Chip Antenna
A chip antenna is a miniature antenna embedded in a ceramic or similar high-dielectric body and soldered onto the board. Working in a volume of a few millimetres saves space; in return it falls behind a wire or printed antenna in gain and efficiency. Its performance depends strongly on board geometry.
A chip antenna radiates largely via the board's own ground area. That is why the same chip gives very different results on two different board designs; the values in the manufacturer's datasheet apply to a specific reference board.
- Placement is critical: the antenna must be positioned close to the board edge, with a clearance free of copper beneath and around it.
- Metal proximity: when a battery, display or metal case enters the near field, the tuning shifts.
- A matching circuit is usually mandatory; the final values are determined by measurement once the board goes into production.
On the application side, a chip antenna is preferred for small handheld units where volume is genuinely restricted. On the receiver side, where range is the deciding factor, using an external antenna is the better decision. This is exactly the reason why in AXI's ST and SF sets the receiver is supplied with an external antenna and cable gland: to keep the antenna not on the board but in an open and free position.
Context in which this term is used: 433 MHz or 2.4 GHz?