WO2008023095A1 - Antenne à plusieurs résonances - Google Patents

Antenne à plusieurs résonances Download PDF

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Publication number
WO2008023095A1
WO2008023095A1 PCT/FI2007/050434 FI2007050434W WO2008023095A1 WO 2008023095 A1 WO2008023095 A1 WO 2008023095A1 FI 2007050434 W FI2007050434 W FI 2007050434W WO 2008023095 A1 WO2008023095 A1 WO 2008023095A1
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WO
WIPO (PCT)
Prior art keywords
branch
parasitic element
antenna
coupling area
basic
Prior art date
Application number
PCT/FI2007/050434
Other languages
English (en)
Inventor
Jyrki Mikkola
Petteri Annamaa
Original Assignee
Pulse Finland Oy
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 Pulse Finland Oy filed Critical Pulse Finland Oy
Publication of WO2008023095A1 publication Critical patent/WO2008023095A1/fr

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Classifications

    • 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
    • H01Q1/12—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
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/10—Resonant antennas
    • 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
    • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
    • H01Q5/321—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors within a radiating element or between connected radiating 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
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
    • H01Q5/335—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors at the feed, e.g. for impedance matching
    • 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
    • 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
    • H01Q5/392—Combination of fed elements with parasitic elements the parasitic elements having dual-band or multi-band characteristics
    • 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
    • H01Q9/0442—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular tuning means
    • 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 invention relates to an internal antenna having several resonances and at least two operating bands that is especially intended for small radio apparatuses.
  • Models operating in two or more systems such as different GSM systems (Global System for Mobile telecommunications), which use different frequency ranges, have become common in mobile stations.
  • GSM systems Global System for Mobile telecommunications
  • the basic condition for the operation of a mobile station is that the radiation and receiving properties of its antenna are satisfactory in the frequency bands of all the systems in use. Without limit on size, it is relatively easy to make a high-quality multi-band antenna.
  • the antenna is placed for convenience of use inside the covers of the apparatus. This complicates antenna design.
  • the use of parasitic element(s) is a known way of achieving required characteristics for the antenna.
  • the parasitic element means a structural part which has only an electromagnetic coupling to the immediately fed antenna element, i.e. basic element.
  • the parasitic element can be arranged so that the resonance frequency corresponding to it is the same or almost the same as the resonance frequency corresponding to the basic element or it is relatively far from the resonance frequencies corresponding to the basic element.
  • the characteristics of the antenna are improved in an existing operating band by means of the parasitic element, and, in the latter case, one more operating band for the antenna is formed by means of the parasitic element.
  • Fig. 1 shows a two-band antenna comprising also a parasitic element, known from the publication EP1432072.
  • the circuit board PCB of a radio apparatus is seen in the figure, at one end of which board the antenna is.
  • the main parts of the antenna are its radiators: the basic element 110 and the parasitic element 120.
  • the basic element is here a rigid conductor wire resembling an open rectangular ring which is located slightly above the upper surface of the circuit board.
  • the basic element 110 In a corner of the basic element is its feed point FP which is coupled to the antenna port of the radio apparatus.
  • the upper surface of the circuit board is mostly of conductive signal ground GND. This does not, however, extend at the radiators, the basic element 110 then forming a monopole-type radiator.
  • this monopole radiator is two-band. Its basic resonance frequency is arranged in a frequency range used by one radio system and the nearest harmonic frequency of the basic resonance frequency in a frequency range used by another radio system.
  • the basic element For setting the ratio of the harmonic frequency to the basic resonance frequency to be correct, the basic element has two branches: it is divided as viewed from the feed point FP to the first branch 111 and the second, shorter branch 112. Between the outer ends of these, there is an electromagnetic coupling which reduces said ratio of the harmonic frequency to the basic resonance frequency.
  • the parasitic element 120 is a conductor strip on the surface of the circuit board PCB.
  • the parasitic element is coupled from its one point GP to the signal ground GND via an inductive element 125 which is e.g. a spiral conductor strip on the lower surface of the circuit board.
  • the point GP divides the parasitic element to two parts 121 , 122.
  • the first part 121 together with the inductive element resonates in the lower operating band of the antenna, and the second part 122 together with the inductive element resonates in the upper operating band of the antenna.
  • the parasitic element thus functions here as an auxiliary radiator and improves the antenna gain in both operating bands of the antenna.
  • a two-band antenna which fits even to a flat radio apparatus.
  • a disadvantage is though that especially resonances corresponding to the lower operating band interfere each other so that the frequency range, in which there is an acceptable match, remains narrow. Furthermore, the number of the operating bands is limited to two.
  • Fig. 2 shows a second example of a two-band antenna comprising also a parasitic element, known to the applicant.
  • a part of the circuit board PCB of a radio apparatus is seen in the figure.
  • the basic element 210 and the parasitic element 220 of the antenna are conductor areas on the surface of a small antenna circuit board 201 , which is fastened to the circuit board PCB at a certain distance from it.
  • the upper surface of the circuit board PCB is mostly, also below the antenna circuit board, of conductive signal ground GND.
  • the basic element is connected to the antenna port of the radio apparatus from the feed point FP and to the ground from the first short-circuit point S1.
  • the basic element there is a non-conductive slot starting at its edge so that the element is divided, as viewed from the first short-circuit point, to two branches of different lengths.
  • the second, shorter branch 212 is straight and parallel to one side of the circuit board PCB.
  • the first, longer branch 211 resembles a rectangular letter U circling mostly the second branch 212.
  • the parasitic element 220 is connected to the ground from the second short- circuit point S2.
  • Also in the parasitic element there is a non-conductive slot starting at its edge so that the element is divided, as viewed from the second short-circuit point, to two branches of different lengths, to the third and the fourth branch.
  • the fourth, shorter branch 222 is straight and its direction is perpendicular to the direction of the second branch 212.
  • the third, longer branch 221 resembles a rectangular letter U circling mostly the fourth branch 222.
  • the outlines of both the basic and the parasitic element form an elongated pattern according to the main direction of the radiating branches, and the longitudinal directions of the elements are perpendicular to each other.
  • the feed point FP is between the first S1 and the second S2 short-circuit point relatively close to both.
  • the starting portion of the basic element 210, as viewed from the feed point, and the starting portion of the parasitic element, as viewed from the second short-circuit point S2, are relatively close to each other. Between these starting portions, there is a slot 205, which is thus very narrow, e.g. 0.2 mm.
  • Both the first 211 and the third 221 radiating branch together with the surrounding antenna parts form a resonator, the natural frequency of which is in the lower operating band of the antenna.
  • both the second 212 and the fourth 222 radiating branch together with the surrounding antenna parts form a resonator, the natural frequency of which is in the upper operating band of the antenna.
  • the resonances in the lower operating band are obtained quite independent from each other, in which case it is possible to implement a relatively wide continuous lower operating band in addition to the wide upper operating band.
  • a disadvantage of this solution is that acceptable operation requires the ground plane beneath the radiators, which results in a considerable space requirement for the antenna.
  • the number of the operating bands is limited to two.
  • the object of the invention is to minimise said disadvantages characteristic to the antennas of prior art.
  • the antenna according to the invention is characterised by what is presented in the independent claim 1. Some advantageous embodiments of the invention are described in the other claims.
  • the internal antenna of a radio apparatus comprises two radiators: a directly fed monopole-type basic element and a short-circuited parasitic element.
  • the elements are conductor patterns on the surface of a low-loss and thin substrate. Between them, at many different points, there is a significant electromagnetic coupling. In addition, both elements separately have adjacent portions between which there is a significant electromagnetic coupling. At least one element can be branching, in which case said portions can be located in different branches.
  • the couplings are implemented so that each element together with the other element has at least two usable resonances.
  • An advantage of the invention is that the resonances of the internal multi-band antenna are quite independent from each other also at frequencies below 1 GHz. This enables constituting a wide operating band in the range in question, covering a frequency range used by more than one system.
  • a further advantage of the invention is that the antenna can be made very small-sized. This is due to the above-mentioned electromagnetic couplings between the elements and within the elements which enlarge the electric size of the elements, and secondly to the absence of the ground plane beneath the elements, which means a flat structure.
  • an advantage of the invention is that the feed point and the short- circuit point of the antenna can be arranged in the middle area of the structure, in which case its omnidirectionality is good.
  • An additional advantage of the invention is that the efficiency of the antenna is good in respect of its size.
  • Fig. 1 shows an example of the internal dualband antenna of a radio apparatus according to prior art
  • Fig. 2 shows a second example of the internal dualband antenna of a radio apparatus according to prior art
  • Fig. 3 shows an example of the internal multi-resonance antenna of a radio apparatus according to the invention
  • Fig. 4 shows a second example of the internal multi-resonance antenna of a radio apparatus according to the invention
  • Fig. 5 shows two examples of the band characteristics of an antenna according to the invention.
  • Fig. 6 shows a modification to the antenna according to Fig. 3,
  • Fig. 7 shows a third example of the band characteristics of an antenna according to the invention.
  • Fig. 8 shows a modification to the antenna according to Fig. 3, related to Fig. 7,
  • Fig. 9 shows a fourth example of the band characteristics of an antenna according to the invention.
  • Fig. 10 shows a modification to the antenna according to Fig. 3, related to Fig. 9,
  • Fig. 11 shows a modification to the antenna according to Fig. 3, related to the third operating band of the antenna,
  • Fig. 12 shows an example of the efficiency of an antenna according to the invention.
  • Figs. 13a,b show examples of the location of an antenna in a radio apparatus according to the invention.
  • Fig. 3 shows an example of the internal antenna of a radio apparatus according to the invention, which antenna has several resonances and at least two operating bands.
  • the radiators of the antenna are the basic element 310 and the parasitic element 320 which are conductor patterns on the surface of the substrate 301.
  • the basic element there is the feed point FP of the antenna, and in the parasitic element there is the short-circuit point SP of the parasitic element.
  • the substrate, the basic element with its feed point and the parasitic element with its short-circuit point form a small antenna circuit board 300 which is fastened to the radio apparatus so that there is no ground plane at the circuit board.
  • the radiating elements are thus of monopole-type.
  • the antenna circuit board comprises a relatively long and narrow part and a transversal part starting from around its centre so that the board resembles a wide letter T.
  • the length of the upper part is e.g. 45 mm and the length of the transversal middle part is e.g. 8 mm.
  • the feed point FP and the short-circuit point SP are contact pads which have a reinforced conductor coating, and they are located next to each other at the outer end of the transversal middle part. From this kind of location in the middle, as viewed in the longitudinal direction, results that the omnidirectionality of the antenna is relatively good.
  • the shape of the antenna circuit board is partly caused by the fact that the speaker and possibly a vibrator of the radio apparatus has been designed to be positioned to the same structural module.
  • the basic element 310 and the parasitic element 320 are folded by shape so that both separately have relatively long parallel and close portions. Between such two close portions in the same element there is a significant electromagnetic coupling. In addition, both elements have portions which are so close to a portion of the other element that there is a significant electromagnetic coupling between such two close portions belonging to different elements.
  • the whole radiating structure is because of said folding of the elements on such a small area that some electromagnetic coupling occurs between very many portions.
  • the term "coupling area" means in this specification and claims only two portions and a slot between them over which slot there is a clearly more significant electromagnetic coupling than between two randomly selected portions on average.
  • the radiating elements are in this example branching.
  • the basic element comprises, starting from the feed point FP, first its head portion 31 H which is divided to the first and the second branch.
  • the free end of the first branch B31 is physically relatively close to the feed point but galvanically farthest from it.
  • the second branch B32 is directed away from the head portion 31 H and the first branch B31.
  • the parasitic element comprises, starting from the short-circuit point SP, first the head portion 32H which is then divided to the third B33 and the fourth B34 branch, the fourth branch is divided to the fifth B35 and the sixth B36 branch, and the sixth branch is divided to the seventh B37 and the eighth B38 branch.
  • the free end of the eighth branch is electrically farthest from the short-circuit point.
  • the first inter-coupling area 31 is next to the feed point and the short-circuit point. It comprises a total of five interlacing strips of the head portion 31 H of the basic element and the head portion 32H of the parasitic element so that the slot between the elements forms a meander pattern in the coupling area.
  • the second inter-coupling area 32 is somewhat farther from the feed and short-circuit point, yet still between the head portions of the basic and the parasitic element.
  • the basic element 310 has a projection which extends at a certain distance very close to the parasitic element 320.
  • the third inter- coupling area 33 is formed by the free ends of said second branch B32 and eighth branch B38 which ends are face to face very close to each other.
  • the basic element 310 has one internal coupling area 311. It is formed so that the head portion 31 H and the first branch B31 of the basic element are side by side for their whole distance.
  • the slot between them comprises, for strengthening the coupling, a meander-shaped portion which is constituted of the area between the total of eight interlacing conductor strips.
  • the parasitic element 320 has four internal coupling areas. Its first internal coupling area 321 is formed so that the tail end of the head portion 32H of the parasitic element travels first beside the fifth branch B35 and then beside the fourth branch B34.
  • the second internal coupling area 322 of the parasitic element comprises the third B33 and the seventh B37 branch. They have the total of fourteen interlacing strips so that the slot between the branches forms a meander pattern.
  • the third internal coupling area 323 of the parasitic element is formed so that the fourth branch B34 and the sixth branch B36 travel side by side.
  • the fourth internal coupling area 324 is formed of the tail portion of the sixth branch and the head portion of the eighth branch B38 travelling side by side.
  • the coupling areas can be arranged so that the antenna has 4-7 significant resonances in two operating bands. At least two of these resonances are located in the lower operating band and the rest in the upper operating band. Also the resonances in the lower operating band are provided quite independent from each other, in which case the lower operating band can be shaped relatively wide.
  • Fig. 4 shows a second example of the internal antenna of a radio apparatus according to the invention, which antenna has several resonances and at least two operating bands.
  • the radiators of the antenna are the basic element 410 and the parasitic element 420, which are also in this example conductor patterns on the surface of an elongated substrate 401.
  • the basic element there is the feed point FP of the antenna, and in the parasitic element there is the short-circuit point SP of the parasitic element.
  • the feed point and the short-circuit point are contact pads with a reinforced conductor coating, and they are located relatively close to each other at the first end of the substrate on the side of the first long side.
  • the substrate, the basic element with its feed point and the parasitic element with its short-circuit point form a small antenna circuit board 400 which is fastened to the radio apparatus so that there is no ground plane at its place.
  • the radiating elements are thus of monopole-type.
  • the size of the antenna circuit board is e.g. 6 mm x 40 mm and the distance of the edge of the ground plane from it is e.g. 7 mm.
  • the basic element and the parasitic element are designed so that there are inter- and internal coupling areas in the antenna principally as in the structure shown in Fig. 3.
  • the basic element 410 comprises, starting from the feed point FP, the starting half 41 H, which goes meandering towards the second end of the substrate and then the tail half 41 T, which goes following the starting half to the opposite direction arriving next to the feed point.
  • the parasitic element 420 comprises, starting from the short-circuit point SP, first the head portion 42H directing towards the second end, which portion is then divided to the first and the second branch.
  • the first branch B41 continues towards the second end.
  • the second branch B42 comprises the first portion extending to the first end, the second portion directing towards the second end and circling behind the first branch, the third portion extending to the second end, the fourth portion parallel to the second end, and the fifth portion extending to the first end on the side of the second long side of the substrate.
  • Both the basic element and the parasitic element comprise a few conductor strips in the small area between the feed and the short-circuit point. These strips are interlaced so that the slot between the elements forms a meander pattern.
  • the area in question between the feed point and the short-circuit point is the first inter- coupling area 41 between the basic element and the parasitic element.
  • the second inter-coupling area 42 is formed of the head portion 42H of the parasitic element and the head portion of the starting half 41 H of the basic element.
  • the third inter-coupling area 43 is formed of the first branch B41 of the parasitic element and the mid portion of the starting half 41 H of the basic element.
  • the fourth inter-coupling area 42 is formed of the third portion of the second branch 42H of the parasitic element and the tail portion of the starting half 41 H of the basic element. Between the starting and the tail halves of the basic element 410 there is only a narrow slot for the whole distance, and thus actually the whole element excluding the conductor strips in the area between the feed and the short-circuit point forms an internal coupling area. However, at the end on the side of the feed point of the element there is the first internal coupling area 411 separating from the other part, in which area there are densely the total of ten interlacing strips so that the slot between the starting 41 H and the tail 41 T halves forms a meander pattern in this coupling area.
  • the parasitic element 420 has three internal coupling areas. Its first internal coupling area 421 comprises the head portion 42H of the parasitic element and the first portion of the second branch B42 abreast with each other.
  • the second internal coupling area 422 of the parasitic element comprises the first branch B41 of the parasitic element and the first and the second portion of the second branch B42.
  • the third internal coupling area 423 of the parasitic element comprises the second portion of the second branch and the tail part of a fourth portion, which part goes abreast with the second portion.
  • Fig. 5 shows two examples of the characteristics of an antenna according to the invention.
  • the curve 51 shows the variation of the reflection coefficient S11 as a function of frequency, when the antenna is according to Fig. 3.
  • the antenna is seen to have two operating bands.
  • the reflection coefficient value of -6 dB is used as the criterion of boundary frequency
  • the lower operating band is about 0.8-1.0 GHz. It covers well both the frequency range of 824-894 MHz used by the American GSM system and the frequency range of 880-960 MHz used by the European EGSM (Extended GSM) system.
  • the bandwidth is ample 200 MHz which is a notably high value.
  • the lowest i.e. the first resonance r1 is the basic resonance of the parasitic element 320 deriving thus from the electric length of the whole parasitic element.
  • the second resonance r2 is the basic resonance of the basic element 310 resulting thus from the electric length of the whole basic element.
  • the upper operating band corresponding to the curve 51 is about 1.45-2.05 GHz, the bandwidth being as high as about 600 MHz (34%).
  • the frequency range 1 ,710-1 ,880 MHz used by the GSM1800 system the frequency range 1 ,850-1 ,990 MHz used by the GSM1900 system and the frequency 1 ,575 MHz used by the GPS (Global Positioning System) system.
  • the upper operating band is based on at least three significant resonances.
  • the third resonance r3 is based on the slot between the third B33 and the seventh B37 branch belonging to the parasitic element, the slot continuing between the fourth B34 and the sixth B36 branch. Its frequency is about 1.5 GHz.
  • the fourth resonance r4 is a harmonic of the first resonance r1 and its frequency is about 1.6 GHz.
  • the fifth resonance r5 is a harmonic of the second resonance r2 and its frequency is about 1.87 GHz. The fifth resonance is especially strong.
  • the curve 52 shows the variation in the reflection coefficient S11 as a function of frequency, when a change shown in Fig. 6 has been made in the antenna according to Fig. 3.
  • the second branch B32 belonging to the basic element 310 has been shortened by removing from it a portion RM1 extending close to the end of the sixth branch B36.
  • the coupling between the second branch and the sixth branch B36 weakens and, as a result, the electric lengths corresponding to the harmonic resonances r4 and r5 decrease and the frequencies correspondingly increase.
  • the frequency of the fourth resonance r4, or the fourth resonance frequency rises to about 1.8 GHz and the fifth resonance frequency to about 2.02 GHz.
  • the latter fact means a further increase in the width of the upper operating band of the antenna, as the upper boundary shifts close to frequency 2.2 GHz.
  • the upper operating band covers also the frequency range used by the WCDMA (Wideband Code Multiple Access) system the upper part of which is 2,110-2,170 MHz.
  • the fourth resonance is clearly stronger than in the antenna represented by the curve 51 , but an offset of this advantage is that the matching deteriorates a little at the GPS frequency 1 ,575 MHz.
  • the changes are small; only the second resonance frequency rises a little widening the lower operating band a little.
  • Fig. 7 shows a third example of the band characteristics of an antenna according to the invention.
  • the figure includes the same reflection-coefficient curve 52 as in Fig. 5 corresponding to the antenna of Fig. 6.
  • the curve 71 shows the variation in the reflection coefficient as a function of frequency, when a change shown in Fig. 8 has been made to the antenna according to Fig. 6.
  • the basic element 310 has been shortened by short-circuiting the slot between its head portion 31 H and the first branch B31 relatively close to the closed end thereof by a conductor SHT.
  • the electric length corresponding especially the second resonance r2 decreases, and the frequency of the second resonance correspondingly rises.
  • the change shown in Fig. 8 further means the strengthening of said resonances except the third resonance r3 based on the slot between the third B33 and the seventh B37 branch and between the fourth B34 and the sixth B36 branch belonging to the parasitic element, which resonance on the contrary weakens a little.
  • the matching of the antenna is deteriorated a couple of decibels at the GPS frequency 1 ,575 MHz.
  • Fig. 9 shows a fourth example of the band characteristics of an antenna according to the invention.
  • the figure includes the same reflection-coefficient curve 52 as in Fig. 5 corresponding to the antenna of Fig. 6.
  • the curve 91 shows the variation in the reflection coefficient as a function of frequency, when a change shown in Fig. 10 has been made to the antenna according to Fig. 6.
  • the parasitic element 320 has been extended from the free end of the seventh branch B37 belonging to it with a conductive extension LNG.
  • the electric lengths corresponding to the first resonance r1 and especially to its harmonic fourth resonance r4 increase and the frequencies of these resonances correspondingly lower.
  • the antenna according to Fig. 3 has a weak resonance also in the range of, inter alia, 2.7 GHz. If this range is desired to be utilised, the resonance in question can be strengthened by shortening the fifth branch B35 belonging to the parasitic element 320 in a way shown in Fig. 11. Here a portion RM2 has been removed from the free end of the fifth branch, which portion is almost a half of the whole branch. Shortening the branch weakens the coupling between the fifth branch B35 and the head portion 32H of the parasitic element and also the coupling between the fifth and the eighth branch B38.
  • the width of the lower operating band of which located below the frequency 1 GHz is e.g. 250 MHz.
  • the matching is only adequate, the reflection coefficient being in the range of the whole lower operating band -5 ⁇ -7 dB. Instead, a good matching is obtained in the upper operating band e.g. in the frequency range of
  • One resonance of the antenna is also arrangeable at the GPS frequency 1 ,575 MHz.
  • Fig. 12 shows an example of the efficiency of an antenna according to the invention.
  • the efficiency curves 01 and 02 have been measured in the antenna according to Fig. 3. It is seen that in the lower operating band the efficiency is on average about 0.42 and in the upper operating band on average about 0.65. Efficiency values are notably high.
  • Figs. 13a and 13b show examples of the location of an antenna according to the invention in a radio apparatus.
  • the radio apparatus RD1 is a baton- shaped mobile station, and it is shown as a simplified longitudinal cross section.
  • the antenna 500 is located at the other end of the circuit board PCB of the radio apparatus, on its outer side as viewed from the side of the display and keyboard of the apparatus.
  • the antenna circuit board is supported to the circuit board PCB at e.g. 5 mm distance from it.
  • the feed and short-circuit point are connected to the circuit board using some kind of spring contacts.
  • the edge of the ground plane GND on the circuit board is at a certain distance from the place of the antenna circuit board.
  • the radio apparatus RD2 is a foldable mobile station, in which case it comprises a first turning part TP1 and a second turning part TP2 joining a hinge HG.
  • the radio apparatus is shown as a simplified longitudinal cross section.
  • the first turning part TP1 comprises, i.a., the keyboard and the microphone of the apparatus
  • the second turning part comprises, i.a., the display and the speaker of the apparatus.
  • the second turning part is thus the part held on the ear of the user of the apparatus.
  • An antenna 700 is located at the opposite end of the first turning part TP1 as viewed from the hinge HG. Its arrangement is otherwise similar to the one in Fig. 13a.
  • the dimensions of the component formed by the antenna circuit board and its supporting structure are only a few millimetres both in the longitudinal direction of the circuit board PCB and the direction of the normal of the circuit board. Thus, the antenna fits well inside a small and flat turning part.
  • a functioning antenna is obtained when an antenna circuit board e.g. according to Fig. 3 or 4 is attached to a radio apparatus in the above-described way so that the short-circuit point is connected to the ground plane which is away from the radiators.
  • antenna circuit board e.g. according to Fig. 3 or 4
  • antenna circuit board e.g. according to Fig. 3 or 4
  • antenna circuit board e.g. according to Fig. 3 or 4

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Waveguide Aerials (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)

Abstract

L'antenne interne selon l'invention (300) est dotée d'au moins deux bandes d'exploitation tout particulièrement destinées à de petits appareils radio. L'antenne comprend un élément de base de type monopôle directement alimenté (310) et un élément secondaire court-circuité (320). Les éléments sont des tracés conducteurs sur la surface d'un substrat mince et à faibles pertes (301). Entre ces éléments, au niveau de nombreux points différents (31, 32, 33), il existe un couplage électromagnétique significatif. De plus, les deux éléments ont des parties adjacentes distinctes entre lesquelles il existe un couplage électromagnétique significatif. Les éléments peuvent être des éléments à branchements, dans quel cas lesdites parties peuvent être situées dans différentes branches. Les couplages sont implémentés de manière à ce que chaque élément avec l'autre élément ait au moins deux résonances utilisables. Les résonances de l'antenne sont relativement indépendantes l'une de l'autre y compris à des fréquences inférieures à 1 GHz, ce qui permet de constituer une large bande d'exploitation dans la plage en question couvrant une plage de fréquences utilisée par plus d'un système. D'autre part, l'antenne est très petite et son point d'alimentation (FP) ainsi que son point de court-circuit (SP) peuvent être agencés dans la zone centrale de la structure, l'omnidirectionnalité étant alors bonne.
PCT/FI2007/050434 2006-08-25 2007-07-24 Antenne à plusieurs résonances WO2008023095A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20065528A FI119268B (fi) 2006-08-25 2006-08-25 Moniresonanssiantenni
FI20065528 2006-08-25

Publications (1)

Publication Number Publication Date
WO2008023095A1 true WO2008023095A1 (fr) 2008-02-28

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PCT/FI2007/050434 WO2008023095A1 (fr) 2006-08-25 2007-07-24 Antenne à plusieurs résonances

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WO (1) WO2008023095A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010125240A1 (fr) * 2009-04-27 2010-11-04 Pulse Finland Oy Combinaison d'antennes
WO2012101320A1 (fr) * 2011-01-25 2012-08-02 Pulse Finland Oy Antenne à multi-résonance, module d'antenne et dispositif radio

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6433745B1 (en) * 2000-04-11 2002-08-13 Murata Manufacturing Co., Ltd. Surface-mounted antenna and wireless device incorporating the same
US20030045324A1 (en) * 2001-08-30 2003-03-06 Murata Manufacturing Co., Ltd. Wireless communication apparatus
EP1345282A1 (fr) * 2002-03-14 2003-09-17 Sony Ericsson Mobile Communications AB Antenne intégrée multibande composée d'éléments d'antennes planaires principale et parasites en "l" inversé
US6657593B2 (en) * 2001-06-20 2003-12-02 Murata Manufacturing Co., Ltd. Surface mount type antenna and radio transmitter and receiver using the same
US6903690B2 (en) * 2003-10-09 2005-06-07 Amphenol Socapex Internal antenna of small volume

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6433745B1 (en) * 2000-04-11 2002-08-13 Murata Manufacturing Co., Ltd. Surface-mounted antenna and wireless device incorporating the same
US6657593B2 (en) * 2001-06-20 2003-12-02 Murata Manufacturing Co., Ltd. Surface mount type antenna and radio transmitter and receiver using the same
US20030045324A1 (en) * 2001-08-30 2003-03-06 Murata Manufacturing Co., Ltd. Wireless communication apparatus
EP1345282A1 (fr) * 2002-03-14 2003-09-17 Sony Ericsson Mobile Communications AB Antenne intégrée multibande composée d'éléments d'antennes planaires principale et parasites en "l" inversé
US6903690B2 (en) * 2003-10-09 2005-06-07 Amphenol Socapex Internal antenna of small volume

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010125240A1 (fr) * 2009-04-27 2010-11-04 Pulse Finland Oy Combinaison d'antennes
WO2012101320A1 (fr) * 2011-01-25 2012-08-02 Pulse Finland Oy Antenne à multi-résonance, module d'antenne et dispositif radio
US9203154B2 (en) 2011-01-25 2015-12-01 Pulse Finland Oy Multi-resonance antenna, antenna module, radio device and methods
KR101797198B1 (ko) 2011-01-25 2017-11-13 펄스 핀랜드 오와이 다중 공진 안테나, 안테나 모듈 및 무선 기기

Also Published As

Publication number Publication date
FI119268B (fi) 2008-09-15
FI20065528A0 (fi) 2006-08-25
FI20065528A (fi) 2008-02-26

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