Broadband multiple element antenna system

Information

  • Patent Grant
  • 6281850
  • Patent Number
    6,281,850
  • Date Filed
    Monday, July 7, 1997
    28 years ago
  • Date Issued
    Tuesday, August 28, 2001
    24 years ago
Abstract
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 operate in combination 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 a second end of the circuitry connector that connects to radio circuitry. The antenna system may be part of a radio module that includes a radio module shell containing radio circuitry, with the plurality of antenna elements substantially conforming to the radio module shell. The plurality of antennas may reside upon a dielectric layer disposed upon an external portion of the radio module shell. The circuitry connector extends through the radio module shell and dielectric layer to connect the radio circuitry to the plurality of antenna elements. Insulative spacers may 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 to enhance performance.
Description




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.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a mostly diagrammatic perspective view illustrating an antenna system disposed upon a radio module according to the present invention;





FIG. 2A

is an schematic diagram illustrating an equivalent circuit of the antenna system of

FIG. 1

according to the present invention;





FIG. 2B

is a schematic diagram similar to

FIG. 2A

but showing an exemplary embodiment of a circuitry connector according to the present invention;





FIG. 3

is a collection of graphs illustrating return loss characteristics of an antenna system according to the present invention as compared to return loss characteristics of other antennas;





FIG. 4A

is a sectional side view of a radio module including an antenna system according to the present invention;





FIG. 4B

is a sectional side view of an alternative radio module including an antenna system according to the present invention;





FIG. 4C

is a diagrammatic perspective view of a radio module having an antenna system according to the present invention;





FIG. 5A

is a sectional side view of a portable terminal having a radio module that includes an antenna system according to the present invention;





FIG. 5B

is a sectional side view of a portable terminal including an alternative embodiment of an antenna system according to the present invention;





FIG. 5C

is a sectional side view of a portable terminal including another alternative embodiment of an antenna system according to the present invention;





FIG. 5D

is a sectional side view of a portable terminal including still another alternative embodiment of an antenna system according to the present invention;





FIG. 6A

is a diagrammatic top view of antenna elements of an antenna system according to the present invention;





FIG. 6B

is a diagrammatic top view of an alternative embodiment of antenna elements of an antenna system according to the present invention; and





FIG. 6C

is a diagrammatic top view of still another embodiment of antenna elements of an antenna system according to the present invention.











DETAILED DESCRIPTION





FIG. 1

illustrates an antenna system


100


constructed according to the present invention. The antenna system


100


includes a first antenna element


104


, a second antenna element


106


and a third antenna element


108


disposed upon a dielectric layer


110


that resides upon a radio module shell


102


. A first phase shifting element


112


connects the first antenna element


104


to a common antenna connection


118


while second


114


and third


116


phase shifting elements connect the second


106


and third


108


antenna elements to the common antenna connection


118


, respectively.




As is known, operating characteristics of antenna elements vary with the size, shape, resitivity, proximity to dielectric and conductive structures as well as with various other physical properties of the antenna elements. Each of the antenna elements in the embodiment illustrated in

FIG. 1

has similar operating characteristics due to their similar construction. However, in other embodiments, to be described later herein, operating characteristics of the antenna elements vary.




The particular antenna system


100


system illustrated in

FIG. 1

is designed to operate over a frequency range reserved for spread-spectrum communications, the range generally extending from 902 to 928 Megahertz (MHz). Thus, the design of the antenna elements individually, and the antenna system


100


as a whole, is optimized for operation over this frequency range. Nonetheless, the teachings of the present invention apply to other frequency ranges as well.




As previously described, an operating difficulty associated with many wireless devices relates to the protruding nature of conventional antennas. While protruding antennas may present few problems when used with stationary wireless devices not limited to a physical space, protruding antennas often interfere with the operation of portable units, such as hand-held terminals, the antennas often being damaged during use. Therefore, as illustrated in

FIG. 1

, the antenna system


100


according to the present invention does not protrude from the radio module shell


102


upon which it is mounted so that it may not be damaged during normal use. Further, when attached to a host unit, such as a portable terminal, the antenna system


100


does not protrude from the portable terminal in a fashion which interferes with the operation of the portable terminal.




In the design of the antenna system


100


of

FIG. 1

, performance across a frequency design range, e.g. 902 MHz to 928 MHz, is required. The use of relatively small antenna elements


104


,


106


and


108


such as those illustrated in

FIG. 1

typically produces a narrow bandwidth due to the small dimensions of the antenna elements relative to wavelengths in the frequency design range. However, as will be further described herein, each of the antenna elements


104


,


106


and


108


exhibits adequate performance across a relatively narrow bandwidth. To compensate for such narrow bandwidths, the antenna system


100


according to the present invention employs the phase shifting elements


112


,


114


and


116


to frequency shift the bandwidths of each of the antenna elements


104


,


106


and


108


. Once frequency shifted, the bandwidths are presented at the common antenna connection


118


. By selectively frequency shifting the bandwidths of the antenna elements


104


,


106


and


108


, the antenna system


100


exhibits a wider bandwidth than does any of the antenna elements


104


,


106


and


108


individually. Phase shifting elements


112


,


114


and


116


provide transmission paths of varying lengths between their respective antenna elements and the common antenna connection


118


, the respective phase shifts also providing the desired bandwidth shifts.





FIG. 2A

is an schematic diagram illustrating generally an equivalent circuit of an antenna system


200


similar to the antenna system


100


of FIG.


1


. For illustrative purposes,

FIG. 2A

shows four antenna elements


202


,


204


,


206


and


208


. However, in other embodiments as few as two antenna elements or in excess of four antenna elements could be employed in constructing the antenna system


200


. The antenna elements


202


,


204


,


206


and


208


connect to a common antenna connection


218


via phase shifting elements


210


,


212


,


214


and


216


, respectively.




The circuitry connection


220


phase shifts the impedance of the antenna system at the common antenna connection


218


prior to its connection to radio circuitry


222


. However, the circuitry connection


220


is designed so that the impedance presented to the radio circuitry is minimized at harmonics of the frequency design range while providing satisfactory performance over the frequency design range. In the embodiment illustrated, the circuitry connection


220


transforms the impedance of the antenna system at the common antenna connection


218


so that it presents a short to the radio circuitry


222


. Impedance transformations, as well as bandwidth shifting, using same or similar techniques, is known in the art and will not be further described herein except to expand upon the teachings of the present invention.





FIG. 2B

is a schematic diagram similar to

FIG. 2A

but in addition showing an exemplary embodiment of a circuitry connector


220


according to the present invention. Numbering conventions remain consistent with

FIG. 2A

for common elements. As shown, the impedance at the common antenna connection


218


may be transformed using a section of transmission line, the length of which in wavelengths at a harmonic of the frequency design range, transforms the impedance so as to present a short circuit (or minimum impedance) to the radio circuitry


222


at the harmonic of the frequency design range. By presenting a short circuit to the radio circuitry


222


, the radio circuitry


222


can deliver no power for transmission to the antenna elements


202


,


204


,


206


and


208


, thus complying with FCC requirements. In other embodiments of the antenna system


200


, the circuitry connector


220


may include tuning stubs, shorts or lumped elements to assist in presenting a short circuit (or minimum impedance) to the radio circuitry


222


at the harmonic frequencies of the frequency design range.





FIG. 3

is a collection of graphs illustrating operating characteristics of an antenna system according to the present invention as compared to individual antenna characteristics. In particular, the collection of graphs compares characteristics of a three antenna element antenna system, same or similar to the antenna system


100


of

FIG. 1

, to characteristics of individual antennas. Each of the graphs plots return loss in decibels (dB) on the vertical axis versus frequency on the horizontal axis. Return loss is a measure of energy not radiated by an antenna which “returns” to the radio circuitry.




UHF antenna return loss characteristics


302


shows that a respective UHF antenna has a minimum return loss at a center design frequency


303


at which point the antenna provides maximum transmission of energy delivered to it by the radio circuitry. While the UHF antenna exhibits a relatively wide bandwidth, its relatively large construction is unsuitable for those uses contemplated by the antenna system according to the present invention.




One-element antenna return loss characteristics


304


provide a minimum return loss at a center design frequency


305


but has a relatively narrow bandwidth. Such return loss characteristics may be produced by one of the antenna elements


104


,


106


or


108


of the antenna system


100


illustrated in FIG.


1


. The return loss characteristics


306


of a three-element antenna system wherein the bandwidths of the antenna elements are frequency shifted with respect to one another produces minimum return loss at three separate frequencies


307


,


308


and


309


. With the frequency shifting of these three elements correctly executed, bandwidths of the antenna elements overlap to produce the three-element antenna system return loss characteristics


310


illustrated, such return loss characteristics corresponding to the antenna system


100


illustrated with reference to FIG.


1


. As is illustrated, the bandwidth


312


extends across the frequency design range, 902 to 928 MHz in the present embodiment.




The teachings of the present invention may be extended to antenna systems having two antenna elements or in excess of three antenna elements, depending upon the requirements of the particular design. As is apparent from

FIG. 3

, application of the teachings of present invention for a five antenna element system, for example, would produce return loss characteristics across a design range with five sub-minimas of return loss, each of the sub-minimas corresponding to one of the five antenna elements of the antenna system.





FIG. 4A

is a sectional side view of a radio module


400


including an antenna system according to the present invention. The radio module


400


includes a radio module shell


402


formed of a thin, light-weight metal and adapted to be received by a portable terminal, such as a hand-held portable data terminal. The radio module


400


interfaces with a host system via a PCMCIA, PCI, ISA or other standard or proprietary interface. The radio module


400


could also be received by other portable devices such as code readers, scanners, printers and other portable devices that employ wireless communications. Further, the radio module


400


could also be used with a stationary device as well.




The radio module includes radio circuitry


404


contained within the radio module shell


402


. The radio circuitry


404


includes, for example, a radio processor, a radio transceiver, memory, host interface circuitry and various other circuitry mounted on a printed circuit board


405


held in place within the radio module shell


402


by insulating mounts


406


.




The circuitry connector


408


is partially mounted upon the circuit board


405


that also contains the radio circuitry


404


. However, in other embodiments, the circuitry connector


408


may be disposed on an inner surface of the radio module shell


402


. When the circuitry connector


408


is disposed upon an inner surface of the radio module shell


402


, the circuitry connector


408


must be electrically isolated from the conductive radio module shell


402


. As an example of the construction that may be employed, the circuitry connector


408


may include an insulated cable


409


that extends through the radio module shell


402


to make connection at the common antenna connection.




An antenna element


410


(other antenna elements are not shown since the FIG. is a side view) resides upon a dielectric layer


412


, both of which conform to an outer surface of the radio module shell


402


. For optimum performance, the dielectric layer


412


comprises a dielectric having a relatively small dielectric constant. Teflon, for example, has a relative dielectric constant of approximately 2.2 and enhances operation of the antenna element


410


by effectively reducing the wavelength of radiated waves. Thus, shorter antenna elements


410


may employed to produce equivalent performance when using the relatively lower dielectric constant material for the dielectric layer


412


.





FIG. 4B

is a sectional side view of an alternative radio module


450


including an antenna system according to the present invention. The radio module


450


differs from the radio module


400


of

FIG. 4A

in that an antenna element


460


(one of a plurality) is raised above a dielectric layer


452


that provides insulation from the conductive radio module shell


402


. Insulative spacers


454


, formed of nylon, for example, support the antenna element


460


above the dielectric layer


452


at an angle with respect to the dielectric layer


452


. By raising the antenna element


460


above the dielectric layer


452


and by using a slightly larger antenna element


460


, equivalent performance may be achieved using a less expensive, relatively lower dielectric constant material, such as FR


4


which has a relative dielectric constant of approximately 4.2.





FIG. 4C

is a diagrammatic perspective view of a radio module


470


having an antenna system constructed according to the present invention, similar to the antenna system illustrated with reference to FIG.


4


B. The antenna system includes first


472


, second


474


and third


476


antenna elements raised above a dielectric layer


478


residing upon the radio module shell


402


. Insulating spacers


480


connect the antenna elements


472


,


474


and


476


to the dielectric layer


478


, positioning the elements so that an array formed by the elements has improved performance. A first end


482


of first antenna element


472


resides more closely to the dielectric layer


478


than does a second end


484


of the first antenna element


472


. Thus, a longitudinal axis of the first antenna element


472


resides non-parallel to the dielectric layer


478


. A horizontal axis of the first antenna element


472


also resides non-parallel to the dielectric layer. In the illustrated embodiment, the second antenna element


472


resides substantially parallel to the surface of the dielectric layer


478


. Further, the third antenna element


474


orients to complement orientation of the first antenna element


470


so that, in combination, the antenna elements provide enhanced performance over a desired frequency range.





FIG. 5A

is a sectional side view of a portable terminal


500


A having a radio module


502


that includes an antenna system according to the present invention. The portable terminal


500


A may include, for example, terminal processing circuitry, a display, a keypad, a battery pack and other components that may be required to perform data collection, data processing and data communication functions. While installation of the radio module


502


within the portable terminal


500


A is illustrated, the radio module


502


could also be installed within scanners, code readers, digital cameras, portable printers, data pads and other units requiring a wireless communication link with a remote location.




A thin, lightweight metal radio module shell


503


houses radio circuitry


504


as well as a circuitry connector


512


that performs the previously described impedance transformations. The radio circuitry


504


includes interface circuitry that allows the radio module


502


to communicate with the portable terminal


500


A.




A first antenna element


508


resides atop a dielectric layer


506


that isolates the first antenna element


508


from the radio module shell


503


. Additional antenna elements are not shown in this sectional side view but reside adjacent the first antenna element


508


, the construction similar to that illustrated with reference to FIG.


1


. The circuitry connector


512


includes a short insulated cable section


514


that passes through a hole formed in the radio module shell


503


and that makes connection with the first antenna element


508


via a common antenna connection.




The antenna elements of the illustrated radio module


502


reside directly upon the dielectric layer


506


which resides directly upon the radio module shell


503


. Thus, as previously described, the configuration requires a dielectric with a relatively low dielectric constant for maximum performance. With the illustrated compact construction, a protective covering


510


that is transmissive to generated radio waves may be constructed simply and inexpensively to protect the antenna elements and those portions of the dielectric layer exposed.





FIG. 5B

is a sectional side view of a portable terminal


500


B having a radio module


520


that includes an alternative embodiment of an antenna system according to the present invention. As contrasted to the construction of the radio module of

FIG. 5A

, the first antenna element


522


of the radio module


520


is supported adjacent the dielectric layer


506


by insulating spacers


524


, such construction similar to that illustrated with respect to FIG.


4


C. To protect the antenna elements, protective cover


526


, constructed of a material transmissive at radio frequencies extends beyond the antenna elements and provides a barrier to contact.





FIG. 5C

is a sectional side view of a portable terminal


500


C having a radio module


550


that incorporates another embodiment of an antenna system according to the present invention. The radio module


550


houses radio circuitry as well as the components of the antenna system. Thus, the radio module shell


553


is transmissive to radio waves produced by the antenna system and is constructed of plastic or another transmissive material that provides protection to the components housed within the radio module shell


553


. Radio circuitry components are disposed upon a printed circuit board


554


mounted within the radio module shell


553


. The printed circuit board


556


includes shielding that shields the radio circuitry components from transmissions produced by the antenna elements. A dielectric layer


556


connects directly to the shielded printed circuit board with the antenna elements residing atop the dielectric layer


556


. The first antenna element


552


, as well as additional antenna elements, not shown, couple to the radio circuitry via a circuitry connector


512


that includes a shielded cable


514


that that extends through the printed circuit board


556


and dielectric layer


556


.





FIG. 5D

is a sectional side view of a portable terminal


500


D having a radio module


570


that includes still another alternative embodiment of an antenna system according to the present invention. Construction of the radio module


570


is similar to that of the radio module


550


illustrated with respect to FIG. SC except that the first antenna element


572


(as well as other antenna elements) are located apart from the dielectric layer


556


, mounted via insulative spacers


574


. Thus, a dielectric having a different dielectric constant may be used with the construction of

FIG. 5D

to obtain performance similar to that obtained by the construction of FIG.


5


C.





FIG. 6A

is a diagrammatic top view of a portion of an antenna system


600


according to the present invention. In the embodiment, antenna elements


600


are disposed upon a dielectric layer


602


and are formed of a conductive material such as a thin layer of copper. First


608


, second


610


and third


612


antenna elements are cut separately from a sheet of copper using techniques known in the art and then be disposed upon the dielectric layer


602


. The antenna elements may be either disposed directly upon the dielectric layer or be attached by insulative spacers


620


so that at least some of the antenna elements reside above the dielectric layer


602


.




First


614


and second


616


phase shifting elements couple antenna elements


608


,


610


and


612


, respectively, to a common antenna connection


618


. A circuitry connector (not shown) connects the common antenna connection


618


to radio circuitry (not shown) in a manner previously described. As illustrated the phase shifting elements


614


and


616


provide transmission paths of varying length between the common antenna connection


618


and respective antenna elements. In this fashion, the bandwidth of respective antenna elements is shifted prior to connection at the common antenna connection


618


to produce the relatively wide bandwidth of the antenna system as a whole. The phase shifting elements


614


and


616


may also have characteristic impedances that are tailored so as to perform the designed phase shifting.




Impedance matching elements


603


,


604


,


615


,


617


,


619


and


621


are designed such that the impedances of the antenna elements


608


,


610


and


612


at connection points to the phase shifting elements


614


and


616


match the impedance of the phase shifting elements


614


and


616


. The length and width of these impedance matching elements are designed to perform such impedance matching. In the case of the antenna system


600


, the impedance of each phase shifting element


614


and


616


is approximately 150 Ohms. The impedance matching elements


603


,


604


,


615


,


617


,


619


and


621


are designed, therefore, to match such 50 Ohm impedance at corresponding connection points. The combined impedance at the antenna connector


618


is then the parallel combination of three 150 Ohm loads, which is 50 Ohms. In an exemplary embodiment, 50 Ohms is the impedance seen by connected radio circuitry, such impedance at the desired design input level.





FIG. 6B

is a diagrammatic top view of an alternative embodiment of an antenna system


640


according to the present invention. A first


642


and second


644


antenna elements are disposed upon or substantially adjacent to a dielectric layer


602


. Insulative spacers


620


may be employed to physically separate all or a portion of the antenna elements


642


and


644


from the dielectric layer


602


to enhance performance of the antenna system


640


.




As shown, a phase shifting element


648


couples the second antenna element


644


to a common antenna connection


650


with a phase shift. The design of such phase shifting element


648


, as discussed with reference to

FIG. 3

, shifts the bandwidth of antenna element


644


so that the bandwidth of the antenna element in combination with the bandwidth of antenna element


642


exceeds the individual bandwidths of the antenna elements


642


and


644


. Impedance matching elements


649


and


651


match the impedance of antenna element


644


to phase shifting element


648


. Further, impedance matching elements


646


and


647


match the impedance of antenna element


642


to the phase shifting element


648


and such that a design impedance is presented at the common antenna connection


650


.




Thus, constructed in combination as it is, the antenna system


640


provides a relatively wider bandwidth from a relatively smaller antenna package. As is evident, the principles discussed with respect to construction of an antenna system according to the present invention may be extended to a greater number of antenna elements using the same or similar principles.





FIG. 6C

is a diagrammatic top view of still another embodiment of an antenna system


670


according to the present invention. The antenna system


670


includes a first antenna element


672


that conforms to radio circuitry contained within a radio module or to an inner surface of a radio module shell in which it is contained. Thus, the antenna system


670


may be contained in a radio module, such as the one illustrated with respect to FIG.


5


C. In another embodiment, the antenna elements may be disposed outside of the radio module shell in a pattern to enhance gain or bandwidth of each antenna element or the antenna system as a whole.




A second antenna element


674


may include a standard shape such as that illustrated, or may include an differing shape designed to conform to other components within the radio module. Phase shifting element


676


couples the antenna element


674


to a common antenna connection


618


. Impedance matching elements


681


and


683


match the impedance of the antenna element


674


to the phase shifting element. Further, impedance matching elements


678


and


679


match the impedance of antenna element


672


to the impedance of the phase shifting element


676


and such that a design impedance is presented at the common antenna connection


618


. A circuitry connector, such as one previously described, couples the common antenna connection


618


to radio circuitry contained within the radio module.




In view of the above detailed description of the present invention and associated drawings, other modifications and variations will now become apparent to those skilled in the art. It should also be apparent that such other modifications and variations may be effected without departing from the spirit and scope of the present invention as set forth in the claims which follow.



Claims
  • 1. A broadband antenna system comprising:a plurality of antenna elements, each antenna element having a respective antenna element operating bandwidth; a plurality of phase shifting elements, each phase shifting element connecting a respective one of the plurality of antenna elements to a common antenna connection with a respective bandwidth shift, at least two of the phase shifting elements providing transmission paths of different lengths between a respective one of the plurality of antenna elements and the common antenna connection; a circuitry connector coupled to the common antenna connection; and the plurality of antenna elements, bandwidth shifted by the plurality of phase shifting elements, in cooperation providing an operating bandwidth exceeding the individual element operating bandwidths.
  • 2. The broadband antenna system of claim 1, the circuitry connector transforming frequency design range harmonic impedance at the common antenna connection to a minimum impedance at a second end of the circuitry connector.
  • 3. The broadband antenna system of claim 1, further comprising:a radio module shell; radio circuitry contained within the radio module shell coupled to the common antenna connection via the circuitry connector; and the plurality of antenna elements substantially conforming to the radio module shell.
  • 4. The broadband antenna system of claim 3, further comprising:a dielectric layer disposed upon the radio module shell; and the plurality of antenna elements disposed upon the dielectric layer.
  • 5. The broadband antenna system of claim 3, further comprising:a dielectric layer disposed upon the radio module shell; and a plurality of insulative spacers connecting 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.
  • 6. The broadband antenna system of claim 5, the plurality of insulative spacers positioning the plurality of antenna elements angularly with respect to the radio module shell to enhance performance.
  • 7. The broadband antenna system of claim 1, further comprising:a radio module shell; radio circuitry contained within the radio module shell connected to the common antenna connection via the circuitry connector; a portion of the plurality of antenna elements substantially conforming to the radio module shell; and a portion of the plurality of antenna elements substantially conforming to the radio circuitry.
  • 8. The broadband antenna system of claim 1, further comprising:a radio module shell; radio circuitry contained within the radio module shell connected to the common antenna connection via the radio circuitry connector; and at least a portion of the plurality of antenna elements residing within the radio module shell.
  • 9. A broadband radio for operation with a host unit, the broadband radio comprising:a radio housing; radio circuitry contained within the radio housing; a plurality of antenna elements, each antenna element having a respective antenna element operating bandwidth; a plurality of phase shifting elements disposed adjacent the radio housing, each phase shifting element connecting a respective one of the plurality of antenna elements to a common antenna connection with a respective bandwidth shift, at least two of the phase shifting elements providing transmission paths of different lengths between a respective one of the plurality of antenna elements and the common antenna connection; a circuitry connector that couples the radio circuitry to the common antenna connection; and the plurality of antenna elements, bandwidth shifted by the plurality of phase shifting elements, in cooperation providing an operating bandwidth exceeding the individual element operating bandwidths.
  • 10. The broadband radio of claim 9, the circuitry connector transforming frequency design range harmonic impedance at the common antenna connection to a minimum impedance at the radio circuitry.
  • 11. The broadband radio of claim 9, the plurality of antenna elements substantially conforming to the radio housing.
  • 12. The broadband radio of claim 9, further comprising:a dielectric layer disposed upon the radio housing; and the plurality of antenna elements disposed upon the dielectric layer.
  • 13. The broadband radio of claim 9, further comprising:a dielectric layer disposed upon the radio housing; and a plurality of insulative spacers connecting 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.
  • 14. The broadband radio of claim 13, the plurality of insulative spacers positioning the plurality of antenna elements angularly with respect to the radio housing to enhance performance.
  • 15. The broadband radio of claim 9, wherein:a portion of the plurality of antenna elements substantially conform to the radio housing; and a portion of the plurality of antenna elements substantially conform to the radio circuitry.
  • 16. The broadband radio of claim 9, wherein:a portion of the plurality of antenna elements resides within the radio housing; and a portion of the plurality of antenna elements reside external to the radio housing.
CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation in part of U.S. patent application Ser. No. 08/800,399, filed Feb. 14, 1997, now abandoned, which in turn claimed priority under 35 U.S.C. Sec. 119(e) to U.S. Provisional Application Serial No. 60/011,844 filed Feb. 16, 1996. Such applications are hereby incorporated herein by reference in their entirety.

US Referenced Citations (2)
Number Name Date Kind
4356492 Kaloi Oct 1982
5440318 Butland et al. Aug 1995
Provisional Applications (1)
Number Date Country
60/011844 Feb 1996 US
Continuation in Parts (1)
Number Date Country
Parent 08/800399 Feb 1997 US
Child 08/888660 US