We discussed the radiation and reception properties of an array antenna with a decoupling and matching feeding network. When the feeding network is designed and constructed to satisfy the matching condition of the array antenna, each port pattern exhibits orthogonal property and eigen mode patterns when the orthonormal matrix, which constitue the sub matrix of the feeding network, is an unit matrix. When the spacings of the array are small compared to the wavelength, the radiated power of each antenna element considerably deviates and the reactive energy stored around the array increases. To show this quantitatively, we proposed Q factor of the array and showed numerical result. As for the reception properties of the array, we presented the total received power when the plane wave is incident. Averaged gain in the horizontal plane for the four elements array is also presented and it is shown that this can be larger by four times than that of a single dipole. The reason of this phenomena comes from the narrower beam width in the vertical plane as well as in the horizontal plane.
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