Bluetooth tag antenna

Bluetooth tag key data

• Client: Not named
  
• Website: Not named
• IoT application: Bluetooth tag
  
• Wireless technology used: Bluetiooth low energy
  
• Frequency range: 2400 MHz
  
• Type of antennas: Chip antenna, later 0 USD Antennity chip loop antenna
  
• Task: Optimisation of the Bluetooth antenna and replacement to 0 USD Antennity chip loop antenna
  
• Solution: Optimisation of antenna design through better matching and change to Antennity chip loop antenna
  
• Special feature: Significant increase in range, reduction in energy consumption and reduction of the BOM

Optimisation of a Bluetooth tag

The focus of this project was to improve an existing Bluetooth tag. Two major challenges were successfully overcome:

1. Antenna matching: The originally installed chip antenna had a suboptimal matching. Careful retuning significantly increased the range of the tag. This significantly improved the performance and reliability of the device.
2. Antenna change: In a second optimisation step, the chip antenna was replaced by a low-cost Antennity Chip-Loop antenna. This step was necessary because the manufacturer of the original antenna had discontinued it. The new antenna offers several advantages:
• Inexpensive: At 0 USD for the chip antenna because it is just 0.005 cents for a capacitor
• Durable: No ‘end of life’ as with conventional chip antennas
• Reliable: Our antenna is a simple off-the-shelf capacitor

Technical aspects

When developing Bluetooth devices with integrated antennas, the size of the ground plane is a critical factor. A ground plane smaller than λ/4 (lambda/4) leads to a reduction in antenna efficiency. For Bluetooth at 2.4 GHz, λ/4 is about 31.25 mm. The PCB used is based on a CR2030 button cell, whose diameter has been extended by 8 mm. This results in a total diameter of about 28 mm, which is just below the ideal size for optimal antenna performance.

Conclusion and outlook

The optimisations carried out significantly improved the performance of the Bluetooth tag. Using the Antennity Chip-Loop antenna not only offers a cost-effective solution, but also a future-proof one. Do you need support with antenna matching, antenna development or the development of complete IoT devices? Contact us for customised solutions that take your products to the next level.