A modular material antenna assembly is provided that includes an antenna block having a portion with a shape that interlocks with a corresponding portion of an electrically non-conductive frame and secures the antenna block to the electrically non-conductive frame. The electrically non-conductive frame is attached to an interior of an electrically conductive housing so that the electrically non-conductive frame and the electrically conductive housing form an integrated structure. An antenna flex is then mechanically secured to the antenna block. The antenna flex may also be electrically connected to a circuit board. The frame is designed to support a cover glass for the portable electronic device and may be affixed to a housing. The dielectric constant of the antenna block is substantially less than the dielectric constant of the frame.