To produce realistic scattered fields of a honeybee

To produce realistic scattered fields of a honeybee, it is required to develop an organismal honeybee model that includes as much detail as possible. The three main parts of a honeybee are the head, thorax, and the abdomen with fine details such as six legs, a pair of antenna, compound eyes, and wings were obtained from SolidWorks 3D Computer Aided Design (CAD) software 37 and imported into electromagnetic software FEKO, as shown in Figure 3.6, for RCS calculation and analysis. The backscattering cross sections are calculated for both the horizontal and vertical polarizations. The horizontal cross section refers to the electric field of the calculating scattering radiation orientated parallel to the model of the honeybee body whereas the vertical cross section refers to the electric field orientated perpendicular to the model of the honeybee body, as illustrated in Figure 3.7.
For comparison, another simplified model was defined as sphere which has a size to be comparable with that of the honeybee volume. In general, the volume of the honeybee is in the range of 100-150 ?mm?^3 and was measured using the liquid displacement method in a graduated cylinder, which is described in chapter 2. The sphere of fixed radius R=3 mm, representing volume of the honeybee was modeled in FEKO software for backscattering cross sections calculation.
Our goal is to develop a model that matches RCS signatures of the alive honeybee. After defining the geometric structure of the honeybee, the complex relative permittivity that obtained by dielectric properties measurements in chapter 2 was used. These permittivity measurements are discussed into more detail in chapter 2. The complex relative permittivity of ?=10.81-j2.49 with a loss tangent of tan?= 0.23 were assigned to the entire body parts of the modeled honeybee. To avoid creating internal boundaries and complexity to the model, the wings are modelled as 1-nm thin dielectric sheet (TDS) with the same permittivity as the rest of the body parts
The honeybee model time requirement and computational complexity for the backscattering cross sections calculations depends directly on the calculated number coefficients of MoM solution. The total number of these coefficients can be obtained through the structure elements of the model and its electric properties. To reduce the number of unknowns by almost half, the option of symmetry was employed which results in reduction of computations complexity. Therefore, the result of solving for these unknowns will be considered as the solution of the induced currents across the surface of the honeybees. Consequently, this solution can also be used to solve for the complex scattering matrix, and therefore RCS, using Maxwell’s equations.