The lack of understanding of how airborne insects interact with radio waves, limits our ability to develop classification system for biological observations from radar data. There were several of experimental measurements effort to understand the interactions of aerial animals, i.e. insects, with radio waves 14-19. Although these interactions have produced a meaningful of radio waves scattering information, they often only report the measurements at select wavelengths, viewing angles, and polarizations. In addition, these measurements are also complex and expensive to build and operate, and they are typically lack of full azimuthal or elevation angles radio scattering data. To overcome radar entomology limitation in qualitative analysis and interpretation, developing a standardized technique for quantifying radio wave scattering at multiple wavelengths or polarizations and diverse viewing angles is needed. Indeed, this technique should have both analytical model associated with experimental studies validation.
In the early 20th century, extensive analytic studies describing electromagnetic radiation interactions with simple physical objects have proposed 20. However, adequate proposed solutions for objects with more complex shapes have not been approached. Recently, a several numerical approaches have been conducted to estimate the RCS values for different objects, but with only few numbers of researches on airborne species 21-23.
To determine the RCS of complex objects, such as insects, solving Maxwell’s equations in their general form are required. However, this task is not simply possible in analytic form for non-basic geometric shapes. To overcome this issue, a numerical solution of some variation of Maxwell’s equations is needed in either integral or differential form. Generally, computational electromagnetics method (CEM) techniques have been developed and implemented to solve different kinds of similar problems 26. A block diagram of these methods is illustrated in Figure 3.1.
