  Low Temperature Cofired Ceramics (LTCC) has been a popular multi layer
ceramic (MCM) packaging material for many electronic applications. The main
advantage with LTCC would be its ability to embed a major part of the
electronic circuit within itself, apart from its enhanced RF functionality as
against many lossy materials used. The advantages of LTCC in terms of frequency
response, cost, ease of fabrication, etc over many other packaging materials
are presented. The applicability of LTCC as a packaging material, circuit
mounting material, substrate material or a base material for micro devices is
discussed. Switches and filters fabricated on LTCC as a substrate are presented
and their enhanced functionality is shown. Planar switches and RF MEMS switches
on LTCC are discussed with regard to their isolation, insertion losses, return
losses, repeatability, quality factor, parasitic effects and frequency
response. Concern is also shown to parameters like actuation voltages,
actuation times and complexity of fabrication. The parameters studied with
design and fabrication of filters is also discussed, like Q factor, dispersive
effects, limits on frequencies, etc. Discussion is also done with regard to
LTCC as a base material for MEMS sensors and actuators and the performance
variables of the same. Fabrication process parameters are presented. The
important issue of feasibility of integration with microelectronic integrated
circuitry is discussed and its effects are shown.
