A Capacitive Pressure Sensor Based on Cofirable Ceramic/Glass Materials with LTCC Technology

Because of good thermal, electrical, and mechanical properties, low-temperature cofired ceramic (LTCC) has shown great potential in microelectronic applications. One of the most promising directions of LTCC technology development are integrating and packing sensors. In this article, a wireless passive capacitive pressure sensor operating in the MHz range based on cofiring of heterogeneous materials with LTCC technology is proposed, and the design, simulation, and fabrication of the sensor are demonstrated and discussed. It consists of a circular spiral inductor and a capacitor of two electrodes separated by a glass medium. Furthermore, a unique process of cofiring of heterogeneous materials was introduced to avoid deformation of the capacitive embedded cavity during lamination or sintering. The results show that the inductance of the inductor and the capacitance of the capacitor embedded in the sensor are .28 μH and 16.80 pF, respectively. The novel sensor has a sensitivity of approximately 847 Hz/MPa within the pressure range from atmospheric pressure to 100 MPa.