Implantable infusion pump with level measurement

A compact implantable infusion pump comprising:

• a) a housing having a base plate and a propellant chamber disposed below the base plate, the base plate including a top and bottom surface and a depression formed in the base plate bottom surface,
• b) a bellow mechanism positioned within the housing propellant chamber underneath the housing base plate, the bellow mechanism having a base member and an internal volume, the base member having a bottom surface, the bellow mechanism internal volume receiving a medicament for delivery into a patient's body,
• c) a constriction section communicating with the bellow mechanism internal volume and a catheter disposed within the patient's body for transferring the medicament into the patient's body from the bellow mechanism internal volume through the catheter and into the patient's body,
• d) an electrical conductive coating disposed along the bellow mechanism base member bottom surface,
• e) a material cover disposed upon the housing base plate bottom surface, the material cover transparent to electromagnetic energy, and
• f) a resonant circuit including an inductance and a capacitance, a resonant frequency determined by a distance measured between the bellow mechanism base member and the housing base plate and a flat coil disposed within the depression.