Elyas Palantei

Rectangular Patch with Parasitic Folded Dipoles: A Reconfigurable Antenna

In this paper, the tuning and steering of a rectangular patch antenna is controlled by switching the patch and folded dipoles configuration. This reconfigurable antenna is controlled by the changing the voltage across a number of P.I.N. diodes in the parasitic elements. This antenna with the associated RF control unit forms a reconfigurable antenna which provides one solution to a number of communications problems.

Symmetry problems in switched parasitic smart antennas

Radiation pattern symmetry of a switched parasitic smart antenna is important for full 360deg azimuthal coverage. The ideal symmetrical beam patterns are hard to achieve in reality due to a number of crucial problems related to the need for precision design and manufacture, and the accuracy of the supporting electronics. These factors are examined on this paper.

Four elements array of lungs shape patch antenna for nanosatellite telemetry

The paper discusses some technical issues on the construction of antenna system incorporated with a designed nano satellite. The preliminary LEO satellite model has been developed for the environmental telemetry application. The designed four elements lungs patch structure was initially installed outside the prism body of nano satellite. The lungs antenna array was constructed in such away for electronic rotateable along 90° rotation, vertical or horizontal orientation. Both the numerical and experimental evaluations of 2.4 GHz lungs array confirmed a sufficient operation bandwidth suitable for long distance telemetry application, abruptly, 50 MHz could be achieved. The elliptical polarization property was verified via the numerical computation where the axial ratio was slightly greater than 5 dB.

Yagi-Uda antenna human proximity effects on the link budget at 300 MHz

Yagi-Uda antennas are commonly used for data communications. Link budgets are calculated to ensure adequate fade margin. The presence of adjacent conducting material can affect antenna gain and impedance matching. Numerical modeling demonstrates that the gain of a 12 element Yagi-Uda is degraded by more than 2 dB when a human model is located in close proximity to the rear of the antenna. There are similar impedance matching losses. This has a significant effect on link reliability in RFID and wireless sensor networks where power is restricted.

Ultra Wide Band (UWB) antenna design for fetal monitoring

UWB microstrip antenna has been designed using UWB technology and the principle of Microwave Imaging system that works at UWB frequencies. The Simulation performed using Ansoft HFSS version 13 software to construct the microstrip antenna with some important parameters, such as reflection coefficient (S11) and radiation pattern. This purpose of the antenna is fetal detecting and monitoring system in dual band at (2.54 - 4.45) GHz with the bandwidth of 1.91 GHz and (6.53 - 7.97) GHz with the bandwidth of 1.44 GHz. The antenna will be tested with two conditions, with fetal and without fetal model to find the difference characteristic of each tissue layer.

A robust wireless power transmission for charging low power consumption appliances

A novel method for transferring electrical power wirelessly in order to charge various low power consumption appliances is presented. In practice, a variable power and wideband Agilent N5182A transmitter and an RF electronic receiver were configured in such manner to examine and to demonstrate the constructed WPT system. The RF-circuit part of the receiver consisted of the antenna system, RF-signal processing and converter, DC-operational amplifier and the electronic load. The distance separation between the transmitter and the receiver was varied to measure the transmission performance. Several critical factors influence the performance of WPT design such as the strength of transmitter power, moving objects surrounding the receiver, the absorbed obstacle existed, and the pointing angle of the energy illumination were also investigated.

Comments on "A Novel Planar Switched Parasitic Array Antenna With Steered Conical Pattern

A number of problems with p.i.n. diode switching circuits have been identified which might affect the Chen et al. results. A number of design requirements must be met to obtain ideal antenna performance. If switch activation symmetry is maintained, the centre frequency should not change. If a change in centre frequency is observed experimentally, then the cause might lie in imperfections inthe switching network. Note also that if beam elevation is to be controlled, a conducting skirt can be added to the ground plane.

Optimizing and Implementation Contactless Tag-Reader System for Smart Classroom and Laboratory Access

Advances in wireless technology support smart card technology became contactless technology. Wireless technology allowed users to access or controlling. However, existing contactless smart cards have limited coverage with low security levels. Therefore, this research perform optimization on user access further with better security assurance. This research implemented in classroom and laboratory access. Hardware that used consists of Smart cards and Raspberry Pi that serves as a host and card reader that could be interconnected with the microprocessor. On the smart card stored user data (registration number and name) and on the Raspberry server stored user data that could access the class or laboratory. Users data on smart cards were stored on chips that act like RAM (Random Access Memory). The chip was embedded in the Smart card in the same function as storage media. Raspberry that had function as server and microprocessor that provide access to registered users. This study produced classroom access system by using smart card with distance > 5cm with automatic access system for user registered on system. It was according to this research proposed about security and historical data. Reader in this research use wireless transmission system. Historical data stored on the server (Raspberry pi) which records the time in and out, and the duration of time while in the room. Additional technology in the classroom access system is equipped with an automatic door close system for double security in the classroom. The advantages of this system was using server and microcontroller in one package so that in terms of cost is cheaper than the smart card access technology available today.

Low-cost switched array-wide band antenna for Search and Rescue disaster management

The activity of SAR (Search and Rescue) is an activity that requires speed in finding the location point. Successfully search for victims can save many lives. Direction finder is proposing to accelerating search survivors. Direction finder can detect the direction and track the radio transmitter using Doppler function. The design, measuring, testing and integrating wideband switched parasitic antenna for direction finder application are conducted in the research. In this paper direction finder antenna made with simple devices and the materials can be found in Indonesia. The proposed architecture has advantages for cost-effective, easy to design and to integrate. The antenna design successfully reaches maximum gain by simulation and field test. The antenna success passes S11 measurement, in accord with international standards of antenna manufacturing. The antenna successfully tracks the transmitter using zero cross detector software.

Utilization of HF electromagnetic waves availability for charging mobile communication device

Wireless technology has an important role in the development of mobile telecommunication devices. This study aims to develop a mobile communications device charging applications by leveraging the availability of the exist electromagnetic waves. To achieve these objectives, this study designed a rectenna consisting of microstrip antenna array and RF circuits that operate at a frequency of 2.4-2.5 GHz (IEEE 802.11b, 802.11g, 802.11n) and of 5.8 GHz (IEEE standard 802.11a). The design of Rectenna was simulated using HFSS 13 and the results will be compared to the measurements results of the prototype rectenna. S11, VSWR and radiation pattern are the used parameters to determine the performance of the rectenna. The results show that the rectenna can operate at dual-band frequency operation of 2.5 GHz and 5.8 GHz. For a frequency of 2.5 GHz, the simulation and measurement results show almost the same achievement and show a significant difference for a frequency of 5.8 GHz. For example, in simulation of 5.8 GHz, S11, VSWR and Bandwidth obtained -11.17 dB, 1.78 and 570 MHz, respectively. However, in measurement, the results obtained S11 of -14.03 dB, VSWR of 1.49 and bandwidth of 1230 MHz. The output voltage of the rectenna system achieves 3.8 volts.