Ultra-Wideband High-Gain Millimeter Wave Antenna-in-Package With Small Gain Ripple

This paper presents an ultra-wideband high-gain antenna-in-package, operating at millimeter-wave frequencies, featuring two identical radiating patches, two embedded feeding structures, and a coplanar open-cavity. The feeding structures and the cavity are constructed with metallic vias embedded in the substrate for impedance and gain bandwidth enhancing purposes. Two additional structural modifications, involving 12 shorting vias and a rectangular ring strip, are used to further improve the antenna's impedance and gain bandwidths. The new antenna design yields a 96.5% and 83.25% of impedance and gain bandwidths, in which S
₁₁
<;-10 dB and gain>9 dBi, respectively. In addition, the antenna is light, compact, and easy to be integrated with planar circuits because all the structures are implemented with planar fabrication technologies, such as LTCC and HDI processes.