Communications: radio wave antennas – Antennas – Microstrip
Patent
1999-06-11
2000-09-19
Wong, Don
Communications: radio wave antennas
Antennas
Microstrip
343829, 343846, H01Q 138
Patent
active
061219312
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to planar antenna assemblies for use in radiowave communications in general and in mobile satellite communication systems in particular.
PRIOR ART
The following is a list of references which are believed to be pertinent to the present invention: Microstrip Antennas," 5th International Conference on Antenna and Propagation, ICAP 87, pp. 485-488, March-April, York, UK. Letters, Vol. 24, No. 2, pp 96-97. Broadcast Systems for Train Applications," International Symposium of Antennas and Propagation, Tokyo, Japan, August. Periodic Metal Grids or Plates," IEEE Transactions and Antennas and Propagation, Vol. AP-30, pp. 904-909.
The above references will be referred to herein by indicating, within brackets, the name of the author or company and the year of publication, or the patent number, whatever the case may be.
BACKGROUND OF THE INVENTION
A major requirement in achieving a satisfactory communication link between a ground station and a satellite is that the ground station antenna point in the direction of the satellite, i.e. that the maximum of the ground station antenna's beam pattern be aligned along the line of sight between the ground station and the satellite. If the ground station is a mobile platform and/or the satellite orbit is geostationary, high or medium earth orbit then the antenna has to track the satellite in order to continuously point in the direction of the satellite so as to maintain a reasonable quality communication link.
In the following description and claims reference will be made to K.sub.u -band and L-band frequency ranges which are generally accepted to be defined as follows:
Various approaches are known for the architecture of antenna assemblies for mobile and non-mobile communication systems. The most common of these is a two-axis mechanical tracking system. The antenna itself may be a microstrip type or another, such as the NEC (see, e.g., Hiroyuki Inafuku, et al. (1989)) or KVH (KVH Industries, Inc., Middletown, R.I. U.S.A.) systems for, respectively, K.sub.u -band and L-band transmissions.
By another mechanical approach a single-axis mechanical tracking system is used, a typical example being the Nippon Steel's single-layer slotted-waveguide array system for K.sub.u -band transmission (Nippon Steel Corporation, Tokyo, Japan).
By yet another approach a combination of mechanical and electrical tracking is used, such as in the Ball communications system (Ball Telecommunication Products Division, Colorado, U.S.A.).
There are also known non-mechanical antenna assemblies for mobile communication systems. One such non-mechanical antenna described by CAL (CAL, Ottawa, Ontario, Canada) employs phase control on one axis and fixed beams on the other. A two-axis electrically-steered antenna assembly employing conventional phase control schemes has been described by TECOM (TECOM Industries, Inc., Chatsworth, Calif., U.S.A.).
All these known antenna assemblies for mobile communication systems suffer from the common drawback of operating in a single frequency band. Consequently, if one were interested in a mobile communication system operating in two different frequency bands then two of the above-mentioned antennas would have to be used which obviously increases significantly the spatial requirements. If the two-band service is provided through two different satellites, a mechanical pedestal cannot serve the two antennas. Furthermore, the antennas of the first three groups mentioned above suffer from the additional drawback of having mechanical-tracking systems which tend to be cumbersome and slow, limited in their angular coverage, and which are not planar and have to protrude from the surface to which they are applied. Thus, if such an antenna were to be mounted on a mobile platform such as the roof of a land vehicle, it would alter the aerodynamics of such platform.
There are known dual frequency planar antenna arrays in the art (e.g., U.S. Pat. No. 5,043,738 and U.S. Pat. No. 5,262,791). However, none of the known antennas of thi
REFERENCES:
patent: 5003318 (1991-03-01), Berneking et al.
patent: 5262791 (1993-11-01), Tsuda et al.
Chen Shih-Chao
Skygate International Technology NV
Wong Don
LandOfFree
Planar dual-frequency array antenna does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Planar dual-frequency array antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Planar dual-frequency array antenna will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1077969