Communications: radio wave antennas – Antennas – Balanced doublet - centerfed
Reexamination Certificate
2001-07-30
2003-06-03
Nguyen, Hoang (Department: 2821)
Communications: radio wave antennas
Antennas
Balanced doublet - centerfed
C343S733000, C343S806000
Reexamination Certificate
active
06573874
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an antenna device used in a mobile communication system such as a PHS or the like, and a radio apparatus having the antenna device built therein.
BACKGROUND ART
Heretofore, a high gain was required of an antenna device used in a radio base station apparatus or fixed radio terminal apparatus in a mobile communication system such as PHS or the like. Therefore, a multistage collinear array antenna was used, for example, as shown in JP-A-5-267932, JP-A-9-232851 and JP-A-8-139521. In the antenna of this type, antennas non-directional in a horizontal plane with respect to vertically polarized wave were arranged multistageously vertically to narrow directivity in a vertical plane to thereby secure a high gain.
An end-fire array antenna represented by a Yagi antenna or a reflector-containing dipole antenna was also used, for example, as shown in JP-A-5-259733 and JP-A-8-304433. In the antenna of this type, passive elements were arranged in parallel to the direction of main radiation to thereby secure a high gain.
A broadside array antenna represented by a patch array antenna was further used, for example, as shown in JP-A-6-334434. In the antenna of this type, a plurality of antennas were arranged in a plane perpendicular to the direction of main radiation to perform distributive feeding to thereby secure a high gain.
A low-profile antenna represented by a reflector-containing loop antenna or a slot antenna was further used, for example, as shown in JP-A-6-268432 and JP-U-6-44219.
On the other hand, an antenna formed from two one-wavelength antennas arranged into the form of a square or a circle, for example, as shown in“Antenna Handbook” (CQ Publication Co., Ltd.) p.366 is known as a broadside array antenna mainly used in a VHF band.
In the aforementioned conventional multistageous collinear array antenna, it was however necessary to arrange a large number of antennas vertically multistageously in order to secure a high gain. For example, a height of about 1 m was needed to obtain a gain of 10 dB in a 1900 MHz band. Hence, there was a problem in making sure of the antenna-setting space and mechanical strength. Further, the antenna of this type was unsuitable for being built in a radio apparatus because of its height.
Further, in the aforementioned conventional end-fire array antenna, it was necessary to arrange a large number of antennas in the direction of main radiation in order to secure a high gain. Hence, there was a problem in making sure of the antenna-setting space and mechanical strength. Further, the antenna of this type was unsuitable for being built in a radio apparatus because of its structure.
Further, in the conventional broadside array antenna, it was necessary to arrange a large number of antennas in a plane perpendicular to the direction of main radiation in order to secure a high gain. Hence, the total area of the antenna increased, so that there was a problem in making sure of the antenna-setting space and mechanical strength. Further, the antenna of this type was unsuitable for being built in a radio apparatus because of its large area.
In addition, although the conventional low-profile antenna was formed in a small-size low-profile configuration, there was a problem that the radiation directivity could not be optimized to provide desired characteristic.
In the aforementioned antenna formed from two one-wavelength antennas arranged into the form of a square or a circle, only the radiation directivity in a predetermined vertical plane and in a predetermined horizontal plane could be obtained, and there was a problem that the radiation directivity could not be optimized to provide desired characteristic.
The present invention is designed to solve the conventional various problems generally and it is an object of the present invention to provide an antenna device in which the optimal radiation directivity can be obtained in the broadside array antenna having two one-wavelength antennas, in which a high gain and a high function can be obtained with a simple configuration and which can be used as a small-size low-profile antenna for a mobile communication system in UHF and sub-micro wave bands.
DISCLOSURE OF THE INVENTION
The present invention is devised so that the angle of bending in the center of each one-wavelength antenna element in a broadside array antenna having two one-wavelength antenna elements arranged therein is selected to be an optimal angle. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a simple configuration and which has a high gain.
Further, the present invention is devised so that a plurality of antennas are connected in an opening portion at a forward end of each of the aforementioned antennas. Hence, there can be provided an antenna device which has a high gain with a simple planar configuration.
Further, the present invention is devised so that a plurality of antennas are connected in parallel with each other in a feeding portion. Hence, there can be provided an antenna device which has a high gain with a simple planar configuration.
Further, the present invention is devised so that the aforementioned antennas are formed by a pattern printed on a dielectric substrate. Hence, there can be provided an antenna device in which desired directivity can be obtained with a small-size and simple configuration and which has a high gain.
Further, the present invention is devised so that the plurality of antennas are connected to one another through transmission lines each having a predetermined electrical length. Hence, there can be provided an antenna device in which the antenna as a whole can be extended in the Y-plane direction easily, in which desired directivity can be obtained and which has a high gain.
Further, the present invention is devised so that the two pairs of aforementioned antennas are arranged with directions of main polarization perpendicular to each other and so that the antenna devices are fed with phase differences of 90 degrees. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a simple planar configuration to achieve a circular polarization antenna having a high gain.
Further, the present invention is devised so that the two pairs of aforementioned antennas are formed by print patterns arranged on opposite surfaces of a dielectric substrate. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a small-size and simple planar configuration to achieve a circular polarization antenna having a high gain.
Further, the present invention is devised so that a reflection plate is provided in proximity to the antenna. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a simple planar configuration and which has a high gain.
Further, the present invention is devised so that a plurality of passive elements are provided in proximity to the antenna. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a simple planar configuration and which has a high gain.
Further, the present invention is devised so that the aforementioned antennas are arranged as a radiator and a reflector while a plurality of wave directors each having a shape similar to that of each of the antennas are arranged in the directions of the main radiation. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a simple configuration and which has a high gain.
Further, the present invention is devised so that the two pairs of aforementioned antennas are arranged with the directions of main polarization being made identical with each other and with the directions of main radiation being made different from each other so that the antennas are fed with phase differences of 90 degrees from each other. Hence, there can be provided an antenna device in which desired radiation directivity can be obtained with a
Haruki Hiroshi
Saito Yutaka
Nguyen Hoang
Pearne & Gordon LLP
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