Diamond-Enabled Electromagnetic-Thermal Co-Design for Mobile Terminals: Achieving Ultra-Small Antenna Clearance and Efficient Heat Dissipation Capability

The limited internal space of mobile terminals has led to a scarcity of research on electromagnetic-thermal co-design, as the co-design typically requires large-scale structures that don’t fit within compact devices. This communication, for the first time, incorporates diamond into electromagnetic-thermal co-design within mobile terminals, significantly enhancing both antenna and heat dissipation performance while achieving ultra-small antenna clearance. Three copper patches printed on low-loss diamond substrate constitute the radiative metasurface, which can produce abundant radiative modes and greatly broaden the impedance bandwidth of the frame monopole. Under a clearance of only 0.1 mm, the measured −6–dB bandwidth of the frame monopole is improved from 350 MHz to 770 MHz at 5.5 GHz with the addition of the copper-diamond composite material. More importantly, diamond achieves an exceptional heat dissipation effect due to its remarkable thermal conductivity of 2200 W/(m·K): the measured maximum temperature is 12.6 °C and 0.9 °C lower than traditional dissipation solutions using traditional substrate and graphene film, respectively, which is a significant cooling effect for space-constrained devices like smartphones, where even a small temperature reduction matter.