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 15x15x1 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.