mm-Wave 3-D-Printed 2 × 2 Antenna Subarray With Structurally Packaged Beamforming IC and Thermal Management

A mm-wave 2×2 antenna subarray is structurally packaged with a beamforming integrated circuit (BFIC) chip using laser-enhanced direct print additive manufacturing (LE-DPAM). Unlike prior art in additive manufacturing of antenna arrays and structural IC packaging, BFIC is an active IC that also requires thermal management. Therefore, the capabilities of LE-DPAM are harnessed for the first time to create a 3D antenna shape in the form of pyramids, simultaneously achieving thermal management and structural integration of the BFIC. The subarray consists of five dielectric and six conductive layers. Three different conductive inks and four different dielectric materials with varying properties (dielectric constant, electrical conductivity, and thermal conductivity) are strategically utilized to simultaneously achieve the best RF and thermal management performances. The subarray operates at the 26.5 GHz 5G communication band with a 1.6 GHz impedance bandwidth. It has been experimentally characterized to perform beam steering controlled by the BFIC while achieving a maximum realized gain of 27.0 dBi in receive mode. Under the peak DC power consumption of 830 mW in the transmit mode, the proposed co-design approach reduces the peak simulated temperature from 106.4 °C to 78.9 °C. In receive mode with a 420 mW of DC power consumption, the peak temperature decreases from 66.5 °C to 52.8 °C, which was verified by a thermal meter measurement of a stabilized surface temperature of 45.4 °C.