Optimal Design of Antenna for Radio Frequency Energy Acquisition System

At present, many sensors are gradually developing in the direction of ultra-low power consumption, miniaturization, and low cost, which makes radio frequency energy acquisition technology a popular research field with a wide range of applications. However, traditional sensors are generally powered by batteries, which greatly increases the size of the device. Furthermore, antenna is an important module for radio frequency energy acquisition, and optimization of its sensitivity and other performance is particularly important. This article uses HFSS electromagnetic simulation software to simulate antenna elements and arrays made of PTFE, and simulates various parameters. And optimization, an antenna array element whose port impedance characteristics and unit antenna gain both meet the design requirements is constructed. Finally, the gain of the 2×2 array antenna after parameter optimization is 13.8dB, which greatly improves the gain of the receiving antenna.

ESTIMATION DE LA VISIBILITÉ MÉTÉOROLOGIQUE À L’AIDE DES LIENS MICRO-ONDES COMMERCIAUX DE TÉLÉCOMMUNICATIONS

Several factors can attenuate radio signal between transmitting and receiving antenna. One can cite: vegetation, atmospheric gases, fog, water vapor, transmission instruments, rain, temperature, etc... The sources of attenuation differ according to the climate and the relief of each continent or even each country. In this work we aim to show that there is link between microwave signal attenuation and weather visibility in the presence of dust. Weather visibility is a very important factor for the safety of road, sea, rail and air transportation. In the presence of dust, the visibility is strongly reduced and there is also a strong attenuation of the microwave signal propagating between two antennas. By performing a linear regression on the attenuation-visibility scatter plot, we propose a method for real-time estimation of the visibility knowing the microwave signals attenuation. A correlation measurement between the visibility estimated by our method from the real attenuation data of the mobile phone operator Telecel Faso SA (Burkina Faso) and the visibility measured by the National Meteorological Agency of Burkina Faso (ANAM) gave a correlation coefficient of 0.86.

State-of-the-Art Techniques in RF Energy Harvesting Circuits

The exigency for continuous use of electrical devices has created greater demands for electricity along with more efficient transmission techniques. Energy from natural resources can be solar, thermal, vibration, friction, or Radio Frequencies (RF) signals. This state-of-the-art work provides a summary of RF energy harvesting techniques and can be used as a guide for the manufacture of RF energy scavenging modules. The use of Radio Frequency (RF) Energy Harvesting (EH) technique contributes to the development of autonomous energy devices and sensors. A rectenna system includes three main units: the receiving antenna, the impedance matching network, and the rectifier. We thoroughly analyze how to design a rectenna system with special emphasis given on the design of the rectifier. At the same time many works of the last 10 years are presented. This review article categorizes the used topologies depending on the type of antennas, IMNs, and rectifiers and comparatively presents their advantages and disadvantages.

Single-Sensor EMI Source Localization Using Time Reversal: An Experimental Validation

The localization of electromagnetic interference (EMI) sources is of high importance in electromagnetic compatibility applications. Recently, a novel localization technique based on the time-reversal cavity (TRC) concept was proposed using only one sensor, and its application to localize EMI sources was validated numerically. In this paper, we present a validation of the proposed time-reversal process in which the forward step of the time-reversal process is performed experimentally and the backward step is carried out via numerical simulations, a realistic scenario which is applicable to practical source localization problems. To the best of the authors’ knowledge, this is the first implementation of a three-dimensional electromagnetic time-reversal process in which the forward signal is provided experimentally while the backward propagation step is carried out numerically. The considered experimental setup is formed by a partially open cavity and two monopole antennas to emulate the EMI source and the sensor (receiving antenna), respectively. Assuming that the location of the source is the feed point of the monopole antenna, the resulting three-dimensional location error in the experimental validation was only 1.49 cm, which is about one-third the length of the monopole antenna, corresponding to about λmin/2 (diffraction limit).

Wide Band Micro-Strip Antenna Design for Higher “X” Band

The article uncovers a rectangular multi-opening microstrip reception apparatus with wideband working frequencies for the uses of the 'X' band. Grave choice of measurement, the situation of feed, and opening are mulled over lady to accomplish the objective properties of the reception apparatus. Articulate receiving wire execution parameters like return misfortune, voltage standing wave proportion, increase, and effectiveness are determined utilizing the reception apparatus plan programming. Created results are additionally approved with the manufactured receiving standards. Sets of rectangular equal openings are cut on the fix for radiation. The significant recurrence of activity of the reception apparatus is between 11-12GHz, and data transmissions are in the scope of 250 MHz to 2.5 GHz at different frequencies. Discretionally, other execution parts of the receiving antenna are likewise in won understanding. Structured receiving antennae are straightforward, easy, light in weight, and furthermore simple to produce. Union with these elements receiving antennae is adjusted and is likewise having a wide scope of working recurrence.

CALCULATION OF POLARIZATION LOSSES FOR HF COMMUNICATION CHANNEL (PART 2)

The article is devoted to the description of the procedure for calculating the loss for polarization mismatch in the receiving antenna. The results of a computational experiment of these losses are presented as a function of the operating frequency, azimuth of the receiving antenna, its geographic position and the elevation angle of the rays at the reception center. Based on the results of the calculation, conclusions are drawn about the dependence of losses on various parameters, and practical recommendations are given on the location and polarization of receiving antennas.