| 摘要 |
A dual frequency communication system utilizes an antenna (100) and a diplexer (102) for operating at a first frequency and a second, preferably widely separated, lower frequency. The antenna is preferably a loop antenna (100) and the diplexer (102) including both capacitative (104, 106, 108) and inductive (110, 112) elements provides an impedance match at both the first and second operating frequencies as well as combines both signals such that a single coaxial cable may be used with the antenna. In a preferred embodiment, the antenna is fabricated on a standard printed circuit board using a standard printed circuit board fabrication process. The passive electrical elements of the diplexer are also fabricated on the same board, thereby resulting in an integrated planar dual frequency antenna system. |
