The Microelectromagnetic Devices Group studies the electromagnetic behavior of structures fabricated using integrated circuit processing techniques. For instance, understanding high-speed digital signal propagation between integrated circuits, IC packages, and high-performance printed wiring boards requires a background in solid-state devices, IC fabrication, and electromagnetics. Similarly, constructing new devices and circuits that operate at extremely high frequencies requires the same background. A major Microelectromagnetic Devices Group objective joins these diverse areas to explore high-speed and high-frequency circuit and device behavior, through both models and experiment.
An exciting new area of research involves the development of new sensors using microfabrication techniques. In some cases these sensors are analogs of natural senses; for instance, we are working on an "electronic tongue" for use in new chemical and biological agent sensors. Another area of research is the study of how biological entities detect infrared radiation, and the application of this knowledge to engineered IR detectors (such as microbolometers). We are also investigating the use of simple, low cost wireless sensors for "structural health monitoring" to identifying material degradation in large civil structures (bridges and buildings) before actual failure of the structure. This work is all generally related to the fabrication and design of new micro-sensors and actuators using IC processing and silicon micromachining (mems). These sensors include optically interrogated pressure sensors using micromachined Fabry-Perot cavities, and microminiature inductive proximity sensors. We have also investigated the application of MEMS technology in such novel environments as mechanical bearings and fluid seals.
Another major emphasis of our group has been the development of models of lossy transmission lines and interconnects. We are particularly interested in the impact of finite metal conductivity on interconnect characteristics, as well as the effect of substrate conductivity (e.g., semiconductor substrates) on signal propagation. Our models focus on the prediction of inductive and resistive effects, from dc resistance and internal inductance to skin-depth and proximity effect-dominated behavior, in both the frequency and time domains. We have done a variety of studies on planar inductors, including the effect of semiconductor substrate resistivity on inductor behavior.
Our group has done extensive work on monolithic microwave, millimeterwave, and far infrared devices, in particular on planar antennas, FIR detectors, microbolometers, high frequency resonant tunneling diodes, and coplanar waveguide phase shifters and delay lines.
Dr. Neikirk's group has also investigated devices based on quantum interference effects. His group developed several quantum transport models which were used to design heterostructure devices and, using the molecular beam epitaxial crystal growth technique, these devices were fabricated. These devices contained layers that are only a few atomic planes thick, causing very strong quantum interference. Originally these devices were investigated for use as high frequency oscillators, and were later studied for possible use as memory devices.