Antenna Design for mm-Wave Polarimetric Imaging System

We present the design of an antenna and its feed usable in a millimeter wave polarimetric imaging system. The antenna is an off-axis parabolic reflector fed by a pyramidal horn with an orthomode transducer (OMT). OMT is used to separate the polarization of the reflected wave from the object into two orthogonal polarization vectors. Through full-wave simulations, we have shown that the object can be differentiated from the background in the cross-polarization response. It is shown that the resolution of such polarimetric imaging system can be different for cross- and co- polarized responses. Such system can be used to detect concealed objects under clothing in security applications where the reflection from the body itself is high at mm-wave range.