At present, many terminal products, such as mobile phones, include the functions of near field communication (NFC) and frequency modulation (FM). A winding planar coil with a large enough area is taking as an antenna of the NFC, and the FM generally uses an external headphone cable as a reception antenna or uses a built-in mini-type Printed Circuit Board (PCB) antenna, and both the antennas thereof need to occupy a certain space. By contrasting and analysing the antennas thereof carefully, it could be found that the following features exist:
1. By means of a rough estimation, if the NFC coil winds 4 turns according to the size of 4×5 cm, then the total length of the winding is 70 cm, whereas the FM antenna generally needs 80 cm routing length according to the principle of ¼ wavelength, the two lengths are comparable.
2. The NFC and the FM are working in the vicinity of 13.56 Mhz and 100 Mhz respectively, guaranteeing that an isolation requirement there between is satisfied.
3. Both the NFC antenna and the FM antenna are required to be provided on a peripheral area or a surface area of a terminal body, away from the influence of the PCB, and the FM reception antenna does not need a very high efficiency.
On the basis of the above-mentioned features, the technical feasibility is only provided for the sharing of two antennas. At present, there is no design for a common antenna.