| 摘要 |
An antenna is located in the body of a removable memory card in such a way that at least one part of the antenna (2) is adjacent to that outer rim (10) of the card, which is near the entrance of the SD card slot after the card is inserted into the slot. The surface of the removable memory card (1) is covered with a ferrite layer (4) and a metal layer (4). The metal layer (4) screens the antenna (2) besides the uncovered zone (9), which is next to the outer rim (10) of the card. The uncovered zone (9) can be formed by a stripe with a width of up to 2 mm. The metal layer (4) can be made of copper or of aluminium and the ferrite layer (3) contains at least 50%, preferably however more that 60% of ferrite. The antenna (2) can be made of conductive loops basically of a rectangular shape, preferably in two separate parts on both sides of a PCB layer (5). The material of the card can contain a powder ferrite with at least 25% volume share. The powder ferrite can be made of ferrite particles having various chemical composition and various shape, preferably with a granularity from 20 µm to 70 µm. |
