A pulse generator that includes a communications module is disclosed herein.The communication module includes atransceiver and an antenna circuit. The antenna circuit includes a firstpathway having a capacitor and a second, parallel pathwayincluding a capacitor, and a resistor, and a radiating element arranged inseries. The antenna circuit is tuned to have a resonantfrequency corresponding to a desired transmission frequency and a bandwidthcorresponding to shifts in the resonant frequency arisingfrom the implantation of the antenna circuit in a patient's body.
