M. Fathipour, M. H. Refan, S. M. Ebrahimi,
Volume 6, Issue 2 (6-2010)
Abstract
High Q frequency reference devices are essential components in many Integrated
circuits. This paper will focus on the Resonant Suspended Gate (RSG) MOSFET. The gate
in this structure has been designed to resonate at 38.4MHz. The MOSFET in this device
has a retrograde channel to achieve high output current. For this purpose, abrupt retrograde
channel and Gaussian retrograde channels have been investigated.
A. Acharyya, J. P. Banerjee,
Volume 7, Issue 3 (9-2011)
Abstract
The effect of optical illumination on DC and dynamic performance of Si1-xGex based double drift region (DDR) (p+pnn+) IMPATT diode operating at W-Band is investigated and compared with its Silicon counterpart. Top Mounted (TM) and Flip Chip (FC) structures are chosen and the composition of photocurrent is altered by shining light on the p+ side and n+ side of the device through optical windows. A double iterative computer simulation method based on drift-diffusion model has been used to study the small signal performance and subsequent modification of the small signal parameters owing to optical illumination. The role of leakage current in controlling the dynamic properties is studied by varying the current multiplication factors for electrons (Mn) and for holes (Mp). It is observed that both the DC and small signal parameters of both the diodes are affected significantly due to optical illumination. Under optical illumination of the device, the frequency shift is observed to be more upwards upon lowering of Mn than lowering of Mp for both the diodes. The frequency chirping in both Si1-xGex and Si IMPATTs are found to be of the order of few GHz, thereby indicating their high photo-sensitiveness at W-Band. But the results significantly indicates that photo-sensitiveness of Si1-xGex IMPATT is much greater than the Si IMPATT which is one of the major findings of this work.
S. V. Akram, R. Singh, A. Gehlot, A. K. Thakur,
Volume 17, Issue 4 (12-2021)
Abstract
Waste management is crucial for maintaining the hygienic environment in urban cities. The establishment of a reliable and efficient IoT system for waste management is based on integrating low power and long-range transmission protocol. Low Power Wide Area Network (LPWAN) is specially designed for the aforementioned requirement of IoT. LoRa (Long Range) is an LPWAN transmission protocol that consumes low power for long-range transmission. In this study, we are implementing long-range (LoRa) communication and cloud applications for real-time monitoring of the bins. The customized sensor node and gateway node are specifically designed for sensing the level of bins using ultrasonic sensor and communicating it to the cloud via long-range and internet protocol connectivity. Blynk and cayenne are the two cloud-based applications for storing and monitoring the sensory data receiving from the gateway node over internet protocol (IP). The customization of nodes6 and utilization of two cloud-based apps are the unique features in this study. In the future, we will implement blockchain technology in the study for enabling a waste-to-model platform.
M. Soruri, S. M. Razavi, M. Forouzanfar,
Volume 18, Issue 3 (9-2022)
Abstract
Power amplifier is one of the main components in the RF transmitters. It must provide various stringent features that can lead to complicating the design. In this paper, a new optimizing method based on the inclined planes system optimization algorithm is presented for the design of a discrete power amplifier. It is evaluated in a 2.4-3 GHz power amplifier, which is designed based on “Cree’s CGH40010F GaN HEMT”. The optimization goals are input and output return losses, Power Added Efficiency, and Gain. Large signal simulation of the optimized power amplifier shows a good performance across the bandwidth. In this frequency range, the input and output return losses are about lower than -10 dB, the Power Added Efficiency is greater than 51%, while the Gain is higher than 13.5 dB. A two-tone test with a frequency space of 1 MHz is applied for the linearity evaluation of the designed power amplifier. The obtained result shows that the power amplifier has good linearity with a low memory effect.
Ali Zarghani, Pedram Dehgoshaei, Hossein Torkaman, Aghil Ghaheri,
Volume 20, Issue 1 (3-2024)
Abstract
Losses in electric machines produce heat and cause an efficiency drop. As a consequence of heat production, temperature rise will occur which imposes severe problems. Due to the dependence of electrical and mechanical performance on temperature, conducting thermal analysis for a special electric machine that has a compact configuration with poor heat dissipation capability is crucial. This paper aims to carry out the thermal analysis of an axial-field flux-switching permanent magnet (AFFSPM) machine for electric vehicle application. To fulfill this purpose, three-dimensional (3D) finite element analysis is performed to accurately derive electromagnetic losses in active components. Meanwhile, copper losses are calculated by analytic correlation in maximum allowable temperature. To improve thermal performance, cooling blades are inserted on the frame of AFFSPM, and 3D computational fluid dynamics (CFD) is developed to investigate thermal analysis. The effect of different housing materials, the external heat transfer coefficient, and various operating points on the components' temperature has been reported. Finally, 3-D FEA is used to conduct heat flow path and heat generation density.
