| 摘要 |
A dual band (900MHz and 1800MHz) antenna has a first metallic layer acting as resonator plane and defining at least two radiating element 48, 49 separated by a first slit 46 and a second metallic layer arranged substantially in parallel with the first metallic layer and acting as ground plane for the antenna device. Feeding means are connected to said first and the second metallic layer for feeding an RF signal to the antenna device, said feeding means includes a feeding point 42 the first metallic layer. The first metallic layer is provided with a second slit)extending from said first slit with the feeding point 42 placed on a metallized tongue 45 between the first and the second slit, whereby surface currents have to pass around the tips of the slits towards the radiating elements. The resonating plate or layer is formed from three parts, with the 1st 39 and 2nd 48 parts forming a first receiving/emitting element for one frequency and the 1st 39 and 3rd 49 forming a second receiving/emitting element for another frequency. The 2nd and 3rd parts are capacitively coupled 54 (58, fig 6) to the ground plane. The slit between the 1st and 2nd parts may be bent (fig 8) or continue into the capacitive coupling (fig9). Antennas of this type are also known as a Planar Inverted F-Antennas (PIFA). |
