Embodiments of the invention are directed toward a novel printed antenna that provides a low-loss transition into waveguide. The antenna is integrated with a heat spreader and the interconnection between the antenna and the output device (such as a power amplifier) is a simple conductive connection, such as (but not limited to), a wirebond. Integrating the antenna with the heat spreader in accordance with the concepts, circuits, and techniques described herein drastically shortens the distance from the output device to the waveguide, thus reducing losses and increasing bandwidth. The transition and technique described herein may be easily scaled for both higher and lower frequencies. Embodiments of the present apparatus also eliminate the complexity of the prior art circuit boards and transitions and enable the use of a wider range of substrates while greatly simplifying assembly.