Driven by the great potential to revolutionize short-range high-speed wireless personal area network systems, designs towards low-cost highly-integrated 60-GHz radios in silicon semiconductor technology have received great attention in recent years. To provide 60-GHz radio chipsets with low-cost packaging and antenna solutions, the Antenna-in-Package (AiP) designs have shown promising results [1-3]. However, as the current AiP designs use only one antenna element, the gain is not enough, it is therefore necessary to extend it to an array antenna to achieve higher gain. Microstrip patch and slot array antennas designed for 60-GHz applications has been reported. However, they suffer from the complex feeding network, sophisticated process techniques to achieve enhanced performance. To avoid these problems, the grid array antenna was adopted in our work [4]. We show that a grid array antenna is an excellent array antenna candidate for 60-GHz applications and is particularly suitable for fabrication in LTCC or integration in packages [5-6].