Measurement of normalised radar cross‐section of polystyrene foam at 60 GHz

Abstract

The backscattering measurement of a rectangular solid volume of polystyrene foam (width: 0.92 m; height: 0.9 m; depth: 1.82 m) carried out at frequencies ranging from 59 to 60 GHz is described with horizontal polarisation for both transmission and reception antennas. The volume fraction of polystyrene in the measured material is about 0.01. The normalised radar cross-section of the measured polystyrene foam sample is estimated as 2.9 × 10 −3 ( ± 3 × 10 −4 ) m 2 /m 3 by using the rangeresolved data of the backscattered power arising from inside of the polystyrene foam volume. When using polystyrene foam as a support for radar targets in radar measurements, this result is considered useful for quantitatively estimating the intensity of the unwanted backscattered waves due to the foam.

Measurement of enhanced backscattering from randomly distributed conductive spheres with concentrically different number densities at 60 GHz

“…The scattering volume consists of conductive spheres of a diameter of 1 cm randomly embedded inside a cylindrical polystyrene foam volume of diameter 0.9 m and height 0.9 m, with concentrically different scatterer number densities. The polystyrene foam has a volume fraction value of about 0.01, and its index of refraction and co‐polarised normalised radar cross‐section are about 1.006–j0.00001 [4] and 2.9 × 10 −3 m 2 /m 3 , respectively [5]. The diameter of the inner cylindrical region is 0.64 m, and the number densities of the conductive spheres for the inner and outer cylindrical regions are 6462 and 3318 m −3 , respectively.…”

“…For the purpose of faithful comparison with the present experimental results, a small modification of the computer simulation technique was made in order to take into account the effects of the half mirror, polystyrene foam, the polarisation plane mismatch between the transmitting and receiving antennas, oxygen absorption and non-uniform effective propagation constants inside the scattering volume. In the computer simulation, the following measured input parameters were used: the complex refractive index of soda-lime glass [3], the complex refractive index and co-polarised normalised radar cross-section of polystyrene foam (the effect of cross-polarisation components can be ignored) [4,5] and the cross-polarisation discrimination value of 24.3 dB from the polarisation plane mismatch between the transmitting and receiving antennas. This made the computer simulation as faithful to the compared experiment as possible.…”