Integrated 5.7 GHz chip-size antenna for wireless sensor networks

We report on design, fabrication and characterization of chip-size antennas for operation at 5.7 GHz and use in wireless sensor networks. Application of wafer-level chipscale packaging (WLCSP) techniques like adhesive wafer bonding and through-wafer electrical via formation, combined with the selected antenna types (patch and folded patch) allows on-chip integration and is the main novelty of our work. A short-range wireless link between two systems both equipped with an 8x8 mm2 patch antenna (measured characteristics: 5.705 GHz central frequency, 90 MHz bandwidth @ -10 dB, 0.3 dB gain, 18% efficiency) realized on a high-resistivity silicon (HRS) substrate is demonstrated. A folded-patch antenna built on two stacked glass substrates allows size reduction down to 4.5x4x1 mm3 and has a projected efficiency of 60%.Fundação para a Ciência e Tecnologia (FCT), project (SFRH/BD/4717/2001 and POCTI/ESE/38468/2001)