PURPOSE: To remarkably improve the directivity and gain by a simple constitution, by installing a parastic loop element whose circumferential length is about 2 wavelength, in a virtual plane containing a feed antenna, and also so as to surround the feed antenna.
CONSTITUTION: A parasitic loop 3 whose circumferential length C is about 2 wavelength is installed symmetrically to the center of a feed antenna 2, so as to be in parallel with a limited long passive reflector 1 of several wavelength or less, and also in a virtual plane containing the feed antenna 2. In this case, when the available wavelength is denoted as λ, the circumferential length C of the parasitic loop 3 is about 2λ, therefore, the diameter of the parasitic loop 3 is size of about 0.6∼0.7λ, and on the other hand, size of a 1/2 wavelength antenna of the feed antenna 2 is 0.5λ, and the diameter of the passive reflector 1 is between 0.5 wavelength and several wavelength in order to have an effect as a passive reflector. Accordingly, size of this parasitic loop 3 is almost the same as the feed antenna 2, is small, and also is light since it is linear. Also, the directivity and gain are improved remarkably.
| JPS60189116 | [Title of the device] Ghost out MK2 |
| WO/2004/025778 | COUPLED MULTIBAND ANTENNAS |
| JP3646782 | ANTENNA DEVICE AND COMMUNICATION EQUIPMENT USING THE SAME |
OKABE YOSHIKATSU
KAZAMA YASUHIRO
| JP45004122A |