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Antenna Technology and Applied Electromagnetics and the Canadian Radio Science Meeting, 2009. ANTEM/URSI 2009. 13th International Symposium on

Date 15-18 Feb. 2009

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Displaying Results 1 - 25 of 90
  • 2009 Proceedings [front matter]

    Publication Year: 2009 , Page(s): 1 - 16
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    Freely Available from IEEE
  • Flat-top power patterns of arbitrary footprint produced by arrays of arbitrary planar geometry

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (829 KB) |  | HTML iconHTML  

    This paper presents a novel technique for synthesis of flat-top power patterns with desired footprints, generated by array elements positioned on an arbitrary planar geometry. Traditionally, this problem had been considered as a protracted complex nonlinear optimization problem specially when the number of array elements is large for obtaining a desired and detailed pattern. Using the formulation of patterns generated by circular apertures the problem is converted to a collocation problem which not only reduces the number of unknowns but also generalizes the method to any arbitrary planar aperture. Derivation of the closed form formulae specially for the the nonlinear problem simplifies implementation of the method. View full abstract»

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  • A compact UWB butterfly shaped planar monopole antenna with bandstop characteristic

    Publication Year: 2009 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB) |  | HTML iconHTML  

    In this paper, a novel compact butterfly shaped planar monopole ultra-wideband (UWB) antenna is presented. This antenna is proposed and designed with a standard printed circuit board (PCB) process for suitable integration with MMICs and other components. The calculated impedance bandwidth of the proposed antenna ranges from 3 GHz to 12 GHz for a return loss S11 less than -10 dB. Also, it has a relatively stable radiation patterns over its whole frequency band of interest. By introducing a slit ring resonator (SRR) in the feedline, a bandstop of 830 MHz (from 5.0 to 5.83 GHz) for band rejection of WLAN can be achieved. So, the proposed antenna is considered a good candidate for UWB applications. View full abstract»

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  • Reducing crosspolarization of an offset reflector antenna using a dual-mode horn feed

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (395 KB) |  | HTML iconHTML  

    The effect of a dual-mode circular horn antenna, as a feed in offset reflector antennas, on the crosspolarization field is studied using the physical optics, geometrical optics, and geometrical theory of diffraction software GRASP. It will be shown that, one can reduce the crosspolarization of an offset reflector antenna by properly exciting two modes in circular horn antenna. These two modes are the fundamental mode, TE11, and the higher order mode, TE21. The results for some offset reflectors, with different f/D ratios, will be presented to investigate the above property. View full abstract»

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  • A compact and broadband NRI-TL metamaterial monopole antenna

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    A compact and broadband negative-refractive-index transmission-line (NRI-TL) metamaterial antenna is proposed, which consists of a conventional printed monopole loaded in a left-handed fashion. The metamaterial loading allows the antenna to be modeled as a short folded monopole around 5.5 GHz, and simultaneously acts as a a balun for the ground plane around 3.55 GHz, therefore enabling the ground plane to radiate at this frequency. Consequently, the metamaterial-loaded monopole antenna exhibits a very wide impedance bandwidth by virtue of the orthogonality between these two radiating modes. The NRITL metamaterial monopole antenna has a simulated -10 dB return-loss bandwidth of 3.84 GHz while maintaining a very high efficiency in the order of 90%, and achieves orthogonal pattern diversity in both the 3.3 - 3.8 GHz WiMax and 5.15 - 5.85 GHz WiFi bands. View full abstract»

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  • Mutual coupling reduction in MIMO antennas using artificial magnetic materials

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (7)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1959 KB) |  | HTML iconHTML  

    In this paper, artificial magnetic resonators are used in order to reduce mutual coupling in Multiple-input Multiple-Output (MIMO) systems. Split-ring resonator (SRR) inclusions are inserted between closely-spaced high-profile monopole antenna elements. It is shown that mutual coupling between the antenna elements can be reduced significantly by incorporating such magnetic inclusions. The magnetic materials work as insulators, and thus can be applied in a variety of antenna applications. View full abstract»

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  • Differential LNA considerations for the Square Kilometer Array

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (513 KB) |  | HTML iconHTML  

    This paper summarizes the approach of the implementation of a differential input and single-ended output low noise amplifier for the square kilometer array development system. A new procedure to test such LNAs has also been proposed here. As a part of the initial approach for this design idea two MIC LNAs have been designed to be tested in the proposed method. Avago Technology's ATF33143 pHEMT transistors have used to develop the designs. LNA1 has a flat gain of more than 30 dB with noise figure of around 0.6 dB. The return losses are also good over the band. The LNA2 displays gain over 28 dB and noise figure less than 0.7 dB almost all across the band. The true differential mixed mode S-parameter response of both the LNAs has been presented here. With success these design and testing procedures would be implemented on future MMIC LNAs to be developed for the SKA. View full abstract»

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  • Low cost low noise phased-array feeding systems for SKA pathfinders

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (483 KB) |  | HTML iconHTML  

    Developments in radio astronomy instrumentation drive the need for lower cost front-ends due to the large number of antennas and low noise amplifiers needed. This paper describes cost reduction techniques for the realization of antennas and low noise amplifiers in combination with a noise budget calculation for array systems in the absence of cryogenic cooling. View full abstract»

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  • Buried cable parameter extraction using a full-space unbounded conformal mapping technique

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB) |  | HTML iconHTML  

    In this paper a full-space conformal mapping technique is used to extract the parameters of buried multiconductor cables. The quasi-electric and quasi-magnetic approximations of Helmholtz equation are employed and necessary scaling factors are applied to the governing equations and post processing energy relations. The modified equations are numerically solved using a finite-element-based method. The calculated results for typical buried circular cable geometries are compared with those obtained from bounded-space cases and with analytic formulation. Comparison shows very a good agreement between analytical and the mapping technique results in a wide frequency range. View full abstract»

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  • Enhanced directivity of a tapered slot antenna for near-field imaging

    Publication Year: 2009 , Page(s): 1 - 3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (570 KB) |  | HTML iconHTML  

    This paper investigates the application of a novel feature called the ldquodirectorrdquo to a tapered slot antenna. This director, previously designed for a balanced antipodal Vivaldi antenna, consists of a profiled piece of higher dielectric introduced in the antenna aperture. Its effect is to increase the antenna directivity in the near-field by focusing the radiated energy in the end-fire direction. Simulated results show that the director may be highly beneficial for the tapered slot design. View full abstract»

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  • Signal detection performance in indoor environments with a synthetic antenna array

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB) |  | HTML iconHTML  

    This paper analysis the performances of a single antenna handheld receiver in detecting a signal in a Rayleigh multipath fading environment. If the antenna is spatially fixed during the time interval that the signal is sampled then signal coherency is maintained. However, the signal will be subject to statistically large fading losses. The alternative is to spatially translate the antenna along some arbitrary random trajectory during the snapshot interval. It will be shown that a significant net processing gain resulting from randomly moving the antenna relative to keeping it stationary is achievable. It is further demonstrated that for a given utilization scenario, there is an optimum trajectory size which maximizes the processing gain advantage of the moving antenna. An extensive set of measurements based on CDMA - 2000 pilot signals propagated from outdoor terrestrial base stations, captured in indoor multipath environments using stationary and moving antennas are used to experimentally verify these theoretical findings. View full abstract»

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  • Narrowband signal detection in correlated Rayleigh fading with a moving antenna

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    The performances of a single moving antenna receiver in detecting a narrowband signal in a correlated Rayleigh fading is considered. The single moving antenna captures spatial samples during antenna displacement that provides a realization of a synthetic antenna array. It is shown that there is a net processing gain in applying synthetic antenna array over keeping antenna stationary. This processing gain is subject to have uncorrelated signals at different antenna position. This paper examines the performance of synthetic array in correlated Rayleigh fading environment. An optimum detector based on estimator-correlator (EC) is developed and its performance is compared with that of non-coherent suboptimal equal-gain (EG) combiner in different channel correlation scenarios. An extensive set of measurements based on CDMA-2000 pilot signals using stationary and moving antennas are used to experimentally verify these theoretical findings. View full abstract»

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  • Investigation into phase quantization effects of synthesized array factor having a main beam and a prescribed null using a Dolph-Chebyshev array

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (349 KB) |  | HTML iconHTML  

    Investigations into the phase quantization effects for a 16 - element Dolph-Chebyshev linear array with half-wavelength element spacing and digital phase shifters are reported in this article for an array factor having a main beam and a prescribed null. The main beam is fixed, and the prescribed null angular position varies between 1 and 60deg. Based on results with perfect phase, the effects of phase quantization on the radiation characteristics are studied. Particularly, one can notice that the main beam angular position and half-power beamwidth errors are negligible. However, phase quantization greatly affects the prescribed null position and depth, proportionally to the sidelobe ratio. View full abstract»

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  • Comparison of microwave and laser surface detection for microwave imaging systems

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2284 KB) |  | HTML iconHTML  

    Radar-based microwave breast imaging techniques involve transmitting and receiving microwave pulses from a number of antenna locations. The data collected benefit from antenna positions that are within a certain range relative to the breast surface. Thus a requirement for prior knowledge of the breast size, shape, and location arises. This paper presents application of a laser sensor to estimate a number of points on the surface of simple breast phantoms. Results demonstrate faster scan times as well as improved results when using a laser sensor. View full abstract»

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  • Numerical prediction of neural activation in electrically stimulated retina

    Publication Year: 2009 , Page(s): 1 - 3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1484 KB) |  | HTML iconHTML  

    Degenerative retinal diseases such as Retinitis Pigmentosa (RP) and Age Related Macular Degeneration (AMD) result in progressive loss of photoreceptor cells in the retina without completely disrupting the rest of the visual neural path. Implantable retinal prostheses have been shown to be capable of restoring some form of vision to patients affected by these conditions by providing systematic electrical stimulation to the retinal ganglion cells, thus partially replacing the functionality of the diseased photoreceptors cells. In this paper, we determine the areas where retinal ganglion cells are depolarized and hyperpolarized by the artificial electrical stimulation. This is achieved by calculating the activation function from the potential scalar field obtained using the admittance method with three-dimensional models of the retina, implanted electrode, and surrounding tissue. View full abstract»

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  • Wideband reflectarray research at the Communications Research Centre Canada

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (478 KB) |  | HTML iconHTML  

    This paper provides an overview of different types of ring geometries that have been investigated recently in communications research centre Canada as the building block of wideband reflectarray elements. The superior performance of these reflectarrays in terms of operating bandwidth was demonstrated experimentally. Techniques for the design of wideband reflectarray with ring type elements will be presented. View full abstract»

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  • Development of composite radio telescope reflectors

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2139 KB) |  | HTML iconHTML  

    One of the keys to the success of the square kilometre array (SKA) radio telescope will be the development of cost effective collecting area. Development of construction techniques for composite reflectors is an active R&D focus at the National Research Council's Dominion Radio Astronomical Observatory (DRAO), near Penticton, Canada. Composite materials offer a range of benefits over traditional metal structures in the construction of large (10 m+ diameter) reflectors. The high specific modulus of composite materials results in the construction of lighter and stiffer reflectors and the low CTE of these materials yields thermally stable structures. New developments in composite manufacturing processes have the potential to make composites a cost effective alternative for reflector antennas. The team at DRAO constructed and tested its first 10 -m diameter prototype reflector, the Mk1, in 2007, a second prototype, Mk2, incorporating improvements in performance and manufacturability was completed in the fall of 2008. This paper presents a review of the Mk1 measurement results and the preliminary measurements of the Mk2. View full abstract»

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  • A low weight S-band quadrifilar helical antenna for satellite communication

    Publication Year: 2009 , Page(s): 1 - 3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    In this paper, a new design of an S-band, self-phased, one-turn quadrifilar helical antenna (QHA) has been presented. The antenna has been analyzed in purposed of desired radiation pattern by numerical method. A new matching technique has been used to improve VSWR of the QHA. The experimental results show the radiation pattern has Nadir null of about 6 dB and Axial Ratio is better than 1 dB. In addition, VSWR is less than 2 in frequency bandwidth of 120 MHz. The antenna has low weight, size and cost which is suitable for satellite communication systems. View full abstract»

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  • Laser micro-fabrication in RF MEMS switches

    Publication Year: 2009 , Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1221 KB) |  | HTML iconHTML  

    The RF MEMS Switch is the key element in the field of microwave and mm-wave signal control. In recent years it has been investigated widely because of its advantages of low insertion loss, low power consumption, high isolation, excellent compatibility with silicon and high linearity over PIN diode or FET counterpart. Meanwhile as the development of laser technology it has demonstrated extensively to be a very valuable tool for the development of high quality processes in micro-applications. The use of lasers in the field of MEMS is multiple. Starting from characterization, testing and going to technology and working principle of the microsystems and nanosystems, the lasers find applications in any of these areas. The paper overviews some of the laser micro fabrication in RF MEMS switches such as laser deposition, laser lithography, laser direct writing etc. We present the respective technologies, their working principles, their advantages and drawbacks. In some cases the examples of microstructures realized by using laser techniques have been showed. View full abstract»

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  • A novel block elimination procedure for general linear systems of equations

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    Groups of unknowns in linear systems of algebraic equations are eliminated by solving smaller systems whose coefficients are just coefficients in the original systems, with no matrix inversions and multiplications being involved. This could yield solutions with improved accuracy with respect to other solution methods. The amount of computation involved is only slightly higher than that in the Gaussian elimination. View full abstract»

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  • Arrays of 4 circularly polarised aperture-coupled-fed stacked patch antennas for GPS interference mitigation

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    This paper presents an array antenna composed of 4 identical circularly polarised aperture-coupled-fed stacked patches for mitigation of GPS interference. The individual radiating elements have been designed to cover the three GPS frequency bands L1, L2 and L5, with a good polarisation ratio over the top hemisphere. Two array topologies are considered. The characteristics of the arrays are presented in terms of return loss, mutual coupling, gain and axial ratio. Radiation patterns synthesized for a boresight beam and, as rejection is of interest, for a boresight null, are provided and analyzed. The results give insights on the capability of the array for GPS interference mitigation. View full abstract»

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  • Phantoms for testing radar-based microwave breast imaging

    Publication Year: 2009 , Page(s): 1 - 4
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (523 KB) |  | HTML iconHTML  

    In order to test and improve radar-based microwave imaging systems, realistic breast phantoms have been developed. Eight hemispherical and four realistic breast models were created utilizing tissue-mimicking materials introduced in [1]. Implementing a stepwise procedure and creating various molds allowed phantoms with skin, gland, fat and tumour materials to be constructed and imaged. View full abstract»

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  • RCS of circular carbon NANO tube antenna array

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB) |  | HTML iconHTML  

    A novel THz antenna structure, made of carbon nanotube arrays is suggested. Using CST MICROWAVE STUDIO (CST MWS), the capabilities of carbon nanotube terahertz (THz) antenna arrays have been simulated and this CNT antenna array has been fabricated. View full abstract»

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  • Fast shielding effectiveness evaluation of a thin wall rectangular enclosure with numerous small circular apertures

    Publication Year: 2009 , Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (803 KB) |  | HTML iconHTML  

    In this paper, an extremely fast technique is introduced to evaluate the shielding effectiveness os a thin-wall rectangular enclosure with numerous circular small apertures. The technique is based on the traditional waveguide circuit model where the enclosure is replaced with an equivalent shorted transmission line. In the proposed circuit model, the perforated thin wall is replaced by a proper equivalent impedance that is derived from the reflection coefficient. The computation results are in very good agreement with measurements. Besides accuracy, the method is extremely efficient and easy to implement compared to the numerical techniques. View full abstract»

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  • Circuits with light at the nanoscale

    Publication Year: 2009 , Page(s): 1 - 2
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (110 KB) |  | HTML iconHTML  

    Imagine circuit elements so small that you could fit many of them in a tiny microscale volume (e.g., a cell)! Imagine that such circuits could work with light at the nanoscale instead of electricity! What could you do with such optical nanocircuits? Would you be able to use them in wireless gadgets at nanoscales, like a ldquonanoradiordquo, that may connect our nanoworlds? Could these tiny optical nanocircuits be coupled with biological entities and thus provide nanoscale sensors? The fields of metamaterials and plasmonic optics may provide road maps for such futuristic nanocircuits and wireless nanosystems and sensors. We have been developing and investigating some of the fundamental concepts and theories, and key features of such metaplasmonic structures, devices, and circuits. These circuit elements and components may be envisioned as a tapestry of nanostructures of sizes much smaller than the wavelengths of light. This field, for which I have coined the term metactronics, addresses metamaterial-inspired optical nanocircuits and nanosystems (See references below).. In my group, a variety of ideas and paradigms for nanocircuit functions, optical antennas and sensors for beam shaping and photonic wireless at the nanoscale, optical nanoscopy, nanospectrometer for molecular spectroscopy, cloaking of particles, nanotagging and barcodes based on these optical circuits are being studied. In this talk, I will give an overview of these studies, present insights into these findings, and forecast future ideas and road maps in these areas. For more information, please see the references below. View full abstract»

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