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An eigenanalysis of an array of periodically located wires covered with axially magnetized ferrites is presented. The interest in this structure stems from our previous study which revealed that such a wire may support backward surface and possibly backward leaky waves. These possibilities are examined herein by using our two - dimensional curvilinear frequency domain finite difference (FDFD) toward...
Lowering antenna gain, sidelobes growing, boresight errors and depolarization field of aperture antennas and antenna arrays caused by radomes are under consideration. Transmission and reflection of electromagnetic waves by sandwich type antenna radomes are analyzed. The Green's functions of layered structures and equivalent currents are used for electric field calculation. Reflection and transmission...
The aim of this paper is to investigate the potential of suspended planar patch antenna with rectangular patch slots for transferring wireless energy by collecting electromagnetic waves from ambient microwave sources. The operating frequency is aimed to cover both the 3G mobile communication band of 2.11–2.17 GHz as well as WiFi band of 2.45 GHz, hence, the required bandwidth is approximately 15%...
This paper presents an experimental study of localisation of a body mounted ultra-wideband (UWB) antenna. Several three-dimensional localisation experiments have been performed, using a miniature tapered-slot antenna mounted on the human body as a mobile station and three Vivaldi antennas as base stations, to comprehend the level of accuracy that can be achieved and assess how precisely the tiny movements...
This paper presents a new topology to excite microstrip patch antennas and to produce dual circular polarization over a bandwidth of 20% to 30%. A stacked patch antenna is excited with four microstrip lines through a ring shaped aperture, using a sequential feeding scheme for improved polarization quality on a broad range of angels. The overall antenna is designed to operate from 10.7GHz to 12.7GHz...
In this paper, a novel time delay reflector based on frequency selective surface (FSS) for time-domain pulse splitting is proposed. By employing dipole arrays and half-wave length resonators of the reflector, continuous incident wave with one polarization can be delayed for required time delay without affecting the incident wave with orthogonal polarization. This characteristic of the reflector is...
Helical antennas are versatile, but they have almost purely resistive input impedance, so lumped element matching networks inevitably incur power loss. We investigate an alternative matching technique that claims up to 1∶1 VSWR with post-fabrication tuning, by using an extension above the ground plane. However, our results show that the lowest return losses may actually occur outside the desired band...
This paper proposes a new perspective to the liquid level monitoring and control technique by deploying energy efficient passive UHF RFID tags as liquid level sensors. The system consists of the pump, storage tank, level sensors (passive tags), RFID tag reader, pump control circuit, alarm circuit, and an indicator circuit. The tags are sealed (air and water tight), programmed with unique level labels...
It is known that the phase center of some antennas can shift its position over frequency. The effects of such a phase center movement on the time domain behavior of an antenna were analyzed within an earlier publication. It could be shown that contrary to expectations the pulsewidth of the antenna impulse response increases with increasing antenna bandwidth under certain boundary conditions. These...
In this paper, the performance of a proposed antenna selection algorithm is evaluated that is based on cooperative interference mitigation among neighbouring base stations. This algorithm has been evaluated in MIMO - OFDMA multicellular networks, for various bit rates per mobile user and blocking probabilities via extended Monte Carlo simulations. As results indicate, for 64QAM modulation type and...
A miniaturized triple band Artificial Magnetic Conductor (AMC) Antenna system is presented. The AMC is designed at 430MHz, 688MHz, and 1GHz featuring minimum mutual coupling between unit cell elements by incorporating guard conductors. Miniaturization is achieved using lumped element loading and a unit cell of 0.03λ, calculated at the lowest operating frequency of 430MHz, is presented. A small split...
In addition to the mutual coupling between array elements, the coupling to the characteristic current modes of the chassis has to be considered. In this paper, the performance of a two-element monopole antenna on a small rectangular ground plane is analyzed based on a decomposition of the contributions from the elements and the coupled chassis modes. A resonator-based equivalent circuit is proposed...
The goal of the study presented in this work is to evaluate the performance of OFDMA networks for different subcarrier allocation strategies. Considering no Channel State Information at the transmitter, two low-complexity subcarrier allocation strategies are employed so as to combat interference among inter-cell mobile subscribers and to judicious distribute power budget among them. In comparison...
In this paper a three dimensional Mode Matching technique is proposed for the analysis of a spheroidal cavity loaded with a spherical inhomogeneity around one of its focuses. Analytical electromagnetic field eigen-solutions expressed in terms of spheroidal and spherical wave functions are utilized for the field expansions. The boundary conditions on the spherical surface are enforced through a coordinate...
This paper presents an implementation of the IEEE 802.15.3c standard, in Simulink, for high data-rate applications. The recent standard IEEE 802.15.3c provides the implementation of such wireless communication system using the 60GHz frequency band. OFDM and SC-FDE are the two transmission schemes adopted by the standard. Performance of these technologies at mm-wave signals are severely affected by...
A leaky-wave antenna based on a rectangular waveguide with partially dielectric filling and transverse slots is investigated. A velocity factor dependencies for uniform filling and different slot lengths are presented. Also, dielectric layer thickness variations are considered. The influence of the dielectric layer position in the waveguide on the antenna characteristics is estimated. The radiation...
Rapid multi-objective design optimization of ultrawideband (UWB) multiple-input-multiple-output (MIMO) antenna is presented. Our approach allows for finding the best possible design trade-offs (a so-called Pareto set) with respect to the two objectives: minimization of the reflection coefficient and reduction of the antenna footprint. Computational efficiency is obtained by using variable-fidelity...
Two Cylindrical Dielectric Resonators DR asymmetrically placed on a thin dielectric substrate and fed by a single rectangular slot for wideband wireless applications are presented. Optimized design procedures were applied within a well-known electromagnetic solver to achieve the improved elements dimensions of the antenna geometry. The simulated and measured results show that the proposed DRA can...
In the present paper, the applicability of various on-ground antenna type at 2.45 GHz for launching creeping waves is examined. The performance of three antenna configurations is compared with the discone having purely dominant normal polarization to a body surface. The results are set against an analytical path loss model for a wireless body area network. The type of the studied antennas on a ground...
A novel design of miniature inverted-F antenna (IFA) with no empty space is proposed for indoor energy scavenging of Wi-Fi signals. The antenna configuration was designed based on planar inverted-F antenna (PIFA) with meandered line structure for antenna size miniaturization. The proposed antenna has dimensions of only 8 (L)× 3 (W) × 4 (H) mm to be integrated into low power miniaturized devices. Moreover,...
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