Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
1997-07-07
2001-08-28
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S7000MS
Reexamination Certificate
active
06281850
ABSTRACT:
BACKGROUND
1. Technical Field
The present invention relates generally to wireless communications, and, specifically, to an antenna system that includes a plurality of antenna elements, each of which is phase shifted so that the antenna system provides a relatively wide bandwidth of operation. The present invention further relates to an antenna system having phase shifting circuitry that produces an apparent short circuit to connected radio circuitry at harmonic frequencies of a frequency design range.
2. Related Art
It is well known to couple an antenna to radio circuitry contained within a host unit to enable wireless communication between the host unit and remotely located units. Typical implementations of such technology include cellular systems wherein portable terminals wirelessly communicate voice and data information to and from central locations via a wireless link.
A particular problem in the design of portable terminals operating in such systems relates to the antennas employed. Such antennas must perform adequately within a frequency design range while not interfering with space considerations and other physical aspects of the portable terminal. Antennas that protrude from the portable terminal perform well, but cause problems where the terminal must be able to dock into another device, and tend to be susceptible to breakage in rugged environments. Antennas that conform to the outer perimeter of the portable terminal do not interfere with physical aspects of the portable terminal, but their characteristics at harmonic frequencies do not always conform to FCC power level requirements, such requirements limiting permissible emissions at harmonic frequencies of the frequency design range.
In many applications, such as with spread-spectrum radio technology that has become popular in portable radio terminal communications, antennas must be designed to operate over a relatively large bandwidth. As the physical size of antennas decreases, however, so does respective bandwidth and gain. Prior, non-protruding antennas provided insufficient bandwidth and gain in spread-spectrum applications. Thus, heretofore, protruding antennas have proven the solution of choice in spread-spectrum applications even though they are often damaged during use.
Thus, there lies a need for an improved internal antenna design that provides adequate performance, operates adequately over a large bandwidth, conforms to FCC harmonic power level requirements, and yet is reasonably inexpensive to implement in portable terminals.
SUMMARY OF THE INVENTION
In one embodiment of the present invention a broadband antenna system includes a plurality of antenna elements, a plurality of phase shifting elements, and a circuitry connection. Each of the antenna elements has a respective antenna element operating bandwidth dependent upon the construction of the element. Each phase shifting element connects a respective one of the plurality of antenna elements to a common antenna connection with a respective bandwidth shift. The circuitry connector couples the common antenna connection to radio circuitry. With the plurality of antenna elements bandwidth shifted by the plurality of phase shifting elements, the antenna elements provide an antenna system with an operating bandwidth a multiple of the element operating bandwidths.
The circuitry connector transforms a frequency design range harmonic impedance at the common antenna connection to a minimum impedance at connected radio circuitry. Thus, with the frequency design range extending from approximately 902 Megahertz to approximately 928 Megahertz, the designated spread-spectrum bandwidth, transmitted harmonics are diminished to comply with FCC rules.
In one embodiment, the antenna system is part of a radio module that inserts into a portable terminal for operation. The radio module includes a radio module shell that contains the radio circuitry, with the plurality of antenna elements substantially conforming to the radio module shell. In the embodiment, a dielectric layer is disposed upon an external portion of the radio module shell and the plurality of antenna elements are disposed upon the dielectric layer. In the embodiment, the circuitry connector extends through the radio module shell and dielectric layer to connect the radio circuitry to the plurality of antenna elements.
In another embodiment, a plurality of insulative spacers connect the plurality of antenna elements to the dielectric layer such that the antenna elements reside adjacent to, and at least partially away from, the dielectric layer. In this fashion, the insulative spacers may be constructed to position the plurality of antenna elements with respect to the radio module shell to enhance performance.
In still other embodiments, a portion of the plurality of antenna elements substantially conforming to the radio module shell while a portion of the plurality of antenna elements substantially conform to the radio circuitry contained within the shell. In still further embodiments, a portion of the plurality of antenna elements reside within the radio module shell while a portion of the plurality of antenna elements reside external to the radio module shell.
Moreover, other aspects of the present invention will become apparent with further reference to the drawings and description which follow.
REFERENCES:
patent: 4356492 (1982-10-01), Kaloi
patent: 5440318 (1995-08-01), Butland et al.
Akin Gump Strauss Hauer & Feld L.L.P.
Clinger James
Intermec IP Corp.
Wong Don
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