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
  • H01Q9/045—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
  • 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
  • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
  • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q21/00—Antenna arrays or systems
  • H01Q21/30—Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• • 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
  • H01Q5/378—Combination of fed elements with parasitic elements
  • H01Q5/385—Two or more parasitic elements
• • 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
  • H01Q5/40—Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements
• • 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
• • 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
  • H01Q9/0471—Non-planar, stepped or wedge-shaped patch

Definitions

• the invention relates to a microstrip antenna arrangement in a communication device according to claim 1 and a communication device according to claims 7 and 8.
• a further important design parameter is related to obtaining a robust construction.
• a robust device When designing mobile handheld communication devices, it is of great importance that a robust device be obtained as mobile devices are often accidentally more or less damaged during daily use of the device.
• the most vulnerable part of a mobile device is typically an external antenna, e.g. a whip antenna .
• a disadvantage of an internal patch antenna is that it requires very high-skilled designers, as the internal arrangement of the antenna elements occupies more space than that which is available inside a device. Despite this, it has nevertheless been possible to design very compact and small high-quality devices.
• a microstrip antenna arrangement in a communication device comprises
• a multi- band antenna arrangement suitable for multi-band operations has been obtained.
• the obtained antenna arrangement is suitable for utilisation in applications offering very little space for the mechanical arrangement.
• the above-mentioned arrangement tolerates a certain divergence between the radiation patterns of the directional antennas of the arrangement .
• the minimum dimension of the ground plane should preferably be greater than 0.095 times the wavelength of the primary operating resonance frequency, thus ensuring sufficient directionality and minimised mutual divergence in the direction between the antennas.
• the invention teaches that directional performance of the antennas may be obtained if the ground plane is shared by two or more antennas, as a relatively broad ground plane is required in order to obtain directional characteristics for both antennas.
• the price of a dual band directional radiation pattern is a small inclination between the directions of the two characteristics.
• the directions ⁇ l, ⁇ 2 of said radiating patterns define an angle ⁇ at other than 0°, an advantageous embodiment has been obtained, as mutual spacing between the radiating elements should be kept as low as possible.
• angle ⁇ primarily defines a horizontal angle between the directions of the radiating patterns and the normal of the ground plane, as ⁇ is the more critical of the two angles with respect to the normal, see fig. 4.
• angle ⁇ should be interpreted broadly as incorporation of the angle ⁇ as an inclination in the longitudinal direction of the ground plane may be tolerated, too, according to the invention.
• both ⁇ and ⁇ should be kept as low as possible in the transverse and the longitudinal directions of the ground plane, respectively.
• the angle ⁇ is between 0° and 170°, preferably between 0° and 50°, a further advantageous embodiment of the invention has been obtained.
• the antenna arrangement comprises two antenna elements, each adapted to frequency bands at substantially 900 MHz and substantially 1800 MHz, respectively, a preferred and advantageous embodiment of the invention has been obtained, as a dual band version of the physical requirements GSM and the DCS systems may be combined, benefiting from the fact that existing GSM directional patch arrangements may be modified without making substantial changes in the design of the mechanical system of e.g. cellular phones.
• each antenna performs as a TM 1 0 mode antenna, i.e. having one dominating excitation frequency, a further preferred embodiment of the invention has been obtained.
• microstrip radiator shapes are possible within the scope of the invention, such as the above-mentioned and preferred rectangular or substantially rectangular patches, circular patches or ring patches. Larger bandwidths can be obtained by increasing the electrical thickness of the substrate of a patch antenna and choosing a substrate with a lower dielectric constant .
• Other variations within the scope of the invention with respect to microstrip designs include a stacked microstrip antenna in which a parasitic patch is added load a double-layer structure.
• a further preferred embodiment of the invention may be obtained by establishing radiation directed away from the user, thus obtaining minimal SAR values and maximised efficiency.
• a communication device has a multi -band antenna, said multi -band antenna having at least two radiator antenna elements sharing a ground plane, each of said at least two radiator elements being adapted to radiation of an electromagnetic wavelength ⁇ ⁇ said radiator antenna elements and said ground plane comprising an electronically conductive material, the minimum effective dimension W of said shared ground plane being greater than or equal to 0.095 ⁇ m , with ⁇ m as the longest wavelength of the wavelengths ⁇ 1 , and preferably greater than 0.1 ⁇ m , an advantageous embodiment of the invention has been obtained.
• a shared ground plane is a ground plane of which at least part of the ground plane is shared by the radiators.
• the shared ground plane of the multi -band antenna provides directional radiation characteristics of the radiator antenna elements.
• the different radiators are adapted to different wavelengths and do consequently have different physical dimensions. Even when sharing the same ground plane of one common physical dimension adapted for operation as a resonance element for each of the multi -band radiators, it has been recognised that it is possible to obtain directional characteristics for each of the radiators. It should be noted that the desired directional characteristics are obtained, even if the different radiation elements are mutually spaced, as a small divergence in the directional characteristics may be tolerated according to the invention.
• more antenna elements may be arranged on top of the same ground plane, and need not necessarily be symmetrical with respect to the relative positioning between the ground plane and the antenna elements in order to provide multi-directional radiation patterns. Still, all radiation patterns may point in the same direction, i.e. often away from the head of the user.
• the antenna radiator elements are fed by means of at least one proximity coupling, a further advantageous embodiment of the invention has been obtained.
• the antenna radiator elements are fed by means of one shared proximity coupling, a very compact version of the antenna is obtained, as the proximity coupling may be implemented by means of only one feeding line.
• the antenna radiators comprise a multi -band antenna comprising at least two TM 1 0 mode antenna radiator elements, each antenna element having substantially one dominating resonance frequency,
• said multi -band antenna having at least two radiator antenna elements having a shared ground plane, each radiator element being adapted to radiation of an electromagnetic wavelength
• radiator antenna elements and said ground plane comprising an electrically conductive material
• radiator antenna elements (11, 12) being grounded to said ground plane (14) , and the antenna elements (11, 12) having free resonance ends being extended in such a way that said free resonance ends (11A, 12A) are substantially facing each other, an advantageous embodiment of the invention has been obtained.
• a coupling from at least one of the radiator antenna elements to said ground plane has a width smaller in size than that of said radiator antenna element, it is possible to reduce the length of the radiator antenna element .
• the length controls the frequency of the antenna element where a longer antenna means a lower frequency radiation.
• the lower frequency can be obtained from the antenna element without extending the length.
• fig. 1 shows a preferred patch antenna arrangement according to the invention
• fig. 2 shows the principles of inclination of the patch antennas according to the invention
• fig. 3 is an illustrative view of the arrangement of some key components according to an embodiment of the invention.
• fig. 4 shows the directionality between two radiation patterns of the invention in the cross-section plane of the antenna arrangement .
• the antenna arrangement comprises a ground plane 14 incorporated in a PCB and two patch antennas 11 and 12 galvanically coupled to the ground plane 14 via two groundings 17A and 17B.
• the width W of the ground plane 14 is preferably at least 0.095 times the wavelength of the signal at the lowest frequency required by the antennas .
• the patch antenna 12 is connected to the ground plane 14 in its entire width, i.e. the grounding 17B must be just as wide as the antenna.
• the antenna 11 is only connected to the ground plane 14 by parts of its width, i.e. the grounding 17A only covers a fraction of the width of the antenna.
• the rest of the width is at a small distance 19 from the antenna 11 to the ground plane 14. This distance 19 could preferably be made by milling off an appropriate part of the patch antenna 11.
• Each antenna 11, 12 has a free resonance end 11A or 12A. These ends face each other and are separated by a channel of dielectric 18B.
• the width of the dielectric 18B i.e. the distance from 11A to 12A, is in the range 0.1 mm to 10.0 mm, with 2.0 mm as the preferred width.
• Both antennas 11, 12 are fed through a feeding line 13 which establishes a shared proximity coupling to both antennas 11, 12.
• the feeding line 13 is distanced from the antennas 11, 12 by a channel of dielectric 18A.
• the feeding line is connected to a receiving and transmitting circuit (not shown) through the ground plane 14 via a feeding pin 16.
• the above-mentioned antenna elements are arranged on a solid dielectric 15.
• the shape of the solid dielectric 15 is a wedge, giving the two antennas 11, 12 an inclination.
• Each of the antennas 11, 12 is adapted to a specific frequency band. According to the shown preferred embodiment, antenna 11 is adapted to 900 MHz GSM signals, and antenna 12 is adapted to 1800 MHz DCS signals, and the free resonance ends 11A and 12A act as the active radiators .
• the inclination of the antennas ensures that the thickness of the dielectric 15 is sufficient to ensure the desired bandwidth for each antenna 11, 12.
• the described microstrip antenna arrangement is a patch antenna arrangement benefiting from the regular forms of antennas 11, 12, i.e. the front resonance edges 11A and 12A are the primary radiating sources.
• fig. 2 illustrates the inclination of the antennas 11 and 12 in fig. 1.
• the resonance ends 11A and 12A of the antennas 11, 12 are shown relatively to the ground plane 14 and the corresponding vertical distance to the ground plane 14 are shown as DH and D .
• the capacitive coupling of the free resonance ends 11A and 12A providing the aforementioned improvement in signal quality, is different due to the difference between DH and DL. Nevertheless, the coupling between the ground plane 14 and DH and DL, respectively, is comparable and the capacitive coupling of the antenna 12A is influenced by the fact that the further distance, i.e. the lower capacitance, will belong to the antenna having the highest frequency, thus resulting in an improvement of the effective coupling to the ground plane 14.
• the lower capacitive coupling will always belong to the antenna having the highest frequency.
• a modified design of the antenna arrangement would be possible as the shorter antenna 12 could be further inclined than the antenna 11, thus resulting in an improved capacitive coupling of the front end of the short-wave antenna 12.
• FIG. 3 is a cross section view of the antenna in fig. 1, in which a cross section 311 of the antenna 11 and a cross section 312 of the antenna 12 are shown relative to a cross section 314 of the shared ground plane 14. Furthermore, a cross section 313 of the feeding line 13 is shown.
• Each antenna establishes directional radiation patterns ⁇ l, ⁇ 2 having corresponding directions 111 and 112.
• Fig. 4 shows the above-mentioned inclination, of which direction 111 represents the main direction of the radiation pattern of the antenna 11 and direction 112 represents the main direction of the radiation of the antenna 12.
• angle ⁇ in this illustration is only a two-dimensional angle between the directions of the radiating patterns in a plane defined by the transverse cross-section of the antenna arrangement of fig. 1.
• the invention teaches that directional performance of the antennas may be obtained if the ground plane is shared by two or more antennas, as a relatively broad ground plane is required in order to obtain directional characteristics for both antennas.
• the price for a dual band directional radiation pattern is a small inclination between the directions of the two characteristics.
• One embodiment includes the possibility of having each of the resonance ends face the ends of the radiator antenna element. The coupling to the ground plane will then be shared by the radiator antenna elements and divide the wedge of solid dielectric in two.
• a further embodiment includes the possibility of having each resonance end face the same way, either by facing the back end or the front end of the wedge of solid dielectric. The coupling to the ground plane will then be made at the opposite end.

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

Applications Claiming Priority (3)

Publications (1)

Family

ID=8092224

Family Applications (1)

Country Status (5)

Families Citing this family (19)

Family Cites Families (3)

• 2000
  • 2000-03-03 WO PCT/DK2000/000091 patent/WO2000054367A1/en not_active Application Discontinuation
  • 2000-03-03 CA CA002364445A patent/CA2364445A1/en not_active Abandoned
  • 2000-03-03 CN CN00804685A patent/CN1343380A/zh active Pending
  • 2000-03-03 AU AU29036/00A patent/AU2903600A/en not_active Abandoned
  • 2000-03-03 EP EP00907459A patent/EP1157440A1/de not_active Ceased

Non-Patent Citations (1)

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