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The plan of the environment used in a ray tracing simulation is not usually in exact accordance with the actual environment plan. Errors on the order of several centimeters may be present in describing the lateral wall positions. Such errors are comparable to the wavelength in indoor wireless applications and hence, can severely alter the phases of multipath components and lead to inaccurate electromagnetic...
A spectral representation for the electromagntic fields is developed in 3D in cylindrical coordinates for propagation over a Terrain. The result is obtained for a planar terrain and for an homogeneous atmosphere and ground. The spectral representation is related with both the vertical and azimuthal variables. For the vertical variable, this spectral representation contains a discrete component associated...
In this article, we present a study about the impact of embedded wafer level ball grid array (eWLB) on characteristics of antenna. The antenna in package is a promising solution for integration of antennas and eWLB technology enables integration of passive components and antennas into the redistribution layer (RDL). The antenna radiates perpendicular to the package in broadside into the package. There...
This paper discusses about design, analysis and optimization aspects of metasurface antennas. The design procedure of metasurfaces for the realization of shaped beam antennas and application examples are presented. For the fast analysis and for a suitable use in an optimization loop a customized efficient full wave tool has been developed within the 3DAMxLAD module of ADF-EMS (Antenna Design Framework...
In this paper, new planar spiral antennas for passive RFID tag application at UHF band are designed and optimized using the Artificial Bee Colony (ABC) algorithm. The optimization goals are antenna size minimization, gain maximization and conjugate matching. The antenna dimensions were optimized and evaluated using ABC in conjunction with commercial EM software. The optimization results produced show...
The reflection phase of a mushroom like structure is determined based on the capacitance value. However, the gap width and length between mushroom patches that determine the capacitance value cannot be decided independently for vertical and horizontal polarizations. This paper proposes a novel H-type mushroom structure to achieve polarization-independent design and adopts the H-type mushroom structure...
In this paper we present an alternative procedure for the prediction of propagation path loss in urban environments, which is based on Artificial Neural Networks (ANN). The goal of this work is to synthesize and model ANNs which would require entering at the input nodes a detailed and the same time small amount of information about the propagation environment. We apply the Differential Evolution (DE)...
Designing an RFID tag and placing it at an appropriate position, are both strongly responsible for proper functioning of the tag. In this article we present a study on the performance of three different UHF RFID tags placed on metallic cylinders of different radii. One of them is printed dipole antenna, the second one is a commercial tag (Alien 9540-02 squiggle UHF RFID tag), and the third one is...
In this paper we give an overview about the design and qualification of the Medusa feed system. Results of the qualification tests as well as comparisons of predicted and measured performance data are given.
This work analyzes the impact of vegetation coupling on the impedance of a monopole antenna operated in a Brazilian Atlantic rainforest site, in the HF and low VHF bands. A theoretical analysis was performed in order to have a first order estimate of the differences between the impedance responses in a forest spot and in an open area. Next, the impedance of a 3-m monopole was measured in those sites...
The complex dielectric constants of building materials are present in the reflection, transmission and diffraction coefficients of the ray tracing formulation. Any deviation of the dielectric constants included in ray tracing simulation from the actual material properties may be a source of inaccuracy of the simulation results. This paper explores the sensitivity of ray tracing results to the inaccuracy...
A compact dual-band planar inverted-F antenna (PIFA) working in the GPS (1572 MHz), DCS (1800 MHz) and WiMAX (3500 MHz) frequency bands is presented. The antenna based on split-ring (SR) resonators provides 30% and 11% impedance bandwidth performance at the respective bands. Also, the antenna exhibits uniform radiation pattern at both frequency bands.
In this paper we demonstrate a low profile slot antenna having wide impedance and axial ratio bandwidth. Slot is excited by a dipole placed inside the slot itself. By choosing a wideband dipole oriented at an appropriate angle, it is possible to obtain 3dB axial ratio bandwidth of 53% and 10dB input reflection coefficient bandwidth of 75%.
In this work, a new antenna design for UHF RFID near-field and far field applications is presented. The design propos a planar antenna that combines a microstrip patch antenna with a segmented loop. This configuration has been designed to achieve the features of propagation in the two interested field zones. The both antennas are simultaneously excited by a coupled line. The novelty brought by present...
In this paper, a study of a compact microstrip antenna based on composite right/left-handed (CRLH) metamaterial transmission line is presented. The physical size and operational frequencies of the antenna are determined by the CRLH unit cell. The antenna exhibits monopolar radiation at its fundamental mode of resonant frequency. It is well known that the composite right/left-handed (CRLH) transmission...
A flat car-roof antenna module for phone and GPS applications is proposed. The module consists of a planar inverted-F antenna (PIFA) for the phone operation and a planar loop antenna for the GPS one. The two antennas are located in a same plane parallel to car roof and put close to each other so that the dimension of the module is only 50 × 80 mm2 in plane. Gap between the antenna plane and the car...
Transmission line mode theory is used to analyze wideband/multiband small antennas consisting of several conductors. First, the modal theory is introduced with equations in order to implement the theory to antenna analysis. Eigenvalue and eigenvector matrices generated by the theoretical calculation are shown. As an example of simple analysis, ILA with a folded structure consisting of two-wire (FILA)...
This paper presents a design of a wideband array antenna consisting of a leaf-shaped bowtie slot antenna (LSBSA). A four-element LSBSA array is designed such that the array operates over the frequency band of 7–10GHz. In order to demonstrate the effective performance of the presented configuration, characteristics of the designed LSBSA array are evaluated by the finite-difference time domain (FDTD)...
As an emerging antenna concept, reconfigurable sensing antennas (RSAs) are presented in this paper. In order to clearly demonstrate the RSA concept and its operation principle, three RSA designs that use different sensing mechanisms for temperature sensation are proposed. Three temperature-sensing materials: water, high density poly-ethylene-Ba0.3Sr0.7TiO3 (HDPE-BST), and mercury, are integrated into...
This paper studies a case where a modern RF communications system require internal EMC filtering and shielding up to frequencies of 20GHz or more even when the operating frequencies of the system are only around 2GHz. The results of this study pinpoint the importance of system co-design with mechanics, filtering and related electromagnetic phenomena taken into consideration as key drivers for high...
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