KT6368A Bluetooth Chip Used in BMS Battery Metal Shell: RF Distance Performance and Optimization Strategies

The customer's product is a BMS protection board. Due to its application in a waterproof scenario, it adopts a fully - enclosed design and is completely wrapped in metal, as shown in the following figure.

The customer reported that because the device has no openings at all, the Bluetooth communication distance is less than 1 meter, and the wireless signal is completely shielded by the metal. In response to this situation, the following optimization methods can be tried:

• Product Opening: Openings should be made on the product, such as interface holes for 485 interface connectors, 4G antenna connectors, etc., so as to reserve a plastic area in the metal structure.

• Antenna Position Adjustment: Place the Bluetooth antenna near the plastic position, so that the signal can be transmitted to a certain extent.

• Antenna Selection Change: Abandon the onboard antenna and choose a ceramic antenna instead.

The relevant material screenshots are marked as follows:

• Poor Design Case: The following figure shows a customer's design that is relatively unsuccessful. An onboard antenna is used, and the antenna is not placed near the plastic position.

• Successful Design Case: The following figure shows the design of another customer. Under the condition of being fully wrapped in metal, the Bluetooth communication distance can reach about 10 meters.

• Ceramic Antenna Usage Instructions: For the usage of ceramic antennas, please refer to another document of ours. The path is as follows:

In such a complex environment, the only way is to optimize from component selection and structural design. There is no other alternative.

Product details, product information, and sample acquisition and ordering links: KT6368A