System and method for making an antenna. An implantable medical device has a housing, a bobbin and a coil. The housing has an interior generally tubular cross-section with a longitudinal axis, the housing having a lateral portion of a segment of the tubular cross-section along the longitudinal axis. The bobbin has a first side nearest to the interior of the housing and a second side opposite the first side. The coil, wound around the bobbin on a winding axis orthogonal to the longitudinal axis of the tubular cross-section, has a greater number of complete turns proximate the second side of the bobbin than proximate the first side of the bobbin, with the coil having a cross-sectional shape selected for a space between the bobbin and the interior of the housing in the lateral portion of the segment of the tubular cross-section along the longitudinal axis of the housing.