mmWave Antenna Design in Advanced Fan-Out Technology for 5G Application

Abstract

In this paper, the fabrication process of AiP is based on Fan-Out substrate. This solution brings short interconnection between die to die and die to antenna for excellent electrical performance. They tend to offer the lowest transition loss due to circuitry directly connected to the antenna. In this study, the package height is slightly less than 0.75 mm, with three RDL layers, two mold layers for antenna design, mold thickness of 250um, and ball height of 200um. Its benefits include a smaller package footprint compared to conventional organic substrate or laminate packages, higher maximum connection density, as well as desirable electrical and thermal performance. In this work, the stacked patch antenna is a wideband design to improve the bandwidth. Based on design theory of antenna, proper design requires careful optimization of the thickness, feed point and width of patch atenn. By choosing the antenna parameters properly, the proposed stacked patch antenna on fan-out package has better than 10dB return loss in 26.8-32.5 GHz range, with ~5.7GHz bandwidth and provides a high-gain (above ~10.3 dBi) radiation pattern with 2×2 patch antenna array. Beamforming array is a very important technique in 5G application. The proposed thin profile AiP solution can achieve both broadband and high directivity characteristics, which meet the requirement of 5G systems in the allocated frequency bands at 28 GHz applications.