Fig. 1

Gastric Pacer System Design. A Wireless power transmitter (Tx) consisted of a 26 AWG copper wire, shaped into a planar circular coil 40 mm in diameter, a power supply, support circuitry with a power amplifier and tank circuit, and control circuitry to regulate pacing frequency, duration, and amplitude. B Wireless pacer consisted of a 30 AWG copper wire, folded into a semi-cylindrical power-receiving (Rx) coil 2.8 mm in diameter and 15 mm in length, a pair of platinum treated copper electrodes, and a support circuity with a tank circuit and AC-DC converter. For insulation against the conductive blood, the internal components were encapsulated by polydimethylsiloxane. The transmitter would ultimately take the form factor of an external belt to control the intravascular implanted gastric pacer on the stomach serosal wall