The paper considers the further development of a nanophotonic supersensitive sensor proposed by the authors earlier. The sensor is oriented for a wide range of engineering applications. The main idea of the device is to estimate the external pressure loading of the sensor by the electromagnetic field measurements. The nanophotonic sensor structure is irradiated by the electromagnetic source operating in the frequency domain. The light beam is passing through the internal cone structure of the sensor, and the output electric field is measured. The proposed mathematical modeling gives the opportunity to connect the radius of the inclusion in the sensor longitudinal section and the out put electric field intensity in the reference measurement's point. A 3D simulation of high-frequency electromagnetic wave propagation in a photonic microsensor structure was performed in a formulation close to the real one in the following paper. The mathematical modeling is carried out by the vector finite element method implemented in the author's software. The conducted numerical research allows us to make design decisions about the optimal overall dimensions of the sensor and the operating frequency of the electromagnetic radiation source.