Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/0464—Annular ring patch
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/0414—Substantially flat resonant element parallel to ground plane, e.g. patch antenna in a stacked or folded configuration
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
  • H01Q1/246—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for base stations

Definitions

• Dual polarization states can increase performance of a base station antenna that is designed to communicate with portable communications units having mobile antennas.
• the effectiveness of dual polarization for a base station antenna relies on the premise that transmit polarization of a typically linearly polarized mobile or portable communications unit will not always be aligned with a vertical linear polarization for the antenna at a base station site nor will it necessarily be in a linearly polarized state.
• depolarization which is the conversion of power from a reference polarization into the cross polarization, can occur along the multi-path propagation between the mobile user and a base station.
• dual polarization can be employed at a base station antenna in order to communicate with mobile or portable communication units.
• dual polarization or polarization diversity typically requires a significant amount of hardware that can be rather complex to manufacture.
• conventional dual polarized antennas typically cannot provide symmetrical radiation patterns where respective electric field (E) and magnetic field (H) plane beamwidths are substantially equal.
• conventional antenna systems usually cannot provide for a wide range of magnetic field (H) plane beamwidths from a compact antenna system.
• the conventional art typically requires costly and bulky hardware in order to provide for a wide range of operational beamwidths, where beamwidth is measured from the half-power points (- 3dB to -3dB) of a respective RF beam.
• Figure 14 is an exemplary logical flow diagram describing a method for producing dual simultaneous polarization states and a rotationally symmetric radiation pattern where the electric field and magnetic field beamwidths of individual radiating elements are substantially equal and symmetrical.
• Figure 3 further illustrates an isometric view of the antenna system 100 which can comprise one or more radiating elements 110 and beam forming elements 140.
• the antenna system 100 as illustrated in Figure 3 is very compact yet high performance product that can be placed or positioned in a very narrow or small volume such as a radome.
• the length L can be approximately 48 inches while the width W can be approximately 8 inches.
• the height H of the antenna system 100 (including a radome) can be 2.75 inches.
• the operating frequency range is approximately from 806 MHz to 896 MHz. In terms of wavelength, this means that the width W can be less than or equal to a six-tenths (0.6) of a wavelength.
• FIG. 6 is a functional block diagram illustrating the various components which make up the compact antenna system 100. This figure highlights one exemplary and preferred arrangement of the components of the antenna system 100. Of the components illustrated in Figure 6, there are a select few which may be considered the core components of the Antenna System 100 that provide the enhanced functionality in such a compact antenna volume.
• the core components may be considered as the beam forming element 140, the radiating element 110, the printed circuit board 150, the ground plane 530 with slots 700, and the cavity 200.
• FIG. 7A further details of the slots 700A-C disposed within the ground plane 530 are shown.
• the ground plane 530 contains the slots 700 used to excite the cavity 200. These slots 700 can be preferably etched out of the ground plane 530 by photolithography techniques.
• the cavity 200 is preferably made from aluminum and has a design which promotes accurate repeatability while substantially reducing passive intermodulation (PEM).
• PEM passive intermodulation
• the cavity 200 comprises walls 1000A-D that are spaced apart from each other by a predetermined distance d (See Figure 10B).
• This predetermined distance d between the walls 1000 at the corners allows for reasonable tolerances in manufacturing, but is typically small enough such that the cavity 200 electrically operates as a closed boundary for RF energy propagating within the cavity 200.
• the cavity 200 can function electrically as a closed boundary when mechanically the cavity has open corners.
• the open corners of the cavity typically have dimensions that permit resonance while substantially reducing passive intermodulation (PIM).
• the open corners of the cavity also function as drainage holes for any condensation that may form within a respective cavity 200.
• this figure illustrates a linear plot of antenna gain versus the angular position of a radiation pattern for a ninety (90) degree beamwidth embodiment of antenna system 100. That is, this graph illustrates the gain for an antenna system 100 designed to have 90 degrees of coverage between respective three (3) dB or half power points in a radiation pattern.
• This graph demonstrates that the (E) and (H) beamwidth of an independent polarization are substantially equal. Substantially equal (E) and (H) plane beamwidths will maintain the orthogonality of the two polarization states over a given angular region to insure that two received signals are highly decorrelated. Two polarization states are not shown in Figure 12 A, only one polarization state with substantially equal E and H planes is illustrated. For this particular exemplary embodiment, the angular region has been designed for 90 degrees.
• this figure illustrates a plot of antenna gain versus the angular position of a radiation pattern for a sixty-five (65) degree beamwidth embodiment of antenna system 100. That is, this graph illustrates the gain for an antenna system 100 designed to have 65 degrees of coverage between respective three (3) dB or half power points in a radiation pattern.
• This graph also demonstrates that the (E) and (H) beamwidth of an independent polarization are substantially equal. Substantially equal (E) and (H) plane beamwidths will maintain the orthogonality of the two polarization states over a given angular region to insure that two received signals are highly deco ⁇ elated.
• the logical flow diagram 1400 highlights some key functions of the antenna system 100.
• Step 1410 is the first step of the inventive process 1400 in which the slot 700 disposed within the ground plane 530 are oriented orthogonal to one another. By orienting the slots orthogonal to one another in step 1410, isolation between separate RF polarizations can be maintained while cross-polarization can be reduced.
• step 1430 RF energy is propagated along the feed network 130 of the printed circuit board 150.
• step 1440 heat is dissipated from the feed network 130 into flanges 520 of the cavity 200.
• Figure 16 illustrates an exemplary beam width adjustment routine 1480 of Figure 14.
• Routine 1480 begins with step 1600, in which it is determined whether the beamwidth of the antenna system 100 needs adjustment. If the inquiry to decision step 1600 is positive, then the "y es " branch is followed to step 1610. In step 1610, the beamwidth of the antenna system 100 can be adjusted by changing the spacing between the beam forming element 140 and the radiating element 110. Typically, the spacing is of a non-resonant dimension since in one exemplary feature of the present invention, the beam forming element 140 does not resonate RF energy. If the inquiry to decision step 1600 is negative, then the "no" branch is followed to step 1640. In step 1620, it is determined whether further beamwidth adjustment is needed.
• the present invention employs circular metallic radiating elements for the purpose of obtaining circular and symmetric (E) and (H) plane 3 dB beamwidths having simultaneous slant 45 dual polarization states.
• the spacing S2 of the radiating element 110 relative to the printed circuit board 150 and the diameter of the radiating element 110 is used to improve the impedance beamwidths of the antenna system 100.
• the beam forming element 140 is used to vary the 3 dB beamwidths to obtain desired values by adjusting its diameter and varying its spacing SI between the radiating element 110 and the beam forming element 140.
• the present invention further incorporates a low PIM design approach by utilizing capacitive coupling of all potential metal-to-metal junctions through employing non-conductive planar fasteners and open corners for the resonant cavity 200.
• the low PIM design approach also yields efficient and low cost manufacturing methods.
• the planar fasteners 540 eliminate any need for soldering the resonant cavity 200 to the ground plane 530.
• the use of dielectric spacers 500 further eliminates any need for costly dielectric spacer sheets while also reducing assembly time.

Landscapes

• Waveguide Aerials (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Aerials With Secondary Devices (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

ID=21742348

Family Applications (1)

Country Status (5)

Cited By (2)

Citations (6)

• 2001
  • 2001-02-16 MX MXPA03007355A patent/MXPA03007355A/es unknown
  • 2001-02-16 WO PCT/US2001/005232 patent/WO2002067376A1/en not_active Application Discontinuation
  • 2001-02-16 BR BR0116898-3A patent/BR0116898A/pt not_active IP Right Cessation
  • 2001-02-16 EP EP01912807A patent/EP1360742A1/en not_active Withdrawn
  • 2001-02-16 CA CA002438545A patent/CA2438545C/en not_active Expired - Fee Related

Patent Citations (6)

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