Pressure sensing unit, system and method for remote pressure sensing

A pressure sensing method, comprising:

• using an excitation coil arrangement to wirelessly excite a pressure sensing unit into a resonant oscillation, wherein the pressure sensing unit is implanted into a human subject and comprises:
• a structure defining a dosed cavity, wherein the structure comprises at least one membrane forming an outer wall portion of the dosed cavity;
• a first permanent magnet inside the dosed cavity and coupled to the at least one membrane;
• a second permanent magnet inside the dosed cavity, wherein the second permanent magnet is coupled to the structure by a fixed coupling, wherein the fixed coupling prevents rotational movement of the second permanent magnet with respect to the structure, and wherein the first permanent magnet is coupled to the membrane by an elongate structure, wherein the elongate structure allows rotational movement of the first permanent magnet with respect to the structure, wherein at least a part of magnetic moment between the first and second permanent magnets is oriented perpendicular to a rotation axis of the first permanent magnet, wherein the first permanent magnet is excited into the resonant oscillation;
• measure a magnetic field which is altered by the resonant oscillation;
• and
• determine a pressure from the frequency of alteration of the measured magnetic field.