Efficient Computational Tool for RF-Induced Thermal Response

ABSTRACT: RF transmitting devices are found nearly everywhere today, ranging from lower-power cell phones to radar equipment to high-energy weapons systems. Accidental exposure of humans to the RF radiation emanating from these devices can cause harmful thermal effects including tissue damage or death. Modeling these thermal effects across a whole population of humans is difficult and time consuming using today"s tools and can constitute a very expensive phase during the design of RF transmitting equipment. We will reduce this expense by introducing two new thermal modeling tools: a fast, parallel finite volume thermal solver, and an even faster tool that solves a reduced system, phenomenological model of the human body. The former tool will use GPU and multi-core CPU architectures when they are available, combining a traditional finite volume approach with a novel recursive method of estimating maximum temperature rises in human tissues. The latter tool will be coupled to the former tool, acting as an ultra-fast surrogate model whose various parameters can be easily changed. Combined, these tools will provide fast, high-resolution results when necessary, as well as the capability to run broad parameter studies that are similar in total computational cost to a single high-resolution result. BENEFIT: These new algorithms and tools will enable the RF device manufacturing community to rapidly assess the possibility of RF overexposure caused by new device designs. They will be used in guiding new hyperthermia treatments for malignant tumors. The tools will immediately give feedback to physicians about possible under or overexposure of target tissues as well as the surrounding tissues, making the treatments more effective and safer for the patient. Our tools will also be used for thermal comfort design by the HVAC and technical fabric communities. In this context, the tools will help the designers evaluate the effects of design decisions on not just one thermal manikin, but across a whole population of individuals having different metabolisms, sweating rates, fat contents, etc. The third community that will benefit from these next-generation thermal modeling tools is the cell phone industry. Our tools will help cell phone tower operators to design safer operating and maintenance procedures when RF exposure may be necessary for the job. The tools will also be useful for determining temperature distributions in humans when they are using a cell phone. In particular, the fast speed of the tools will finally make it easy for manufacturers to predict and correct for exposure levels during the design phase of new cell phones, long before the FCC certification process.