EP1892798A1 - Gefaltete planare Monopolantenne - Google Patents

Gefaltete planare Monopolantenne Download PDF

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Publication number
EP1892798A1
EP1892798A1 EP06017438A EP06017438A EP1892798A1 EP 1892798 A1 EP1892798 A1 EP 1892798A1 EP 06017438 A EP06017438 A EP 06017438A EP 06017438 A EP06017438 A EP 06017438A EP 1892798 A1 EP1892798 A1 EP 1892798A1
Authority
EP
European Patent Office
Prior art keywords
antenna
monopole antenna
circuit board
printed circuit
folded
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06017438A
Other languages
English (en)
French (fr)
Inventor
Michail Tzortzakakis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to EP06017438A priority Critical patent/EP1892798A1/de
Publication of EP1892798A1 publication Critical patent/EP1892798A1/de
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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
    • 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
    • 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 invention relates to antennas, especially, but not exclusively, electrically small planar antennas for use in portable wireless devices such as mobile (cellular) telephones, personal digital assistants (PDAs) and similar devices.
  • the present invention relates to the operation and the characteristic of folded planar monopole antennas for use in such devices.
  • the present invention provides a planar antenna which has a very low profile that is very thin.
  • the antenna occupies a small volume and can be used for mobile phones which are also targeted to be very thin.
  • the antenna of the present intention satisfies these conditions.
  • the planar antenna is supported by a substrate material which can be either plastic or ceramic. Although the thickness of this substrate is not critical for the operation of the antenna it must be taken into account in the initial design.
  • the antenna of the present invention is a monopole antenna for transmitting and receiving signals at a wireless communication device.
  • a monopole antenna consists of a single wire or antenna element that is coupled to a transceiver within the communication device which transceiver is provided on a printed circuit board (PCB). Analog or digital information for transmission is input to the transceiver where it is modulated onto a carrier signal. Then, the modulated carrier signal is transmitted by the monopole antenna, and vice versa.
  • the folded monopole antenna of the present invention comprises two main elements which are connected to a transceiver circuit of the wireless device.
  • GSM element - GSM Global System for Mobile Communications
  • the main reason for this structure is not to reduce the size but to minimize the influence that the printed circuit board (and all the metal components on it) have on the antenna performance.
  • the length of the GSM element is equal to the ⁇ e/4 of the operating frequency which in this case is around 920 MHz.
  • the zigzag structure of the GSM element is placed on a critical place for the antenna element. At its open end, the current distribution is high, thus the placement of such a structure is most effective there.
  • any electromagnetic coupling is reduced, which is performed between the current, which flows on the antenna GSM element and on the PCB metallization, i.e. the metallization of the printed circuit board of the communication device which is coupled to the antenna substrate.
  • This coupling is the cause of an increased capacitance seen in the input terminals and input impedance of the antenna. This increase in capacitance has the effect of lowering the resonance frequency of the antenna, reducing its operating bandwidth, increasing its radiation Q.
  • the antenna is moved, electrically, more away from the PCB, thus increasing its radiation resistance and thus its input impedance.
  • the benefit is that this is done only electrically and not physically. Therefore, the small size and volume of the antenna is maintained, but the antenna assumes that it is actually more away for the PCB that it actually is.
  • Increasing the input terminal resistance results to an increase of the radiation resistance and, therefore, of the efficiency and radiation of the antenna itself.
  • the second monopole element of the antenna of the present invention is a monopole element for the DCS (Digital Cellular System) and PCS (Personal Communication Service) operation.
  • This second monopole antenna element is strategically inserted between the folded GSM element. Its position is very important to achieve a good matching and good radiation response. So it is necessary to be inserted between the GSM folding element sections.
  • the length of the DSC/PCS monopole antenna element is equal to the ⁇ e/4 of the operating frequency which in this case is around 1800 MHz.
  • Embodiments of the present invention provide improvements in monopole antennas which are used in, for example, wireless communication devices such as mobile phones, personal digital assistants (PDA), Bluetooth apparatuses and similar devices.
  • wireless communication devices such as mobile phones, personal digital assistants (PDA), Bluetooth apparatuses and similar devices.
  • FIG. 1 shows a perspective view of the printed circuit board (PCB) 10 of a wireless communication device.
  • the electronic components including the transceiver portion are mounted at the PCB 10.
  • Any kind of plastic materials or other non-conductive materials can be used for the PCB.
  • FR4 an epoxy material reinforced by glass fiber
  • This material is commonly used for PCBs as known by a person skilled in the art.
  • the length of the PCB 10 is about 75 mm, and the width of the PCB 10 is about 40 mm, however, these dimensions are merely a non-limiting example, and any other suitable dimensions can be used.
  • the PCB 10 is electrically coupled with a printed circuit antenna board 20, with is also made of FR4 or another suited material.
  • the dimensions of the antenna printed circuit board or antenna substrate 20 are about 9 mm in length (i.e. in longitudinal direction of the length of the PCB 10) and about 40 mm in width and having a thickness of about 1 mm.
  • the gap 30 between PCB 10 and antenna PCB 20 is about 1 mm, and the coupling is realized by means of flexible wiring 40.
  • the conductive planar monopole antenna elements are formed by etching or other suitable production methods which are known by a person skilled in the art.
  • FIG. 2 shows a top view of the printed circuit board 20 for the folded monopole antenna of the present invention.
  • the monopole antenna comprises two main elements 50, 60 which are connected to a transceiver printed circuit board 10 the wireless device.
  • the first monopole element 50 is a GSM element (Global System for Mobile Communications) which is a long and folded monopole antenna which at its open end is further folded and reduced on length by using a zigzag, saw-tooth like structure.
  • GSM element Global System for Mobile Communications
  • the GSM element 50 consists of a short terminal section 51 extending from the flexible wiring connection 40 and having a length of about 9 mm, a first long section 52 extending substantially perpendicular to the terminal section 51 and having a length of about 32 mm, a short connecting section 53 extending perpendicular to the long first section 52 and having a length of about 4 mm, and a second long zigzag-section 54 extending perpendicular to the connecting section and having a length of about 20 mm.
  • the first long section 52, the connecting section 53 and the second long section 54 form a substantially U-shaped configuration in width direction of the PCB 20.
  • the effective length thereof is more than said 20 mm.
  • the main purpose of the zigzag- or saw-tooth structure is not only to reduce the length of the second long section 54 but to minimize the coupling between the GSM element 50 and the ground plane. This in turn leads to a reduced coupling capacitance and to an increase in terminal resistance.
  • the above antenna has a terminal resistance of about 12 ohms (merely 6 ohms is achieved when using a straight line).
  • the second monopole element 60 of the antenna is a DSC/PSC monopole element which is strategically inserted between the folded GSM element sections 52 and 54, i.e. substantially within the U-shaped configuration of the first monopole element 50. This position is very important to achieve a good matching and good radiation response.
  • the length of the DSC/PCS antenna element 60 is equal to the ⁇ e/4 of the operating frequency which in this case is about 1800 MHz.
  • Figure 3 above shows how and where the current flows when the antenna 20 of the present invention resonates at its self-resonant frequency of 920 MHz.
  • Currents on the zigzag structure 53, 54 are floating in the inside of the structure between the folding arms thus minimizing the coupling to the ground plane.
  • the trace elements of the zigzag structure are now mostly orthogonally arranged with respect to the PCB, since the straight line has been replaced with a zigzag element.
  • Figures 5 and 6 are the same except from the DCS/PCS monopole element 60, which is wider with a width of 2 mm. For all the other elements in all designs the width is kept to 1 mm. By making the monopole element 60 wider, the performance of the GSM element is even more optimized.
  • the difference of the zigzag structure has the following effect on the antenna performance that can be observed from Figures 8 and 9 which show the input impedance characteristic of the antenna.
  • Figure 8 shows the imaginary part of the impedance or differently the reactance
  • Figure 9 the real part or else the radiation resistance of the antenna.
  • the zigzag shape is exactly designed to increase this real part to higher values at the resonance frequency point and the frequency band of interest which for GSM is from 880 MHz to 960 MHz. It is noted that no matching circuit is used here.
  • the input resistance of the straight-line design has increased only by 1 Ohm resulting to a total of 11 Ohms, as opposed for the design of Figure 5 which has a resistance of 14,5 Ohms and the design of Figure 6 with a resistance of 17,5 Ohms. That means that with the optimized design, the design of Figure 6, using a zigzag structure, a radiation resistance 6,5 Ohms higher than with conventional shapes is achieved.
  • the input resistance shown in Figure 9 is the sum of the radiation resistance plus the loss resistance, that the denominator of equation (1).
  • the loss resistance for all the designs remains always the same, since the materials are all the same as well as the electrical lengths of all the elements.
  • the loss resistance may only come from material losses or conducting losses. Since therefore, in designs of the present invention, the loss resistance is always the same, this means that the radiation resistance is increasing. This will result to higher efficiency according to equation (1). Radiation efficiency is very important in mobile phones since more power will be transmitted thus saving battery power and increasing battery life.
  • the height of the printed circuit board substrate of the antenna element is relevant in case the height (thickness) is less than 1 mm (which is preferred). As shown in the diagram of Figure 11, the effect of a thickness below 1 mm is severe only for higher frequencies and not for the GSM.
  • Figure 12 shows a diagram of the simulated network for the DCS/PCS antenna element and the GSM antenna element.
  • Figure 13 shows the simulation results with matching wherein the upper diagram shows the "Voltage Standing Wave Ratio" (VSWR) versus frequency.
  • VSWR Voltage Standing Wave Ratio
  • Figure 14 shows the simulated radiation patterns for GSM (920 MHz) and DCS/PCS (1800 MHz).
  • Figure 15 shows the simulation results without matching for GSM and DCS/PCS.
EP06017438A 2006-08-22 2006-08-22 Gefaltete planare Monopolantenne Withdrawn EP1892798A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06017438A EP1892798A1 (de) 2006-08-22 2006-08-22 Gefaltete planare Monopolantenne

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06017438A EP1892798A1 (de) 2006-08-22 2006-08-22 Gefaltete planare Monopolantenne

Publications (1)

Publication Number Publication Date
EP1892798A1 true EP1892798A1 (de) 2008-02-27

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Family Applications (1)

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EP06017438A Withdrawn EP1892798A1 (de) 2006-08-22 2006-08-22 Gefaltete planare Monopolantenne

Country Status (1)

Country Link
EP (1) EP1892798A1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2018067860A (ja) * 2016-10-21 2018-04-26 タイコエレクトロニクスジャパン合同会社 アンテナ
US10044110B2 (en) 2013-07-01 2018-08-07 Qualcomm Incorporated Antennas with shared grounding structure
CN108649332A (zh) * 2018-04-23 2018-10-12 歌尔科技有限公司 一种多频微带天线和电子设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0762539A1 (de) * 1995-08-17 1997-03-12 Murata Manufacturing Co., Ltd. Chip Antenne
JP2004228640A (ja) * 2003-01-20 2004-08-12 Taiyo Yuden Co Ltd 誘電体アンテナ及びそれを内蔵する移動体通信機
WO2005076409A1 (en) * 2004-01-30 2005-08-18 Fractus S.A. Multi-band monopole antennas for mobile network communications devices
EP1569300A1 (de) * 2004-02-26 2005-08-31 Matsushita Electric Industrial Co., Ltd. Drahtloses Gerät mit Antenne

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0762539A1 (de) * 1995-08-17 1997-03-12 Murata Manufacturing Co., Ltd. Chip Antenne
JP2004228640A (ja) * 2003-01-20 2004-08-12 Taiyo Yuden Co Ltd 誘電体アンテナ及びそれを内蔵する移動体通信機
WO2005076409A1 (en) * 2004-01-30 2005-08-18 Fractus S.A. Multi-band monopole antennas for mobile network communications devices
EP1569300A1 (de) * 2004-02-26 2005-08-31 Matsushita Electric Industrial Co., Ltd. Drahtloses Gerät mit Antenne

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10044110B2 (en) 2013-07-01 2018-08-07 Qualcomm Incorporated Antennas with shared grounding structure
JP2018067860A (ja) * 2016-10-21 2018-04-26 タイコエレクトロニクスジャパン合同会社 アンテナ
CN108649332A (zh) * 2018-04-23 2018-10-12 歌尔科技有限公司 一种多频微带天线和电子设备

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