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Antennas and Propagation, 2003. (ICAP 2003). Twelfth International Conference on (Conf. Publ. No. 491)

Date 31 March-3 April 2003

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  • Global FDTD simulation technique for analysis and design of millimetre-wave receivers

    Publication Year: 2003 , Page(s): 542 - 545 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (262 KB)  

    A global FDTD simulation technique is applied to a millimetre-wave receiver at 90 GHz. The RF signal and LO power are fed quasi-optically and received by the antenna functioning as a mixer. The method takes into account the close proximity among the antenna and the passive and active devices, which conventional mixer circuit analysis does not. The mixer performance, i.e. the conversion loss, can be calculated directly from a simple DFT of the voltages and currents. The frequency response of the mixer provides vital information to optimise the performance of the millimetre-wave receiver. View full abstract»

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  • Analysis of tissue-coupled antennas for UHF intra-body communications

    Publication Year: 2003 , Page(s): 747 - 750 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    For the first time, FDTD analysis was used to investigate the two-port coupling between tissue-implanted thin-wire dipole antennas. Two scenarios were considered for human applications: coupling between the neck and the abdomen, and between the neck and the pectoral region. The simulation results show that 15-mm dipole antennas coated with a low loss dielectric can be used to establish a communication link within the human body at frequencies between 300 MHz and 1.5 GHz. For example, the peak value of |S21| for the abdomen scenario was -82.3 dB at 840 MHz, while it was -74.1 dB at 1.31 GHz for the pectoral scenario. View full abstract»

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  • A dielectric material loaded TEM horn antenna

    Publication Year: 2003 , Page(s): 489 - 492 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    The TEM horn antenna is a well-known type of ultra-wideband antenna. Unlike most TEM horns developed, the antenna discussed in this paper is loaded with a dielectric material and the intention is to make the antenna smaller while maintaining a good performance over an extremely wide band. Various issues linked to the optimal design (including balun) are considered FDTD method is employed to predict its performance. The antenna is built and tested. The measurement results shown that the VSWR is smaller than 2 over the frequency range of 500 MHz to 14 GHz, which is better than expected. View full abstract»

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  • Transient behaviour of nonlinearly loaded wires in the presence of a dielectric half-space

    Publication Year: 2003 , Page(s): 557 - 560 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (318 KB)  

    The transient analysis of wires having a nonlinear load in the presence of a half-space is carried out directly in the time domain. The nonlinear wire problem is formulated by the time domain Hallen integral equation. The effect of a two-media configuration is taken into account via the reflection coefficient appearing within the integral equation kernel. The resulting integral equation is solved by the space-time Galerkin-Bubnov boundary integral equation method (GB-BIEM). Some illustrative numerical results are presented. View full abstract»

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  • Millimeter wave propagation modelling for indoor high-speed PC systems

    Publication Year: 2003 , Page(s): 767 - 770 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    This paper examines the performance of the indoor wireless communications systems in the millimeter wave band and investigates the data transmission rate in terms of base station antenna locations by using the ray-tracing technique. In order to validate the model, continuous wave (CW) experimental measurements are conducted and have successfully fitted the simulation data. The undertaken scenarios are: ceiling mounted base antenna (CeMBA), corner mounted base antenna (CoMBA), and wall-mounted base antenna (WMBA). The data analysis of the simulation demonstrates that the WMBA is the best scenario since its channel exhibits the lowest RMS delay spread and behaves as a Ricean channel. View full abstract»

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  • COST 280: propagation impairment mitigation for millimetre wave radio systems

    Publication Year: 2003 , Page(s): 573 - 576 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (392 KB)  

    European COST Action 280 (see www.cost280.rl.ac.uk) aims to improve the design and planning of present and future millimetre wave broadband telecommunications systems and services through the development of knowledge and tools for a refined evaluation of their performance. The Action co-ordinates work in the areas of: development of propagation impairment mitigation techniques (PIMT); channel modelling for Earth-space and terrestrial paths above about 20 GHz for application in PIMT development and system design; PIMT performance assessment by simulation. The paper gives an overview of the Action, its scope and organisation. It also highlights some of the results achieved thus far and describes plans for the remainder of the Action's lifetime. View full abstract»

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  • Estimation of far-field distances for antennas close to ground and implications for simple gain measurement methods

    Publication Year: 2003 , Page(s): 699 - 702 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (345 KB)  

    The widely quoted far-field distance of 2D2/λ for simple gain measurements is shown to be inappropriate for antennas that are operated in the vicinity of a ground plane, as well as for simple dipole antennas in free space. A more general expression for these systems has been derived from consideration of a pair of point sources, from which the 2D2/λ result can also be derived as a limiting case. It is also shown that the commonly used phase error criterion of π/8 radians is too large to ensure acceptable accuracy in simple gain measurements for dipole antennas, both in free space and above a ground plane. View full abstract»

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  • A mode-matching analysis of transverse radiating slots in an H-plane dielectric-filled rectangular waveguide

    Publication Year: 2003 , Page(s): 682 - 685 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (299 KB)  

    A rigorous mode-matching analysis is presented for extracting the equivalent circuit parameters of transverse slots in the broadwall of a rectangular waveguide partially filled with an H-plane slab. Both self-impedance and mutual coupling between slots can be characterized over a wide frequency range. The proposed method is numerically efficient and can take the effect of wall thickness into account, and therefore can be very useful for designing large slot arrays. View full abstract»

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  • Neural network modeller for multilayered microstrip patch antennas

    Publication Year: 2003 , Page(s): 614 - 617 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    This paper presents the development of a neural network modeller for the optimisation of a dual band multilayer microstrip patch antenna. The multilayer antenna is built on an in-house semi-insulating GaAs substrate and poses a challenge to the EM based optimisation. The developed neural modeller speeds up design optimisation by replacing repeated EM simulations and retains good accuracy compared with the MoM modelling. View full abstract»

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  • PMC as an antenna structural component

    Publication Year: 2003 , Page(s): 599 - 602 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (539 KB)  

    The perfect magnetic conductor (PMC) is well established as a theoretical concept from which to study various electromagnetic scenarios. It is the electromagnetic dual of a perfect electric conductor (PEC). PEC can take a simple physical form: conducting metal for example. PMC on the other hand does not exist in nature, but lately a number of novel structures have been reported (see Sievenpiper, D. et al., IEEE Trans MTT, vol.47, no.11, p.2059-74, 1999; Yang, F.-R. et al., IEEE Trans MTT, vol.47, no.11, p.2092-8, 1999; Ma, K.P. et al., Electron. Lett., vol.34, no.21, p.2041-2, 1998) which realise some of the properties of a PMC, generally by enforcing a zero tangential magnetic field boundary condition at a surface over a limited frequency band. We examine the behaviour of various classical antenna types incorporating such material. PMC offers the antenna designer considerable scope for achieving good impedance and pattern characteristics simultaneously, especially when used in conjunction with PEC. View full abstract»

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  • Improved equivalent circuit for aperture-coupled stacked printed arrays

    Publication Year: 2003 , Page(s): 633 - 636 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (311 KB)  

    Two improved equivalent circuits have been proposed for aperture-coupled multilayer printed arrays. It has been checked that the undesired back radiated power is modelled by the losses in a transmission line and by the parallel impedances. The second equivalent circuit, which uses only lumped impedances and a lossless transmission line is more convenient for the design of the array feeding network. View full abstract»

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  • Investigation of rectangular dielectric resonator antennas for direction finding application

    Publication Year: 2003 , Page(s): 755 - 758 vol.2
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (261 KB)  

    A DOA receiver using RDRAs as receiving elements has been described. The receiver operates at 2.37 GHz. It has been demonstrated in the laboratory scale that the direction of arrival can be determined using the DOA receiver with two RDRAs. The receiver has benefited from the low level mutual coupling and low cross polarisation level of the RDRAs, which reduces the interference between channels and simplifies the design of circuits for phase measurements. View full abstract»

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  • Design, fabrication and measurement of an encapsulated inverted F dual band antenna for the gathering of data on seals at sea using SMS over a GSM system

    Publication Year: 2003 , Page(s): 739 - 742 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    In this paper a novel encapsulated dual band planar inverted F antenna is presented designed for the specific application of gathering data on seals at sea. A mobile phone module with the above antenna is encased in epoxy resin and affixed to a seal for transmission of sensor data via the short message service over GSM in both European frequency bands. Results are presented for a prototype both in anechoic facilities and affixed to a seal at sea. Finite element software is used for optimisation. View full abstract»

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  • Copyright

    Publication Year: 2003 , Page(s): iii
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (197 KB)  

    First Page of the Article
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  • New construction of tapered slot antennas

    Publication Year: 2003 , Page(s): 693 - 694 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (237 KB)  

    We have investigated a novel design of TSA. In order to avoid losses in the dielectric, the antenna presented here does not contain any dielectric parts. It has only metallic parts. The results of measurements of the antenna discussed show that it may be used in telecommunications and radar as a single antenna or as an element of radiation phased arrays with single and dual polarization. It may be useful especially in high power arrays because of its high electrical durability. View full abstract»

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  • Modelling real practical antennas - guidelines and tips from code users' notebooks

    Publication Year: 2003 , Page(s): 712 - 715 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (474 KB)  

    The computational electromagnetics (CEM) code NEC-4 has been validated, and its use demonstrated as an aid in the design of complex monopole antenna systems. The value of the model in understanding how to tune the antenna, and what trends to expect is enormous. MININEC cannot be used to model real Earth beneath the antenna, but our study shows that the prediction of base impedance is precise enough for coupling unit design purposes if base capacity is taken into account, and the vertical radiation patterns (VRPs) predicted with change in model parameters show the right trend. This paper considers only MF antennas for broadcast application, since the purpose of the paper is to compare numerical modelling with measurements in full scale, a study is needed to validate methods of modelling and the NEC code. The results obtained and the techniques developed can of course be applied to any frequency, suitably scaling frequency and antenna size. View full abstract»

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  • Matrix compression techniqes for large arrays: synthetic local and global functions

    Publication Year: 2003 , Page(s): 458 - 461 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (353 KB)  

    Innovative approaches are presented for the computational simulation of planar array antennas. They are based on the integral-equation (IE) formulation at large, and consistently employ synthetic local and global basis functions. The local basis function are provided by the full-wave solution of a reduced problem of small size, but with the same local boundary conditions and relevant IE. The global basis function are indeed provided by asymptotic solutions of a canonical array. Numerical examples are shown, which demonstrate the efficiency and accuracy of the proposed methods for patch arrays and open ended waveguide arrays. View full abstract»

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  • High performance digital radio channel sounder for use at 2 and 5 GHz

    Publication Year: 2003 , Page(s): 805 - 808 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (350 KB)  

    A digital channel sounder has been built to perform measurements of radio channels targeted for 3G and 802.11a operating at 2 and 5 GHz. The novel aspect of the architecture used is that a completely digital wideband modulator and demodulator has been built to allow extensive use of digital signal processing. Such an architecture results in an instrument with significant flexibility, short measurement durations, a rapid update rate and the ability to automatically acquire time and frequency lock. View full abstract»

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  • Very low-profile multilayer broadband microstrip antenna

    Publication Year: 2003 , Page(s): 481 - 484 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    A low-profile triple-patch stacked microstrip antenna is proposed. The antenna, which has a thickness of 3 mm, provides 22% bandwidth about a centre frequency of 5 GHz. In order to achieve the wide bandwidth, the dimensions of the patches are chosen to be slightly different and the feed is applied to the middle patch. View full abstract»

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  • A new approach to propagation prediction

    Publication Year: 2003 , Page(s): 788 - 791 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    In this paper, a software tool has been developed that provides accurate, site specific radio signal predictions for outdoor to indoor or outdoor to outdoor locations. The tool provides results very quickly, and is adept at providing new results for changes in transmitter and/or receiver antenna locations, and building geometries. The propagation prediction tool combines techniques from several different disciplines, including computer graphics and asymptotic electromagnetic theory, to reduce the calculation time without compromising accuracy. Using computer graphics techniques, the time necessary for shooting the rays through the urban geometry is greatly reduced. View full abstract»

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  • A single aperture antenna fed by N parallel strip lines

    Publication Year: 2003 , Page(s): 618 - 621 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (318 KB)  

    A single aperture antenna with N parallel equally spaced strip lines (probes), constructed using a triplate transmission (TT)-line, has been analysed using the FDTD method. The analysis is classified into two cases: (1) an infinite size case, where the upper and lower conducting plates of the TT-line are of infinite extent; and (2) a finite size case, where the upper and lower conducting plates are of finite extent. View full abstract»

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  • Twelfth International Conference on ANTENNAS & PROPAGATION CAP 2003

    Publication Year: 2003 , Page(s): 0_1
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    First Page of the Article
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  • COST 273 - towards mobile broadband multimedia networks

    Publication Year: 2003 , Page(s): 569 - 572 vol.2
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (351 KB)  

    A brief overview is presented on COST 273. This COST (European cooperation in scientific and technical research) Action deals with radio aspects of mobile and wireless networks. In particular, radio interface, propagation and antennas, and radio network aspects are addressed by the three working groups of the project. Within the working groups, sub-working groups deal with more specific issues, namely, MIMO systems, antennas for mobile terminals, measurements procedures, and scenarios for network planning. View full abstract»

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  • High performance digital radio channel sounder for use at 2 and 5 GHZ

    Publication Year: 2003 , Page(s): 804
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (197 KB)  

    First Page of the Article
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  • A far-field approximation for the fast-multipole method applied to dielectric scatterers in the resonance region

    Publication Year: 2003 , Page(s): 603 - 605 vol.2
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (275 KB)  

    A full wave 3D moment-method (MoM) analysis is discussed which has had a far-field approximation introduced to simplify the application of the fast-multipole method (FMM). The embedded FMM is applied to the combined field integral equation, which is applicable for scattering from dielectric/magnetic material. Far-field scattering and surface currents computed by the FMM and the original MoM are shown to be in good agreement. View full abstract»

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