335 research outputs found

    Antenna on microstrip line with orthogonally placed dielectric resonator

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    Single-element antenna that uses microstrip line as a feeder and cylindrical dielectric resonator orthogonally oriented relative to the line as a radiating element has been investigated. The complete mathematical model of proposed design consisting of a number of analytical expressions for main antenna characteristics is obtained and verified. The analytical relation for antenna return loss versus stub length and coupling coefficients of dielectric resonator with the feeding line and open space is derived. The assessment of the potential possibility and conditions of perfect antenna matching with feeding line is carried out. The influence of main parameters of a dielectric resonator antenna on its characteristics is examined. The numerical analysis of different antenna parameters proving the obtained analytical expressions is performed. The results of theoretical analysis are in good agreement with experimental data

    Dual frequency bi-othogonally polarized antennas for GPS applications

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    Dual frequency bi-orthogonally polarized antenna to be used in Global Positioning System applications operating in Li (1575.42 ± 10.23 MHz) and L2 (1227.60 ± 10.23 MHz) Bands has been studied. To ensure compatibility with existing applications, the antenna size is limited in dimensions to 4.120 x 4.680 x 1.250 including the radome. Orthogonally placed two dual frequency probe excited patches were designed using a high dielectric constant substrate (ε r = 9.8 and thickness of 250 mils, Rogers TMM10i material) to obtain vertical and horizontal polarization for each band. The measured performance of this antenna showed good agreement with the specifications required to meet the application needs. As an attractive alternative a stacked dual patch antenna configuration has been suggested and a prototype antenna has also been developed. Using low and high dielectric constants of 2.20 and 9.8 and relative thicknesses of 125 and 250 mils for each layer an orthogonally placed dual patch configuration has been designed, fabricated and tested on a 2 square feet ground plane. Effects of radomes using materials with different permittivities have been studied through numerical simulations and radomes have been fabricated using plastic materials including UMHW, HDPE and Delrin. Numerical simulations have been carried out using IIE3D software package developed by Zeland Software Inc. Antennas that were fabricated based on optimized parameters have further required tuning due to inaccuracies in simulation and material properties. The measurement setup has been enhanced to accommodate axial ratio measurements in polarization pattern characterization by adding a rotary joint to rotate a linearly polarized antenna operating in the receiving mode. The performance characteristics showed that adequate bandwidths and beam widths were obtained and gain of these antennas were measured to be in the order of 3.5 dBi along the main lobe. Further work is continuing to obtain antennas with wider bandwidths using thicker substrates

    Wideband and UWB antennas for wireless applications. A comprehensive review

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    A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

    Dielectric Materials for Compact Dielectric Resonator Antenna Applications

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    Introduction Dielectric resonators using high-permittivity materials were originally developed for microwave circuits, such as filters or oscillators as tuning element [1]. Indeed, in the late nineteen sixties, the development of low-loss ceramic materials opened the way for their use as high-Q elements [2-4]. Then, making use of dielectric materials to create the dielectric resonator antenna (DRA) illustrates the ingenuity of Professor S. A. Long [5], who was the first to propose such a procedure in the early nineteen eighties. Indeed, it introduced the use of a dielectric resonator as an antenna by exciting different modes using multiple feeding mechanisms. During the nineties, emphasis was placed on applying analytical or numerical techniques for determining input impedance, fields inside the resonator and Q-factor [6]. Kishk, Junker, Glisson, Luk, Leung, Mongia, Bhartia, Petosa and so on, have described a significant amount of DRAs' analyses and characterizations [7-18]. Petosa and al. proposed both in literatures and book [6,12] many of the recent advances on DRAs. Current DRA literatures focus on compact designs to address portable wireless applications. Among them, new DRA shapes or hybrid antennas are developed to enhance the antenna impedance bandwidth [13-19] or for multiband antenna applications [20-22]. The first part will address a brief overview of the most common used DRA shapes and structures including both rectangular and cylindrical DRAs. The emphasis will be placed on better understanding what DRAs exactly are and how to develop such an antenna. This part will detail fundamental modes of DRAs, their resonant frequencies, fields inside the resonator and radiation patterns corresponding to these modes. A second part will focus on the relevant dielectric material properties having a significant contribution to achieve better antenna performances. It will detail the kind of materials DRAs can use, which is closely linked to the targeted application. Multiple techniques to miniaturize such an antenna will be presented in the third part, supported by concrete examples. At the same time, everyone will be able to appreciate that dielectric material properties have a major role to play in designing a DRA. It should be noted that the material choice is even more critical when the targeted challenge is the antenna size reduction. Therefore, depending on the intended applications, this part will enable to find the best trade-off between the material choice and its shape. Although some wideband or multiband DRA structures have been introduced in the third part, the fourth and last part will be dedicated to a new method to design a DRA. It will address engineering design data on hybrid modes creation to enhance the bandwidth or develop multiband antennas. This part will include many references to clearly explain this research method while highlighting their contribution to expand the use of DRA in new kind of mobile handheld devices (e.g. new tablets)

    Antenna-coupled TES bolometers used in BICEP2, Keck array, and SPIDER

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    We have developed antenna-coupled transition-edge sensor (TES) bolometers for a wide range of cosmic microwave background (CMB) polarimetry experiments, including BICEP2, Keck Array, and the balloon borne SPIDER. These detectors have reached maturity and this paper reports on their design principles, overall performance, and key challenges associated with design and production. Our detector arrays repeatedly produce spectral bands with 20%-30% bandwidth at 95, 150, or 220~GHz. The integrated antenna arrays synthesize symmetric co-aligned beams with controlled side-lobe levels. Cross-polarized response on boresight is typically ~0.5%, consistent with cross-talk in our multiplexed readout system. End-to-end optical efficiencies in our cameras are routinely 35% or higher, with per detector sensitivities of NET~300 uKrts. Thanks to the scalability of this design, we have deployed 2560 detectors as 1280 matched pairs in Keck Array with a combined instantaneous sensitivity of ~9 uKrts, as measured directly from CMB maps in the 2013 season. Similar arrays have recently flown in the SPIDER instrument, and development of this technology is ongoing.Comment: 16 pgs, 20 fig

    Design of Square Patch Microstrip Antenna for Circular Polarization Using IE3D Software

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    Communication between humans was first by sound through voice. With the desire for slightly more distance communication came, devices such as drums, then, visual methods such as signal flags and smoke signals were used. These optical communication devices, of course, utilized the light portion of the electromagnetic spectrum. It has been only very recent in human history that the electromagnetic spectrum, outside the visible region, has been employed for communication, through the use of radio. One of humankind’s greatest natural resources is the electromagnetic spectrum and the antenna has been instrumental in harnessing this resource.The thesis provides a detailed study of how to design and fabricate a probe-fed Square Microstrip Patch Antenna using IE3D software and study the effect of antenna dimensions Length (L), and substrate parameters relative Dielectric constant (εr), substrate thickness (t) on the Radiation parameters of Bandwidth and Beam-width

    Symmetry-Related Electromagnetic Properties of Resonator-Loaded Transmission Lines and Applications

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    This paper reviews the recent progress in the analysis and applications of the symmetry-related electromagnetic properties of transmission lines loaded with symmetric configurations of resonant elements. It will be shown that the transmission characteristics of these reactively loaded lines can be controlled by the relative orientation between the line and the resonant elements. Two main types of loaded lines are considered: (i) resonance-based structures; and (ii) frequency-splitting structures. In resonance-based transmission lines, a line is loaded with a single resonant (and symmetric) element. For a perfectly symmetric structure, the line is transparent if the line and resonator exhibit symmetry planes of different electromagnetic nature (electric or magnetic wall), whereas the line exhibits a notch (resonance) in the transmission coefficient if the symmetry planes behave as either electric or magnetic walls (symmetric configuration), or if symmetry is broken. In frequency-splitting lines, paired resonators are typically loaded to the transmission line; the structure exhibits a single notch for the symmetric configuration, whereas generally two split notches appear when symmetry is disrupted. Applications of these structures include microwave sensors (e.g., contactless sensors of spatial variables), selective mode suppressors (of application in common-mode suppressed differential lines, for instance) and spectral signature barcodes, among others

    Design and Analysis of Dual-Linearly Polarized Dielectric Resonator Antenna Array

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    Dielectric resonators have been widely used as narrowband shielded circuit components. The dielectric resonator antenna is an implementation of using an unshielded dielectric structure in order to extract the radiation of electric fields. Dielectric materials can have low dielectric loss and the absence of metallic surfaces also reduces conduction losses. A dielectric resonator antenna can have efficiencies above 95% for several hundred megahertz. The versatility in choice of shape, relative permittivity and size enables a whole spectrum of operating frequency ranges (1GHz-40GHz), sizes, radiation patterns and bandwidths. The far field radiation pattern is a characteristic of the resonating modes. In this project the investigation of dielectric resonator antennas was quantitatively realized by the design and evaluation of one omni-directional wideband dielectric resonator antenna with operating frequency range 3.9GHz to 6.2GHz and two dual linearly polarized broadside antenna arrays in L, S and C band applications. Transverse modes with rotational symmetry are preferred for an omni-directional radiation pattern, whereas a hybrid mode is suitable for a broadside radiation pattern. The modes can be excited by feeding from microstrip lines and coaxial probes. The location of the excitation determines what mode is excited. The resonant frequency is controlled by size, shape and permittivity of the DR element. Dual polarization is achieved by exciting two orthogonal modes simultaneously in the resonator. The cross coupling between the feeding networks and the matching of these becomes a crucial step in the design of a dielectric resonator antenna. The broadside antenna elements have been arranged in a linear as well as planar array to increase the directivity

    Hybrid Microstrip Antennas

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