| 摘要 |
A broadband antenna of miniature size employs an array of dipole elements whose inner ends are connected to a pair of closely spaced parallel central conductors. Three pairs of dipole elements are disposed in a symmetrical array and extend outwardly from the central conductors. The longest pair of dipole elements are capacitively end loaded and the length of that longest pair is approximately one eighth of a wavelength at the lowest frequency in the broadband. The length of the shortest pair of dipole elements is in the range of a third to a quarter of the wavelength at the highest frequency in the broadband. The third pair of dipole elements is a half wavelength at an intermediate frequency in the broadband. At the points where their inner ends are connected to the central conductors, adjacent pairs of dipole elements are spaced apart by a distance in the range of a half to a quarter of the wavelength at the highest frequency in the broadband. To enable the antenna array to be disposed on a support that is suitable for a picture frame, the dipole elements are slanted with respect to the central conductors and the two longest pairs of dipole elements are arranged to approach convergence at their outer ends. To provide two panels, each of which can act as a frame for a picture, the support can be hinged with the hinge being disposed between the closely spaced parallel central conductors.
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