A Radio⁃Frequency Loop Resonator for Short⁃Range Wireless Power Transmission

A microstrip loop resonator loaded with a lumped capacitor is proposed for short-range wireless power transmission applications.The overall physical dimensions of the proposed loop resonator configuration are as small as 3 cm by 3 cm.Power transmission efficiency of greater than 80%is achieved with a power transmission distance smaller than 5 mm via the strong coupling between two loop resonators around 1 GHz,as demonstrated by simulations and measurements.Experimental results also show that the power transmission performance is insensitive to various geometrical misalignments.The numerical and experimental results of this paper reveal a bandwidth of more than 50 MHz within which the power transmission efficiency is above 80%.As a result,the proposed microstrip loop resonator has the potential to accomplish efficient wireless power transmission and high-speed(higher than 10 Mbit/s)wireless communication simultaneously.

Design and Construction of A Single-Phase Power Factor Meter

It is known that the power consumption and efficiency of an equipment owes directly to its power factor.The lower the power factor of the equipment the more the energy consumption of such equipment and vice-versa.Hence,the need to develop an equipment to measure accurately the operating power factor of domestic and industrial equipment and appliances[1].The operating principle of this power factor meter design is based on Zero Crossing detection principle,the principle is utilized using Arduino Nano,instrument transformers,LM324 operational amplifier,generic resistor,generic XOR Gate 7488 and 2X16LCD.The input current and voltage signal is taken by the transformers and sent to the op-amp which carries out the zero crossing detection in order to get the time difference after which the microcontroller does the calculation to determine the power factor and the deficit reactive power which is then displayed on an interface[2].

Some Explanation on Vector Diagram for Power System Analysis

The generating currents in the generator and the dissipating current at the load are completely different and they are out of phase.The magnitude of those currents is equal and the direction is opposite to each other.The resistive,inductive and capacitive loads dissipate completely different voltages which concern each of character of these loads.The direction of vectors of generated voltage and dissipated voltage must be drawn opposite to each other in the vector diagram.The vector of consumed voltage at the resistive load and the vector of the current through this load are in phase while the vector of generated voltage of the main source is out of phase.The resistive load consumes the voltage which is generated by the main source.The inductive load consumes the voltage which is induced or generated in the inductor caused by the inductance due to the current flow through the network.The vectors of consumed voltage at the inductive load and the vector of current through this load are in phase while the vector of generated voltage in the inductor caused by the inductance is out of phase.The capacitive load consumes the voltage which is generated at the capacitor caused by the capacitance due to the current flow through the network.The vector of consumed voltage at the capacitive load and the vectors of current through this load are in phase while the vector of generated voltage at the capacitor caused by the capacitance is out of phase.

Study on the pre-chopper in CSNS LEBT

Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstanding feature of the design is that both the gap and the width vary with the beam envelope size. So both the requried deflecting voltage and the loaded capacitance are lowered. In order to avoid destruction of the space charge neutralization by the pre-chopper in the whole LEBT, an electron-trapping electrode is arranged to confine the electrostatic field of the pre-chopper to the local area. To examine the reliability of the pre-chopping design in CSNS LEBT, a similar pre-chopping design in ADS RFQ LEBT is set up and an experiment on the pre-chopper is prepared. 3-dimensional simulations are carried out to determine the loaded capacitance and the applied voltage of the electron-trapping electrode.

High isolation dual-element modified PIFA array for MIMO application

In this paper, we focus on antenna array design for mobile phone with finite volume and propose a novel antenna element structure by capacitive feeding and capacitive loading method based on the planar inverted F antenna （PIFA）. State-of-the-art development on this issue is reviewed. Then, a novel capacitively fed and capacitively loaded PIFA structure is proposed and studied. The results of the experiments showed that our structure can reduce the coupling of antenna elements from - 13.4 dB to -24.5 dB. Finally, a design with a bandwidth of 100 MHz centered at 2.35 GHz and envelopment correlation coefficient of 0.01 2 is provided and the diversity performance of the dual-element modified PIFA array is evaluated in both simulation and measurement. In a word, our novel design reaches broadband, miniaturization, high isolation and offers excellent diversity performance.