Flexible PCB antennas, or FPC antennas, consist of thin layers of polymer and copper to form a thin strip (0.15mm thick). They are flexible and bendable, making them easy to implement into the design of many devices across a wide range of frequency bands. They are also highly reliable and efficient, characteristics many small IoT and wearable devices require.
Even though flexible PCB antennas often solve a wide array of problems that arise in small devices, they can run into difficulties with extremely compact products as some models lose efficiency if bent or folded too far. FPC antennas still provide ease of integration as they do not require tuning to the matching network, but unfortunately require manual labour to fit onto the PCB as opposed to the pick & place automation of SMD antennas.