Two R18 hollow rectangular waveguides (131 mm x 65 mm x 425 mm) operating in TE10 mode were used with a removable short cut making them a resonating cavity. They were equipped with ventilation holes, a fan and several sensors. Data from all sensors (field strength, air temperature, fan driving current) were collected every 10 s in a data logger also controlling the GSM frame unit and the RF switch. The whole setup with dimensions of approx. 50 x 25 x 45 cm³ was placed in a CO2 incubator.
Six 35 mm Petri dishes fixed in two holders were placed in each waveguide, and in the H-field maxima being separated by 106 mm. The amplified RF signal was connected to one of the waveguide cavities by a computer-controlled switch enabling a double-blind study design.
The field was monitored by a monopole antenna, installed at the location of an E field maximum, and a Schottky diode detector. The validation of the FDTD simulations using the DASY3 near field scanner, the determination of the dielectric constants, the investigations for the temperature load during RF exposure, evaluation of SAR, and uncertainty analysis of SAR and the measurement results of the ambient electric fields are given in detail in the reference article.
Schuderer J et al.
High Peak SAR Exposure Unit With Tight Exposure and Environmental Control for In Vitro Experiments at 1800 MHz