Gain Compression of n-MESFET for High Power Applications in MIMO

In this paper, a new n-type recessed Metal semiconductor field effect transistor (MESFET) with GaAs/ SiC materials is designed for high power applications in Multi Input Multi Output (MIMO) systems. Based on electrical characteristics of MESFET, a SPICE model of the proposed device is developed. For power switches, the power MESFETs are used. The feasibility of the technology is validated by the electrical measurements of the device. The operational technology has been shown by the characterizations done on the proposed device. To optimize the electrical performance, the contact resistance technique has to be enhanced. In this work, the output power and Gain compression of proposed n-channel MESFET at 100 MHz and 1 GHz for high input power is obtained. The output power at fundamental frequency of operation for high input power is also obtained.

A Review on Smart Pendent

The world is facing a dangerous pandemic and it is a transmissible virus that infects people who came in contact with the infected person and with the things used by them. Many industries see huge economic losses, and businesses are going ruined. Although, unlock process is started still many industries facing problems due to the increasing rate of Covid positive patients, it is not possible to close working after the detection of individual positive employees. Also, it is difficult to find contacted employees with Covid positive employees. .It became a challenging task to find out how many people came in contact with the infected people. So, to make this process somehow easy we have designed a small device. In this paper, we have described the smart pendent a small device that helps to detect how many people come in contact with the coronavirus infected person. It is a wearable RF device in the form factor of a Pendant, suitable for powering a smart Rf device. An experimental comparison between multistage Cockcroft-Walton and Dickson RF-DC converters shows that the Dickson topology offers higher efficiency at high input power, whereas the Cockcroft- Walton converter performs better for low input power. The pendant can produce up to 23.2 µW at 10.4 m from a commercial isotropic 3 W RF power transmitter.

Simple Adaptive Rectifier with High Efficiency over a Range of 21 dBm Input Power for RF Energy Harvesting Applications

This paper presents a novel simple adaptive and efficient rectifier for Radio Frequency (RF) energy harvesting applications. Traditional rectifiers have maximum RF-DC Power Conversion Efficiency (PCE) over a narrow range of RF input power due to diode breakdown voltage restrictions. The proposed adaptive design helps to extend the PCE over a wider range of RF input power at 2.45GHz using a simple design. Two alternative paths arecontrolled depending on the RF input power level. Low input power levels activate the first path connected to a single rectifier; low power levels make the diode operate below its breakdown voltage and therefore avoiding PCE degradation. High input power levels activate the second path dividing it into three rectifiers. This keeps input power at each rectifier at a low power level to avoid exceeding the diode break down voltage. Simulated PCE of this work is kept above 50% over a range of 21.4 dBm input power from -0.8dBm to 20.6dBm.

Self-Adaptive Rectenna with High Efficiency over a Wide Dynamic Range for RF Energy Harvesting Applications

This paper presents a novel simple adaptive and efficient rectenna with automatic power distribution to achieve high radio frequency-direct current (RF-DC) power conversion efficiency (PCE) over a wide range of RF input power. This design employs two rectifier paths operating at low and high-power levels, respectively. Automatic power distribution method exploits the power-dependent input impedance of the rectifier and routes the RF input power into the assigned path according to the input power level. A distinctive enhancement in the rectifier dynamic range is achieved when dividing the high path power equally into two or more parallel diode cells, which helps the high path to camouflage the diode breakdown voltage in case of high input power level. The proposed adaptive design applies two different rectifier topologies, one by using shunt diode topology and the other by using voltage doubler topology at 2.45 GHz. Simulated PCE of this work is kept above 50% over a range of 25.1 dBm from -5.7 to 19.4 dBm of RF input power using shunt diode topology and over a range of 30 dBm from -6.3 to 23.7 dBm of RF input power using voltage doubler topology.

Compact Rectifier Circuit Design for Harvesting GSM/900 Ambient Energy

In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. GSM/900 is among the favorable RF Energy Harvesting (RFEH) energy sources that span over a wide range with minimal path loss and high input power. The proposed RFEH rectifier achieves measured and simulated RF-to-dc (RF to direct current) power conversion efficiency (PCE) of 43.6% and 44.3% for 0 dBm input power, respectively. Additionally, the rectifier attained 3.1 V DC output voltage across 2 kΩ load terminal for 14 dBm and is capable of sensing low input power at −20 dBm. The work presents a compact rectifier to harvest RF energy at 900 MHz, making it a good candidate for low powered wireless communication systems as compares to the other state of the art rectifier.