J. Gavan

Bio: J. Gavan is an academic researcher from Sami Shamoon College of Engineering. The author has contributed to research in topics: Headset & Band-stop filter. The author has an hindex of 1, co-authored 5 publications receiving 4 citations.

Mitigation techniques for enhancing mobile radio EMC performances

Abstract: The number of mobile Radio equipments has increased tremendously which enhance harmful mutual interference and people exposed to non ionized radiation. The levels of Electromagnetic field effects from base stations affecting people are significantly lower than from headsets due to the separation distances and far field propagation conditions. Are presented main mitigation techniques for enhancing base station performances and a thorough analysis of near field mobile headsets EMF effects. Main headsets mitigation techniques are discussed: Using an auxiliary antenna, distancing the headset radiating parts from their users, space polarization diversity and meta-material antennas. Simulation and computation results are added.

MW WPT for HAPS and SPS: Concepts, EMI and biological hazards issues

Abstract: The long distances Microwave (MW) Wireless Power Transmission (WPT) concepts are followed by the presentation of high Altitude Platforms (HAPS) principles. Stratospheric HAPS operation requiring up to a few hundreds kW of electrical power is limited by long sun eclipses. The realization of terrestrial MW WPT systems feeding HAPS could be useful for their long duration operation and for the preliminary tests of more complex and power demanding Solar Power Satellites (SPS) systems. Electro Magnetic Interference (EMI) and biological hazards issues will be discussed for selected frequencies and compared for terrestrial, HAPS and SPS long range MW WPT systems.

A new effective antenna for mobile headsets

Abstract: The main problems concerned with the design of mobile headsets antennas treated in this paper are low efficiency and the difficulty of installing two antennas or more for Multiple Input-Multiple Output (MIMO) applications. This paper proposes a radical solution to the mentioned problems by avoiding the use of special antennas as radiating elements. The proposed efficient radiating element is the mobile headset printed circuit board. The proposed solution is compared with other classical solutions.

A simple odd-symmetric filter for digital broadcasting

Abstract: A new odd-symmetric filter for ISI suppression and VSB transmission is proposed. The frequency response of the proposed filter is similar to that of an ideal raised-cosine filter, but in contrast to raised-cosine the new filter is realizable, e.g. using simple active filters. Simulation results show that concerning ISI suppression the new filter is significantly more efficient than the classical Butterworth or Chebyshev filters. The proposed filter can be also used as a VSB filter for TV modulators and demodulators.

HAPs special OFDMA technique for fast mobile radio systems

Abstract: In this paper we investigate the performances of the Orthogonal Frequency Division Multiple Access (OFDMA) and Frequency Bank Signal (FBS) methods over High Altitude Platforms (HAPs) systems with different Doppler scales. FBS is an enhanced OFDMA technique, which is capable to eliminate the negative effects of Doppler shifts even in extreme cases, such as non-uniform Doppler shifts across the OFDMA subcarriers. Our simulations show that HAP- OFDMA systems can work if frequency shift due to Doppler Effects is smaller than 2% of carrier frequencies separation. These conditions correspond to the frequency band of 2GHz and train velocity 120 km/h. FBS method allows increasing the permissible Doppler shift up to 6-8 %, hence enabling higher carrier frequency bands and higher speed vehicles.

Radio frequency smog reduction from future heterogeneous base station

Abstract: In modern era, communication technologies need a significant development In order to improve the capacity and coverage, a massive technological advancement has become a widespread subject However, the pollution caused by Radio Frequency Electromagnetic Field (RF-EMF) radiation is considered as the greatest environmental hazard Hence, the present analysis proposes a suitable solution to mitigate the RF pollution or smog from base station installation in hot spot areas On the basis of mitigating the RF frequencies, much amendment has to be made on the design of base station, decreasing of signal transmission between the entities and also considering the distance Heterogeneous networks security will increase the signalling transmission for getting user authentication On the basis of authentication, fast authentication and re-authentication, this paper mainly focuses on the reduction of communication signal transmission between the entities Before data transmission, the entities have to get the mutual negotiation The performance metrics of base station depends on power required for transmission and reception, radiation pattern, distance between the entities and message transmission that leads to considerably decrease the R F smog and interference reduction The main aim of this paper extenuates human health care from RF field interference occurring in Future Heterogeneous Base Station (FHBS) and standard limitation is provided in the RF interference range

RF energy harvester for FM frequency band

Abstract: The central idea of this paper is to show the prospect of RF energy harvesting and converting the energy into DC, utilizing the reasonable power obtained, for low power device applications. The system harvests energy from various frequencies available in the spectrum band. The first part introduces some of the disadvantages of larger antenna height in KHz and higher path loss in GHz band of frequencies compared to MHz band of frequencies. Power used for the experiments is from FM band station of 90.8MHz. The second part of this paper is a voltage multiplier with a conversion ratio of four and the antenna used which is a wide band VHF antenna in order to cover frequency range from 80 to 110 MHz with a gain of 2.14dBi. Then a matching circuit to match the antenna impedance with the input impedance of the voltage multiplier is built in the third part of this paper. At the end, comparison of several power devices for load is made in this paper.

Rectenna panel design optimization for maximum RF power utilization

Abstract: Now-a-days, far-field wireless power transfer/energy harvesting is underutilized due to the unavailability of proper methodology to design efficient system for maximum radio frequency (RF) power utilization. For efficient utilization of far-field RF energy an array/grid of rectenna, i.e. rectenna panel is required to generate the power from wireless signal. To minimize the engineering design phase period (design trials), this paper mathematically derives and summarizes the approach required for optimum rectenna panel design based on power available in the environment, RF transmit source capability, receiver power requirement and the design cost. For maximum power interception through a rectenna panel, its design parameters such as -panel size, number of rectenna, rectenna arrangement pattern, and rectenna spacing has been optimized in our work. Based on the optimization required, we have proposed the compact grid pattern with heterogeneous rectenna spacing. It has been proved theoretically in this paper that if a hexagonal shape panel is designed by placement of rectenna at vertices of equilateral triangle (with side length governed by antenna aperture) then, it is capable of intercepting maximum RF energy available at its location with the least number of rectenna.