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Abstracts - Budapest 2003
On the improvement of characteristic mode theory for the effective modeling of antennas and arrays
Marta Cabedo-Fabrés, Alejandro Valero-Nogueira, Miguel Ferrando-Bataller and José I. Herranz-Herruzo
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In this paper the characteristic mode theory is revisited as an instrument to generate an efficient set of entire domain basis functions to handle large antenna arrays. The main disadvantages of the theory are discussed and two solutions are proposed to solve them. Firstly the inclusion of an additional entire domain basis function to model the behaviour of the reactive current at the feed point. Secondly to generate a new set of frequency-independent basis functions from the original set to provide convergent results over a wide frequency band.
Fresnel zone plate reflectors simulation and radiation diagram analysis
Julio Gutiérrez-Ríos and Juan Vassal'lo Sanz
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Fresnel Zone Plate Reflectors (FZPR) have the advantage of being easy to construct, cheap and reduced in filled room in comparison with parabolic reflectors, due to their flat shape. Besides they have good possibilities to be folded and deployed for spatial applications. In this paper, we introduce a general procedure for simulation, in order to predict the radiation pattern, bandwidth and other capabilities. This procedure is based on general diffraction theory and provides good computational efficiency. Though it is very appropriated for FZPR simulation, it also is very suitable for any other non plane reflectors able to be represented in cylindrical co-ordinates, not necessarily with revolution symmetry.
Simulation of the radiation characteristics of 3D quasi self-complementary arrays
X Dardenne and C Craeye
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Self-complementary arrays potentially exhibit a very large bandwidth. However, their bi-directional radiation characteristic limits their range of applications, and the introduction of a ground plane below the array dramatically reduces the achievable bandwidth. We confirmed the latter point by applying infinite-array MoM simulations on planar bicone arrays. When the required instantaneous bandwidth is not very large, by just moving the ground plane, the array can be operated over a quite large total frequency band. Simulation results showed a total frequency band of one octave, made of 10% instanstaneous bands. Another approach consists of folding the plates to form TEM horn arrays. In that case, 3D MoM simulations showed that a total instantaneous bandwidth of 75% can be opened. In this case, moving the ground plane has little effect.
Progress and problems with conformal array modelling using FDTD
IJ Craddock, DL Paul, R Nilavalan and CJ Railton
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This contribution considers approaches to full-wave, time-domain, modelling of conformal arrays using FDTD. Results for typical structures are presented and the strengths and shortcomings of the approaches are discussed.
Approximate integral equation of EM penetration through slots
JR Mosig
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A modified integral equation is solved iteratively for a not-too-thick slot. The two original integral equations degenerate in the limit of the infinitely thin slot. The original integal equations are replaced by their sum and their difference. A single iteration suffices for slots thinner than 1/10 wavelength.
Numerical implementation of thick slots into an integral equation model
D Llorens del Rio, I Stevanovic and JR Mosig
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A full wave method to analyze slots in thick conducting screens is presented. The method is partially based on the fact that spectral-domain transmission line Green's functions for a multilayered structure (and in particular for a parallel-plate structure) are closed-form integrable along the axis normal to the stratification. This property is exploited to obtain a fast, full wave mixed spectral/spatial Method of Moments (MoM) formulation. For electric elements, a mixed potential formulation is employed. Interaction between electric and magnetic elements is handled with a field formulation. The advantages of these choices are briefly discussed. Two examples are discussed. Comparisons with measurements and alternative approaches are presented.
Design of integrated multiband antennas for personal communications handsets
M Martínez-Vázquez, O Litschke and D Heberling
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The advent of new, multi-standard mobile phone devices is a real challenge for antenna designers, as they have to implement integrated antennas with multiband operation within a volume that is rapidly shrinking. In this paper, some investigations concerning the input return loss, radiation characteristics and efficiency of novel internal, multiband patch antennas are presented.
Small antennas with a slot cut in the ground plate
Pawel Kabacik, Arkadiusz Byndas and Robert Hossa
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When the desired number of resonances is already achieved in a small antenna, normally a lot of research effort must be spent on providing the required bandwidth properties. The latter issue generally is the most difficult task to accomplish. To cope with this problem, we have been investigating the incorporation of a variety of slots and the application of slot cuts in the grounds of small antennas. The incorporation of the slot cut in the ground offers such major benefits as tuning of resonant frequencies and further shift of the lowest resonant frequency towards the permissible limits of radiation. However, the most valuable benefit is bandwidth broadening, which generally does not imply any decrease in the value of the best return loss match. Enabling radiation at frequencies lower than 800 MHz for handy terminals is another potential benefit. Such challenging effect can be achieved by extending the length of the ground plate section surrounding the cut slot.
Compact antenna structures for mobile handsets
Juha Villanen, Jani Ollikainen, Outi Kivekäs and Pertti Vainikainen
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In recent studies the effect of mobile handset chassis on antenna performance has been examined. It has been noticed that especially at the E-GSM900 frequencies and with small internal antennas, the chassis works as the main radiator. The results of the mentioned studies suggest that using practically non-radiating coupling structures, which as efficiently as possible excite the low-Q resonant wavemodes of the chassis, could considerably reduce the size of an internal mobile handset antenna. In this paper, very simple and compact mobile handset antenna structures based on the above mentioned idea are presented. Based on the novel antenna structure, two different antenna models were designed and single-band prototypes for the E-GSM900- and the GSM1800-systems were fabricated from both models. The volume of the smaller antenna model was only 1.3 cm3. Both models fulfilled the bandwidth and SAR requirements of E-GSM900- and GSM1800-systems. Efficiencies were high and radiation patterns suitable for use in mobile handsets.
Active equalised broadband transmitting patch antenna from a dual frequency one
D Segovia, V González, JL Vázquez, E Rajo and C Martín
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This paper presents an active transmitting patch antenna working in the 1650MHz-2300MHz band. An increase in EIRP of 11 dB has been achieved by measuring both the passive and active radiator. The proposed active antenna has been designed from a dual frequency stacked patch antenna (1785-2250 MHz) fed directly through the output probe of a resistive equalised broadband amplifier.
Antennas on elliptical surfaces
G Amendola and G Di Massa
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A survey of the techniques for the analysis of the radiation from structures conformal on elliptic cylinders is presented. Results on the effects of the eccentricity of the cylinders on the electrical properties of the antennas are also presented.
Patch array design for an active low cost steerable antenna for multimedia satellite communication (ALCANT)
Florian Pivit, Dietmar Löffler and Werner Wiesbeck
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In this paper an antenna for the satellite communication system INMARSAT is presented. The INMARSAT System (Downlink: 1525-1559 MHz, Uplink: 1626.5-1660.5 MHz) was mainly build for voice and data communication between offshore ships and the mainland. Therefore these antennas have to have a steerable beam, so they can be pointed to the satellite regardless of the ships position on sea, as well as to compensate for the movement of the ship itself. So far the antennas for such systems have been steered mechanically. In this paper the design of a cost effective and electronically steerable conformal patch array antenna for the INMARSAT system is presented.
Recent results on conformal antennas at the University of Zagreb
Z Sipus, N Burum and J Bartolic
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The purpose of this paper is to present different programs, developed recently at the University of Zagreb, which rigorously analyze different types of cylindrical and spherical arrays. The analysis approach is based on solving the electric field integral equation via moment method approach. The three-dimensional problem is reduced to a spectrum of one-dimensional problems by applying the Fourier transformation in the directions where the structure is homogeneous. Consequently, the elements of the moment method matrix and the excitation vector are calculated in the spectral domain. The kernel of the integral operator is a Green's function, which is different for different structures. In order to analyze various structures we have developed an algorithm, called G1DMULT, that calculates spectral-domain Green's functions of multilayer planar, circular-cylindrical and spherical structures.
Recent developments of theoretical and numerical methods for studying integrated conformal antennas and circuits
Filiberto Bilotti, Andrea Alù and Lucio Vegni
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The paper presents some recent developments on the theoretical and numerical methods for studying integrated antennas and circuits mounted on curved surfaces. The theoretical investigation is focused on the derivation of a new set of transmission line equations relating the transverse field components in the generalized orthogonal curvilinear reference system and in presence of any linear (even complex) material. An interesting isomorphism between the sets of conformal and planar components, based on this theoretical formulation, is then presented and it allows an easy numerical solution of conformal structures through their planar equivalents. Then, a review of the main numerical methods, commonly employed to solve the electromagnetic field when curved geometries are involved, is given. Finally, the attention is focused on a proper extension of the Method of Line numerical algorithm to solve conformal structures in presence of complex materials.
Overview on TASFR activity on Conformal Antennas
Michel Soiron (presented by Jean-Pierre Daniel)
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A large number of antenna function are required on future fighter aircraft, but the number of favourable locations is very limited. The CNI (GPS, MIDS, TACAN and IFF) functions are combined into a single L-band multi-function conformal array. A new tile technology provides high density integration, lower thickness (40mm) and lower EM signature. A C-to-X band array operates over 6-9/12 GHz.
On the pattern control of an annular slot antenna operating in its 'DC' mode
PR Urwin-Wright, GS Hilton, IJ Craddock and PN Fletcher
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Electrically-small antennas are well-known as being narrow-band structures. The addition of a tuning network not only allows these structures to work well across a wide band, but provides a degree of stability over the element's radiation pattern and polarisation. In this paper the radiation characteristics of an electrically-small annular slot operating in its 'DC' mode as a function of frequency are presented. It is shown that over the tuning range of the slot these radiation patterns remain relatively constant. Consideration is also given to the gain and efficiency variations of the slot over this range too.
Measurements of effective, apparent and actual diversity gain of two parallel dipoles close to a lossy cylinder in a reverberation chamber
Kent Rosengren and Per-Simon Kildal
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We use a reverberation chamber to measure diversity gain of two parallel dipoles close to a lossy cylinder at 900 MHz. We define an actual diversity gain as the diversity gain of the dipole pair by comparison with a single separate dipole in the same location and orientation. We observe a significant actual diversity gain of 6 dB for this case, when the dipoles are 2 cm from the lossy cylinder and two cm apart. This value is very inspiring for making use of diversity on small handheld terminals even at 900 MHz.
Foam and membrane technology for millimeter-wave antenna applications
Michel M Ney, Christian Person, Eddy Jehamy and Gabrielle Landrac
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With the increasing demand for multimedia services and therefore higher bit rate equipments, research activities are focused today on the development of millimeter waves modules. If MMICs are available up to 60 GHz, antennas remain external critical functions for which efforts still have to be produced concerning both technologies and design methodologies. This paper describes recent advancements in the design of original antennas where technological constraints as well as electrical conditions are considered for optimizing performances. Emerging technologies, entirely designed, built and tested at the LEST site, based upon foam waveguide or/and membrane configurations are presented. Hybrid structures are proposed for improving gain and/or bandwidth while controlling cost and reliability. Simulation and measurement results are shown and demonstrate the feasibility of the above-mentioned technologies for applications up to 76 GHz.
Brain storming activity
Antoine Roederer
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The Focus Area Organiser defines a number of problems that need your attention:
1. Simplified steerable pencil beam forming.
2. "Butler" type matrix for cylindrical array.
3. Identical 20/30 GHz feed horns for identical beam foot prints.
4. Multiple overlapping beam forming for radar.
5. Broadening the bandwidth and the potential of reflectarrays for low-cost single beam reconfiguration.
6. Switching or phasing? Advantages and limitations of MEMS for reconfigurable beams.
Microstrip reflectarrays as versatile solution for beam-scanning and multi-beam applications
G Amendola, G Angiulli, L Boccia, S Costanzo, G Di Massa, F Venneri
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Passive and active microstrip reflectarrays are investigated as versatile solution for beamscanning and multi-beam applications. A new approach based on a varactor loaded patch is proposed for dynamic reflectarray beam steering. A phase only synthesis algorithm is adopted to synthetize multi-beam reflectarray radiation patterns. Both experimental and simulated results are presented.
Phased array antenna terminals for satellite communications - Fixed and mobile applications
Mario Gachev
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The presented material describes the developments in SkyGate, connected with phased array antenna terminals, dedicated to the fixed and mobile applications. The terminals are designed to work in Ku band with DBS and/or FSS satellites over the continental territory of USA and Europe. Flat multi-layer technology, initial elements grouping and proprietary designed MMIC phase controlling devices with high stage of integration are used in order to reduce size, power consumption, complexity and cost, as well as to achieve low profile suitable for integration in the vehicle's roof. Recently developed antenna prototypes are tested in Europe and USA to work successfully on different mobile platforms such as cars, vans, buses, trains etc., receiving TV programs and Internet.
Low cost multi feed antenna for X-band SAR
R Zahn and C Heer
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Satellite synthetic aperture radar with multi-feed reflector antenna system.
Planar and conformal PBG antennas for multi-beam applications
K Mahdjoubi, H Boutayeb and AC Tarot
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This subject is composed of two parts : planar PBG structures and cylindrical ones. The cylindrical PBG structure is a completely new concept that is introduced by our laboratory to be used for beam steering and multi-beam applications. In the first part, the gain enhancement property of planar PBG antennas is revisited shortly in order to present the modeling methods developed for studying these structures. The investigations are then pushed further to highlight the frequency dependence property of the beam direction. Hence, some new possible applications are proposed for frequency beam scanning or multi-beam shaping. In the second part, we explain the problem that occurs for handling the cylindrical periodic structures. The planar modeling methods are then generalized to study these structures. One application will finally be presented.
PRESENTATIONS BY HUNGARIAN INSTITUTIONS AND PARTNERS
Left handed and photonic materials in electrodynamics
László Zombory
Head of Dept. of Broadband Infocommunication Systems, BUTE
Possibility of negative epsilon and mu. Both left and right handed materials. One and two-dimensional materials implemented about 10 GHz. Another 2D material with inductive rods and crossed microstrips with capacitive gaps. Nanowires at optical wavelengths? If materials exist, applications are high directivity antennas (Tayeb, Fresnel Institute, Marseille with plasma type material), high directivity couplers, travelling-wave antennas, cavity waveguide structures, wideband PGB patches...
Two issues to be solved are:
* detailed microscopic EM theory of LHMs, and
* composition of "tailored" metamaterials.
The radiation condition still applies. The analyses assume lossless materials.
Small loop antennas for RFICs
Ferenc Mernyei
Integration Associates
Integration Associates is a combined Ungarian/American company (Mountain View in Silicon Valley). Fab(rication)less semiconductor company. Fabrication and packaging are outsourced. The antenna should be cheap (printed on PCB), no tuning, no external components, low current consumption, and low supply voltage. See Website at www.integration.com.
Latest developments in antenna research
Bela T Ladanyi
Grante Rt
Glider production 1943-73. Parabolic antennas 1-40 GHz etc. Hot standby of GSM basestation antennas with (Tanaka type) ridged waveguide coupler with TE10, TE20 and TE30 modes. FEM solution with support from BUTE. Microwave windows in sandwich material for basestations in church tower windows etc.
Microstrip antenna R&D in Hungary
Ferenc Völgyi
Dept. of Broadband Infocommunication Systems, BUTE
Many rectangular microstrip antenna implementations for various applications. Introduces new antenna parameter "specific gain" defined as Gain / frequency2 / mass. Systems for microwave drying, specification of prices in supermarkets (back scattering), determining freshness of eggs (attenuation and back scattering), and determining moisture content of wooden boards (glue contents, holes), in bins of raw materials and in concrete. Calibration systems to same.
Application of advanced antenna systems in cellular networks - Capacity and coverage investigations in WCDMA systems
Joseph Barta and Bo Hagerman
Ericsson Research Budapest and Steckholm
Narrow beams towards user also suppressing interference. Downlink is the limiting factor in C/I scenarios. Multiple beams in up and downlink. Beam selection algorithm in uplink. Butler matrix on downlink. Mixed traffic scenarios 60% 12.2 kbps with 2% accepted quality speech users, 20% 64 kbps with 15 % accepted quality streaming users, and 20% 384 kbps 20% accepted quality best effort packet users. "Wrap around" includes interference from adjacent cells.
Optical feed for phased array antennas
Márk Csörnyei, Eszter Udvary, Tamás Bánki and Tibor Berceli
Dept. of Broadband Infocommunication Systems, BUTE
Generate modulated optical carrier by two lasers locked to each other by offset satebilization, two-mode laser (injection locked), or single-mode laser with (expensive) external modulator. New approach with more direct modulation of the laser requires more complex optical receiver extracting reference signal and information on subcarrier. The reference signal is transmitted from the transmitter. Rare-earth doped fibre amplifiers or semiconductor optical amplifiers amplifies in the optical domain.
GSM band direction finding system applying adaptive antenna principle
Gyula Mikó, Csaba Kalmár, Rudolf Seller, Victor Forkman
Dept. of Broadband Infocommunication Systems, BUTE
The Fourier (Bartlett) method with sinc functions has high sidelobe and broad signal with poor angular resolution, but is robust. The Capon minimum variance maximum entropy and the Music methods have better resolution. Overview of implemented system and measurements in 900 MHz GSM uplink band. Four omnidirectional I-Q receivers. Supported by Bonn Hungary Electronics. Bonn cooperates with ISRO, Korean companies and DLR.
Compact dual band GSM and GPS satellite antennas as stacked patches
Lajos Nagy
Dept. of Broadband Infocommunication Systems, BUTE.
Rectangular, triangular and U-shaped patch simulation results. GPS upper on upper layer and inner and outer patch for GSM 900 and 1800 MHz bands. Two unequal arms to obtain two resonant modes. Future plans are to measure and redesign for smaller size.
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