One of the main problem which threatening health in middle-aged women around the world is breast cancer. Not only a physical painfulness but also including her own family and victim relatives who suffering from this unavoidable pity fate. To detect those cancerous tumors as in an earlier stage as possible seem to be the best way to handle with this hazard. Besides from x-rays mammography and a conventional diagnostic ultrasound, microwave radiation tomography technique is a promising method to investigate any abnormality forming in her mammalian gland. In this paper, we propose a simulation of microwave radiation using a finite element method (FEM) of our modified imaging setup system for female breast cancer diagnosis. By using FEM, we propose a preliminary study of microwave breast cancer detection from a patch antenna propagation in 3D tissue space approaching. In term of wave penetration, voluminous 3D distribution geometry of electrical field in nonhomogenous simple breast phantom model was presented. These simulations not only show a promising result but also encourage us to develop a real imaging setup system in the near future.