Integration of Quadruple Linearly-Polarized Microstrip Grid Array Antennas for 60-GHz Antenna-in-Package Applications

This paper demonstrates the integration of quadruple linearly-polarized microstrip grid array antennas in Ferro A6M low-temperature cofired ceramic technology for 60-GHz antenna-in-package (AiP) applications. An emphasis is given to the optimization of via transitions in the design of the low-loss array feeding network based on stripline quarter-wave matched T-junctions for the multilayer AiP structure. This paper also demonstrates the capabilities of a fully automatic probe-based antenna measurement setup for 3-D radiation pattern at 60 GHz. A special focus is placed on the calibration procedure to achieve an overall uncertainty of ±1 dB for the measurement of the realized gain of any antenna. The AiP module of dimensions 15 × 15 × 1 mm is fabricated and measured. The measured results are in good agreement with the simulated ones, showing that the AiP achieves excellent antenna performance: 10-dB impedance bandwidth (BW) from 50 to 65.6 GHz (or 25.4% at 61.5 GHz), broadside radiation from 55 to 67 GHz (or 19.5%), and 3-dB gain BW from 58.5 to 67 GHz (or 13.8%) with the maximum gain of 15 dBi at 62 GHz.