| 摘要 |
PURPOSE: A portable terminal which performs wireless communication based on TDD(Time Division Duplex) method by using a couple of dipole antennas is provided to improve an SAR(Specific Absorption Rate) as well as optimize communication performance. CONSTITUTION: A feeding circuit(30) comprises as follows. A power distributor/synthesizer(33) is connected with a transceiving circuit(6) through a coaxial cable(7). Phase shifters(34,35) control phases of each antenna current. Balun(Balance-unbalance) converters(36,37) convert the phase-controlled currents by unbalance-balance systems, and supply the converted currents to each antenna. Each of the phase shifters(34,35) controls a transmission power phase and a receiving power phase for each dipole antenna by transmitting/receiving switch signals(10). The power distributor/synthesizer(33) controls ratios of transmission power distribution and receiving power synthesis by the transmitting/receiving switch signals(10).
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