Ventral-aspect radar cross sections and polarization patterns of insects at X band and their relation to size and form
International Journal of Remote Sensing
Taylor & Francis for Remote Sensing and Photogrammetry Society
Reason for embargo
A data set of ventral-aspect insect radar cross-sections (RCSs) and polarization patterns, measured at X band (9.4 GHz, linear polarization) in laboratory rigs, has been collated from a number of sources. The data have been analysed to identify relationships between RCS parameters (one representing size and two the polarization-pattern shape) and the insects’ masses and morphological dimensions and forms. An improved mass-estimation relationship, with appropriate asymptotes for very small and very large insects, is presented. This relationship draws only on the RCS size parameter and it is shown that incorporating one or both of the RCS shape parameters provides little additional benefit. Small insects have polarization-pattern shapes that fall within a relatively limited region of the range of parameter values allowed by electromagnetic scattering theory. Larger insects have shapes that extend beyond this region, following a broad trajectory as size and mass increases; at masses above ~0.6 g, the pattern becomes ‘perpendicular’, with maxima when the E-field is orthogonal to the body axis rather than parallel to it. RCS shape can be used to infer morphological form for small insects (<80 mg), but not for larger ones. These results are consistent with observations from X-band vertical-beam entomological radars and provide a basis for identification, at least to broad taxon classes, of the targets detected by such radars.
JWC and KSL were supported by the Biotechnology and Biological Sciences Research Council (UK) under grant BBS/E/C/00005195 and the Science and Technology Facilities Council (UK) under Newton Fund grant ST/N006712/1.
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.
Vol. 38 (18), pp. 5022 - 5044