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Distinguished IEEE Lecturers

Distinguished Lecturers of the AP-Society
Monday 12th April
Hall 133,134            14:30



 

 

Reconfigurable Multifunctional Antennas
Christos Christodoulou, University of New Mexico

The requirements for increased functionality, such as direction finding, radar, control and command, within a confined volume, place a greater burden on today's transmitting and receiving systems. A solution to this problem is the reconfigurable antenna. Antennas that can be used for multiple purposes, that function over several frequency bands, and that can be integrated in a package for mass production are the ultimate goals of commercial and defense investigators. Furthermore, applications of such systems in personal and satellite communications impose the requirement for elements miniaturized in size and weight.
Key elements to obtain reconfigurability in many RF circuits are the radio-frequency micro-electromechanical systems (RFMEMS). Even though RF-MEMS have been used in the past to reconfigure filters, phase-shifters, capacitors, and inductors, their integration in an antenna system has been limited, as it faces a plethora of issues that need to be resolved. The absence of reconfigurable RF-MEMS antenna systems and the recent advances in fractal - and, especially, Sierpinski-gasket antennas – combined with the availability of series cantilever RF-MEMS switches, sparked the pioneering idea to design a multiple-frequency antenna that will radiate, on demand, the same radiation pattern at various frequencies. Such a system was designed and successfully implemented, as the first functional, fully integrated RF-MEMS reconfigurable self-similar antenna.
In this talk, several reconfigurable antennas are presented and discussed. The antennas to be presented cover a wide range of designs, such as fractal antennas, triangular antennas, dipoles, and monopoles with variable sleeves. All of these antennas make use of MEMS switches to make them reconfigurable. Some of the challenges that the designer has to face in biasing and integrating these switches with the antenna are also presented and discussed.

 

Hall 133,134 16:40



 

 

Three Dimensional Propagation Modeling and Characteristics For High Speed Mobiles
Werner Wiesbeck University of Karlsruhe (TH), Germany

 

In existing wireless telecommunication systems a user can choose either a high data rate or a high mobility. For various applications it would be desirable to have both at the same time: the freedom to move with a very high velocity without loosing the high data rate. Systems based on Orthogonal Frequency Division Multiplexing (OFDM) seem to be suitable to satisfy these conditions. However, the high-speed aspect has to be considered more closely. High-speed links between receivers and transmitters cause varying Doppler-, delay- and angular spread, which may result in inter-carrier interference  (ICI) and inter-symbol interference (ISI). ICI and ISI are both a challenge and a limiting factor for a wireless communication system.
Applications for high-speed mobile stations are for example on planes, fast cars (C2C), high-speed trains and so on. Several scenarios are chosen for the simulations and partly verified by measurements. For cars these are urban and a high way scenarios (C2C, C2BS), for trains high speed tracks with buildings or forest environment are chosen.
For the wave propagation a 3D ray-tracing tool, based on the theory of geometrical optics (GO) and the Uniform Theory of Diffraction (UTD), is used. The model includes modified Fresnel reflection coefficients for the reflection and the diffraction based on the UTD.
The propagation channels are characterized by delay spread, Doppler spread and angular spread for different situations. These statistical parameters are compared to measurements. Dynamic simulations will be illustrated by movies. The traffic scenarios are real world with multiple lanes, line of sight and non line of sight.

 

Tuesday 13th April
Hall 133,134 14:30

The fascinating evolution of reflector antenna developments: Past, present and future
Yahya Rahmat-Samii, University of California Los Angeles (UCLA), USA

 

The dual roles of a reflector antenna are to confine the electromagnetic energy over a distributed aperture into a focal plane or to radiate the electromagnetic beam for communication or energy transfer. The main focus of this presentation is to discuss a good portion of the fascinating history of reflector antenna developments including past, present and future. Throughout history, reflector antennas have seen a wide range of applications. Broadly speaking among other antenna topologies reflectors provide the highest gain, widest bandwidth, and best angular resolutions at the lowest costs.  Typical reflector antenna configurations consist of conic sections, which include the parabola, ellipse, hyperbola and sphere, etc.  Recent Internet search yields about 6x105 web sites entries associated with the phrase “reflector antenna,” and over 105 images with the phrase “reflector antenna image.”  This author was so fascinated by the reflector antenna when he designed the IEEE Antennas and Propagation Logo he used a rendition of a reflector antenna in the logo artwork. Reflector antennas are key components in diverse applications, such as radio astronomy, communications, remote sensing, radar, weaponry and medical devices. Many books, book chapters and technical papers have been published on the subject of reflector antennas. Reflector antennas may be classified according to pattern type, reflector surface type, and feed type. Pencil-beam reflectors are perhaps the most popular ones and are commonly used in point-to-point microwave communications and telemetry. Recent generations of satellite reflectors have produced other popular types of pattern classifications: contour (shaped) beams and multiple beams. These applications require reflectors with improved off-axis beam characteristics, which require more sophisticated configurations. The presentation will start with a dramatic story of the use of parabolic reflectors in the ancient legend of Archimedes using them to focus the Sun’s heat to burn attacking Roman ships to modern giant spaceborne mesh and membrane reflector antennas for satellite communications, remote sensing and radio astronomy applications. Novel out-of-the-box concepts will also be highlighted.

 

Hall 133, 134 16:40


Microwave Antennas for Medical Applications
Koichi Ito, Chiba University, Japan

 

In recent years, various types of medical applications of antennas have widely been investigated and reported.  Typical recent applications are:
(1) Information transmission:
   - RFID (Radio Frequency Identification) / Wearable or Implantable monitor
   - Wireless telemedicine / Mobile health system
(2) Diagnosis:
   - MRI (Magnetic Resonance Imaging) / fMRI
   - Microwave CT (Computed Tomography) / Radiometry
(3) Treatment:
   - Thermal therapy (Hyperthermia, ablation, etc)
   - Microwave knife
In this presentation, three different types of antennas which have been studied in our laboratory are introduced.  Firstly, a pretty small antenna for an implantable monitoring system is presented.  A cavity slot antenna is a good candidate for such a system.  Some numerical and experimental characteristics of the antenna are demonstrated.  Secondly, some different antennas or “RF coils” for MRI systems are introduced.  In addition, SAR (specific absorption rate) distributions in the abdomen of a pregnant woman generated in a bird cage coil are illustrated.  Finally, after a brief overview of thermal therapy and microwave heating, coaxial-slot antennas and array applicators composed of several coaxial-slot antennas for minimally invasive microwave thermal therapies are introduced.  Then a few results of actual clinical trials by use of coaxial-slot antennas are demonstrated from a technical point of view.  Other therapeutic applications of the coaxial-slot antennas such as hyperthermic treatment for brain tumor and intracavitary hyperthermia for bile duct carcinoma are introduced.

Wednesday 14th April
Hall 133,134 14:30

Design of Miniaturized UWB Antennas
Zhi Ning Chen, Institute for Infocomm Research, Singapore

 

Ultra-wideband (UWB) has become the promising wireless technology in commercial applications such as next-generation short-range high-data-rate wireless communications, high resolution imaging, and high accuracy radar. The antenna is one of key designs in UWB wireless systems. This talk starts with a brief introduction of design challenges of UWB antennas, followed by state-of-the-art solutions. Then, the miniaturization technologies of UWB antennas are mainly addressed. The planar designs are highlighted due to their unique merits and wide adoption in practical applications. First, the newly developed technique to achieve the ground plane independent UWB antenna performance, one of the most challenging issues in small antenna design, is addressed. A design example is used to elaborate the mechanism of the method. Based on this concept, the antenna with further reduced size is designed to fit wireless USB dongles. Furthermore, an innovative compact diversity UWB antenna shows the advantage of ground-independence of small antenna in diversity applications. Last, the UWB antennas co-designed with filtering performance by using bandpass/bandstop filters integrated into the antenna is proposed to reduce the overall size of devices and enhance antenna performance. In the end, the trend of UWB antenna R&D is discussed according to applications and market demands. 

 

Hall 133, 134 16:40

Miniature antennas and Special Materials
John L. Volakis, Ohio State University, USA

We already print more transistors than letters per year [IEEE Spectrum, 2008; http://www.ieee.org/]. But to the average person, a more tangible technological impact has come from the proliferation of wireless devices that have changed our way of living, habits and business culture worldwide. Over the next decade, wireless devices and connectivity are likely to have even more transformational impact on our everyday life.  Key to the wireless revolution is the implementation of multi-functionality and broadband reception at high data rates. This was a neglected area for several years as the industry was focusing on compact low noise circuits, and low bit error modulation techniques. However, as noted in a recent RF & Microwaves Magazine (www. mwrf.com) article, nearly 50% of a system-on-chip is occupied by the Radio Frequency (RF) front-end. Not surprising, the need for small antennas and RF front ends without compromising performance has emerged as a key driver in marketing and realizing next generation devices.
The challenge in miniaturizing the RF front end was already highlighted by Harold Wheeler, a pioneer of small-size antennas. He noted that “… [Electrical Engineers] embraced the new field of wireless and radio, which became a fertile field for electronics and later the computer age. But antennas and propagation will always retain their identity, being immune to miniaturization or digitization.”  However, novel materials, either natural or synthetic
(metamaterials) f and a variety of synthesized anisotropic media are changing the status-quo. Also, materials such as
modified polymers (friendly to copper) for silicon chip integration, high conductivity carbon nanofibers and nano-tubes, all coupled in 3D packaging are providing a new integration paradigm attractive to the IC industry. Certainly, low loss magnetics, such as multiferroics or synthetic structures emulating magnetic structures, when and if realized, will provide one of the most transformational design impacts in the wireless industry.
This presentation will provide an overview of the upcoming wireless applications and challenges. We will then discuss efforts towards the realization of novel materials (metamaterials and crystals, carbon nano-tubes, carbon nano-fibers, body worn devices, printing on polymers, multiferroics, etc) for RF miniaturization, including antennas that reach the optimum size limits.

 

Thursday 15th April
Hall 122,123 14:30


 

Some Design Requirements of Smart Antenna Systems

CANCELLED

 

Hall 133,134 14:30

Terahertz Technology for Space and Earth Applications or EBG's
Peter de Maagt, European Space Agency, The Netherlands

 

The terahertz (THz) part of the electromagnetic spectrum falls between the lower-frequency millimeter-wave region and, at higher frequencies, the far-infrared region. The frequency range extends from 0.1 THz to 10 THz, where both of these limits are rather loose. As the THz region separates the more-established domains of microwaves and optics, a typical THz technique will incorporate aspects of both realms, and may even draw on the best of both. The two bounding parts of the spectrum also yield distinct sets of methods for generating and detecting THz waves.

These approaches can thus be categorized as having either microwave or optical/photonic origins. As a result of breakthroughs in technology, the THz region is finally finding applications outside of its traditional heartlands of remote sensing and radio astronomy. Extensive research has identified many attractive uses, and has paved the technological path towards flexible and accessible THz systems . Examples of novel applications include medical and dental imaging, gene theory, communications, and detecting the DNA sequences of virus and bacteria. The presentation will discuss the range of THz applications, and will present the components and systems that are utilized for the frequency region.

 

Hall 133, 134 16:40

Challenges in practical design of planar arrays
Marta Martinez, IMST, Germany

 

The development of new multimedia services is progressing at a rapid pace, and requires the use of agile antenna frontends that are also compact, highly efficient and cost-effective. These antennas are rarely off-the-shelf solutions. On the contrary, custom-tailored solutions are usually preferred, in order to optimise the performance, and facilitate their integration into the final product.
In many applications, the best compromise for an antenna solution with respect to cost, performance and often also size is the use of a planar array. Real-life communications systems require planar arrays with different degrees of complexity. Designs can vary from small structures with only a limited number of transmitters and/or receivers to large arrays with hundreds of receive and/or transmit channels. A skilful symbiosis of industrial development and innovative research projects is the key to provide extremely efficient solutions.
Considerable experience is required in the design and realisation of planar antenna arrays at microwave frequencies, especially if relatively large bandwidths are needed. It is not only necessary to develop innovative concepts beyond the standard patch arrays, but it becomes unavoidable to cope with material and manufacturing tolerances when realising the antennas using soft and hard substrates. Special care has also to be invested in the RF-feeding network and the transition between antenna and RF-circuitry, as the latter can become a bottleneck at high frequencies, hence limiting the available bandwidth.
In order to provide cutting-edge solutions, it is important not only to develop systems based on state-of-the art antenna concepts. Fast and highly accurate EM solvers are indispensable tools to simulate the whole antenna system. Access to prototyping tools and accurate measurement facilities are also desirable. The integration of all these services helps reduce the number of iterations to obtain high-performance antennas, thus leading to a shorter development time. A complete industrial solution for complex planar arrays must cover the whole development chain, starting with the conceptual design and the development of new solutions, going through the prototyping and optimisation process, including antenna characterisation and diagnosis, up to the preparation of line production and qualification phase.
The range of applications of planar arrays considered here include agile RF-frontends for mobile satellite terminals, radar systems for automotive, sensor and security applications and millimetre wave point-to-point or point-to-multipoint radio links for multimedia wireless networks.
This paper presents an overview of the main challenges encountered during the design of planar arrays for practical applications. The whole design process, including technology aspects, EM-simulation of complex front-ends, advanced prototyping and accurate measurements, will be presented, and illustrated with real life examples.

 


 






 
 
 

Organised by:

Organised By

Supported by:

Supported by

Important Deadlines:


Abstract submission
30th September 2009

Notification of acceptance
30th November 2009

Submission of final papers
30th January 2010

Exhibitor registration
15th February 2010



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