The near-field millimeter-wave imaging can be used as a non-invasive tool for the early detection of skin cancer. Such a tool uses high frequency electromagnetic fields at mm-wave frequencies to detect differences in the phase and amplitude of the reflected signals from the skin. In the near-field approach, the fields do not radiate out from the probe but are restricted around its open end. In this paper, a tapered waveguide probe is designed and modeled at 30 GHz. Electromagnetic simulations are carried out to determine electric field behavior around the open end of the waveguide and to determine the variations in the reflection coefficient (magnitude and phase) when the probe faces healthy and diseased skin models. The obtained initial results confirm the potential of such a probe for skin cancer detection.