| 摘要 |
PURPOSE:To attain low cost, miniaturization and light weight of a portable radio equipment for duplex communication system having a reception diversity function by providing exclusively a small-sized inverted F type antenna with thin profile respectively for transmission and reception. CONSTITUTION:The inverted F type antennas 14, 15 resonated at a reception frequency band and the inverted F type antenna 16 resonated at a transmission frequency band are provided respectively near the surface opposed to a case 13 of the portable radio equipment and adjacent to a face fitted with the said antennas. Since the antenna elements 14-16 are thin and plate-shaped conductor elements and its surrounding length is 1/2 of the operating wavelength, they act as 1/2-wavelength folded slot antennas, receive efficiently horizontal and vertical polarized wave components, have a low Q, and even when the three sets of the antennas are arranged nearby, the operating frequency band and gain are ensured. A feeding coaxial cable 23 is provided to grounding sections 18, 19, 21 and their vicinity of each antenna and variable capacitors 17, 20, 22 for minute adjustment of the resonance frequency are provided. |
