The present invention provides exemplary antenna coil assemblies and substrate processing chambers using such assemblies. In one embodiment, an antenna coil assembly (100) for a substrate processing chamber includes an antenna coil (102) disposed in a frame (104). The frame includes a plurality of spaced apart tabs (120) around a periphery of the frame, with the coil coupled to the frame at the tabbed locations. At least one notch (122) is provided between each pair of adjacent tabs. The notches are adapted to facilitate thermal expansion and contraction of the frame at the notched locations to reduce stresses on the frame and coil connections.