Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/20—Frequency-selective devices, e.g. filters
  • H01P1/2005—Electromagnetic photonic bandgaps [EPB], or photonic bandgaps [PBG]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P3/00—Waveguides; Transmission lines of the waveguide type
  • H01P3/18—Waveguides; Transmission lines of the waveguide type built-up from several layers to increase operating surface, i.e. alternately conductive and dielectric layers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P1/00—Auxiliary devices
  • H01P1/20—Frequency-selective devices, e.g. filters
  • H01P1/201—Filters for transverse electromagnetic waves
  • H01P1/2016—Slot line filters; Fin line filters
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P3/00—Waveguides; Transmission lines of the waveguide type
  • H01P3/02—Waveguides; Transmission lines of the waveguide type with two longitudinal conductors
  • H01P3/08—Microstrips; Strip lines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P3/00—Waveguides; Transmission lines of the waveguide type
  • H01P3/16—Dielectric waveguides, i.e. without a longitudinal conductor

Definitions

• the present invention relates to a new microwave device of the slot type or slot-based structure (slot-line, wiggly slotline, etc.) comprising at least one structure with photonic bandgap (BIP)
• BIP photonic bandgap
• BIP photonic Band Gap Structure
• PBG Photonic Band Gap Structure
• ASA Hardmonic-less Annular Slot Antenna
• FIGS. 1A and 1B such a microwave device comprises a substrate 1, one face 2 of which has been metallized.
• a slit line 3 is produced by etching the metal layer.
• the substrate 1 has a height h and is made of a known dielectric material such as the materials known under the name "Ro4003" or "FR4", the metallic layer preferably being made of copper or any other conductive material.
• the BIP structure is obtained by making patterns
• the patterns or pellets 4 are generally produced by etching a metallic layer and are located opposite the slot-line
• the patterns 4 are repeated periodically and are spaced apart by a distance which gives the repetition period of the pattern. This distance fixes the central frequency of the forbidden band when the patterns are identical. Therefore, the distance a is of the order of k ⁇ g / 2 where ⁇ g is the guided wavelength in the slit-line 3 at the center frequency of the photonic band gap and k is a positive integer greater than or equal to 1.
• Pattern 4 can be of any shape. However, the equivalent surface of the pattern determines the width and / or the depth of the prohibited band.
• the rejection at the central frequency of 8.25 GHz is -17dB.
• the present invention relates to an improvement to the above structure. This improvement allows, among other things, to strengthen the effect of the photonic band gap, taking full advantage of the slit line on which the BIP structure intervenes. Thus, at constant bulk, it is possible to increase the rejection of the forbidden band, or, at constant rejection, to minimize the bulk of the structure.
• the use of two different substrates offers an additional degree of freedom for adjusting the rejection of the filter as well as the central frequency and the width of the band gap.
• the present invention therefore relates to a microwave device of the slit line type with a photonic band gap structure (BIP) characterized in that it comprises, at least: - a first substrate made of a dielectric material having a first permittivity ⁇ r1, - a second substrate made of a dielectric material having a second permittivity ⁇ r2, and - between the two substrates, a conductive layer in which is etched at least one slit line, - with, on the face of the first and second substrates opposite the face in contact with the conductive layer, facing the slit line, periodic metallic patterns.
• the permittivities ⁇ r1 and ⁇ r2 of the first and second substrates can be equal or different.
• the period between two metallic patterns is equal to k ⁇ g / 2 where ⁇ g is the guided wavelength in the slot at the center frequency of the photonic band gap and k is a positive integer greater than or equal to 1.
• the periodic patterns have an equivalent surface depending on the width and depth of the forbidden band.
• the period of the patterns produced on the first substrate is identical to the period of the patterns produced on the second substrate.
• the periodic patterns produced on the first substrate are opposite the patterns produced on the second substrate or, according to a variant, the patterns produced on the first substrate are offset from the periodic patterns made on the second substrate.
• the photonic band gap structure described above can be used with a slit line etched in the conductive layer, this slit line having a width varying according to a periodic law.
• This form of slot-line is known under the name “Wiggly-slotline”.
• this structure can be used with any other device based on a slit line (filter, etc.).
• a “wiggly” type slot line this invention makes it possible to strengthen the filtering function.
• FIG. 1A and 1B are respectively a schematic perspective view and a sectional view of a microwave device of the slit-line type provided with a structure with photonic bandgaps according to the prior art.
• "" Figure 2 represents curves giving the parameters S as a function of the frequency obtained by simulating a structure as shown in Figure 1A.
• Figures 3A and 3B are respectively a schematic perspective view and a sectional view of a microwave device of the slit-line type provided with BIP structures in accordance with an embodiment of the present invention.
• FIG. 4 represents curves giving the parameters S as a function of the frequency of a simulated device such as the device of FIG. 3A.
• Figure 5 is a schematic perspective view of another embodiment of the present invention.
• FIG. 1A and 1B are respectively a schematic perspective view and a sectional view of a microwave device of the slit-line type provided with a structure with photonic bandgaps according to the prior art.
• Figure 2 represents curves giving the
• FIGS. 7A and 7B are section views of another embodiment of a device conforming to the present invention.
• a first microwave device according to the present invention is shown diagrammatically in FIGS. 3A and 3B. More specifically, this device comprises a first substrate 10 made of a dielectric material such as Rogers Ro4003. This first substrate has a permittivity ⁇ r1.
• a conductive layer 12 In known manner, one of the faces of the substrate 10 has been covered with a conductive layer 12, more particularly with a metal layer such as a copper layer in which a slot line 13 has been etched.
• a second substrate 11 of dielectric material having a permittivity ⁇ r2 has been deposited under the layer 12.
• the permittivities ⁇ r1 and ⁇ r2 of the two substrates can be identical or different.
• the use of a different permittivity gives an additional degree of freedom in the realization of the desired filter in terms of rejection, width and central frequency of the forbidden band.
• the fact of using two different substrates modifies ⁇ eff seen by the line; however this value intervenes in the relation which links the central frequency of the forbidden band to the dimensioning of the BIP structure. .lambda.o
• the patterns 14 are constituted, in the embodiment shown, by disc-shaped pellets, namely five metallic pellets.
• the pads 14 are spaced a distance a 'which gives the repetition period of the pattern. This distance fixes the central frequency of the forbidden band when the patterns are identical.
• the distance a 'between the patterns is of the order of k' ⁇ g / 2 where ⁇ g is the wavelength guided in the slot 13 at the center frequency of the selected band gap and k' a positive integer greater than or equal to 1.
• periodic metallic patterns 15 have been etched on the face of the substrate 11 opposite the face in contact with the metallic layer 12.
• This structure formed by the patterns 15 is, in this embodiment, identical to the structure formed by the patterns 14 and the patterns 14 and 15 are opposite one another.
• identical patterns have been produced on both sides of the slot 13, namely the space between the patterns 14 or 15 and the number of patterns has been preserved.
• 3A and 3B has been simulated by directly exciting the slit line.
• the transmission and reflection parameters S are presented in FIG. 4.
• the forbidden band has a width of 1.4 GHz and is centered at 8.3 GHz.
• This strip is therefore wider than the strip obtained with a device according to FIGS. 1A and 1B.
• the rejection at the center frequency of the band gap is then -23dB, an improvement of 6dB compared to the structure of Figures 1 A and 1 B.
• Figure 5 another embodiment of the device microwave according to the present invention.
• the 20 is constituted by a line having a width modulated periodically.
• the modulations consist of circles 21 A spaced periodically on line 21.
• a dielectric substrate is provided on each side of the metal layer 20.
• photonic bandgap structures have been produced constituted by metal pellets 22 periodically spaced opposite the slot 21, according to a period a ".
• This structure has was simulated using for the period a ", a value of 12.7 mm, this periodicity being used also for the circles 21a.
• the line has twelve circles 21a. The results of the simulation are given in FIG. 6.
• the parameters S are given as a function of the frequency.
• the device consists of two substrates 30, 31 made of a dielectric material having respective permittivities ⁇ r1 and ⁇ r2. Between the two substrates is provided a metal layer 32 in which a slit line 33 has been produced by etching. On the faces opposite the face in contact with the layer 32, structures with photonic band gaps 34 and 35 have been produced. As shown in FIG.
• the photonic band gap structure 35 consists of patterns spaced from each other by a distance ai which gives the periodicity of the patterns.
• the patterns 34 also have a periodicity a ⁇ but they are not opposite the patterns 35.
• the patterns are in fact offset above and below the slit line.
• the effect obtained is quite complex.
• shifting the metal pellets can be seen as a modification of the shape / surface of the elementary cell, especially when the pellets above and below the slit line partially overlap.
• the offset between the layer of metal pellets above and below the slit line offers an additional degree of freedom, whether with two identical or different substrates.
• the present invention has been described with reference to patterns in the form of a disc. However, the invention also applies to patterns of any shape, knowing that the equivalent surface of the pattern determines * ⁇ , the width and or the depth of the prohibited band. "J * 20

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• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Optics & Photonics (AREA)
• Control Of Motors That Do Not Use Commutators (AREA)

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• 2004
  • 2004-01-07 FR FR0450036A patent/FR2864864B1/fr not_active Expired - Fee Related
• 2005
  • 2005-01-03 JP JP2006548358A patent/JP4448143B2/ja not_active Expired - Fee Related
  • 2005-01-03 KR KR1020067013531A patent/KR101126652B1/ko not_active Expired - Fee Related
  • 2005-01-03 CN CNA2005800021280A patent/CN1954458A/zh active Pending
  • 2005-01-03 EP EP05717648.9A patent/EP1719201B1/de not_active Expired - Lifetime
  • 2005-01-03 WO PCT/FR2005/050001 patent/WO2005067094A2/fr not_active Ceased
  • 2005-01-03 US US10/585,489 patent/US8264304B2/en not_active Expired - Fee Related

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