PURPOSE: To send/receive a radio wave without receiving adverse effect of a construction material being a radio wave shield by adopting an antenna comprising a planer ground conductor and a radiation plate smaller than the ground conductor located opposite to each other for a repeater antenna.
CONSTITUTION: An inverted-F plate antenna 11a is made up of a planer ground conductor 11 made of a metallic conductor, a radiation plate 11e whose size is smaller than the conductor 11d and made of a metallic conductor, and a short-circuit plate 11f used to short-circuit the ground conductor 11d and the radiation plate 11e. An inverted F plate antenna 12a opposite to the antenna 11a and connecting to ground is configured similarly to above. Since an inverted- F plate antenna is configured to produce a current by opposing radiation plates 11e, 12e with a comparatively small area to ground plate conductors 11d, 12d with a comparatively larger area and applying a voltage between the opposed plates, even when a radio wave shield approaches the side of the antenna at which no radiation plate 11e(12e) is in existence, the effect in the mirror effect is hardly caused on the antenna during transmission reception of a radio wave. Thus, the inverted-F plate antennas 11a, 12a are installed close to a construction material of a building.
OIKAWA HIROSHI
KASAI HIDEKI
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