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    IEEE Standard for Definitions of Terms for Antennas


    IEEE Std 145-2013 (Revision of IEEE Std 145-1993)

    DOI: 10.1109/IEEESTD.2014.6758443
    Publication Year: 2014 , Page(s): 1 - 50

    IEEE Standards

    Definitions for antennas and for systems that incorporate an antenna as a component of the system are established in this standard. View full abstract»

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    IEEE Standard Definitions of Terms for Antennas


    IEEE Std 145-1993

    DOI: 10.1109/IEEESTD.1993.119664
    Publication Year: 1993 , Page(s): 1 - 32
    Cited by:  Papers (3)  |  Patents (20)

    IEEE Standards

    Definitions of terms in the field of antennas are provided. View full abstract»

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    IEEE Standard Definitions of Terms for Antennas


    IEEE Std 145-1993

    DOI: 10.1109/IEEESTD.2013.6507364
    Publication Year: 2013 , Page(s): 1 - 32

    IEEE Standards

    Definitions of terms in the field of antennas are provided. View full abstract»

  • Full text access may be available. Click article title to sign in or learn about subscription options.

    UHF deployable antenna structures for CubeSats

    Costantine, J. ; Tawk, Y. ; Ayoub, F. ; Christodoulou, C.G. ; Olson, G. ; Pellegrino, S.
    Radio Science Meeting (USNC-URSI NRSM), 2014 United States National Committee of URSI National

    DOI: 10.1109/USNC-URSI-NRSM.2014.6928057
    Publication Year: 2014 , Page(s): 1

    IEEE Conference Publications

    Summary form only given. Antenna design for small satellites such as CubeSats constitute a challenge for designers especially at UHF frequencies. The small size of the CubeSat (10 cm × 10 cm × 10 cm) imposes several constraints on the antenna design. Extreme packaging ratios and advanced deployment mechanisms have to be employed to cater for UHF antennas on a CubeSat platform. Many types of deployable antennas have been used on orbit. Reflector types constitute their widest category. Other deployable structures made with folded hoops or ribs are also used for space communications. Other researchers have resorted to tape springs and neutrally stable material to design their structures. An example of potential CubeSat deployable antenna candidates is a log periodic crossed dipole antenna array. The log periodic crossed dipole antenna array, constructed with a bi-stable composite material, exhibits a directive beam with a wide bandwidth. The characteristics of the bi-stable composite material allow a more efficient antenna deployment mechanism. A log periodic crossed dipole antenna array can extend up to 55 cm for UHF frequency operation with the longest element being around 60 cm. Another potential antenna candidate is the conical log spiral antenna. The conical log spiral antenna typically fed at its apex exhibits a circular polarization with a wide bandwidth. This antenna radiates outwards from the direction of the antenna's apex and thus, it has to deploy in a manner to radiate away from the satellite. A typical conical log spiral antenna's height can extend up to 62 cm with a bottom circular base of radius 23 cm and a top radius of 5 cm. Other configurations of the conical log spiral antenna can also be proposed to satisfy various constraints such as a narrower base or a bigger height. A bottom fed conical log spiral antenna deployed on top of a ground plane is another possible candidate. One of the main benefits of this topology is an easier fe- ding mechanism after deployment. In this case the antenna still radiates upward and away from the satellite due to the presence of a significant ground plane under its base. Another candidate for deployment on CubeSat is a Quadrifilar Helix antenna. This antenna built with beryllium copper deploys on top of a ground plane that has a square shape with a side of 1.25λ. The antenna is fed by multiple power dividers and phase shifters to allow a progressive 90° phase shift between the four elements constituting the antenna. This antenna achieves a gain around 8 dB at UHF frequencies with a circular polarization performance. The antenna however exhibits a narrower bandwidth than the previously discussed conical log spiral antenna. Finally there are many possible candidates for antenna deployment on CubeSats as long as these candidates satisfy desired constraints. On the other hand, a deployable UHF antenna for CubeSats imposes an additional storage constraint due to size limitation. View full abstract»

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    The Effect of Antenna Physics on Fading Correlation and the Capacity of Multielement Antenna Systems

    Jianmin Gong ; Hayes, J.F. ; Soleymani, M.R.
    Vehicular Technology, IEEE Transactions on

    Volume: 56 , Issue: 4 , Part: 1
    DOI: 10.1109/TVT.2007.895500
    Publication Year: 2007 , Page(s): 1591 - 1599
    Cited by:  Papers (1)

    IEEE Journals & Magazines

    In this paper, we investigate the effects of antenna directivity and antenna orientation on fading correlation and, therefore, the channel capacity in multiple-input-multiple-output communication systems by means of a spherical simulation model. The correlation is caused by the mutual interaction of the scattering environment and antenna elements. To study the effect of antenna directivity and orientations on the correlation and channel capacity in a more realistic environment, we extend the ldquoone-ringrdquo model to a spherical scattering environment, which is appropriate for narrowband 3D Rayleigh fading. In our model, scatterers around a subscriber unit are distributed over a sphere centered on the antenna array in the subscriber unit. Antenna directivity is included in a precise way, and the antenna array can be placed in any orientation. Any type of antenna can be studied in the model. Through simulation, we find that directive antenna elements in linear broadside arrays make the channel capacity more strongly directive than when antenna elements are isotropic. Moreover, different antenna patterns and orientations have different outage capacities depending on the interaction of antenna directivities and the incident waves, which shows that the antenna pattern and orientation affect the channel capacity to some extent. In the uniformly scatter-rich environment, the microstrip antenna array can have 10% higher outage capacity than that of the dipole antenna array. View full abstract»

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    Far field antenna factor estimation for a single antenna measurement using time frequency analysis

    Kurokawa, S. ; Hirose, M.
    Antennas and Propagation (ISAP), 2014 International Symposium on

    DOI: 10.1109/ISANP.2014.7026481
    Publication Year: 2014 , Page(s): 3 - 4

    IEEE Conference Publications

    We have already proposed a single antenna method for estimating an antenna factor of log-periodic dipole array antenna at 10 m antenna distance. In this paper, we apply a time-frequency analysis to suppress some undesired reflection waves for our single antenna method. And, we estimate the far field antenna factor using estimated antenna distance that determined by the time-frequency analysis. Further, we apply the antenna radiation center distance modified equation for estimate the far field antenna factor of log-periodic dipole array antenna. We show the result that compare with the estimated far field antenna factor and antenna factors using other methods. The estimated antenna factor by our proposed method has good agreement with far field gain that is less than 0.3 dB difference in the frequency range from 300 MHz to 1000 MHz at antenna height D= 5 m. View full abstract»

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    The Measurement of Complex Antenna Transfer Functions for Ultra-Wideband Antennas in a Compact Range [Measurements Corner]

    Nel, M. ; Joubert, J. ; Odendaal, J.W.
    Antennas and Propagation Magazine, IEEE

    Volume: 56 , Issue: 6
    DOI: 10.1109/MAP.2014.7011037
    Publication Year: 2014 , Page(s): 163 - 170

    IEEE Journals & Magazines

    Ultra-wideband (UWB) communications technology increasingly plays an important role in modern communications systems. The complex antenna transfer function (CATF) of a UWB antenna provides valuable information that can be used for better UWB channel and communication system designs. Currently, only the two-antenna and three-antenna measurement techniques are used to measure the transfer functions and impulse responses of UWB antennas. In this paper, a modified version of the gain-transfer method is presented to enable the characterization of UWB antennas using a compact antenna test range facility (CATR). A double-ridged guide horn (DRGH) antenna was used as a UWB transfer-standard, and the complex antenna transfer function of the transfer-standard was determined a priori using full-wave simulations. The gain-transfer method to measure the complex antenna transfer function of UWB antennas in a compact antenna test range was illustrated with two test cases. In the first test case, the measured complex antenna transfer function of an ETS-Lindgren double-ridged guide horn antenna was verified with numerical data from a FEKO model of the antenna. The second case compared the complex antenna transfer function of a UWB circular disc monopole antenna measured in a compact antenna test range to measured data using two identical antennas in a two-antenna measurement setup. View full abstract»

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    A low cross-polarization circularly polarized spacecraft TC&R antenna

    Eu-An Lee
    Antennas and Propagation Society International Symposium, 1994. AP-S. Digest

    Volume: 2
    DOI: 10.1109/APS.1994.407953
    Publication Year: 1994 , Page(s): 914 - 917 vol.2

    IEEE Conference Publications

    A spacecraft TC&R antenna provides telemetry, command, and ranging operation throughout all mission phases after launch vehicle separation. An ideal TC&R antenna should provide an omnidirectional pattern. In practice, an omnidirectional pattern is approximated by a cardioid pattern. Such cardioid patterns can be generated by a slotted-ring antenna, or a conical spiral antenna. There are two disadvantages associated with the slotted-ring, or the conical spiral antenna. These two disadvantages can be overcome by using a multiple-element TC&R antenna system. Such a system uses at least two identical antenna elements to provide the required coverage. The most commonly used antenna component is the open-end waveguide antenna with a septum polarizer. These antenna components were derived from the INTELSAT-V Hemi/Zone antenna feed array elements by chopping off the flare section in order to broaden the beam. A detailed configuration of the antenna is illustrated. However, the axial ratio performance for such an antenna in the diagonal planes (45/spl deg/ and 135/spl deg/ cuts) is generally poor. This paper presents a technique which utilizes a simple mechanism to improve the axial ratio performance (at 4 and 6 GHz) for such an antenna in the diagonal planes to a value better than 5 dB at /spl plusmn/70/spl deg/ from the antenna boresight.<> View full abstract»

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    On-body directional antenna design for in-body UWB wireless communication

    Qiong Wang ; Hahnel, R. ; Hui Zhang ; Plettemeier, D.
    Antennas and Propagation (EUCAP), 2012 6th European Conference on

    DOI: 10.1109/EuCAP.2012.6206211
    Publication Year: 2012 , Page(s): 1011 - 1015
    Cited by:  Papers (5)

    IEEE Conference Publications

    A planar Vivaldi UWB antenna design is proposed as the on-body wearable receiver antenna for medical in-body wireless communications in this paper. The proposed antenna connects two opposite Vivaldi variants on one side of the substrate and is fed by a radial stub microstrip on the other side. With a metallic reflector at the Vivaldi side, a strong broadside radiation can be obtained from two opposite end-fire radiations resulting from two opposite planar Vivaldi variants. The proposed antenna shows good far field gain in free space measurement with certain optimized spacing distance of the metallic reflector. The impedance matching characteristics have been validated by measurements both in free space as well as on body surface. A 4-element circular-polarized configuration antenna is proposed with good impedance matching and radiation gain characteristics. A dual-polarized diversity reception antenna is also fabricated based on two in-phase fed perpendicular placed antenna elements. A good decoupling between both polarizations in the far field can be concluded. A receiver antenna belt can be expected by integrating multiple dual-polarized antenna units in an antenna array. View full abstract»

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    Modular antenna for reactive and radiative near-field regions of UHF-RFID desktop readers

    Michel, A. ; Caso, R. ; Buffi, A. ; Nepa, P. ; Isola, G.
    General Assembly and Scientific Symposium (URSI GASS), 2014 XXXIth URSI

    DOI: 10.1109/URSIGASS.2014.6929139
    Publication Year: 2014 , Page(s): 1 - 4

    IEEE Conference Publications

    A general and reconfigurable antenna scheme for RFID desktop readers operating in the UHF band is here proposed. To maximize the electromagnetic field in a confined volume within the antenna near-field region (namely, in both the reactive and radiative near-field regions), a travelling wave antenna is combined with a low-gain resonating antenna, which share the surface of the desktop reader antenna. The travelling wave antenna allows for covering the reactive near-field region, with almost uniform electric and magnetic fields up to a few cm from the antenna surface. The low-gain resonating antenna is used to cover the radiative near-field region, up to a few tens of cm from the antenna surface, yet radiating a relatively low field in the antenna far-field region as required by antennas for desktop readers. In such a way, a satisfactory tag readability is expected independently on the material of the item the tag is attached to and the effect of the mutual coupling among stacked tags. The suggested modular configuration can be realized by using different technologies for the travelling wave antenna (microstrip, coplanar waveguide, slotline, etc.), as well as different layouts for the resonating antenna. Above degrees of freedom allow the antenna designer to easily meet the specifications on antenna size and RFID read range. The antenna modules used to realize the reader antenna can be combined through either a shunt or series feeding connection; as an alternative, a few switches and variable power splitters could be added to implement a reconfigurable desktop reader antenna. View full abstract»

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    Enabling Antenna Systems for Extreme Deep-Space Mission Applications

    Schulze, R. ; Wallis, R.E. ; Stilwell, R.K. ; Cheng Weilun
    Proceedings of the IEEE

    Volume: 95 , Issue: 10
    DOI: 10.1109/JPROC.2007.905068
    Publication Year: 2007 , Page(s): 1976 - 1985
    Cited by:  Papers (3)

    IEEE Journals & Magazines

    Two NASA deep-space probes, Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) and New Horizons (NH), are moving towards the extremes of our solar system (Mercury and Pluto). The delivery of the science in these extreme environments is a challenge, and the missions require unique approaches. MESSENGER'S antenna system utilizes the first electronically scanned high-gain array for a deep-space telecommunication application. The array, which provides the high-data-rate downlink, is scanned in one dimension and is circularly polarized. Although a linearly polarized array would have satisfied the minimum mission science data rate requirements, MESSENGER'S circularly polarized array doubles it. To achieve this, the Johns Hopkins University/Applied Physics Laboratory (JHU/APL) developed an innovative technique to produce circular polarization from a narrow-wall slotted waveguide array. The new technique uses short parasitic monopoles mounted to the exterior of the waveguides. The result is a simple, lightweight, and all-metal circularly polarized array capable of operating at +300 OC, and a variety of measurement techniques were used to verify phased-array antenna system performance during qualification. The NH antenna system is a stack arrangement of a high-gain antenna (HGA), medium-gain antenna (MGA), and low-gain antenna (LGA). To minimize mission operating costs, the spacecraft is spin stabilized at all times except during encounters to maintain a fixed spacecraft attitude. This approach and application for a narrow beamwidth antenna is unique for a deep-space mission, resulting in new approaches to accurately measure the gain and radio-frequency (RF) boresight direction in a compact range facility. Because of the importance of the HGA function to overall mission success, testing of the HGA system at operational temperatures of -200 OC was also performed. Recent in-flight measurement of the NH HGA pattern verified ground - alignments. The RF design of the NH antenna also forms the baseline RF design for a deployable antenna system JHU/APL is developing called the Hybrid Deployable Antenna (HDA). The HDA combines a fixed parabolic dish with a deployable/inflatable reflector annulus that greatly increases antenna area after launch. This concept provides a high-payoff deployable antenna system that is being developed to address the "all or nothing" risk by providing a viable backup capability. This paper discusses some of the challenges to advance this concept for a future deep-space mission. View full abstract»

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    A Novel Broadband Planar Antenna for 2G/3G/LTE Base Stations

    Yuehui Cui ; RongLin Li ; Peng Wang
    Antennas and Propagation, IEEE Transactions on

    Volume: 61 , Issue: 5
    DOI: 10.1109/TAP.2013.2244837
    Publication Year: 2013 , Page(s): 2767 - 2774
    Cited by:  Papers (6)

    IEEE Journals & Magazines

    A novel broadband planar antenna is developed for mobile communication base stations. The antenna is composed of a pair of folded dipoles which are coupling fed by an L-shaped microstrip line. Both the dipoles and the coupling microstrip line are etched on the same substrate. The planar antenna achieves a bandwidth of 53% for return loss} > 15 dBi covering the frequency range 1.65-2.85 GHz for 2G/3G/LTE applications. The antenna gain of the broadband antenna element is about 9 dBi. A 45° dual-polarized planar antenna consisting of two broadband antenna elements is proposed, which achieves a bandwidth of about 50% and an isolation of 30 dB. Two 8-element antenna arrays are developed respectively for the broadband antenna and for the ${pm}45^{circ}$ dual-polarized antenna. Both antenna arrays achieve a bandwidth of more than 58% (1.6-2.9 GHz). The antenna gains achieved for the both antenna arrays are higher than 15.5 dBi. The half-power beam widths in the horizontal plane for the antenna arrays are approximately 65pm ± 10°, suitable for base station applications. View full abstract»

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    An optimum quarter-wave impedance matching feedline for circular UWB array antenna with high gain performance

    Jamlos, M.A. ; Jamlos, M.F. ; Khatun, S. ; Ismail, A.H.
    Wireless Technology and Applications (ISWTA), 2014 IEEE Symposium on

    DOI: 10.1109/ISWTA.2014.6981180
    Publication Year: 2014 , Page(s): 165 - 169

    IEEE Conference Publications

    The goal of this paper is to designed ultra-wide band (UWB) array antenna for biomedical application. The array arrangement is introduced to improve the performance of the antenna in terms of return loss, gain, bandwidth, and directivity. In this paper, a four-element antenna array is presented. The antenna array is composed of quarter wave feed network along with four-identical circular patch antenna elements designed and simulated using Computer Simulation Tool (CST) Microwave Environment software. The performance of the designed array antenna evaluated in term of return loss, Voltage Standing Wave Ratio (VSWR), bandwidth, radiation pattern, directivity and gain. The array elements and its feed network are properly designed to have a very wide useful band and high gain antenna against frequency. Introduction of unique mitered structures along the feedline and low right side feed realize UWB array antenna with high gain. The simulation result of return loss shown that the operating bandwidth less than -10 dB is start from 4.5 GHz until more than 20 GHz at gain range of 4.2 dB until more than 8 dB at VSWR less than 2. The antenna has an excellent averaged directivity of 7 dBi and a widespread functioned fractional bandwidth of more than 129%. Simulated result shows that the array has a peak gain of more than 8 dB at 9 GHz. These features lead the UWB antenna array appropriate for microwave imaging purposes. The antenna is fabricated on the low cost FR-4 substrate with dielectric constant of 4.7 and thickness of 1.6 mm. Less complicated fabrication methods is possible due to the feeding network placement is on the same level with the antenna patch elements. View full abstract»

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    Could the antenna pattern be in energy instead of in power?

    Dau-Chyrh Chang ; Chao-Hsiang Liao ; Powen Hsu
    Antenna Technology, 2009. iWAT 2009. IEEE International Workshop on

    DOI: 10.1109/IWAT.2009.4906981
    Publication Year: 2009 , Page(s): 1 - 4

    IEEE Conference Publications

    In general, the limited antenna power patterns in frequency domain are used to describe the antenna performance. It is enough to describe the antenna performance in narrow band communication systems. However, the limited antenna power patterns in frequency domain are not enough for ultra wideband (UWB) antennas or arrays in communication systems. The energy pattern of antenna is the total response of power patterns in frequency domain. It will be easier to describe the energy pattern instead of power pattern for UWB antennas. In this paper, electromagnetic energy, electromagnetic power, energy pattern, energy gain, energy directivity and energy efficiency will be discussed. In order to verify the theory of antenna pattern in energy, Yagi Uda antenna, narrow band multibeam smart antenna, UWB bow-tie slot antenna, UWB comb taper slot antenna, and UWB antenna arrays with different element spacing are studied and measured by the impulse time domain system. The energy pattern is quite similar to that of power pattern for narrow band antennas. The grating lobes of UWB antenna array will not occur at the energy pattern even if the element spacing of array is larger than one wavelength. View full abstract»

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    Microwave ferroelectric and reconfigurable antennas

    Modelski, J.W. ; Yashchyshyn, Y.
    Microwave Workshop Series on Millimeter Wave Wireless Technology and Applications (IMWS), 2012 IEEE MTT-S International

    DOI: 10.1109/IMWS2.2012.6338192
    Publication Year: 2012 , Page(s): 1 - 2

    IEEE Conference Publications

    Nowadays, radioelectronic systems employ multiple antenna systems. Reconfigurable apertures are derived from a new class of antennas, which consist of a matrix of conducting patches with switches between some or all of the patches. These reconfigurable apertures can change functionality by opening or closing different connections between these patches. An example of the second group is the plasma regions with fairly high electrical conductivity, which are temporarily created on a silicon substrate. These regions define the antenna structure, and they can be changed to create different antennas. The key element of the antenna is a semiconductor chip that contains a set of individually controlled PIN structures. Electromagnetic waves propagate through the chip, which also serves as a planar dielectric waveguide. The PIN structures locally affect the wave propagation velocity, and the antenna can form a beam in practically any direction within a wide steering angle (like a leaky-wave antenna). The first investigations of the reconfigurable antennas, which are carried out at our Institute, show the extensive functionalities of this type of antenna. First of all, the reconfigurable antenna can be used as the conventional frequency scanning antenna. It is easy to see, that the reconfigurable antenna can direct radiation beam to desire direction. The first additional possibility in comparison with the conventional waveguide slot antenna, is that the reconfigurable antenna can be used for operating at one frequency, but with generating two or more different radiation patterns at different moments. The second extending possibility of the presented reconfigurable antenna is that the antenna can operate at different frequencies with supporting radiation in the same direction. Presented reconfigurable antenna consists of the reconfigurable aperture which is placed on, instead of the narrow wall of a rectangular waveguide. Aperture consist of a number of the reconfigurable elem- nts which are made as the surface PIN diodes (SPIN), and are excited by means of an electromagnetic field existing in a waveguide. The main drawback of the presented electronically reconfigurable antenna concept is fact that the directions of the beam can be chosen in a discrete way. Increasing the number of the reconfigurable elements causes decreasing of the angle distance between two neighbouring beam directions. However, some parameters of the SPIN diodes made the limitations of their utilization on microwave. Advances in several areas of materials science have led to a variety of new materials with strong potential applications to microwave and millimeter-wave components. The high tunability and low dielectric losses are only the desired properties of material which can be applied in the tunable micro- and mm-wave devices. Despite the enormous effort made to reduce the cost of the tunable devices, the desired progress has yet to be achieved. However a number of the device configurations are a promising solution to inexpensive steering. A new low-cost scan antenna concept (without phase shifters), applying ferroelectrics, has been presented. The property of ferroelectric materials having a dielectric constant which can be modulated at high frequencies, under the effect of an electric field bias operating perpendicular to the direction of propagation of the signal, is very attractive and can be used to develop a new family of devices operating in the microwave and mm-wave range. Ferroelectric materials are in many ways dual to ferromagnetic materials. However, they have a number of advantages over the magnetically controlled ferrites. In ferroelectric, the driven energy required to change the property of material goes primarily to change in the stored energy and is not dissipated in the ferroelectric material. As a consequence, less power is required to control the property of material. Ferroelectrics also allow for faster tuning compared to ferromagnetic materi View full abstract»

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    Simplified cross-polarized multi-antenna system for radio relay transmission in wireless backhaul

    Ikezaki, I. ; Muta, O. ; Furukawa, H.
    Communications and Signal Processing (ICCSP), 2011 International Conference on

    DOI: 10.1109/ICCSP.2011.5739365
    Publication Year: 2011 , Page(s): 480 - 484
    Cited by:  Papers (1)

    IEEE Conference Publications

    Wireless backhaul systems have been considered as a promising candidate of beyond 3G wireless broadband system for mobile communications. The achievable transmission performance over radio relay channel depends on antenna directivity and radiation patterns of each antenna element. To improve the transmission performance and keep radio relay channel in an acceptable condition, it is effective to control the antenna directivity by employing multi-antenna signal transmission and reception. In this paper, we propose a simple method to extend the existing single antenna relay node based on IEEE802.11a to multi-antenna system, where a cross polarized multi-antenna is applied to the existing relay nodes as external equipment. The multi-antenna system is controlled by detecting the antenna control information assigned to the lengths of the packets transmitted from the existing node. The proposed method does not require special change of the existing system such as hardware design on multi-antenna configuration. We also developed a prototype base/relay node with optional multi-antenna equipment and confirmed the effectiveness of the proposed method by experiment. To clarify the effectiveness of the proposed multi-antenna system in wireless backhaul networks, we evaluate throughput performance by system level simulations. Simulation results ensure that the proposed multi-antenna system with highly efficient packet forwarding protocol, called Intermittent Periodic Transmit (IPT), improves throughput performance of the radio relay transmission in wireless backhaul as compared with conventional omni-directional antenna system. View full abstract»

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    Antenna element bandwidth and adaptive array performance

    Gupta, I.J. ; Ulrey, J.A. ; Newman, E.H.
    Antennas and Propagation Society International Symposium, 2005 IEEE

    Volume: 1B
    DOI: 10.1109/APS.2005.1551548
    Publication Year: 2005 , Page(s): 295 - 298 vol. 1B

    IEEE Conference Publications

    It is well known that the radiation patterns of the individual elements, as well as the antenna geometry, affect the performance of an adaptive antenna array. In the open literature, these effects have been studied for single tone (CW) interfering signals. In the real world, the interfering signals incident on an antenna array are hardly single tones. Depending on the environment, the interfering signals can have the same bandwidth as the desired signals. Under these conditions, the response of the individual antenna elements over the system bandwidth would effect the adaptive antenna performance. In general, individual antenna elements are dispersive; i.e., the phase of the signal received by an antenna varies nonlinearly with frequency. This is especially true for narrowband antenna elements (thin dipoles, monopoles, patch antennas, etc.). When these antenna elements are used in an antenna array, the presence of the mutual coupling leads to dissimilar in situ element patterns. Thus, various channels of an adaptive array will be dispersive and dissimilar. This means that the adaptive array may have to use more degrees of freedom to null wideband interfering signals. The choice of individual antenna elements, therefore, can have significant effect on the performance of an adaptive antenna. In this paper, the same is demonstrated using an array of thin dipoles and another array of biconical antennas. It is shown that in the presence of wideband jammers the biconical antenna array performs significantly better than the dipole antenna array View full abstract»

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    Reconfigurable miniature multielement antenna for wireless networking

    Cetiner, B.A. ; Jofre, L. ; De Flaviis, F.
    Radio and Wireless Conference, 2001. RAWCON 2001. IEEE

    DOI: 10.1109/RAWCON.2001.947608
    Publication Year: 2001 , Page(s): 203 - 206
    Cited by:  Patents (2)

    IEEE Conference Publications

    We present a new reconfigurable broadband miniature antenna architecture that is able to change its working frequency, polarization, or radiation pattern to get single broadband or dualband behavior for a single widebeam or multibeam diversity configuration. Two antenna geometries are considered. A single element antenna, the so-called dime antenna, is introduced. A prototype dime antenna operating at 5.2 GHz was fabricated and measured to validate the accuracy of the simulation tool in terms of accurately predicting its impedance behaviour and radiation characteristics. Motivated by the dime antenna another novel miniature antenna geometry, called qdime, was studied in detail. Mutual coupling analysis between qdime antenna pairs with respect to orientation is investigated to determine optimum multielement antenna configuration (less mutual coupling and less space occupation) for use in diversity systems that require sufficiently decorrelated received signals at each antenna element. Short circuit striplines, having typical dimensions of RF MEMS switches, are appropriately located within the antenna structure to change its operating frequency and radiation pattern. Results are presented and discussed View full abstract»

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    Effect of wireless charging antennas on transmission of an antenna pair through human body

    Goh, C.K. ; Xianming Qing ; Zhi Ning Chen ; See, T.S.P.
    Antennas and Propagation (APCAP), 2012 IEEE Asia-Pacific Conference on

    DOI: 10.1109/APCAP.2012.6333138
    Publication Year: 2012 , Page(s): 57 - 58

    IEEE Conference Publications

    In this paper, the effect of the spiral antenna and the loop antenna for wireless charging on the transmission of an antenna pair comprising an external antenna and an implanted antenna through human body is studied. The transmission characteristic of the antenna pair with a wireless charging antenna positioned between the antenna pair is investigated over the frequency band of 3 - 5 GHz. It is found that the loop antenna features a limited effect on the transmission response while the spiral antenna causes the transmission response to change drastically across the frequency band. It is suggested that a loop antenna, compared to a spiral antenna, is a more efficient wireless charging antenna for an implanted radio system and causes less effect on the transmission between the external and the implanted antenna pair. View full abstract»

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    Various antenna design techniques for medical applications

    Jaehoon Choi
    Antennas and Propagation (ISAP), 2012 International Symposium on

    Publication Year: 2012 , Page(s): 198

    IEEE Conference Publications

    In this talk, various antenna design techniques for medical applications are introduced. Three types of antennas for medical application are proposed. To minimize the body effect, high dielectric material, zeroth-order resonance configuration, and an inverted-F structure with a meandered strip line techniques are utilized. I. An implanted compact antenna for an artificial cardiac pacemaker is proposed. The dimension of the pacemaker system, including the antenna element, is 30 mm × 35 mm × 7 mm. Taconic CER-10 with a relative permittivity of 10 is used for the substrate and two superstrates to reduce the effect of high conductive body tissue on the antenna. When the antenna is embedded in a semi-solid flat phantom with equivalent electrical properties as the human body, S11 value is -19.2 dB at 403.5 MHz. The measured specific absorption ratio (SAR) value of the proposed antenna is 0.0079 W/Kg (1 g tissue). Moreover, to estimate the communication performance of the proposed antenna operated in the real environment, a link budget analysis is performed. II. An implantable zeroth-order resonance (ZOR) antenna is proposed. By using chip inductors, an epsilon negative ZOR was generated, while achieving an extremely compact antenna size. The antenna has the overall dimensions of 0.021λ0 × 0.017λ0 × 0.002λ0 at the Medical Implantable Communication Service (MICS) band (402-405 MHz). Furthermore, the performance of the proposed antenna is insensitive to the electrical properties of the human body by virtue of the ZOR phenomenon. III. A capsule antenna used in an ingestible medical device is proposed. To achieve miniaturization and a wide bandwidth, an inverted-F antenna with a meandered strip line was used. The antenna performance in a human voxel model is analyzed through simulation, and the performance of the fabricated antenna is verified by comparing the measured data with that of the simulation when the antenna is- placed in a human-equivalent liquid phantom. View full abstract»

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    Multilayer Antenna Package for IEEE 802.11ad Employing Ultralow-Cost FR4

    Wonbin Hong ; Kwang-Hyun Baek ; Goudelev, A.
    Antennas and Propagation, IEEE Transactions on

    Volume: 60 , Issue: 12
    DOI: 10.1109/TAP.2012.2214196
    Publication Year: 2012 , Page(s): 5932 - 5938
    Cited by:  Papers (3)

    IEEE Journals & Magazines

    This paper demonstrates the possibility and feasibility of an ultralow-cost antenna-in-package (AiP) solution for the upcoming generation of wireless local area networks (WLANs) denoted as IEEE802.11ad. The iterative design procedure focuses on maximally alleviating the inherent disadvantages of high-volume FR4 process at 60 GHz such as its relatively high material loss and fabrication restrictions. Within the planar antenna package, the antenna element, vertical transition, antenna feedline, and low- and high-speed interfaces are allocated in a vertical schematic. A circular stacked patch antenna renders the antenna package to exhibit 10-dB return loss bandwidth from 57-66 GHz. An embedded coplanar waveguide (CPW) topology is adopted for the antenna feedline and features less than 0.24 dB/mm in unit loss, which is extracted from measured parametric studies. The fabricated single antenna package is 9 mm × 6 mm × 0.404 mm in dimension. A multiple-element antenna package is fabricated, and its feasibility for future phase array applications is studied. Far-field radiation measurement using an inhouse radio-frequency (RF) probe station validates the single-antenna package to exhibit more than 4.1-dBi gain and 76% radiation efficiency. View full abstract»

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    Compact switched and reconfigurable 4-ports beam antenna array for MIMO applications

    Viet Anh Nguyen ; Park Seoong Ook
    Intelligent Radio for Future Personal Terminals (IMWS-IRFPT), 2011 IEEE MTT-S International Microwave Workshop Series on

    DOI: 10.1109/IMWS2.2011.6027210
    Publication Year: 2011 , Page(s): 1 - 3
    Cited by:  Papers (5)

    IEEE Conference Publications

    In this paper, we analyze and introduce a practical design for a switched beam planar antenna that can be implemented as a compact and low cost switched and/or reconfigurable beam antenna array. The antenna is composed of a four ports antenna array based on arranged eight L-shaped quarter-wavelength slot antenna elements. This type of antenna array is a planar structure and its maximum directional radiation beam pattern presents in azimuth plane with the covering of 360 degree. The operation of antenna array is based on the statuses of ON/OFF stage of PIN diodes in each individual slot antenna element and the combined signals from four ports. Consequently, by proper controlling the stage of PIN diodes, the antenna can exposes its characteristic of switchable and/or reconfigurable beam patterns in φ-plane. The antenna array size is about 56 mm in square with four ports. To prove the concept, a 2.5-2.8 GHz switched-beam antenna for WLAN applications in MIMO is simulated and fabricated. View full abstract»

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    Double-folded monopole antenna using parallel line or coaxial cable

    Tsukiji, T. ; Kumon, Y. ; Yamasaki, M.
    Microwaves, Antennas and Propagation, IEE Proceedings

    Volume: 149 , Issue: 1
    DOI: 10.1049/ip-map:20020181
    Publication Year: 2002 , Page(s): 17 - 22
    Cited by:  Papers (6)  |  Patents (3)

    IET Journals & Magazines

    It has been shown that loading a certain reactance component at the feeding point of an antenna is useful in reducing antenna size. When a parallel transmission line with a short-circuited end is loaded onto a monopole antenna, we can obtain a small antenna called a parallel line loaded monopole antenna. However, a small antenna usually has low input resistance and low actual gain. The approach outlined is to increase the actual gain of the small loading antenna and utilise knowledge of a folded monopole antenna, which has a very high impedance value. A small folded monopole antenna called the double folded monopole antenna (DFMA) with high resistance and high actual gain can then be realised. An explanation of the operational principles of the DFMA is provided and the characteristics of small antenna design discussed. A coaxial cable is also used as the loading element for the loading antenna. It is proposed that a coaxial cable DFMA can be realised by replacing the parallel transmission line loading with coaxial cable transmission line loading. The advantage of the coaxial cable DFMA is that it has a small cross-sectional area, since the coaxial cable loading is embedded within the cylindrical antenna element. The results of actual testing of the coaxial cable DFMA are presented. All other results are provided by computer simulation using the method of moments, since the results are assumed to be similar to those recorded from practical experimentation View full abstract»

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    A Low-Profile Unidirectional Printed Antenna for Millimeter-Wave Applications

    Mingjian Li ; Kwai-Man Luk
    Antennas and Propagation, IEEE Transactions on

    Volume: 62 , Issue: 3
    DOI: 10.1109/TAP.2013.2295832
    Publication Year: 2014 , Page(s): 1232 - 1237
    Cited by:  Papers (4)

    IEEE Journals & Magazines

    By combining a printed reflector-backed one-wave-length bowtie antenna and a printed double loop antenna, a new wideband high-gain antenna element is demonstrated. Due to its low-profile structure of ~ 0.05λ0, it is attractive to be used in an array environment. Experimentally, a series of antenna arrays operated at 60 GHz are designed and fabricated. They achieve wide impedance bandwidths covering the 57-64 GHz unlicensed frequency band. Over this band, the measured antenna gains are ranged from 14.5-15.5 dBi, 18.3-20.1 dBi and 22.5-25.2 dBi for 4-element, 14-element and 50-element antenna arrays, respectively. The measured radiation pattern has low cross-polarization level and low back radiation. The proposed low-profile antenna and arrays are low-cost in fabrication as they are simply made on a single-layer printed circuit board. View full abstract»

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    Role of Small Permeability in Gigahertz Ferrite Antenna Performance

    Jaejin Lee ; Yang-Ki Hong ; Woncheol Lee ; Abo, G.S. ; Jihoon Park ; Won-Mo Seong ; Seok Bae
    Magnetics Letters, IEEE

    Volume: 4
    DOI: 10.1109/LMAG.2012.2237163
    Publication Year: 2013 , Article#: 5000104
    Cited by:  Papers (1)

    IEEE Journals & Magazines

    We demonstrate that even small relative permeability (μr<; 2) is effective enough in the improvement of gigahertz (GHz) antenna performance. Based on antenna performance simulation results, a 1.57 GHz small permeability (μr = 1.97) hexaferrite antenna (8 mm × 5 mm × 1.5 mm) was fabricated and characterized for antenna miniaturization factor, fractional bandwidth (FBW), and radiation efficiency (RE). Return loss and FBW were 13 dB at the resonance frequency fr of 1.57 GHz and 7% at voltage standing wave ratio of 2.5:1, respectively. On the other hand, antenna simulation results show that an alumina ( εr = 9.4) antenna with tan δε of 0.01 and 0.05 resonates at fr of 1.65 GHz and has FBW of 4.1% and 6.0%. The hexaferrite antenna volume was 30% of the alumina dielectric antenna volume. The experimental RE of the hexaferrite antenna was 66% at 1.57 GHz, which is much higher than the simulated RE of 55.4% for the lossy dielectric antennar = 11; tan δμ = 0; tan δε = 0.05), even though ferrite has tan δμ = 0.05 and tan δε = 0.008. The antenna performance simulation results confirmed that the RE of the ferrite antenna can be increased to 80% at tan δμ of 0.01. Both simulation and experimental results demonstrate that even small permeability of GHz hexaferrite greatly contributes to miniaturization, FBW, impedance matching, and RE. View full abstract»

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