A dual band antenna mounted to a case of an implantable medical device (IMD) for implant within a patient is provided. The dual band antenna includes a first antenna sub-structure (FAS) and a second antenna sub-structure (SAS) each separately tuned to match a corresponding first and second resonant frequency, by adjusting at least one of relative lengths of the FAS and SAS, a capacitance of the FAS, a location of the SAS relative to the FAS and a cross-sectional area of conducting elements forming the components of the antenna. The FAS is formed as an inverted E-shaped antenna having three branches. The first branch of the antenna is capacitive, a second branch provides a radio frequency signal feed and a third branch provides a shunt to ground. The SAS is formed as a mono-pole antenna that is formed integral with, and extends from, the FAS.
