04265252 is referenced by 127 patents and cites 11 patents.

An implantable transensor device containing a passive RF resonant circuit having a natural frequency influenced by the pressure of the sensor's environment in a body cavity of a living entity. The circuit of the transensor includes an inductor and a capacitor, at least one of which varies in value in direct relation to variation of environmental pressure to change the resonant frequency of the circuit. The circuit can be externally interrogated to determine the resonant frequency thereof at any point in time by the imposition thereon of swept frequency electromagnetic radiation provided by a monitoring device which determines when some of the radiation is absorbed as a result of the frequency of the radiation being the same as the resonant frequency of the transensor circuit. An imposed relationship exists between the sensed environmental pressure, and the reactance of the reactive components of the circuit. A natural relationship exists between pressure sensitive reactance, and the resonant frequency of the circuit. As a result, an increase in environmental pressure causes a corresponding increase in frequency and a decrease in environmental pressure causes a decrease in frequency.

Title
Intracranial pressure implant
Application Number
5/897716
Publication Number
4265252
Application Date
April 19, 1978
Publication Date
May 5, 1981
Inventor
James T Turner
Ellicott City
MD, US
John G Chubbuck
Silver Spring
MD, US
Agent
Samuel L Sachs
Robert E Archibald
Assignee
The Johns Hopkins University
MD, US
IPC
A61B 5/02
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