MULTIBAND ANTENNA SYSTEM

摘要

An antenna system internal to a radio device, the system comprising separate antennas and having separate operating bands. The system is implemented as de- centralized in a way that each antenna is typically based on a small-sized chip component (310; 320; 330; 340; 350; 360; 610), which are located at suitable places on the circuit board (PCB) and possibly on also another internal surface in the device. The chip component comprises a ceramic substrate and at least one radiating element. The operating band of an individual antenna covers e.g. the frequency range used by a radio system or only the transmitting or receiving band in that range. At least one antenna is connected to an adjusting circuit with a switch, by which the antenna's operating band can be displaced in a desired way. In this case the operating band covers at a time a part of the frequency range used by one or two radio systems. The antennas can be made small-sized, because a relatively small bandwidth is sufficient for an individual antenna, when there is a plurality of antennas. When the bandwidth is small, a material with higher permittivity can be chosen for the antenna than for an antenna having a wider band, in which case the antenna dimensions can be made correspondingly smaller. In addition, a good matching of the antenna is achieved on the whole width of each radio system, because the matching of a separate antenna having a relatively narrow band is easier to arrange than that of a combined multiband antenna.