Enrichment of Package Antenna Approach With Dual Feeds, Guard Ring, and Fences of Vias

This paper enriches the package antenna approach to wireless modules by introducing the dual feeds, the guard ring, and fences of vias. The dual feeds enable the antenna for not only single-ended but also differential signal operations. The guard ring and fences of vias reduce the antenna backward radiation and improve the isolation between the antenna and radio chip. The design guideline of the guard ring and fence of vias for the package antenna approach is developed for the first time. An example antenna of this package approach using a microstrip patch radiator has been designed and fabricated in a low-temperature cofired ceramic (LTCC) technology for the wireless modules operating at the 5-GHz band. The antenna has a size of 17 $,times,$17 $,times,$2 mm $^{3}$ and contains the open cavity that is large enough to accommodate a radio chip of current size. Simulated and measured input impedance matching and far-field radiation properties are discussed. They show that the antenna achieves over 2.2% bandwidth while maintaining 90% efficiency.