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
  • H01P1/201—Filters for transverse electromagnetic waves
  • H01P1/203—Strip line filters
• • 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
  • H01P1/203—Strip line filters
  • H01P1/20327—Electromagnetic interstage coupling
  • H01P1/20336—Comb or interdigital filters
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P7/00—Resonators of the waveguide type
  • H01P7/08—Strip line resonators
  • H01P7/082—Microstripline resonators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P7/00—Resonators of the waveguide type
  • H01P7/08—Strip line resonators
  • H01P7/088—Tunable resonators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/12—Coupling devices having more than two ports

Definitions

• the present invention relates to a filtering device with an electrically conductive strip structure. It also relates to a filter assembly comprising a plurality of filtering devices of this type.
• the invention applies more particularly to a filtering device with an electrically conductive strip structure, comprising:
• a transmission line formed by an electrically conductive strip printed on one side of an electrically insulating substrate, this conductive strip having two ends respectively forming the only two input and output connection ports of the filtering device, and
• each resonator comprising an electrically conductive strip printed on said face of the substrate.
• a filtering device is produced using electrically conductive strips printed by simple etching on one side of an electrically insulating substrate.
• One or more ground planes can also be made on the same face of the substrate, on another face of the substrate, or by stacking substrates.
• filtering devices printed in micro-ribbon technology use a technique known as "distributed constant" filtering whereby discrete component assemblies are replaced by assemblies of elementary patterns of printed electrically conductive strips, each elementary pattern producing a predetermined function R, L and / or C.
• the elementary patterns are far enough apart from each other not to interfere with each other.
• it is necessary to multiply the number of filtering devices connected in series. This results in filters which have a congestion sometimes penalizing, the latter increasing with the order of the filter, given the frequencies referred (those of the radio frequency spectrum up to 300 GHz) and applications envisaged.
• each resonator has a first end coupled to the transmission line between the two connection ports and at least one second free end or connected to a ground so as to generate an effective fundamental resonance wavelength each resonator on said face of the substrate, and
• the distance between the first ends of the two neighboring resonators of this pair is less than one-tenth of the smallest effective fundamental resonance wavelength of the plurality of resonators on said face; of the substrate.
• ⁇ By “effective fundamental resonance wavelength” of a resonator, is meant, of course, the wavelength effectively generated on said face of the substrate by fundamental resonance of the resonator considered, this wavelength being different from that which would correspond in the air because of the index of refraction of the substrate which is not equal to that of the air.
• first end coupled to the transmission line is meant either a connection of said first end to the transmission line, or possibly a capacitive coupling by approaching said first end and the transmission line. It results from the topology thus proposed a metamaterial structure obtained by micro-ribbon technology which has particularly surprising and advantageous properties.
• the object of the invention is not envisaged as comprising a delay line whose impedance or phase shift is considered.
• the main aim is to obtain a metamaterial effect from resonators coupled to a transmission line that is as short as possible, regardless of its impedance which then becomes negligible and not taken into consideration.
• the conductive strips forming the transmission line and the resonators are rectilinear, the resonators being otherwise parallel to each other so as to form a comb of resonators.
• the resonators are perpendicular to the transmission line.
• the resonators are all of the same nominal length, so as to generate the same nominal effective fundamental resonance wavelength, except at least one short resonator, each short resonator being surrounded by two neighboring resonators length nominal and being shorter than the nominal length so as to generate at least one resonant cavity in said plurality of resonators.
• the resonators are all of nominal length except for a single short resonator so as to generate a single resonant cavity in said plurality of resonators.
• the resonators are all of nominal length except N short resonators, with N ⁇ 2, arranged in a periodic pattern so as to generate N resonant cavities periodically distributed in said plurality of resonators.
• At least one resonator is provided with an electronic component for adjusting its equivalent electrical fundamental resonance frequency.
• the electronic control component comprises one of the elements of the assembly consisting of a PIN diode, a varicap diode, a varistor and a transistor.
• a filter assembly with at least one input connection port and at least one output connection port, comprising a plurality of filtering devices according to the invention, wherein:
• the electrically conductive strips forming the transmission lines and the resonators of the filtering devices are printed on the same face of the same substrate,
• a filter assembly can comprise a single input connection port and a single output connection port, the filtering devices being coupled together in series so that the input connection port the first filter device of the series forms the input connection port of the filter assembly and the output connection port of the last filter device of the series forms the output connection port of the filter assembly.
• FIG. 1 schematically represents the general structure of a filtering device according to a first preferred embodiment of the invention
• FIG. 2 is a diagram illustrating the transfer function of the filtering device of FIG. 1,
• FIG. 3 diagrammatically represents the general structure of a filtering device according to a second preferred embodiment of the invention
• FIG. 4 is a diagram illustrating the transfer function of the filtering device of FIG. 3
• FIG. 5 schematically represents the general structure of a filtering device according to a third preferred embodiment of the invention
• FIG. 6 schematically represents the general structure of a filtering device according to a fourth preferred embodiment of the invention.
• FIG. 7 schematically represents the general structure of a filtering device according to a fifth preferred embodiment of the invention.
• FIG. 8 is a diagram illustrating the transfer function of the filtering device of FIG. 7,
• FIG. 9 schematically represents the general structure of a filter assembly according to a first preferred embodiment of the invention.
• FIG. 10 is a diagram illustrating the transfer function of the filter assembly of FIG. 9,
• FIG. 11 schematically represents the general structure of a filter assembly according to a second preferred embodiment of the invention.
• FIG. 12 is a diagram illustrating the transfer function of the filter assembly of FIG.
• FIG. 13 diagrammatically represents the general structure of a filter assembly according to a third preferred embodiment of the invention.
• FIG. 14 is a diagram illustrating the transfer function of the filter assembly of FIG. 13, and
• FIG. 15 schematically shows the general structure of a filter assembly according to a fourth preferred embodiment of the invention.
• the filtering device 100 shown diagrammatically in FIG. 1 comprises a transmission line 102, for example a line 50 ⁇ formed by an electrically conductive strip printed on one side of an electrically insulating substrate 104.
• This conductive strip 102 has two ends 102
• the conductive strip 102 is rectilinear.
• the filtering device 100 further comprises a plurality of resonators 106 5 106 M , each resonator 106, (1 ⁇ i ⁇ M) comprising a band electrically conductive printed on the same side of the substrate 104 as the conductive strip of the transmission line 102.
• the conductive strip of each resonator 106 has a first end 108, connected to the transmission line 102 between the two connection ports 102
• the conductive strips of the resonators 106 1 106 M are rectilinear, all of the same length L and parallel to each other so as to form a comb of resonators.
• the resonators 106 ⁇ 106 M are further perpendicular to the transmission line 102 and their second ends 1 10-1, 1 10 M are shown free.
• the resonators 106 ⁇ 106 M all have the same effective fundamental resonance wavelength ⁇ equal to four times their length L.
• the resonators 106i, 106 M all have the same effective fundamental resonance wavelength ⁇ equal to twice their length L.
• the distance denoted by e, between the first ends 108 , and 108 i + i of the two neighboring resonators 106, and 106 i + i of this pair is less than one tenth of the smallest effective fundamental resonance wavelength of the plurality of resonators which is, in this example where all the resonators are all of the same length L, the effective wavelength ⁇ mentioned above.
• distances ei, e i M- can even advantageously be less than the tenth, or one hundredth, of the smaller effective fundamental resonant wavelength of the plurality of resonators 106 ⁇ 106 M -
• all these distances e ⁇ e M i are equal and of the same order of magnitude as the width of each resonator.
• This transfer function shows that a band-stop filtering device 100, that is, a band-gap at -30 dB, having good performance, has thus been designed, the forbidden band of transmission starting just after, in the frequency domain, the frequency resonance (about 1.3 GHz) corresponding to the effective wavelength ⁇ mentioned above and extending to about 1.6 GHz. These good performances are furthermore obtained for a filtering device 100 which remains very compact and of minimal bulk.
• the filter structure illustrated in FIG. 1 is only a particular example of a filtering device according to the invention.
• the conductive strips forming the transmission line 102 and 106i resonators 106 M are not necessarily rectilinear, the resonators are not necessarily parallel to each other or perpendicular to the transmission line and are not necessarily of the same length L.
• the distances ei, e M -i are not necessarily equal either.
• it is necessary that for each pair of resonators neighboring the plurality of resonators, the distance between the first ends of the two neighboring resonators of this pair is less than a quarter, or even advantageously to a tenth, of the shortest length of the pair.
• the filtering device 200 shown schematically in FIG. 3 according to a second preferred embodiment of the invention, comprises a transmission line 202 with two ends 202 ! N and 202 ⁇ ⁇ printed on a substrate 204 and resonators 206i, 206 M having first 208i, 208 M and second 210 ! , 210 M ends. It is identical to the filter device 100 to the exception that one 206, its resonators 206i, 206 M is shorter than the others.
• the resonators 206i, 206m are all the same nominal length L, so as to generate the same length of effective fundamental resonance wavelength ⁇ nominal except short resonator ,, 206 disposed somewhere in the metamaterial structure between the first resonator 206-I and the last resonator 206 M so as to generate a resonant singular cavity of very small size in the plurality of resonators 206 ⁇ 206 M -
• the distances ei, e M- i must remain less than a quarter, or even advantageously one tenth, of the smallest effective fundamental resonance wavelength of the plurality of resonators which is, in this example, the effective fundamental resonance wavelength of short resonator 206i.
• the presence of the resonant cavity generated by the short resonator 206 makes it possible to trap certain waves so as to create a resonance peak, this resonance peak being adjustable in position in the forbidden band transmission of the filter device 200 by varying the position and size of the short resonator 206, in the plurality of resonators 206i, 206 M -
• the experiment shows that the resonance peak thus obtained is very narrow, so that it presents a great quality factor.
• the transfer function is obtained illustrated in FIG. 4.
• This transfer function shows that it has thus been conceived a notch-filtering device 200, that is, a bandgap band at -30 dB, which not only has good performance but also high quality resonance in its forbidden band.
• the band-gap at -30 dB which extends from about 1.3 GHz to 1.7 GHz has a resonant peak at just under 1.6 GHz, the rejection being very abrupt around this resonance, 30 dB in a few tens of MHz. These good performances are also obtained for a filtering device 200 which remains very compact and compact.
• the filtering device 300 comprises a two-end transmission line 302 302
• the resonators 306 ⁇ 306 M are all of the same nominal length L, so as to generate the same nominal effective fundamental resonance wavelength ⁇ , except the N short resonators 306 , -i, 306i , N , arranged in the metamaterial structure between the first resonator 306-1 and the last resonator 306 M so as to generate N very small coupled resonant singular cavities in the plurality of resonators 306 ⁇ 306 M - Each short resonator is surrounded by two resonators neighbors of nominal length.
• the N short resonators 306, -1, 306 i N are arranged in a periodic pattern so as to generate N resonant cavities periodically distributed in said plurality of resonators.
• a short resonator is arranged every three resonators.
• Each resulting resonant cavity is then separated from its neighbors by two resonators of nominal length and is therefore coupled directly only with its closest neighbors.
• the width of this frequency band can be modified by modifying the structural parameters of the filtering device 300. This makes it possible to produce a filter type with even more abrupt frequency transitions (ie increasing the order of the filter) and easier to adjust.
• Another effect resulting from the increase in the number of cavities in the metamaterial structure of FIG. 5 is to considerably slow down the group speed of the electrical signals passing through the filtering device, because a band of modes of slow speed propagation.
• the distances ei, e M --i must remain less than a quarter, or even advantageously one tenth, of the smallest effective fundamental resonance wavelength of the plurality of resonators. which in this example is the effective fundamental resonance wavelength of the N short resonators 306, 1, 306 i N -
• the filtering device 400 comprises a transmission line 402 with two ends 402
• the component 412 is for example a PIN diode, a varicap diode, a varistor or a transistor.
• the distances ei, e M- i must remain less than a quarter, or even advantageously one tenth, of the smallest effective fundamental resonance wavelength of the plurality of resonators which is, in this example, the effective fundamental resonance wavelength corresponding to the equivalent electrical resonance frequency of the resonator 406,
• the filtering device 450 comprises a transmission line 452 with two ends 452
• each resonator 456 or 456 M is not directly connected to the transmission line 452, but capacitively coupled with it by approaching without contact, and
• each resonator 456i, or 456 M has two second free ends 460i, or or 460 M consisting of a band conductor split in the middle part according to a general form of tuning fork.
• This split form of the so-called fractal resonators can be generalized into a multi-second tree shape for each resonator. It makes it possible to shorten the length of each resonator for the same effective resonance wavelength, at the cost of greater lateral bulk.
• the distances ei, e M- i must remain less than a quarter, or even advantageously one tenth, of the smallest effective fundamental resonance wavelength of the plurality of resonators which is, in this example, the effective fundamental resonance wavelength corresponding to the fundamental resonator equivalent electrical frequency of the short resonator 456 ,.
• the -30 dB band gap which ranges from about 1.45 GHz to 2.55 GHz, has a resonant peak at 1.9 GHz in a bandwidth of -30 dB which ranges from about 1, 8 GHz to 2.4 GHz. These good performances are also obtained for a filtering device 450 which remains very compact and compact.
• a filter assembly with at least one input connection port and at least one output connection port, having a plurality of filtering devices according to the invention can be designed. All the electrically conductive strips forming the transmission lines and the resonators of the filtering devices of such a filter assembly are printed on the same face of the same substrate. Furthermore, the filtering devices are coupled together in series and / or in parallel according to topologies that can be very diverse. It is thus possible to conceive a filtering unit that achieves ambitious objectives in terms of bandwidth, bandwidth loss and rejection level around this bandwidth.
• the filtering devices are coupled together in series, so that the filter assembly comprises only one input connection port and one output connection port, the port of the first filtering device of the series forming the input connection port of the filter assembly and the output connection port of the last filtering device of the series forming the output connection port of the filter assembly.
• FIG. 9 A first embodiment of a filter assembly according to the invention and according to this first family of topologies is illustrated in FIG. 9.
• N and 502 ⁇ ⁇ illustrated in this figure comprises two filtering devices 504, 506 of the same type as the filtering device 200, that is to say resonators all the same nominal length except one.
• the input connection port 502 ! N corresponds to the input connection port of the first filter device 504 and the output connection port 502 ⁇ ⁇ corresponds to the output connection port of the second and last filter device 506.
• the two transmission lines of the two filtering devices 504 and 506 are in the extension of each other and the output connection port of the transmission line of the first filtering device 504 is coupled to the connection port of input of the transmission line of the second filter device 506 with a printed capacitive element 508.
• the latter is formed of two electrically conductive strips perpendicular to the transmission lines of the two filtering devices 504 and 506 coupled. It makes it possible to maintain the two filtering devices 504 and 506 at a distance from one another while coupling them.
• the transfer function illustrated in FIG. 10 is obtained.
• This transfer function shows that a filtering set has thus been designed. 500 whose band-gap and resonant band-band properties are improved. In particular, a bandwidth at -30 dB of about 100 MHz between 1.5 and 1.6 GHz in the forbidden band and a rejection of 40 dB in a few tens of MHz around this bandwidth are reached, losses at resonance peak being less than 3 dB.
• a second embodiment of a filter assembly according to the invention and according to the first family of topologies is illustrated in FIG.
• the filter assembly 600 with two connection ports 602 ! N and 602 ⁇ ⁇ illustrated in this figure comprises two filtering devices 604, 606 of the same type as the filtering device 200, that is to say with resonators all of same nominal length except for one (the resonant cavity is not arranged at the center of the plurality of resonators, however). These two filtering devices 604 and 606 are arranged in axial symmetry with respect to each other along an axis perpendicular to the transmission lines.
• N corresponds to the input connection port of the first filter device 604 and the output connection port 602 ⁇ ⁇ corresponds to the output connection port of the second and last filter device 606.
• the two transmission lines of the two filtering devices 604 and 606 are in the extension of each other and the output connection port of the transmission line of the first filter device 604 is electromagnetically coupled to the connection port of input of the transmission line of the second filtering device 606.
• the two coupled ports are brought closer to one another and the coupling is done directly without any particular element. This coupling varies as a function of the separation distance of the two filtering devices 604 and 606.
• the transfer function illustrated in FIG. 12 is obtained.
• This transfer function shows that a filtering set has thus been designed. 600 whose band-gap and resonant band-band properties are improved. In particular, a bandwidth at -30 dB of around 50 MHz in the forbidden band and a rejection of 40 dB in a few tens of MHz around this bandwidth are reached, the losses at the resonant peak being less than 3 dB .
• FIG. 13 A third embodiment of a filter assembly according to the invention and according to the first family of topologies is illustrated in FIG. 13.
• N and 702 ⁇ ⁇ illustrated in this figure comprises two filtering devices 704, 706 of the same type as the filtering device 200, that is to say resonators all of the same nominal length except one (the resonant cavity being however not arranged at the center of the plurality of resonators). These two filtering devices 704 and 706 are arranged in central symmetry with respect to one another on a point of the substrate on which they are printed.
• the input connection port 702 ! N corresponds to the input connection port of the first filter device 704 and the output connection port 702 ⁇ ⁇ corresponds to the output connection port of the second and last filter device 706.
• the two transmission lines of the two filtering devices 704 and 706 are parallel without being in the extension of one another.
• the electromagnetic coupling of the two filtering devices 704 and 706 is along two of their close-in resonators, one connected to the output connection port of the first filter device 704, the other connected to the input connection port of the second filter device 706.
• the coupling is done directly without any particular element. This coupling varies according to the separation distance of the two resonators vis-à-vis.
• the previously described filtering devices 100, 200, 300, 400, 450 may be coupled together in parallel so that the filter assembly has a plurality of input connection ports or a plurality of ports. output connection.
• FIG. 1 A fourth embodiment of a filter assembly according to the invention and according to this second family of topologies is illustrated in FIG.
• Nn and an output connection port 802 ⁇ ⁇ illustrated in this figure comprises n filters 804-I, 804 n which may each be the same type as any of the filtering devices 100, 200, 300, 400, 450 or other.
• the input connection port 802, N1 corresponds to the input connection port of the first filter 804-I
• Nn corresponds to the input connection port of the last filter 804 n
• the output connection port 802 ⁇ ⁇ corresponds to the parallel interconnection of the n output connection ports of n filters 804 ⁇ 804 n .
• a signal whose spectrum is included in the forbidden band of each filter 804 ⁇ 804 n
• only the part of the spectrum corresponding to the resonant peak or the bandwidth of the first filter 804i is transmitted by this first filter 804i at the output 802 ⁇ ⁇
• only the part of the spectrum corresponding to the resonant peak or to the bandwidth of the last filter 804 ! is transmitted by this last filter 804 ! at the output 802 ⁇ ⁇ > so that a signal multiplexed according to the different resonant peaks or bandwidths of the n filters 804 ⁇ ,, 804 n is output.
• the filter assembly 800 is passive and therefore reversible. It can then be seen and used as a filter set at an input connection port 802 ⁇ ⁇ and n output connection ports 802
• Nn signal parts respectively corresponding to the n resonant peaks or bandwidths of the n filters 804 ⁇ 804 n.
• filter assemblies with series-coupled filtering devices for example the filter assemblies 500, 600, 700, can also constitute all or some of the filters 804. 804 n coupled in parallel.
• a filter assembly may be designed by serially coupling filter assemblies of parallel coupled filter devices.
• a filtering device or filter assembly such as one of those described above makes it possible to provide a high-performance filter for a minimum space requirement, thanks to a metamaterial structure obtained by bringing together a plurality of resonators so that the distances between neighboring resonators are always less than a quarter, or even advantageously one tenth, of the smallest effective fundamental resonance wavelength of the plurality of resonators.

Landscapes

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

Applications Claiming Priority (2)

Publications (2)

Family

ID=52824330

Family Applications (1)

Country Status (4)

Families Citing this family (4)

Family Cites Families (5)

• 2014
  • 2014-11-27 FR FR1461555A patent/FR3029368B1/fr active Active
• 2015
  • 2015-11-26 WO PCT/FR2015/053224 patent/WO2016083747A1/fr active Application Filing
  • 2015-11-26 EP EP15807957.4A patent/EP3224897B1/de active Active
  • 2015-11-26 US US15/529,850 patent/US10476121B2/en active Active

Also Published As

Similar Documents

Legal Events