A booster antenna (BA) for a smart card comprises a card antenna (CA) component extending around a periphery of a card body (CB), a coupler coil (CC) component at a location for an antenna module (AM), and an extension antenna (EA) component contributing to the inductance of the booster antenna (BA). At least a portion of the coupler coil (CC) component may have a sense which is opposite to a sense of at least a portion of the card antenna (CA) component. At least a portion of one of the components may be interleaved with (i) a portion of another component, or (ii) another portion of the same component. A capacitive extension (CE) may extend from at least one of the card antenna (CA), coupler coil (CC) and extension antenna (EA) components.