A new in vitro exposure device for the mobile frequency of 900 MHz

A wire patch cell has been designed for exposing cell cultures during in vi tro experiments studying possible effects of mobile radio telephone. It is based on the wire patch antenna which works at 900 MHz with a highly homoge neous field inside the antenna cavity. The designed cell structure is symme tric and provides a rather homogeneous field distribution in a large area a round its centre. Moreover, the exposure cell can irradiate equally up to e ight 35 mm Petri dishes at the same time, which enhances the statistical bi ological studies. To improve the specific absorption rate (SAR) homogeneity inside each sample, each dish is placed into another 50 mm dish. This way, SAR inhomogeneity is always proper for biological studies (below 30%). The main advantage of this new device is that it can provide SAR levels 20 tim es higher than those induced by classical Crawford transverse electromagnet ic (TEM) cell. Moreover, this small open device is easy to construct and fi ts into an incubator. However, to be used for in vitro, the wire patch cell is a radiating element with the same radiating pattern as a dipole, and th us some absorbing materials are necessary around the system when used for i n vitro experiments. Secondly, because of its narrow bandwidth, it is diffi cult to maintain its working frequency. To overcome this problem, a matchin g device is integrated into the test cell. In this paper, we present a dera iled explanation of the cell behavior and dosimetric assessments for eight 35 mm Petri dishes exposed. Simulations using the Finite Difference Time Do main technique and experimental investigations have been carried out to des ign the cell at 900 MHz. The numerical dosimetry was validated by dosimetri c measurements. These investigations estimated the dosimetric precision at 11%. (C) 2000 Wiley-Liss, Inc.