Study of turbulence in the high betap discharge using only RF heating on EAST

High poloidal beta scenarios with favorable energy confinement (β_p~1.9, H_98y2~1.4) have been achieved on Experimental Advanced Superconducting Tokamak (EAST) using only radio frequency waves heating. Gyrokinetic simulations are carried out with experimental plasma parameters and tokamak equilibrium data of a typical high β_p discharge by the GTC code. Linear simulations show that electron temperature scale length and electron density scale length destabilize the turbulence, collision effects stabilize the turbulence, and the instability propagates in the electron diamagnetic direction. These indicate that the dominant instability in the core of high β_p plasma is collisionless trapped electron mode. Ion thermal diffusivities calculated by nonlinear gyrokinetic simulations are consistent with the experimental value, in which the electron collision effects play an important role. Further analyses show that instabilities with k_θ ρ_s>0.38 are suppressed by collision effects and collision effects reduce the radial correlation length of turbulence, resulting in the suppression of the turbulence.

AN EXTENSIVE REVIEW ON: LOW NOISE AMPLIFIER FOR MILLIMETER AND RADIO FREQUENCY WAVES

In today’s world, radio receiver system is a prevailing wireless technology in that the major part is Low Noise Amplifier (LNA) which widely used to improve weak signals in many applications with millimeter and radio frequency waves such as optical communication, multimode transceivers and measurement instrumentations. The real drawbacks of LNA is that it fails to maintain specific properties in critical conditions like as minimum power consumption, provide low noise figure, input matching and linearity. Additionally, promoted by various application demands, design methods and control methods must require to improve performance of LNA. The performance of LNA can be improved by adding extra components in basic circuit by proper arrangement for millimeter and radio frequency waves. The review paper provides information about design methodology, optimization techniques and control techniques. The different design of LNA is reviewed and analyzed such as 3-stage near-mm Wave LNA, 5-stage near-mm Wave LNA, common-gate amplifier, shunt-feedback amplifier, Resistor-terminated common-source amplifier, Traditional inductor-less amplifiers, cascode connection and double common source. This review paper also provides the information about design circuit diagram. The performance improvement of LNA can be achieved with the help of different techniques and our review based on optimization and control techniques with parameter tuning. Finally, the direction for the future study is presented based on review analysis of LNA.

UHF RFID in a Metallic Harsh Environment

The use of the UHF RFID system in a warehouse that contains steel coils is a challenge for the technology itself since there are countless reflections of the radio frequency waves in the environment causing the multipath effect, which represents one of the most complex problems for wireless communication. Thus, this effect must be managed with the hardware, such as the antenna radiation diagram, and with the software, in the middleware, the software developed for the application. In this chapter, an application of RFID in metallic items will be discussed, tracking them since the product’s hot rolling, controlling the receiving process, shipping, and inventory, working together with equipment such as overhead crane.

Plus Shaped Chipless RFID Tag

Chip-less radio frequency identification (RFID) technology is capable for detecting, identification, and chasing for the future Internet of Things (IoT) systems and applications. The chipless RFID technology gives us the impression as a rising substitute of the traditional RFID tags and barcodes by encoding data from tags employing the radio frequency waves. The paper presents the design as well as simulation of chip-less Plus shaped RFID tags. The structure is composed of Rogers RT/Duroid 5880 by means of a substrate having the physical dimensions 40mm x 40mm over which eight resonators are placed. This tag is compact, and the resonators are closely placed. The tag is designed using Ansys Electronics Desktop.