Recently, devices that send data collected from sensors by using wireless communication are being developed. Such devices are used for collecting measured data for applications in automotive systems, industrial systems, IoT systems, healthcare systems or the like. The devices need to store a sensor, a battery, an antenna, a wireless communication circuit or the like in a compact body, while maintaining high communication performance and high serviceability.
Since the antennas are located closely to the sensors and communication circuits in these devices, degraded communication performance and fluctuating frequency responses become problems. Depending on the type of sensors and location of circuits, different patterns of electromagnetic coupling and interference may occur. Therefore, it is difficult to find a general solution for the problems. Even though the design changes made to the circuit are small, the whole antenna needs to be redesigned.