WIDEBAND MICROWAVE IMAGING ANTENNA SYSTEM OPTIMIZATION FOR INDUSTRIAL AND MEDICAL APPLICATIONS

IM-Antenna DIT-PRJ-09-017

Status NOT active project
DISI role Coordinator
Project type Education and Mobility Project
Dimension International
Acquisition date 2009-02-19
Start date 2009-02-19
End date 2011-02-18

Project details

Project astract Microwave imaging systems can play a crucial role in several diagnostic applications ranging from medical imaging to the characterization of materials in nondestructive testing or in the detection of buried objects. Microwave frequencies can penetrate materials and the electrical properties can be extracted, providing a powerful imaging tool. Two basic set ups are implemented in those systems, depending if they operate in transmission or reflection modes. In the first case, a set of antennas radiate a wave that is propagated across the object and collected on the other side by a set of receiving antennas, as it happens in many tomographic systems. In the second case, both sets of antennas are placed on the same side of the object and the receiving antennas collect the reflected waves. This is the usual constraint in subsurface prospecting. In both cases, frequencies down to a few hundreds of megahertz can be used to enhance penetration thus posing a serious challenge for the antenna designers. Low profile, compact size and light weight antennas are required, plus unidirectional radiation patterns. The most demanding requirement is to assure that the antennas are focused on the object and the receiver is not blurred by the surface reflection and collects the largest possible amount of energy scattered by the object. As a result the design of a suitable microwave imaging antenna system requires different levels of optimization, from the synthesis of the basic antenna element to the spacing and weighting of the array composed by the antenna elements. The measurement set up has to be also optimized in order to correctly exploit the antenna properties. As a matter of fact, dealing with the basic baseline configuration composed by two side by side antennas (i.e., one transmitting and the other receiving) strong coupling will mask the scattered fields whether the antennas are placed too close. On the other hand, the received fields will be very weak or signal multipath will impair reception if too far apart. As a consequence, the scientific objective of the research project is the synthesis of an effective antenna for a wideband microwave imaging system.<br/>
Keywords Microwave Imaging, Antenna Optimization
Fundings 0 €
Partners
  • DIT - UniTN
  • Universitat Politecnica de Catalunya

DISI Sub-project details

Project astract The proposed research activity will consist of 5 Work Packages (WP), each one being characterized by different tasks. In the following, the description of the activities and the aims of each WP will briefly resumed:<br/><br/>WP1 - Imaging Antenna System Specifications.<br/>In the first stage of the project, the properties/features of an antenna system used in an imaging system will be analyzed. Antenna systems for both medical and industrial applications will be considered by analyzing the state-of-the-art solutions. At the end of WP1, the requirements of the imaging antenna system will be carefully described in terms of input impedance, frequency band of operations, and uniformity of the field distribution radiated by the antennas in the presence of the body or material to be illuminated by the system (that is usually in the near field of the antenna system).<br/><br/>WP2 - Imaging Antenna System Architecture<br/>In any practical microwave imaging system, the most demanding task is concerned with the pattern focusing on the object and the need that the receiver collects the largest possible amount of energy scattered by the object. This requires different levels of optimization of the antenna system, starting from the single antenna element up to the array arrangement of the radiators. Therefore, the design of the Imaging Antenna System will be subdivided in two different activities: (a) the synthesis of an efficient wideband radiator and (b) the optimization of the array structure. Towards this end, this WP is aimed at defining the guidelines and constraints of each sub-system (a)-(b) as well as at selecting the more suitable and promising optimization procedure to be used in the following.<br/><br/>WP3 - Synthesis of the antenna elements<br/>Starting from the consideration that patch antennas are good candidates, the element design will be aimed at properly facing with the need of the antenna system to operate over very large bandwidths. Towards this end, suitable techniques and optimization methods to broaden the patch bandwidth will be studied and applied.<br/><br/>WP4 - Synthesis of the wideband array structure<br/>Although the synthesis of wideband array is a topic of great interest, nevertheless detailed analyses of the performance of wideband arrays as well as careful studies on their practical implementation are still required to properly deal with imaging modalities. Therefore, a customized optimization strategy for wideband array synthesis will be developed taking into account the radiation properties of the array elements.<br/><br/>WP5 - System Integration and Testing<br/>The solutions obtained in WP3 and WP4 will be integrated to obtain the Microwave Antenna System. The reliability of the antenna system will be assessed through simulations and preliminary experimental measurements. In particular, simulations and measurements of prototypes will be carried out to analyze and practically verify the existence or not of the bandwidth enhancement in antenna patches with metamaterials.<br/><br/>
Keywords Microwave Imaging, Antenna Optimization
Fundings 8860 €
Manager Andrea Massa
Participating RP