In Bluetooth low-power products, Bluetooth system usually works in 2.4Ghz band, and ceramic antenna is often used as Bluetooth transceiver antenna in practical products. The performance of the antenna directly affects the working distance of the whole Bluetooth system.
In practical application, even if the mass-produced antenna is used, it has very good performance from the antenna data table, but in actual test, it is found that the resonance point of the antenna will deviate from the 2.4GHz frequency band.
In the final inspection, we found that there are two main problems: too much solder at the solder joint overflows from both sides, which makes the resonance point of the antenna move to the left to the center point (2.4 1GHz-2.48GHz), which exceeds the Bluetooth frequency band (the center point is less than 2.45GHz).
Due to wiring, the actual effective length of the antenna is short, and the resonance point of the ceramic antenna is outside the Bluetooth frequency band (2.4 1GHz-2.48GHz), but it is shifted to the right (the center point is greater than 2.48GHz).