Length of antenna spacing on isp1907

[skzpvls26]

Helo, I have ISP1907 for BLE AoA. 

In my understanding, the antenna spacing should be half of wavelength, in case of BLE, it would be 2.4GHz thus the spacing should be 6.25cm. 
However, the ISP1907 that I have, has antenna spacing of 5cm.

what makes it different with standard BLE ? or is it using different carrier frequency than regular BLE?\

Thank you.

[SwRa]

Hello,

In my understanding, the antenna spacing should be half of wavelength, in case of BLE, it would be 2.4GHz thus the spacing should be 6.25cm. 

Yes, you are correct.. The optimal antenna spacing for Angle of Arrival (AoA) measurements is typically half the wavelength, which would indeed be around 6 cm.

The antenna spacing of ISP1907 is slightly lower than the optimal value. However, this difference doesn't necessarily indicate that it's using a different carrier frequency than regular BLE. There are several practical considerations that can influence the actual antenna spacing in commercial products like physical design constraints, performance optimization etc. 

All BLE devices including the ISP1907 operates under standard BLE frequency (2.4G Hz).

Best Regards,

Swathy

[PaKa]

The optimal spacing for antenna arrays used in Direction Finding should be LESS than half the minimal wavelength. This is done to ensure there is no ambiguity in the angle calculations.