A study in three-dimensional micromachined on-chip inductors and their potential applications in a micro RFID system

The rapid development in modern day's wireless communication has created greater demand for narrower communication bandwidth with high quality signals at higher frequency. High quality miniaturized inductive components for building high quality filter circuits is critical for achieving this goal. However, active solid-state devices used for frequency filtering, tuning and switching applications either experience lower performance due to relatively high noise-to-signal ratio or see limited use because of high manufacturing costs.; As an alternative solution to these problems, micro-machined passive on-chip inductors have been proposed as a candidate for different high frequency applications at lower cost while maintaining a satisfactory performance. In this dissertation, three dimensional (3D) micro inductors in both solenoid and toroidal configurations have been designed, developed and studied. Their high frequency characteristics have been systematically studied according to their geometries in an effort to gain a clear understanding about the impact of different geometrical factors. Based on this knowledge, better RF performance could be achieved in the future based on an optimally designed inductor.; Radio frequency identification (RFID) technology is being deployed more and more in people's everyday life. In a proposal to build a tiny RFID transponder for potential implantable sensor applications, a high quality micro inductor would be essential for conducting the communication between the implanted device and the external reader. Another objective of this research was to investigate the feasibility to combine a micro fabricated inductor and a micro chip in building a micro wireless sensor for such applications. This dissertation has analyzed this proposal through theoretical calculations, computer simulations, as well as a live demonstration of a larger prototype in millimeter scale. Although remaining challenges are still going to be difficult to overcome, the progress made so far has shown a promising trend in realizing such a device within less than the given dimension of 1mm3.