| 摘要 |
<p>A multi-band RF circuit has receive paths for two or more bands, and transmit paths, a bidirectional one-in multiple-out transmission line junction (100) for combining the paths for coupling to an antenna. A switch combines transmit and receive paths, and a receive path circuit (110, 150, 160, 230, 240) is arranged to pass signals of its band, and appear open circuit to signals of the other bands. This means the combiner no longer needs to cut off the receive paths when they are not used. This can reduce components and thus reduce losses in the transmit paths for longer battery life or greater transmit range. A band filter (SAW) and a complementary circuit can achieve the open circuit. The bands can include GSM and GPS bands, the circuits can be used in tri band mobile handsets and handsets for future 3G bands, or base stations.</p> |
