Development of an ion mobility spectrometer in low temperature CO-fired ceramic tape

The development of an ion mobility spectrometer (IMS) using Low Temperature Co-fired Ceramics (LTCC) to reduce sensor size while maintaining accuracy and sensitivity is presented. An IMS, an effective sensor for gas-phase pollutant (NO_x, O₃, SO₂, VOC, etc.) consists of a drift tube section with a constant electric field generated by a series of charged concentric rings. LTCC is a flexible glass-ceramic tape in the green state that is used to fabricate devices in a layered structure composed of different cross sections. The layered LTCC approach allows the rings that generate the electric field in the drift tube to be placed 0.2 mm apart while maintaining large voltage drops through the device. This close-packed ring structure creates a uniform electric field that reduces radial diffusion and maintains sensor sensitivity in a smaller package. The resulting embedded conductor and resistor patterns are effectively sealed in a hermetic ceramic package that is resistant to chemicals and moisture for reliable long-term permanent installation. These advantages in addition to the unique LTCC manufacturing process create a capable sensor device for real-world use. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).