A Ka-Band Silicon-Based Antenna-in-Package Design Using Characteristic Mode Analysis for Bandwidth Enhancement

With the emergence of 5G and satellite communication applications, where millimeter-wave (mm-wave) active phased arrays play an important role, the demand for a highly integrated and cost-effective method to achieve mm-wave antennas is an inevitable trend. Antenna-in-package (AiP) design is therefore becoming a hotspot. This paper presents the design procedure for a broadband silicon-based stacked patch antenna in Ka-band, which realizes a practical AiP structure for phased-array module integration requirements. A stacked-patch antenna on a high-resistivity silicon (HRSi) substrate is demonstrated to effectively extend the bandwidth with the guidance of characteristic mode analysis (CMA).The proposed antenna element and its 2 × 2 array were designed and fabricated using silicon bulk micromachining and wafer-level bonding technology. The measured results from the fabricated antenna prototypes showed that (1) the antenna element had an impedance bandwidth of 13.8% from 26.2 to 30.1 GHz, and the peak gain was 6.1 dBi at 28.9 GHz; (2) the 2 × 2 array realized an impedance bandwidth of 11.4% from 27.2 to 30.5 GHz, and the peak gain was 9.3 dBi at 28.5 GHz.