Communications: radio wave antennas – Antennas – Active sleeve surrounds feed line
Reexamination Certificate
1999-07-30
2001-07-24
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Active sleeve surrounds feed line
C343S874000, C343S875000, C343S895000
Reexamination Certificate
active
06266026
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the art of antennas for radios and communications equipment located in vehicles, and more particularly to a new and improved antenna system having multiple band, broad band operation.
There are many instances when it is desirable to operate commercial radio transmitters from a motor vehicle while remaining covert or undercover. There are times when the need to operate more than one band is also required. Another purpose for using one antenna installation has no covert application, however the cost factor does enter into the picture. One antenna installation costs half as much as two installations. This is true financially and time wise also. There are several combinations that are standard:
Low Band/High Band
Low Band/UHF Band
High Band/UHF Band
High Band/800 MHz to 900 MHz
High Band/900 MHz to 970 MHz
Uhf Band/800 MHz to 900 MHz
UHF Band/900 MHz to 970 MHz
Cellular Band/PCS Band
The foregoing band combinations are a partial list of the band combinations possible using these techniques, but should not be considered a complete listing. As new bands become available for communications these methods can be used to operate multiple bands from one antenna while remaining covert or less expensive.
SUMMARY OF THE INVENTION
The present invention provides an antenna system having one or more of the following characteristics or features:
Disguised Antenna System;
Dual band operation;
Broad band operation;
Isolation between transceivers to eliminate the need for change over switches or relays; and
Built in broadcast coupler
The foregoing can be provided by decoupling the antenna mast for multiple bands by use of a quarter wave decoupling stub or by the use of a frequency selective trap. As a result the antenna has multiple resonances simultaneously. The foregoing also can be accomplished by selecting antenna mast lengths that are harmonically related to provide a single element with multiple resonances without external devices. A diplexer comprising the combination of high and low pass filters and a broadcast coupler can be connected to the antenna feed point with transceivers operating in the different bands being connected to the high and low pass filters. The simultaneous multiple resonances ensure a matched impedance at the antenna feed point so that when a communications device is connected by a length of coax to the antenna feed point the matched impedance will be maintained at the feed point regardless of the length of the coax.
The following detailed description of the invention, when read in conjunction with the accompanying drawings, is in such full, clear, concise and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the invention.
REFERENCES:
patent: 3950757 (1976-04-01), Blass
patent: 4441108 (1984-04-01), Ten Pas
patent: 4509056 (1985-04-01), Ploussios
patent: 4968991 (1990-11-01), Yamazaki
patent: 5311201 (1994-05-01), Lillie et al.
patent: 5451968 (1995-09-01), Emery
patent: 5798736 (1998-08-01), Hall
patent: 5995065 (1999-11-01), Kitchener et al.
patent: 6034648 (2000-03-01), Hope
Hodgson & Russ LLP
Sti-Co Industries, Inc.
Tran Thuy Vinh
Wong Don
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