| 摘要 |
PURPOSE: A portable terminal is provided to have antennas having different frequencies, and to configure a Balun(Balance-unbalance) converter composed of two dielectric cylinders corresponding to multi frequencies and a conductor cylinder on a coaxial cable feeding power to each antenna, to prevent an antenna current from flowing into a PCB, so as to improve an SAR(Specific Absorption Rate). CONSTITUTION: The second PCB(2) is installed on the first PCB(1) having a transceiving circuit(5). The first dipole antenna(3) installed on the second PCB(2) is used in the first frequency. The second dipole antenna(4) is used in the second frequency higher than the first frequency. A coaxial cable(7) connects the first and the second dipole antennas(3,4) with the transceiving circuit(5). A Balun(Balance-unbalance) converter(8) covers an antenna side end of the coaxial cable(7). The Balun converter(8) is composed of the first dielectric cylinder having length in accordance with the first frequency, the second dielectric cylinder having length in accordance with the second frequency, and a conductor cylinder. By inserting the second dielectric cylinder and the conductor cylinder into the first dielectric cylinder, Balun corresponds to a multi frequency. |
