency of this system must be maintained to its desired value by reducing its deviation occurred when there is a mismatch between the load demand and the actual power generation. In order to achieve it, the actual power output of the micro-grid is required to regulate. Therefore, an attempt is made in this paper to design a modified bias (MB) with LDR (load disturbance rejection) based PID (proportional integral derivative) Controller and it can also be called droop based controller (DBC). Simulation of the micro-grid system with proposed MB-LDR based control scheme is successfully done in Real Time Simulation platform using the digital simulator of OPAL-RT OP4510. Simulation results of the system for different conditions are presented and analysis is given in details. Thereafter, comparative performance of the results obtained using proposed MB-LDR based controller with that of LDR and classical controllers is made. Results show that the proposed MB-LDR based controller gives better response as compare to other two methods in terms of peak transient deviation, settling time and number of oscillations.

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