Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/30—Arrangements for providing operation on different wavebands
  • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
  • H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
  • H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point
  • H01Q5/364—Creating multiple current paths
• • 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
  • H01Q9/44—Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions
• • 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
• • 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
  • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
  • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/30—Arrangements for providing operation on different wavebands
  • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
  • H01Q5/342—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes
  • H01Q5/357—Individual or coupled radiating elements, each element being fed in an unspecified way for different propagation modes using a single feed point
  • H01Q5/364—Creating multiple current paths
  • H01Q5/371—Branching current paths
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• • 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
  • H01Q9/045—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means
  • H01Q9/0457—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular feeding means electromagnetically coupled to the feed line
• • 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
  • H01Q9/06—Details
• • 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
  • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
  • H01Q9/40—Element having extended radiating surface
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
  • H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Definitions

• the present application relates generally to wireless communications devices and, more particularly, to antennas used in such devices.
• Many communications devices require multiple antennas that are located in close proximity (e.g., less than a quarter of a wavelength apart) and that can operate simultaneously within the same frequency band.
• Common examples of such communications devices include communications products such as wireless access points and femtocells.
• Many communications system architectures such as Multiple Input Multiple Output (MIMO), and diversity
• MIMO Multiple Input Multiple Output
• diversity that include standard protocols for mobile wireless communications devices (such as 802.11 n for wireless LAN, and 3G data communications such as 802.16e (WiMAX), HSDPA, and IxEVDO) require multiple antennas operating simultaneously.
• a multi-port antenna structure in accordance with one or more embodiments of the invention includes a plurality of electrically conductive elements arranged generally symmetrically about a central axis with a gap between adjacent electrically conductive elements.
• Each of the electrically conductive elements has opposite ends and a bent middle portion therebetween, with the bent middle portion being closer to the central axis than the opposite ends.
• Each of the electrically conductive elements is configured to have an electrical length selected i to provide generally optimal operation within one or more selected frequency ranges.
• Each of a plurality of antenna ports is connected to adjacent electrically conductive elements across the gap therebetween such that each antenna port is generally electrically isolated from another antenna port at a given desired signal frequency range and the antenna structure generates diverse antenna patterns.
• FIGURE 1 is a schematic illustration of an exemplary planar three port antenna in accordance with one or more embodiments of the invention.
• FIGURE 2A is a perspective view of an exemplary single-band planar three-port antenna manufactured on a printed circuit substrate in accordance with one or more embodiments of the invention.
• FIGURE 2B is a top plan view of the antenna of FIGURE 2A.
• FIGURE 3A is a graph illustrating the return loss (S11 ) of the antenna of FIGURE 2.
• FIGURE 3B is a graph illustrating the port to port coupling (S12) for the antenna of FIGURE 2.
• FIGURE 3C is a graph illustrating the of the radiation efficiency for antenna of FIGURE 2.
• FIGURE 3D is a graph illustrating the square of the pattern correlation coefficients for the antenna of FIGURE 2.
• FIGURE 3E is a graph illustrating the azimuthal gain plots for the antenna of FIGURE 2.
• FIGURE 4 is a perspective view of an exemplary dual-band planar three-port antenna manufactured on a printed circuit substrate in accordance with one or more embodiments of the invention.
• FIGURE 5A is a graph illustrating the VSWR of the antenna of FIGURE 4.
• FIGURE 5B is a graph illustrating the port to port coupling (S12) for the antenna of FIGURE 4.
• FIGURE 5C is a graph illustrating the of the radiation efficiency for the antenna of FIGURE 4.
• FIGURE 5D is a graph illustrating the square of the pattern correlation coefficients for the antenna of FIGURE 4.
• FIGURE 5E is a graph illustrating the azimuthal gain plots for the antenna of FIGURE 4 at a frequency of 2440 MHz.
• FIGURE 5F is a graph illustrating the azimuthal gain plots for the antenna of FIGURE 4 at a frequency of 5250 MHz.
• an antenna structure with multiple antenna ports is provided to achieve compact size, while generally maintaining isolation and antenna independence between ports.
• An antenna structure 100 in accordance with one or more embodiments is shown diagrammatically in FIGURE 1.
• the antenna structure 100 includes three conductive elements 101 , 102, and 103, each with an electrical length of nominally one half of the wavelength at the desired frequency of operation.
• the elements 101 , 102, and 103 all lie within a single geometric plane and lie about a common axis of symmetry 110 that is normal to the plane.
• Each element 101 , 102, and 103 includes opposite ends and a bent middle portion therebetween.
• each element 101 , 102, and 103 is closer to the axis of symmetry 110, while the ends extend away from the axis.
• Antenna ports 104, 105, and 106 are positioned across the gaps between adjacent elements 101 , 102, and 103.
• Excitation of the antenna 100 by applying a signal at one of the ports 104, 105, and 106 will evidence a resonant condition with currents flowing on each of the elements 101 , 102, and 103.
• the attachment of ports 104, 105, and 106 between adjacent elements 101 , 102, and 103 however allows for currents to flow on each of the elements 101 , 102, and 103 without passing through the ports, thereby allowing for the ports 104, 105, and 106 to remain generally isolated from each other.
• the degree of isolation is a function of the location of the ports and the coupling between the conductive elements. The coupling is controlled by the distance between the elements, in particular how close the ends of the conductive elements are to each other.
• the input impedance of the antenna is also a function of the geometry and, therefore a particular design may involve a tradeoff between geometry best for isolation and best for a desired input impedance, e.g., 50 ohms. Matching components also may be added to transform the input impedance with some independence from the isolation. Antenna elements with a planar width as opposed to thin wire shapes are generally advantageous for obtaining larger antenna bandwidths and smaller parasitic losses.
• Each antenna port is defined by the location of two terminals on either side of the gap between adjacent conductive elements.
• the port locations may be extended to another location by use of a suitable transmission line.
• a suitable transmission line One example of this is to attach a coaxial cable at the port location by connecting the shield portion to one terminal and the center conductor to the other terminal.
• the cable provides an extension of the port to the desired point of connection such as radio circuitry.
• a more optimal solution may use a balanced transmission line or a balun structure to reduce the effects of the transmission line on the antenna.
• FIGURES 2A and 2B One example of an antenna designed to operate in a single frequency band is shown on FIGURES 2A and 2B.
• the antenna structure 200 includes a dielectric substrate 207 with three generally identical conductive elements 201 , 202, and 203, etched from a single copper layer, three coaxial cables 204, 205, and 206, and three discrete matching inductors 208, 209, and 210 or impedance matching networks.
• the substrate in this example is a circular disk 1 -mm thick and 23-mm radius cut from FR408 material manufactured by Rogers Corporation.
• the copper elements 201 , 202, and 203 are arranged symmetrically about a common center axis such that the ends of the elements fall on a circle of radius 22 mm and the angle between outer points subtends 60 degrees. At this outer radius, the parts are also separated by 60 degrees of arc (approximately 23 mm).
• the space between the adjacent elements 201 , 202, and 203 diminishes to a gap width of 1 mm.
• the coaxial cables 204, 205, and 206 are attached across the 1-mm gaps at a radial distance of 9 mm from the center.
• Each cable passes through a hole 220 on one side of the gap (where the cable shield is soldered) to the adjacent copper element.
• the center conductor 222 of each cable is bent across the gap and soldered to the adjacent copper element on the other side of the gap.
• the matching inductors 208, 209, and 210 are soldered across the gaps next to the feed at a radial distance of 10 mm from the center.
• Each inductor is a wire-wound 0402 chip inductor with nominal value of 4.7 nH.
• FIGURES 3A and 3B The performance of the antenna 200 of FIGURE 2 was simulated using Ansoft HFSS and also measure for a prototype assembly.
• the simulated return loss (S11 ) and coupling (S12) are provided on FIGURES 3A and 3B. Note that for the simulation, the geometry has perfect symmetry, and therefore all the reflection terms are the same as S11 and the coupling terms match S12.
• Measurements of the scattering parameters for the antenna 200 are also shown on FIGURES 3A and 3B.
• three plots are shown, one for each port. The differences in the measured plots are due to variations in the prototype from the design and the repeatability of the measurement.
• the shape of the measured frequency response is in agreement with that predicted by the simulation, but is shifted about 70 MHz (2.3 %) lower.
• FIGURE 3E The measured gain patterns on the azimuth plane at a frequency of 3 GHz are provided in FIGURE 3E.
• Each of the ports produces a radiation similar to that of a dipole lying in the horizontal plane (i.e., the plane of the antenna).
• the attachments to cables 204, 205, and 206 are referred to as Ports 1 , 2, and 3, respectively.
• the pattern produced from excitation of Port 1 is similar to a dipole on the x-axis.
• the other two ports will produce generally the same pattern, but rotated 120 or 240 degrees about the z-axis. These plots exhibit the angular orientation of each pattern.
• the correlation between the patterns produced by any two ports is low as shown on FIGURE 3D.
• the measured realized efficiency is about 70 percent as shown on FIGURE 3C.
• FIGURE 4 Another example of an antenna designed to operate in two frequency bands is shown in FIGURE 4.
• This antenna 400 has the same basic structure as that of the antenna 200 of FIGURE 2, with the salient difference being that each of the elements 402, 404, and 406 has branched ends.
• the lengths of the branches have been optimized to align the frequencies of operation with the WLAN bands within 2.4 to 2.5 GHz and 5.15 to 5.85 GHz.
• the lengths of the inner branches primarily dictate the frequency of the upper band (5 GHz), while the lengths of the outer branches dictate the frequency of the lower band (2.4 GHz).
• the size of the elements 402, 404, and 406 is such that the outer vertices fall on a circle with a radius of 26 mm.
• the dielectric material in this example is cut to a hexagonal shape instead of circular shape. Any shape that maintains regular three-fold symmetry is suitable for maintaining equal performance from all three antenna ports. Because the effect of the dielectric is small, using a shape without this symmetry, e.g., square or rectangular, may also provide acceptable performance in most applications.
• FIGURES 5A and 5B Graphs of the measured VSWR and S21 for the antenna 400 of FIGURE 4 are shown in FIGURES 5A and 5B, respectively. For this design, the desired input impedance was obtained by selection of the port locations and the gap between the conductive elements, and no discrete matching components are used.
• the measured gain patterns on the azimuth plane are provided as FIGURES 5E and 5F for the frequencies of 2440 MHz and 5250 MHz.
• the pattern produced from excitation of Port 1 is similar to a dipole on the x-axis at 2440 MHz, while at 5250 MHz the pattern is more directional.
• the other two ports produce the same patterns, but rotated 120 or 240 degrees about the z-axis. These plots exhibit the angular orientation of each pattern.
• the correlation between the patterns produced by any two ports is low as shown on FIGURE 5D.
• the measured realized efficiency is about 50 percent as shown on FIGURE 5C.
• antennas with three electrically conductive elements and three antenna ports can include any number of electrically conductive elements and antenna ports.
• antennas with two or more electrically conductive elements and antenna ports are contemplated where the elements and ports are symmetrically arranged around a common axis, with the elements being bent such that the middle portion of each element is closer to the axis and the ends are further away from the axis, and the ports are connected across the gaps between pairs of adjacent conductive elements.
• an antenna embodying the features described herein can include electrically conductive elements lying in different planes.
• the electrically conductive elements of an antenna are symmetrically arranged around a common axis, but the ends of the elements are angled upward or downward from a plane normal to the axis.

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)
• Support Of Aerials (AREA)
• Waveguide Aerials (AREA)
• Details Of Aerials (AREA)
• Transceivers (AREA)

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Publications (2)

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• 2009
  • 2009-12-22 KR KR1020117015321A patent/KR101689844B1/ko not_active Expired - Fee Related
  • 2009-12-22 WO PCT/US2009/069225 patent/WO2010075398A2/en not_active Ceased
  • 2009-12-22 CN CN2009801518000A patent/CN102265459A/zh active Pending
  • 2009-12-22 JP JP2011543641A patent/JP2012513730A/ja not_active Withdrawn
  • 2009-12-22 US US12/644,691 patent/US8228258B2/en not_active Expired - Fee Related
  • 2009-12-22 TW TW098144192A patent/TW201032392A/zh unknown
  • 2009-12-22 KR KR1020117015320A patent/KR20110104939A/ko not_active Withdrawn
  • 2009-12-22 WO PCT/US2009/069233 patent/WO2010075406A2/en not_active Ceased
  • 2009-12-22 JP JP2011543643A patent/JP2012513731A/ja not_active Withdrawn
  • 2009-12-22 CN CN2009801517883A patent/CN102265458A/zh active Pending
  • 2009-12-22 US US12/644,718 patent/US8373603B2/en not_active Expired - Fee Related
  • 2009-12-22 TW TW098144193A patent/TW201032388A/zh unknown
• 2013
  • 2013-02-01 US US13/757,192 patent/US8633860B2/en not_active Expired - Fee Related
  • 2013-12-16 US US14/107,568 patent/US9397388B2/en not_active Expired - Fee Related
• 2016
  • 2016-06-15 US US15/182,791 patent/US20160301135A1/en not_active Abandoned

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