The nonlinear response of electromagnetically illuminated objects has been an area of interest for communication systems and remote sensing techniques. Previous work focused on generation of second and higher order harmonics under single frequency excitation for the effects on interference to communication systems. Limited analysis and experiments looked at multiple frequency excitations for utilization in remote sensing applications. The analyses modeled the nonlinear feature of the scattering object as a simple diode component under normal operating conditions. The analytical results were consistent with harmonic and intermodulation product techniques under assumptions utilized in the analyses. All of these studies and experiments were performed with excitation frequencies in the Megahertz (MHz) range and response frequencies that did not exceed 2 Gigahertz (GHz). Recent work with dual frequency illumination of scattering targets using W-Band millimeter wave frequencies has resulted in the observation of nonlinear responses that are not consistent with expected results using nonlinear analytical techniques. This dissertation examines the difference frequency response of a small scattering object under simultaneous illumination by differing millimeter wave frequency fields that are weakly driving the nonlinear element and acquires an analytical technique to describe the response of the scattered field.
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