Ultra-Thinned Metasurface-Embedded Smartphone Antenna-in-Package for Millimeter-Wave 5G/6G Coverage Enhancement

In this study, we present a ultra-thinned metasurface-cased antenna-in-package (MCAiP) for a millimeter-wave (mm-wave) 5G smartphone that operates in the n257 and n258 bands of FR2 (26.5–29.5, 24.25–27.5 GHz). The proposed MCAiP consists of
$1 \,\,\times4$
array patch antennas, inductively loaded metasurface (ILM), a smartphone cover case made on Gorilla Glass 6 (a commonly used material), and four-channel beamforming IC; it has a thin profile of 1.63 mm, making it suitable for insertion into an actual smartphone. To validate the effectiveness of commercializing the proposed MCAiP, all the structures were fabricated using a 12-layer PCB stack-up process, and beam tilting measurement was performed using four-channel beamforming IC. The proposed AiP accomplishes a 10-dB return-loss bandwidth of 23.5–32.2 GHz and a maximum gain of 13.62 dBi. In addition, we combined the four-channel beamforming IC with a metasurface-cased antenna and conducted beam tilting measurements using the all-in-one device. The peak effective isotropic radiated power (EIRP) [dBm]/tilting degree [°] of the proposed MCAiP with an IC are 6.59/0, 5.87/12, and 3.37/27. Conversely, the beam tilting results of a nonmetasurface AiP with an IC are 2.01/0, 1.6/12, and −0.95/30. These results demonstrate that the metasurface enhances the beam coverage of the antenna.