Communications: radio wave antennas – Antennas – With spaced or external radio wave refractor
Reexamination Certificate
2000-07-25
2001-12-11
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
With spaced or external radio wave refractor
C343S754000, C343S766000, C343S91100R
Reexamination Certificate
active
06329956
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-217156, filed Jul. 30, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a satellite communication antenna apparatus which can track a plurality of communication satellites at high precision and transmit and receive radio waves to and from them.
A conventional satellite communication antenna uses a parabolic antenna to transmit and receive radio waves to and from one communication satellite.
In recent years, a communication system is proposed which transmits and receives radio waves to and from, e.g., two satellites, among a plurality of communication satellites, located at the optimum positions for communication. Preferably, this satellite communication system tracks a plurality of communication satellites by changing its position such that its antenna unit is directed toward the positions of the communication satellites, and transmits and receives radio waves to and from the communication satellites.
One of satellite communication antennas used in this communication system uses a spherical radio wave lens and an antenna unit movable on an arcuate guide rail, and positions the antenna unit at a position opposite to the communication satellite through the radio wave lens, so that it can perform communication efficiently with the communication satellite.
The conventional satellite communication antenna described above has the following problems. If the antenna unit is driven along the arcuate rail, the mechanism becomes complicated, and position detection is difficult to perform.
As a driving force transmitting method, a ball screw method and belt method are generally employed. With these methods, however, it is difficult to move the antenna unit along an arc. If a ball screw or belt is added, the resultant mechanism becomes expensive. A guide or driving force transmitting mechanism made of a metal may undesirably disturb the intensity distribution of the radio waves to be transmitted and received. In order to transmit and receive radio waves to and from a plurality of communication satellites, a plurality of antenna units must be moved, leading to a further complicated mechanism.
As a position detection means, one is available that outputs an analog signal in accordance with the position of the antenna unit by utilizing a change in electrostatic capacitance upon movement of the antenna unit, as in a dielectric electrostatic sensor disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-196917. This method, however, lacks linearity, and cannot perform precise position detection.
As a countermeasure, one is available that detects the reception level of the radio waves from the satellite and performs position detection in accordance with the level, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 9-51220. According to this method, the antenna can always be set in a predetermined direction toward the position of the satellite. This method, however, cannot be used when radio waves from the satellite cannot be received.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a satellite communication antenna which can reliably transmit and receive radio waves to and from a communication satellite.
According to the present invention, there is provided a satellite communication antenna apparatus for performing communication with a communication satellite, comprising a spherical radio wave lens, an arcuate guide unit arranged along an outer surface of the radio wave lens and having a central point common with the radio wave lens, and an antenna unit reciprocally movable along the guide unit, wherein the guide unit is made of a material with a low dielectric constant.
According to the present invention, the guide unit is made of a material with a low relative dielectric constant so that it will not adversely affect the intensity distribution of the radio waves. Therefore, radio waves can be reliably transmitted to and received from the communication satellite.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 4531129 (1985-07-01), Bonebright et al.
patent: 5703603 (1997-12-01), Korzhenhov et al.
patent: 5748151 (1998-05-01), Kingston et al.
Hasegawa Yukihisa
Tateishi Taizo
Kabushiki Kaisha Toshiba
Nguyen Hoang
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Wong Don
LandOfFree
Satellite communication antenna apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Satellite communication antenna apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Satellite communication antenna apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2580808