18.3 Antenna

• Make sure to choose an antenna that covers the desired frequency band, in other words, 868 MHz (European), 902-928 MHz (North American), 779 to 78 MHz (Chinese) and 915 to 930 MHz (Japanese).
• Ensure the PCB trace running from the balun output to antenna is designed for single-ended 50Ω impedance.
• Follow the footprint and other recommendations from the antenna data sheet.
• Ensure the dimension of the ground plane in the board meets the dimension requirement specified in the antenna data sheet. A reduced ground plane dimension reduces the efficiency achieved with the same antenna.
• Place the antenna impedance-matching components as close to the antenna pad as possible.