For customers with stringent environmental requirements, MEMtronics’ integrated filters exhibit excellent temperature stability. This stability is inherited from the almost temperature-independent physical characteristics of pure fused silica, used to construct the filter substrate. Building filters with traditional ceramic substrates, such as alumina or beryllium oxide, causes unusually dramatic frequency shifts over temperature (typically 50-200 ppm/°C). In MEMtronics’ filters built with high-purity fused silica, the filters exhibit a frequency stability of -6 ppm/°C to -9 ppm/°C, with a very linear (predictable) temperature profile over broad temperature ranges. This low drift over temperature ensures that MEMtronics filters are rock solid in even the most demanding environmental conditions.
To provide the maximum in mechanical stability, MEMtronics filters are fabricated from a single piece of gold-metallized, fused silica substrate. No attached external inductors, capacitors, or RF components are added. Construction using a single piece of glass ensures there are no modulation spurs in the transmitted signal when the filter experiences acceleration or vibration in harsh environments.