Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
1999-07-30
2001-03-06
Phan, Tho (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S895000, C343S900000
Reexamination Certificate
active
06198443
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a multi-band antenna and more particularly to a switched, dual band, retractable antenna for a cellular communication device with the antenna automatically operating at two different frequency bands when the antenna is in its retracted position and when it is in its extended position.
2. Description of the Related Art
Due to overcrowding of the cellular telephone infrastructure, the cellular telephone industry is looking for ways to create room for the ever-increasing number of cellular telephone subscribers. The creation of room for additional cellular telephone subscribers must be accomplished without degrading the quality of the audio signal or compromising the reliability or integrity of the wireless connection. Much research has been done in this area and several possible solutions have been suggested. One solution is to switch from the existing analog to digital systems, which has been proven to create better performance in terms of quality of signal and speed. In other words, digital technology provides the carrier with the ability to fit more cellular conversations in a given band width as compared to the analog system.
Another solution for the problem described above is to create more room in terms of frequency band width. The FCC has allocated more frequency bands to be used for cellular telephone conversations. This new band of spectrum is located around the 2 Ghz band and is used for telephone systems such as PCS band (Personal Communication System), DCS 1800, and DECT. This higher band was chosen primarily because of the availability of bands close to the original 800-900 MHz.
Unfortunately, the changes outlined above have created additional problems in the industry. The cellular telephone infrastructure in the United States and in other countries was originally built for the 800 to 900 MHz frequencies. Now, with the advent of digital systems and the use of the new higher frequencies, a dilemma arises in switching over to the new system. Many geographical areas will add the higher frequencies and the digital systems as a second system and will keep the original analog system operational. Some locations will stay with the old analog systems longer than others; therefore, to ensure full coverage, the user will either have to carry two telephones or purchase a “Multi-Mode” telephone. A “Multi-Mode” telephone is a telephone that will automatically switch from one system to the other depending upon the way it is programmed.
SUMMARY OF THE INVENTION
The switched, dual band, retractable antenna of this invention provides an antenna system for a cellular communication device which will effectively resonate at two separate frequency bands when the antenna is in its extended position and will resonate at two separate frequency bands when the antenna is in its retracted position. The cellular communication device includes a housing having a receptacle at the upper end thereof which is RF coupled to the circuitry of the device with the circuitry including a matching network. An electrically conductive connector is positioned in the bore of the receptacle and is electrically coupled to the receptacle. An elongated first radiator is provided and has an electrically conductive bottom stop mounted on the lower end thereof which is electrically coupled thereto. An insulating sheath covers the first radiator above the bottom stop and extends beyond or above the upper end of the first radiator. A first electrically conductive contact is positioned on the sheath above the upper end of the first radiator. A second electrically conductive contact is positioned within the connector and is electrically coupled thereto. A non-conductive outer housing has its lower end embracing the upper end of the connector. A third electrically conductive contact is positioned within the outer housing above the second contact and is electrically insulated from the second contact and the connector. Inner and outer helical radiators are positioned in the outer housing and have their lower ends in electrical contact with the third contact. The first radiator is movable between retracted and extended positions with respect to the device and the outer housing. The bottom stop is in electrical contact with the first contact when the first radiator is in its extended position so that the first radiator will be able to transmit and receive in two separate frequency bands in the extended position. When the first radiator is in its extended position, the inner and outer helical radiators are electrically disconnected from the circuitry of the cellular communication device. When the first radiator is in its retracted position, the first radiator is electrically disconnected with the inner and outer helical radiators being connected to the circuitry of the device so that the inner and outer helical radiators will resonate at two separate frequencies.
It is a principal object of the invention to provide an antenna that will resonate at two specific frequencies.
It is a further object of the invention to provide a switched, dual band, retractable antenna for a cellular communication device which is capable of resonating at two separate frequencies when in the extended position and two separate frequencies when in the retracted position.
A further object of the invention is to provide a switched, dual band, retractable antenna which is easily detached from a communication device or secured thereto.
Yet another object of the invention is to provide an antenna of the type described which shows no degradation of electrical performance (gain) when compared to a single band antenna system of equal electrical length.
Still another object of the invention is to provide an antenna of the type described in which the monofilar radiation element and the two helical wound radiating elements operate independently of one another.
Still another object of the invention is to provide an antenna of the type described which is within the packaging parameters of most wireless communication devices.
Yet another object of the invention is to provide an antenna of the type described which has a robust electrical and mechanical design that can easily be tailored to any operational frequency band within the wireless communication frequency spectrum.
These and other objects will be apparent to those skilled in the art.
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“Lightweight
Blacksher Todd M.
Powles Jon J.
Centurion Intl., Inc.
Phan Tho
Thomte Dennis L.
Zarley McKee Thomte Voorhees & Sease
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