| 摘要 |
An antenna assembly which is suited for receiving FM signals, comprises a pair of insulating disc shaped substrates which each have conductive patterns deposited on one surface thereof. The first insulating substrate has an electrically conductive loop element extending around approximately 360 DEG on the first substrate. The loop element terminates at first and second terminals which are adjacent each other. An electrically conductive tap element is deposited on one surface of the second substrate. The tap element extends around approximately 180 DEG and is parallel to half of the length of the loop element. On end of the tap element is electrically connected to a mid-point of the loop element intermediate its first and second terminals. Plate areas are deposited on the substrate and are electrically connected to selected terminals of the loop and tap elements to form capacitors. A first relatively large value capacitor is thus defined between the first and second terminals of the loop element and a second smaller value capacitor is defined between the second terminal of the loop element and opposite end terminal of the tap element. This forms a passive antenna. An active antenna can be formed using discreet components as the capacitors. An amplifier is connected over a signal capacitor to an output of the antenna to form an active antenna assembly.
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