Wireless telemetry electronic circuit board for high temperature environments
View Patent ↗A circuit assembly ( 34 ) resistant to high-temperature and high g centrifugal force is disclosed. A printed circuit board ( 42 ) is first fabricated from alumina and has conductive traces of said circuit formed thereon by the use of a thick film gold paste. Active and passive components of the circuit assembly are attached to the printed circuit board by means of gold powder diffused under high temperature. Gold wire is used for bonding between the circuit traces and the active components in order to complete the circuit assembly ( 34 ). Also, a method for manufacturing a circuit assembly resistant to elevated temperature is disclosed.
1. In a combustion turbine engine, a circuit assembly for receiving sensed information about the condition of a turbine blade in the turbine engine and for transmitting said sensed information to a receiver external to said turbine engine, said circuit assembly comprising:
a printed circuit board affixed to the turbine blade and comprising an alumina substrate and having conductive traces formed of a thick film gold paste deposited thereon;
active and passive components of said circuit assembly being attached to said printed circuit board by means of gold, wherein at least one of said passive components comprises a metal wire air core conductor affixed to said circuit traces of said printed circuit board for forming an inductive element of said circuit assembly; and,
gold wire bonding between said circuit traces and said active components in order to complete said circuit assembly, said gold wire bonding having a longitudinal axis being oriented parallel to a longitudinal axis of the turbine blade;
where said metal wire air core conductor comprises a coil of gold or silver wire covered along its length in an alumina-based potting material and exhibiting a quality factor Q of at least 5 at an operating temperature of the engine and an operating frequency of the circuit assembly.