Micromechanical System for System-on-Chip Connectivity
This Electronics Engineering Seminar Topic deals with the following:
MEMS technology has enabled us to realize advanced micro devices by using processes similar to VLSI technology. When MEMS devices are combined with other technologies new generation of innovative technology will b created. This will offer outstanding functionality. Such technologies will have wide scale applications in fields ranging from automotive, aerodynamics, hydrodynamics, bio-medical and so forth. The main challenge is to integrate all these potentially non-compatible technologies into a single working microsystem that will offer outstanding functionality.
The use of MEMS technology for permanent, semi permanent or temporary interconnection of non-compatible technologies like CMOS, BJT, GaAs, SiGe, and so forth into a System-on-Chip environment can be described using an example application. It is a hearing instrument in which an array of acoustical sensors is used to provide dynamic directional sensitivity that can minimize background noise and reverberation thereby increasing speech intelligibility for the user. The micro array can provide dynamically variable directional sensitivity by employing suitable beam forming and tracking algorithms while implanted completely inside the ear canal.
MEMS ACCOUSTICAL SENSOR ARRAY FOR A HEARING INSTRUMENT
In this application an array of capacitive type sensors are used in a hearing instrument to provide dynamic directional sensitivity and speaker tracking and can be completely implanted in the ear canal. The directional sensitivity is obtained by the method of beam forming. The microphone array is developed using MEMS technology and which can be used to form beam to provide directional sensitivity.
BEAM FORMING USING MICROPHONE ARRAY
The microphone array consists of nine capacitor type microphones arranged in a 3*3 array and utilizes the classical phased array technique for beam forming. In this technique, the relative delay or advance in signal reception is eliminated by applying a delay or advance is that the signal out puts from different microphones can be added to form a beam as shown in figure 1.
It is also possible to steer the direction of the beam by providing additional delay factor that is equal to the negative of the relative delay to the out put of each microphone in the array when a signal arrives from that direction. Figure 2. illustrates the beam steering concept.