EP1841008A1 - Verfahren und zu Erzeugung elektromagnetischer Felder - Google Patents

Verfahren und zu Erzeugung elektromagnetischer Felder Download PDF

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Publication number
EP1841008A1
EP1841008A1 EP06425221A EP06425221A EP1841008A1 EP 1841008 A1 EP1841008 A1 EP 1841008A1 EP 06425221 A EP06425221 A EP 06425221A EP 06425221 A EP06425221 A EP 06425221A EP 1841008 A1 EP1841008 A1 EP 1841008A1
Authority
EP
European Patent Office
Prior art keywords
field vector
target axis
flux lines
vector
components
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.)
Ceased
Application number
EP06425221A
Other languages
English (en)
French (fr)
Inventor
Carlo Buoli
Fabio Dr. Morgia
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.)
Nokia Solutions and Networks Italia SpA
Original Assignee
Siemens SpA
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 Siemens SpA filed Critical Siemens SpA
Priority to EP06425221A priority Critical patent/EP1841008A1/de
Priority to PCT/EP2007/002738 priority patent/WO2007112900A1/en
Publication of EP1841008A1 publication Critical patent/EP1841008A1/de
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/06—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens
    • H01Q19/09—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using refracting or diffracting devices, e.g. lens wherein the primary active element is coated with or embedded in a dielectric or magnetic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/40—Radiating elements coated with or embedded in protective material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/44—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element
    • 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
    • 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
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H01Q9/27—Spiral antennas

Definitions

  • the invention relates to techniques for generating electromagnetic fields.
  • the resistivity of a body tissue is about 5.10 -5 Ohm.meter.
  • X-ray apparatus e. g. as used in material technology investigation or quality control in industry, must be properly shielded for personnel safety while X-ray inspection is resorted to as seldom as possible in current medical practice.
  • imaging techniques such as breast imaging techniques at microwave frequencies a promising field of investigation: see, e.g. E. C. Fear et al. "Enhancing Breast Tumor Detection with Near-Field Imaging” - IEEE Microwave Magazine, March 2002, pp. 48-56 .
  • the object of the invention is thus to provide a solution for generating an electromagnetic with one out of the electrical field vector E and the magnetic field vector H concentrated around a target (or incidence) axis.
  • a preferred embodiment of the arrangement described herein is a device for generating an electromagnetic field E, H having the electrical field vector E or the magnetic field vector H concentrated around a target axis.
  • the device includes an electromagnetic field source for inducing a near-field configuration of the electromagnetic field having flux lines of the electrical field vector E or the magnetic field vector H that have components both along the target axis and orthogonal thereto.
  • a suppressor element is coupled to the field source in order to suppress the components of the flux lines of the electrical field vector E or the magnetic field vector H that extend orthogonal to the target axis, whereby the electrical field vector E or the magnetic field vector H is concentrated around the target axis.
  • the electrical field vector E or the magnetic field vector H is concentrated in a "spot" much smaller than the associated wavelength.
  • these flux lines F would be aligned with a "target” or "incidence” axis z essentially corresponding to the common axis of the distal end of the coaxial cable 10 and the source 16, 18. Then, as the distance from the source 16, 18 increases, these flux lines F would gradually spread out as schematically shown in broken lines in figure 2 to include - at each point in space closely surrounding the target axis z:
  • the magnetic field vector H will have corresponding flux lines that lie in the x, y planes concentric and orthogonal to the z axis.
  • the element designated 22 in figures 2 and 3 is a disc of a ferromagnetic material such as ferrite with a diameter typically much larger than the disc 16 (e.g. 10 times).
  • the ferrite disc 22 surrounds the disc 16 (with the exception of the side exposed to the coaxial cable 10, i.e. opposite the insulating substrate 18) with the purpose of suppressing the components of the flux lines F of the electrical field vector E that extend in the x, y directions, thereby maintaining only those components that are parallel to the axis of incidence z.
  • the electrical field vector E in the space surrounding the target axis z is generally angled to the z axis in that it exhibits, in addition to a component along the z axis, also components in the x, y directions.
  • Figure 3 schematically represents the effect deriving from the presence of the suppressor element 22. Specifically, figure 3 illustrates the typical behaviour (i.e. orientation) of the electrical field vector E up to a distance d of the order of 10cm from the source 16, 18 when the arrangement of figures 1 and 2 is supplemented with the suppressor ferrite disc 22.
  • the electrical field vector E is substantially aligned with the z-axis since its components in the x, y directions are suppressed.
  • the element 22 will thus concentrate the electrical field vector E around the target axis z in that the modulus of the electrical field vector E will have a maximum value in correspondence with the target axis z and a value gradually decreasing with the distance from the target axis z due to the suppression of the components in the x, y directions.
  • the magnetic field vector H will have corresponding flux lines that lie in the x, y planes concentric and orthogonal to the z axis (see figure 3).
  • figure 3 corresponds to an ideal behaviour.
  • the suppressive effect of the ferrite element 22 will not be absolute, so that residues of the components in the x, y directions will cause the electrical field vector E to be slightly diverging with respect to the target axis z, while having a dominant component aligned with that axis.
  • the concentration effect just described can be further increased by superposing to the element 22 a layer 22a (see figure 2) of a resistive material which further enhances the suppression effect of the x, y components.
  • a dielectric lens 22b can be arranged in the space facing the source 16, 18 to perform a focusing action on the (already concentrated) electric field E.
  • FIGS 4 and 5 illustrate an alternative embodiment of the generator described with reference to figures 1 and 2.
  • the generator G is again connected to a source comprised of a metallic pad 16 mounted on an insulating substrate 18.
  • the source 16, 18 is fed with the electromagnetic field generated by the generator G via a so-called strip line 24.
  • the strip line 24 includes a metallic strip-like core 12a extending between metallic ground planes 12b. Again, a ferrite disc 22 is mounted on the metal pad 16 to suppress the components of the electrical field in the x, y plane thus leading to a result substantially similar to that shown in figure 3.
  • suppressor materials can be easily devised e.g. in the form of garnets having the desired properties (e.g. relative magnetic permeability ⁇ r in the range e.g. 100-1000).
  • FIGS. 6 to 8 illustrate the generator G again feeding a strip line 24 including a metallic strip-like core 12a extending between metallic ground planes 12b.
  • a spiral coil 21 extends over the upper surface of the insulating substrate 18 to connect a distal extension of the core 12a and an extension of the upper ground plane 12b of the strip line 24.
  • these flux lines F would be aligned with the target axis z orthogonal to the plane of the support 18, i.e. orthogonal to the plane of the spiral coil or antenna 21. Then, as the distance from the upper plane of the spiral coil or antenna 21 increases, these flux lines F would gradually spread out as schematically shown in broken lines in figure 7 to close around the coil or antenna 21 and thus include - at each point in space closely surrounding the target axis z:
  • the electrical field vector E will have corresponding flux lines that lie in the x, y planes concentric and orthogonal to the z axis.
  • figure 8 shows the effect of placing a suppressor element 22' of a dielectric material surrounding the spiral coil or antenna 21.
  • the magnetic field vector H in the space surrounding the target axis z would be generally angled to the z axis in that would exhibit, in addition to a component along the z axis, also components in the x, y directions (see the aproximately circular trajectories F in figure 7).
  • the dielectric suppressor element 22' when the dielectric suppressor element 22' is present, the components in the x, y directions are suppressed (figure 8) and the magnetic field vector H is substantially aligned with the z-axis.
  • the element 22' will concentrate the magnetic field vector H in that the modulus of that vector will have a maximum value in correspondence with the target axis z and a value gradually decreasing with the distance from that axis due to the suppression of the components in the x, y directions.
  • dielectric materials of the types mentioned in the foregoing are currently available with companies such as TCI Ceramics (USA) or Trans Tech (USA).
  • figure 8 corresponds to an ideal behaviour.
  • the suppressive effect of the dielectric element 22' will not be absolute, so that residues of the components in the x, y directions will cause the magnetic field vector H to be slightly diverging with respect to the z axis, while having a dominant component aligned with the z axis.
  • the power generated by the generator G will depend on the envisaged application of the radiation. Experiments carried out so far by the applicant indicates that power levels in the range between a few milliwatts and a few watts are adapted to cover most applications as envisaged at present in the medical field.
  • coaxial cable 10/strip-line 24 can be notionally of any length, lengths in the range of a few mm to a few meters are typically adopted within the framework of the present invention. These values represent a reasonable compromise between the need of minimizing losses and attenuation along the cable 10 and the need of at least partly remotizing and/or rendering freely displaceable with respect to the generator G the electromagnetic field source 16, 18 fed via the cable 10.
  • the arrangement described herein lends itself to realising multi-beam arrangements including a plurality of sources 16, 18, 21 having associated suppressor elements 22, 22'. Those multi-beam arrangements are adopted to be operated as phased arrays to "steer” the resulting (electrical or magnetic) field in a general scanning movement of the target area.

Landscapes

  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
EP06425221A 2006-03-30 2006-03-30 Verfahren und zu Erzeugung elektromagnetischer Felder Ceased EP1841008A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP06425221A EP1841008A1 (de) 2006-03-30 2006-03-30 Verfahren und zu Erzeugung elektromagnetischer Felder
PCT/EP2007/002738 WO2007112900A1 (en) 2006-03-30 2007-03-28 Method and device for generating electromagnetic fields

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06425221A EP1841008A1 (de) 2006-03-30 2006-03-30 Verfahren und zu Erzeugung elektromagnetischer Felder

Publications (1)

Publication Number Publication Date
EP1841008A1 true EP1841008A1 (de) 2007-10-03

Family

ID=36676024

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06425221A Ceased EP1841008A1 (de) 2006-03-30 2006-03-30 Verfahren und zu Erzeugung elektromagnetischer Felder

Country Status (2)

Country Link
EP (1) EP1841008A1 (de)
WO (1) WO2007112900A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI573108B (zh) * 2016-03-18 2017-03-01 國立虎尾科技大學 電磁感應教具組

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653054A (en) * 1970-10-28 1972-03-28 Rca Corp Symmetrical trough waveguide antenna array
US5327148A (en) * 1993-02-17 1994-07-05 Northeastern University Ferrite microstrip antenna
EP0755092A2 (de) * 1995-07-17 1997-01-22 Plessey Semiconductors Limited Antennenanordnungen
EP1300910A2 (de) * 2000-10-19 2003-04-09 Jastero Trading Limited Verfahren und verkürzte antenne mit gesteigerter effektiver höhe
US20040164907A1 (en) * 2003-02-25 2004-08-26 Killen William D. Slot fed microstrip antenna having enhanced slot electromagnetic coupling

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131896A (en) * 1976-02-10 1978-12-26 Westinghouse Electric Corp. Dipole phased array with capacitance plate elements to compensate for impedance variations over the scan angle
US7088290B2 (en) * 2002-08-30 2006-08-08 Matsushita Electric Industrial Co., Ltd. Dielectric loaded antenna apparatus with inclined radiation surface and array antenna apparatus including the dielectric loaded antenna apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653054A (en) * 1970-10-28 1972-03-28 Rca Corp Symmetrical trough waveguide antenna array
US5327148A (en) * 1993-02-17 1994-07-05 Northeastern University Ferrite microstrip antenna
EP0755092A2 (de) * 1995-07-17 1997-01-22 Plessey Semiconductors Limited Antennenanordnungen
EP1300910A2 (de) * 2000-10-19 2003-04-09 Jastero Trading Limited Verfahren und verkürzte antenne mit gesteigerter effektiver höhe
US20040164907A1 (en) * 2003-02-25 2004-08-26 Killen William D. Slot fed microstrip antenna having enhanced slot electromagnetic coupling

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI573108B (zh) * 2016-03-18 2017-03-01 國立虎尾科技大學 電磁感應教具組

Also Published As

Publication number Publication date
WO2007112900A1 (en) 2007-10-11

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