Simulation and measurement of a heatsink antenna: a dual-function structure

As the demand pushes for increasing chip densities, new mechanisms must be pursued in order to deal with problems such as heat dissipation. This is especially true for high-density three dimensional (3-D) packaging technology for RF devices. Though 3-D system-on-chip (SOC) technology shows promise for increasing chip densities, the heat generated by the RF transmitter's power amplifier poses a threat to the devices. This paper proposes and evaluates a new type of antenna: a heatsink antenna, which simultaneously operates as a radiator of electromagnetic and thermal energy. A patch antenna was used in this study to evaluate the effect of a heatsink structure, though the actual dimensions and antenna/chip structure will depend on the particular system design. Measurements and simulation show that the heatsink lowers the resonant frequency of a patch antenna by 6.8% and 9.7%, respectively. In addition, simulations show that a poor radiation efficiency of the patch antenna fabricated on FR4 PCB can be improved significantly by a heatsink structure. For the antenna in this study, the heatsink improved the radiation efficiency from 33% to 62%.