  We propose to use an antenna composed of two orthogonal helices as a
low-scattering sensor. The vector effective length is derived for the antenna
using the small dipole approximation for the helices. The antenna can transmit
and receive circular polarization in all directions with the Huygens' pattern.
We observe that the antenna geometry does not backscatter, regardless of the
polarization, when the incidence direction is normal to the plane of the
helices. Scattered fields, scattered axial ratio, and the scattering cross
section are presented. We show that the zero-backscattering property holds also
for the antenna when it is capable to receive all the available power with
conjugate loading. The approximate analytical model is validated with full-wave
simulations.
