Characterization of a Tranceiving Antenna Concept for Microwave Heating and Thermometry of Superficial Tumors - Abstract

Abstract

A tranceiving printed circuit antenna concept, intended to be used for simultaneous heating and thermometry in hyperthermia therapy, is introduced and experimentally investigated in a liquid phantom. Two important questions have been addressed. First, optimum antenna design related to the depth-of-sensitivity and lateral beam width for microwave radiometry detection of subcutaneous objects. Second, optimum antenna design aimed at producing large area hyperthermia at superficial depth. Due to the nature of the problem, it is not possible to optimize one antenna configuration design to meet both these criteria. Instead an integrated dual antenna concept, consisting of one transmitting and one receiving antenna, is proposed. By means of a scanning electric field probe the radiated electric field distribution (E²) was measured for the concept in a homogeneous lossy medium. The measurements were further parameterized in terms of four performance indices defined in this work. A microstrip spiral antenna is shown to be appropriate for thermometry in the frequency range from 1400 MHz to 2400 MHz. For microwave heating we propose a microstrip coplanar grounded ring antenna. Analysis reveals that this antenna has the ability to produce effective radiation out to the periphery of the aperture. Due to the integration of both antennas onto thin and flexible printed circuit board substrate, the tranceiving device is both lightweight and conformable. From the analyses we conclude that the concept has the potential of being an effective building block of larger array systems, for noninvasive thermometry and cancer treatment of large superficial tissue regions.