Measuring the complex dielectric properties of forest fire ash at various temperatures

Little is currently known about the effects of microwave scattering on forest fires. A small number of published papers have illustrated significant return signals form large fires around the world. One of the possible sources is particulate scatter, however; little is known about their complex dielectric properties. The investigation of the complex dielectric properties from different Australian forest flora has been presented over a range of different combustion temperatures. The dielectric properties are an important step in characterizing radar scatter in order to solve an inverse scattering model. This builds on previously published work regarding the complex dielectric properties of five different flora samples over X-band frequencies. The approach to solve these complex dielectric properties is to use a Nicholson-Ross-Weir transmission/reflection method within a waveguide. The results take into account the effective volume fractions of the particles (solid/air ratio), as well as the dielectric variation caused by temperature.