PCB antennas are rigid, flat antennas that can be easily glued to the inside of a plastic enclosure.
A PCB antenna often consists of a thin printed circuit board made of FR4 with a structured conductive material. It can be used to develop different types of antennas. The antennas usually have a coaxial cable with a coaxial connector.
Features of PCB antennas
- can be mounted vertically, horizontally or coplanar with the host PCB;
- can be supplied with different cable lengths;
- offer an omnidirectional radiation pattern;
- are cheaper than externally mounted antennas. High power levels can be achieved without the cost of an external antenna;
- can be manufactured using standard PCB fabrication techniques, making them highly reliable and reproducible antennas.
As already documented in the study on DIY antennas, the size of a PCB together with the mass surface used has a direct influence on the performance of an antenna. PCB antennas also require a sufficiently large mass surface (ground plane).
To avoid unpleasant surprises, a test setup with the flexible antenna in the plastic enclosure of the planned IoT device with a test board is recommended. This test board only requires two coaxial connectors. One coaxial connector is used to connect the antenna. The second coaxial connector is used to generate a test signal with the Vector Network Analyser and measure the return loss. You can read more about this test setup here.