The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
An L-band circularly polarized antenna is designed using genetic algorithms. The design has an impedance bandwidth of 12.5% at 1.6 GHz with a remarkably constant 4.2 dBi gain. Further, it is very thin (<lambda/40) and is less than lambda/3timeslambda/3 in aperture.
In this paper, we present an antenna design which can be integrated near the rail and which is sufficiently rugged to withstand weather conditions and rail stresses without appreciable changes in its operational mode. The proposed concept is based on fabricating a metal package mounted to the side of the rail. This metal block serves the purpose of housing the transceiver as well as the antenna. The...
Through-wall radar imaging has received much attention recently for discerning objects inside of a building. Most conventional imaging approaches are based on Fourier spectral transforms and/or far-field approximations, such as inverse synthetic aperture radar (ISAR) and tomographic imaging. These methods assume a simple point-scattering model. On the other hand, model-based imaging is a more general...
Electromagnetic band-gap (EBG) structures have been used to realize highly directive antennas either by using them as substrates and utilizing defect resonances or as a host medium when operating near band edge frequencies. As an alternative, it was recently proposed that degenerate band edge (DBE) crystals can achieve the required resonances using fewer number of unit cells, resulting in low profile...
There is significant interest in developing small ultra wide band (UWB) antennas that operate from 20 MHz up to several GHz. Often, numerous antennas are used to cover such a large frequency range leading to issues such as space limitations, payload and electromagnetic interference (EMI). Moreover, antennas used at lower frequencies tend to be large and protruding making them unsuited for many applications...
Large amounts of worldwide unlicensed spectrum at 60 GHz may provide solutions for future short range very high speed wireless solutions. Based on our previous work, we have established antenna targets of 16 dB gain in an area of less than 25x25 mm2 while allowing for a large number of silicon amplifiers to be combined to achieve system performance.
Given the importance of materials in antenna design, this special session brings together several material scientists to address issues of material fabrication, their properties and their significance. The session addresses the properties and applications of various materials for antenna and microwave applications. Examples of the materials to be discussed in this session are: polymers, liquid crystal...
The need for pliable, multifunctional RF circuits has resulted in the search for low-cost, convenient and flexible techniques, such as soft lithography, where a patterned metal design is printed on a desired polymer substrate. Hence, we present a low-cost and effective method for the formation of micro-patterns on a pliable, low-dielectric constant polymer-ceramic composite substrate for manufacturing...
To successfully reduce the size of UWB antennas requires a good understanding of radiation mechanisms, impedance behaviour, acceptable trade-off between gain and bandwidth and effective methods to reduce phase near-field velocity. The fact that theoretical limitation of a small antenna is determined by the antenna's size in terms of free-space wavelength regardless of the geometry or composition the...
In this paper, we present a wearable antenna design and process using genetic algorithm (GA) optimization. The antenna platform conforms to a human shoulder and all optimization calculations are performed in the presence of the human body. The optimization focuses mostly on the vertically polarized gain pattern (in the azimuth plane) and on matching. The required operational frequency is in the range...
In this paper, hybrid S-matrix approach is demonstrated for relatively complex EMI/EMC problems involving cavity-cable-PCB interactions. The purpose of these simulations is to validate the hybrid S-matrix formulation for EMI illuminations other than plane waves. Consequently, the PCB and cables are placed inside a resonant cavity, thereby exposing system ports to the cavity fields. As demonstrated...
A broadband planar dipole (flare dipole), radiating from 250 to 1000MHz range (Gain>0 dBi), is optimized by altering its shape and applying multistage L-C circuit optimization at its feeding port. After optimization the flare dipole performance is aimed to shift to 150 MHz (a 70% reduction in electrical size). Of particular interest is that this is done without use of materials.
We demonstrated that existing wall models for brick walls are not accurate at high frequencies, particularly for relatively new wireless services. Herewith, we proposed a semi-analytical model to numerically extract equivalent tensors for brick walls that remain valid at higher frequencies (beyond 1GHz). More details and results on our proposed model will be presented at the conference.
A single-fed CP stacked patch antenna is proposed to cover all the GPS bands, including E5a/E5b for the Galileo system. The small aperture size (lambda/8 at the L5 band) and the single feeding property make this antenna a promising element for small GPS arrays. The design procedures and antenna performances are presented, and issues related to coupling between array elements are discussed.
We proposed a novel approach for designing small microstrip antennas by taking advantage of the DBE unit cells printed on a uniform substrate. The remarkably small antenna with very high gain are key features not realized before. Although the antenna design given here has a small bandwidth of 1%, we believe that further investigations on the geometry, feeding type and locations will alleviate some...
Engineered materials, such as new composites, electromagnetic bandgap, and periodic structures have attracted considerable interest in recent years due to their remarkable and unique electromagnetic properties. Among this class of media are the magnetic photonic (MPC) and degenerate band edge (DBE) crystals. These periodic media have the concurrent characteristics of wave slow down and impedance matching...
Engineered materials, such as new composites, electromagnetic bandgap, and periodic structures have attracted considerable interest in recent years due to their remarkable and unique electromagnetic properties. Among this class of media are the magnetic photonic (MPC) and degenerate band edge (DBE) crystals. These periodic media have the concurrent characteristics of wave slow down and impedance matching...
Engineered materials, such as new composites, electromagnetic bandgap, and periodic structures have attracted considerable interest in recent years due to their remarkable and unique electromagnetic properties. Among this class of media are the magnetic photonic and degenerate bandgap crystals. These periodic media have the concurrent characteristics of wave slow-down and impedance matching at their...
A current decomposition method is proposed for the analysis of field coupling to mass wires near complex structures. The foremost attribute of the method is the decomposition of the current on each wire into push-pull and push-push mode currents. The former refers to the perturbation current accounting for the interactions among the wires within the bundle, whereas the latter represents the interactions...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.