Technical Brief 01 · Free

Integrated Wireless Antennas for Wearable Devices

Dual-band BLE / Wi-Fi stamped antenna design with hybrid filter-matching network

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The challenge

The antenna system had to fit inside a 2-inch disk only 10 mm thick, operate while worn on the wrist, support two separate wireless ports, and remain suitable for very low-cost high-volume production.

2.4–2.5 GHzBLE band

5.5–6 GHzWi-Fi band

>30 dBRequired port isolation

Stamped metalManufacturing architecture

Product architecture

The simplified model places stamped antenna elements around the wearable's circumference and a central battery/display assembly. Proprietary implementation details are intentionally omitted from this public edition.

Wearable enclosure and antenna placement diagrams — Wearable enclosure, internal layout, antenna placement, and initial performance discussion.

Electromagnetic analysis

Radiation-pattern and S-parameter analysis verified gain targets and exposed insufficient pre-match isolation in the Wi-Fi band. That result guided the filter-matching network design rather than relying on iterative hardware tuning alone.

BLE and Wi-Fi radiation patterns and pre-match S-parameters — Simulated radiation patterns, pre-match return loss, and port-to-port isolation.

Hybrid filter-matching network

Compact 0201 lumped components were optimized to improve return loss and simultaneously suppress coupling between ports in both operating bands.

Results

The optimized system achieved return loss better than 10 dB across the BLE and Wi-Fi bands and isolation better than 30 dB in both bands.