Multibeam Antenna with a Passive Beamforming System in LTCC Technology for Mm-wave Systems-in-package

This paper presents an innovative switched-beam antenna system at 60 GHz which is completely integrated in a low-profile, planar low temperature co-fired ceramic (LTCC) module. A broadband, wide-angle scanning performance is achieved resorting to parallel-fed continuous transverse stub (CTS) arrays excited by passive, quasi-optical (QO) beamformers. The realization of substrate-integrated CTS arrays is enabled by the unique three-dimensional (3-D) integration capabilities of the LTCC process. The antenna architecture includes two separate CTS arrays, activated one at a time by a co-integrated switch-network. With this choice, the overall system simultaneously achieves low side lobe levels (SLLs) and high overlap of the radiated beams, within an angular sector of ±38° in the scan plane. The proposed technology and module are suitable for realization of low-cost, multi-chip systems-in-package (SiPs) for millimeter-wave (mm-wave) applications, such as wireless access points in fifth-generation (5G) mobile networks.