EP0117178B1 - Microwave filter with line-shaped resonators - Google Patents

Microwave filter with line-shaped resonators Download PDF

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Publication number
EP0117178B1
EP0117178B1 EP84400151A EP84400151A EP0117178B1 EP 0117178 B1 EP0117178 B1 EP 0117178B1 EP 84400151 A EP84400151 A EP 84400151A EP 84400151 A EP84400151 A EP 84400151A EP 0117178 B1 EP0117178 B1 EP 0117178B1
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EP
European Patent Office
Prior art keywords
conductor
resonator
filter according
conductors
filter
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EP84400151A
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German (de)
French (fr)
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EP0117178A1 (en
Inventor
Clément-François Lacour
Patrick Janer
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Alcatel Thomson Faisceaux Hertziens SA
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Alcatel Thomson Faisceaux Hertziens SA
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    • 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
    • H01P1/20354—Non-comb or non-interdigital filters
    • H01P1/20372—Hairpin resonators
    • 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
    • H01P1/205—Comb or interdigital filters; Cascaded coaxial cavities

Definitions

  • the present invention relates to microwave filters of small dimensions, with linear resonators constituted by one or more conductors.
  • the branches of the "U", forming the resonators are mutually parallel and are dimensioned so that the total developed length of each of the "U" is equal to half the wavelength ⁇ agree of the resonator.
  • the coupling coefficient between two resonators depends on the width of the conductor constituting the resonator, on the distance between the branches of two adjacent "U” as well as on the space existing between the two branches of the same "U".
  • the object of the invention is to remedy the aforementioned drawbacks.
  • the subject of the invention is a microwave filter with linear resonators, piece by piece, constituted by at least one conductor placed on the first flat face of a substrate made of dielectric material, the second face parallel to the first face is metallized to constitute a ground plane, the ends of each conductor being connected to the ground plane, characterized in that the length of each conductor is less than the half wavelength of the wave of frequency F o of resonance of the resonator that it constitutes and in that the middle of each conductor is also connected to the ground plane by means of at least one capacitor to tune each resonator to its resonant frequency F o .
  • This arrangement has the advantage that it makes each resonator tunable to the resonant frequency F on which it is desired to be adjusted while eliminating the parasitic resonances at higher frequencies multiple of F o .
  • the filter comprises a substrate 1, having two plane rectangular faces 2 and 3, mutually parallel, spaced a few tenths of a millimeter apart to serve as a support for two conductors 4 and 5 in the shape of a "U" and with two coupling conductors 6, 7 having roughly parallel directions.
  • the substrate 1 is made of a material with high permittivity, of the magnesium titanate, alumina or teflon glass type.
  • the conductors 4,5,6 and 7 are deposited, for example, by metallization of ribbons on the first face 2 of the substrate.
  • the second face 3 of the substrate is covered entirely, by a metallic layer also deposited by metallization or any other equivalent means.
  • the conductors 4 and 5 form, with the metal layer covering the face 3 of the substrate, two resonators which are supplied, in the example, by means of the coupling conductor 6 carrying the microwave signal applied to the input of the filter. These resonators rotate on a member external to the filter, not shown, the filtered signal, by means of the coupling conductor 7.
  • the "U" formed by the conductors 4 and 5 have reversed positions with respect to each other and their respective branches 4a, 4b, and 5a, 5b have directions roughly parallel to the direction of the coupling conductors 6 and 7.
  • the adjacent branches 4b and 5a of each resonator are slightly spaced from one another, to allow their electromagnetic coupling.
  • the branches 4a and 5b are slightly spaced from the coupling conductors 6 and 7 to allow the coupling of the conductors 6 and 7 with each of the resonators.
  • the ends of each of the U-shaped conductors 4 and 5 are connected to the ground plane, covering the face 3 of the substrate 1, by means of the metallized holes 8, 9, 10 and 11.
  • Two capacitors 12 and 13 are respectively placed, between the middle of the conductors 4 and 5 and the ground plane, inside holes made in the thickness of the substrate 1.
  • the plates 12a and 13a of the capacitors 12 and 13 are welded respectively in the middle of the conductors 4 and 5 and the plates 12b and 13b of the capacitors 12 and 13 are welded to the ground plane located on the second face of the substrate 3.
  • the spaces between the plates 12a and 12b on the one hand, and 13a and 13b d on the other hand are adjusted by means of plunger cores, respectively 14 and 15, which can be moved inside reinforcing bodies 12b and 13b.
  • FIG. 2 The diagram of a resonator, applicable to the construction of the filters according to the invention, is shown in simplified form in FIG. 2.
  • the resonator of FIG. 2 is constituted similarly to those of FIG. 1, by a folded line 16 in the shape of a "U", the ends 17 and 18 of which are connected to the filter supply mass, and the middle of which is also connected to the mass, through, of a variable capacitor 19.
  • the length L o of line 16 is chosen to be less than the resonance wavelength to allow tuning of the resonator using the capacitor 19.
  • This type of resonator allows both very good control and very good rejection of the parasitic frequencies.
  • the value of the capacitor 19 is adjusted to a value of almost zero.
  • the spurious responses at frequencies multiple of 2. F are suppressed due to the fact that the branches of the resonator bring a short circuit across the terminals of the capacitor 19.
  • the value of the capacitor 19 must be adjusted to a non negligible value to obtain the resonance of the resonator and the rejection of the parasitic frequencies, multiples, in this case, of il F o , where 8a represents l electrical angle corresponding to the half section of line of length equal to ⁇ .
  • FIG. 3 represents the capacitor 12 of FIG. 1, mounted on the substrate 1.
  • each armature 12a and 12b of the capacitor is connected respectively to the conductor 4 and to the ground plane covering the substrate 1 by the weld beads 20 and 21.
  • each resonator As each resonator is connected by its two ends to ground, the radiating dipole that it forms, emits less energy than a dipole with the open ends of the prior art, so that the couplings between nonadjacent resonators are are found to be greatly attenuated.
  • the structure of each resonator can be reduced to a simple equivalent diagram in the form of a dipole which facilitates the determination, by calculation, of the filters.
  • FIG. 4 An example of an equivalent diagram is shown in FIG. 4.
  • the resonator, formed by the conductor 4a of FIG. 1 is equivalent to a line formed by the conductors 20, 21, short-circuited at one end by a conductor 24 and connected at its other end to the terminals of capacitor 12.
  • conductor 4b is equivalent to a line formed by conductors 22 and 23, short-circuited at one end by conductor 25 and connected at its other end to terminals of the capacitor 12.
  • the conductors 5a and 5b forming the branches of the "U" of the second resonator of FIG. 1 are equivalent to a line formed by the conductors 26, 27 short-circuited at one end by the conductor 28 and connected at its other end to the terminals of the capacitor 13.
  • the conductor 5b is equivalent to a line formed by the conductors 29 and 30, short-circuited at one end by the conductor 31 and connected at its other end to the b ornes of the capacitor 13.
  • FIG. 5 represents an embodiment of a notch filter using the "U" resonators according to the invention which comprises a single access line 35 the two ends of which constitute the inlet and the outlet of the filter respectively .
  • Three resonators 36, 37 and 38 are arranged in the same plane as line 35 with their branches parallel to line 35 and are placed on either side of this line.
  • FIG. 6 represents a transmission curve obtained using a bandpass filter centered on the frequency 1852.5 MHz where it can be seen that up to 12 GHz the filter remains insensitive at spurious frequencies.
  • the invention is also not limited to the number of resonators used, nor to the shape of the resonators which, instead of being in "U" shape, can take any shape, in V, linear or otherwise, nor the type of capacitors used.
  • the capacitors can be either tunable, fixed or formed by inter-digitized capacitors etched on the substrate.

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Description

La présente invention concerne les filtres hyperfréquence de petites dimensions, à résonateurs linéaires constitués par un ou plusieurs conducteurs.The present invention relates to microwave filters of small dimensions, with linear resonators constituted by one or more conductors.

Il est connu de réaliser des filtres passe-bande ou coupe-bande en hyperfréquence à l'aide de résonateurs, formés par des conducteurs en forme de "U", déposés par métallisation ou tout autre moyen équivalent sur une première face plane d'un substrat dont la deuxième face, parallèle à la première face, est métallisée, pour constituer un plan de masse.It is known to produce band pass or band cut filters in microwave using resonators, formed by "U" shaped conductors, deposited by metallization or any other equivalent means on a first plane face of a substrate whose second face, parallel to the first face, is metallized, to form a ground plane.

Selon cette réalisation, les branches des "U", formant les résonateurs, sont parallèles entre elles et sont dimensionnees pour que la longueur totale développée de chacun des "U", soit égale à la moitié de la longueur d'onde λ d'accord du résonateur.According to this embodiment, the branches of the "U", forming the resonators, are mutually parallel and are dimensioned so that the total developed length of each of the "U" is equal to half the wavelength λ agree of the resonator.

Le coefficient de couplage entre deux résonateurs dépend, de la largeur du conducteur constituant le résonateur, de la distance qui sépare les branches de deux "U" adjacents ainsi que de l'espace existant entre les deux branches du même "U".The coupling coefficient between two resonators depends on the width of the conductor constituting the resonator, on the distance between the branches of two adjacent "U" as well as on the space existing between the two branches of the same "U".

Ces filtres ont pour principaux inconvénients de présenter des réponses parasites aux fréquences multiples de leur fréquence centrale de fonctionnement, notamment, lorsqu'ils sont placés à l'intérieur d'un boîtier fermé et d'avoir un encombrement non négligeable, principalement aux fréquences inférieures à 8 GHz.The main drawbacks of these filters are that they present parasitic responses at frequencies that are multiple of their central operating frequency, in particular when they are placed inside a closed housing and that they have a non-negligible size, mainly at lower frequencies. at 8 GHz.

Pour pallier ces inconvénients, on cherche généralement à diminuer les dimensions des boîtiers en diminuant les dimensions des résonateurs. Une solution consiste, par exemple, à placer un condensateur entre les extrémités libres des branches du "U" de chaque résonateur pour l'accorder sur sa fréquence de travail. Cette réalisation a également pour avantage qu'elle permet d'obtenir des filtres possédant une bonne réjection des fréquences parasites. Mais, elle présente l'inconvénient, de provoquer des champs électriques importants au niveau des condensateurs, et des couplages parasites entre résonateurs non adjacents qui perturbent la réponse du filtre. Le comportement physique d'un filtre ainsi obtenu, ne correspond jamais, de ce fait, au filtre théorique attendu mais à une approximation qui d'une part, nécessite plusieurs essais longs et délicats pour son obtention et qui d'autre part, en corollaire, augmente le prix de revient.To overcome these drawbacks, it is generally sought to reduce the dimensions of the boxes by reducing the dimensions of the resonators. One solution is, for example, to place a capacitor between the free ends of the branches of the "U" of each resonator to tune it on its working frequency. This embodiment also has the advantage that it makes it possible to obtain filters having good rejection of the parasitic frequencies. However, it has the drawback of causing large electric fields at the level of the capacitors, and parasitic couplings between nonadjacent resonators which disturb the response of the filter. The physical behavior of a filter thus obtained, never corresponds, therefore, to the expected theoretical filter but to an approximation which on the one hand, requires several long and delicate tests to obtain it and which on the other hand, as a corollary , increases the cost price.

Le but de l'invention est de remédier aux inconvénients précités.The object of the invention is to remedy the aforementioned drawbacks.

A cet effet, l'invention a pour objet un filtre hyperfréquence à résonateurs linéaires pièce par pièce constitués par au moins un conducteur placé sur la première face plane d'un substrat en matériau diélectrique dont la deuxième face parallèle à la première face est métallisée pour constituer un plan de masse, les extrémités de chaque conducteur étant reliées au plan de masse, caractérisé en ce que la longueur de chaque conducteur est inférieure à la demi longueur d'onde de l'onde de fréquence Fo de résonance du résonateur qu'elle constitue et en ce que le milieu de chaque conducteur est également relié au plan de masse par l'intermédiaire d'au moins un condensateur pour accorder chaque résonateur sur sa fréquence de résonance Fo.To this end, the subject of the invention is a microwave filter with linear resonators, piece by piece, constituted by at least one conductor placed on the first flat face of a substrate made of dielectric material, the second face parallel to the first face is metallized to constitute a ground plane, the ends of each conductor being connected to the ground plane, characterized in that the length of each conductor is less than the half wavelength of the wave of frequency F o of resonance of the resonator that it constitutes and in that the middle of each conductor is also connected to the ground plane by means of at least one capacitor to tune each resonator to its resonant frequency F o .

Cette disposition a pour avantage qu'elle rend chaque résonateur accordable sur la fréquence de résonance F sur laquelle on souhaite qu'il soit réglé tout en supprimant les résonances parasites aux fréquences supérieures multiples de Fo.This arrangement has the advantage that it makes each resonator tunable to the resonant frequency F on which it is desired to be adjusted while eliminating the parasitic resonances at higher frequencies multiple of F o .

Elle a aussi pour avantage de réduire dans des proportions importantes le rayonnement du doublet ainsi formé par chaque résonateur puisque, les extrémités des conducteurs sont reliées au plan de masse. Egalement, le rayonnement du condensateur d'accord de chaque résonateur est fortement atténué par la liaison d'une extrémité du condensateur au plan de masse.It also has the advantage of significantly reducing the radiation of the doublet thus formed by each resonator since the ends of the conductors are connected to the ground plane. Also, the radiation from the tuning capacitor of each resonator is greatly attenuated by the connection of one end of the capacitor to the ground plane.

Cette absence de rayonnement parasitaire, qui était difficilement mesurable dans les réalisations des filtres de l'art antérieur, facilite la réalisation physique des filtres. D'autre part, comme il apparaitra dans la suite de la description, le schéma équivalent de chaque résonateur se trouve être très simplifié, ce qui facilite la détermination théorique de ces filtres.This absence of parasitic radiation, which was difficult to measure in the embodiments of filters of the prior art, facilitates the physical production of the filters. On the other hand, as will appear in the following description, the equivalent diagram of each resonator is found to be very simplified, which facilitates the theoretical determination of these filters.

D'autres caractéristiques et avantages de l'invention apparaîtront également à l'aide de la description qui va suivre faite en regard des dessins annexés donnés uniquement à titre d'exemple et dans lesquels:

  • - La figure 1 représente une vue en perspective d'un filtre hyperfréquence selon l'invention.
  • - La figure 2 représente un schéma électrique d'un résonateur de filtre selon l'invention.
  • - La figure 3 est une représentation du mode d'assemblage d'un condensateur sur le substrat du filtre.
  • - La figure 4 est une représentation du schéma équivalent du filtre représenté à la figure 1.
  • - La figure 5 est une représentation d'un deuxième mode de réalisation d'un filtre hyperfréquence selon l'invention.
  • - La figure 6 est une repréntation de la courbe de réponse d'un filtre de l'invention accordé sur une fréquence centrale de 1852,5 MHz.
Other characteristics and advantages of the invention will also appear with the aid of the description which follows, given with regard to the appended drawings given solely by way of example and in which:
  • - Figure 1 shows a perspective view of a microwave filter according to the invention.
  • - Figure 2 shows an electrical diagram of a filter resonator according to the invention.
  • - Figure 3 is a representation of the method of assembling a capacitor on the filter substrate.
  • - Figure 4 is a representation of the equivalent diagram of the filter shown in Figure 1.
  • - Figure 5 is a representation of a second embodiment of a microwave filter according to the invention.
  • - Figure 6 is a representation of the response curve of a filter of the invention tuned to a central frequency of 1852.5 MHz.

Dans le mode de realisation de l'invention représenté à la figure 1, le filtre comprend un substrat 1, ayant deux faces rectangulaires planes 2 et 3, parallèles entre elles, espacées de quelques dizièmes de millimètres pour servir de support à deux conducteurs 4 et 5 en forme de "U" et à deux conducteurs 6, 7 de couplage ayant des directions à peu près parallèles. Le substrat 1 est fabriqué dans un matériau à permittivité élevée, du type titanate de magnésium, alumine ou verre téflon. Les conducteurs 4,5,6 et 7 sont déposés, par exemple, par métallisation de rubans sur la première face 2 du substrat. La deuxième face 3 du substrat est recouverte entièrement, par une couche métallique déposée également par métallisation ou tout autre moyen équivalent.In the embodiment of the invention shown in FIG. 1, the filter comprises a substrate 1, having two plane rectangular faces 2 and 3, mutually parallel, spaced a few tenths of a millimeter apart to serve as a support for two conductors 4 and 5 in the shape of a "U" and with two coupling conductors 6, 7 having roughly parallel directions. The substrate 1 is made of a material with high permittivity, of the magnesium titanate, alumina or teflon glass type. The conductors 4,5,6 and 7 are deposited, for example, by metallization of ribbons on the first face 2 of the substrate. The second face 3 of the substrate is covered entirely, by a metallic layer also deposited by metallization or any other equivalent means.

Les conducteurs 4 et 5 forment, avec la couche métallique recouvrant la face 3 du substrat, deux résonateurs qui sont alimentés, dans l'exemple, au moyen du conducteur 6 de couplage transportant le signal hyperfréquence appliqué à l'entrée du filtre. Ces résonateurs tournissent à un organe extérieur au filtre, non représenté, le signal filtré, au moyen du conducteur de couplage 7.The conductors 4 and 5 form, with the metal layer covering the face 3 of the substrate, two resonators which are supplied, in the example, by means of the coupling conductor 6 carrying the microwave signal applied to the input of the filter. These resonators rotate on a member external to the filter, not shown, the filtered signal, by means of the coupling conductor 7.

Les "U" formés par les conducteurs 4 et 5 ont des positions inversées l'une par rapport à l'autre et leurs branches respectives 4a, 4b, et 5a, 5b ont des directions à peu près parallèles à la direction des conducteurs de couplage 6 et 7. Les branches adjacentes 4b et 5a de chaque résonateur sont légèrement espacées l'une de l'autre, pour permettre leur couplage électromagnétique. De même les branches 4a et 5b sont légèrement espacées des conducteurs de couplage 6 et 7 pour permettre le couplage des conducteurs 6 et 7 avec chacun des résonateurs. Les extrémités de chacun des conducteurs en "U" 4 et 5 sont reliées au plan de masse, recouvrant la face 3 du substrat 1, par l'intermédiaire des trous métallisés 8, 9, 10 et 11. Deux condensateurs 12 et 13 sont respectivement placés, entre le milieu des conducteurs 4 et 5 et le plan de masse, à l'intérieur de trous pratiqués dans l'épaisseur du substrat 1. Les armatures 12a et 13a des condensateurs 12 et 13 sont soudées respectivement au milieu des conducteurs 4 et 5 et les armatures 12b et 13b des condensateurs 12 et 13 sont soudées au plan de masse situé sur la deuxième face du substrat 3. Sur la figure 1, les espaces entre les armatures 12a et 12b d'une part, et 13a et 13b d'autre part, sont ajustés à l'aide de noyaux plongeurs, respectivement 14 et 15, déplaçables à l'intérieur de corps d'armatures 12b et 13b.The "U" formed by the conductors 4 and 5 have reversed positions with respect to each other and their respective branches 4a, 4b, and 5a, 5b have directions roughly parallel to the direction of the coupling conductors 6 and 7. The adjacent branches 4b and 5a of each resonator are slightly spaced from one another, to allow their electromagnetic coupling. Similarly, the branches 4a and 5b are slightly spaced from the coupling conductors 6 and 7 to allow the coupling of the conductors 6 and 7 with each of the resonators. The ends of each of the U-shaped conductors 4 and 5 are connected to the ground plane, covering the face 3 of the substrate 1, by means of the metallized holes 8, 9, 10 and 11. Two capacitors 12 and 13 are respectively placed, between the middle of the conductors 4 and 5 and the ground plane, inside holes made in the thickness of the substrate 1. The plates 12a and 13a of the capacitors 12 and 13 are welded respectively in the middle of the conductors 4 and 5 and the plates 12b and 13b of the capacitors 12 and 13 are welded to the ground plane located on the second face of the substrate 3. In FIG. 1, the spaces between the plates 12a and 12b on the one hand, and 13a and 13b d on the other hand, are adjusted by means of plunger cores, respectively 14 and 15, which can be moved inside reinforcing bodies 12b and 13b.

Le schéma d'un résonateur, applicable à la construction des filtres selon l'invention, est représenté sous forme simplifiée à la figure 2. Le résonateur de la figure 2 est constitué de façon similaire à ceux de la figure 1, par une ligne repliée 16 en forme de "U" dont les extrémités 17 et 18 sont reliées à la masse d'alimentation du filtre, et dont le milieu est également relié à la masse, au travers, d'un condensateur variable 19. La longueur Lo de la ligne 16 est choisie inférieure à la longueur d'onde de résonance pour permettre l'accord du résonateur à l'aide du condensateur 19.The diagram of a resonator, applicable to the construction of the filters according to the invention, is shown in simplified form in FIG. 2. The resonator of FIG. 2 is constituted similarly to those of FIG. 1, by a folded line 16 in the shape of a "U", the ends 17 and 18 of which are connected to the filter supply mass, and the middle of which is also connected to the mass, through, of a variable capacitor 19. The length L o of line 16 is chosen to be less than the resonance wavelength to allow tuning of the resonator using the capacitor 19.

Ce type de résonateur permet à la fois, une très bonne maîtrise et une très bonne rejection des fréquences parasites.This type of resonator allows both very good control and very good rejection of the parasitic frequencies.

En effet, dans le cas où la longueur Lo est à peu près égale mais inférieure à la demi-longueur d'onde À correspondant à la fréquence centrale Fo de résonance du résonateur, la valeur du condensateur 19 est ajustée à une valeur à peu près nulle. Dans ce cas les réponses parasites aux fréquences multiples de 2. F sont supprimées du fait que les branches du résonateur ramènent un court-circuit aux bornes du condensateur 19. Par contre, dans le cas où, la longueur L a une valeur bien inférieure à la demi-longueur d'onde λ, la valeur du condensateur 19 doit être ajustée à une valeur non négligeable pour obtenir la résonance du résonateur et la réjection des fréquences parasites, multiples, dans ce cas, de il Fo, où 8a represénte l'angle électrique correspondant au demi tronçon de ligne de longueur egale à ï.Indeed, in the case where the length L o is approximately equal to but less than the half wavelength λ corresponding to the central frequency F o of resonance of the resonator, the value of the capacitor 19 is adjusted to a value of almost zero. In this case the spurious responses at frequencies multiple of 2. F are suppressed due to the fact that the branches of the resonator bring a short circuit across the terminals of the capacitor 19. On the other hand, in the case where the length L has a value much less than the half wavelength λ, the value of the capacitor 19 must be adjusted to a non negligible value to obtain the resonance of the resonator and the rejection of the parasitic frequencies, multiples, in this case, of il F o , where 8a represents l electrical angle corresponding to the half section of line of length equal to ï.

Le condensateur 19 étant relié par une de ses extrémités à la masse, le rayonnement émis par celui-ci est fortement diminué. Les liaisons d'un condensateur aux circuits d'un résonateur sont représentées à la figure 3 qui représente le condensateur 12 de la figure 1, monté sur le substrat 1. Sur la figure 3, chaque armature 12a et 12b du condensateur est reliée respectivement au conducteur 4 et au plan de masse recouvrant le susbtrat 1 par les cordons de soudure 20 et 21.The capacitor 19 being connected by one of its ends to ground, the radiation emitted by the latter is greatly reduced. The connections of a capacitor to the circuits of a resonator are represented in FIG. 3 which represents the capacitor 12 of FIG. 1, mounted on the substrate 1. In FIG. 3, each armature 12a and 12b of the capacitor is connected respectively to the conductor 4 and to the ground plane covering the substrate 1 by the weld beads 20 and 21.

Comme chaque résonateur est relié par ses deux extrémités à la masse, le dipôle rayonnant qu'il forme, émet moins d'énergie qu'un dipôle aux extrémités ouvertes de l'art antérieur, de sorte que, les couplages entre résonateurs non adjacents se trouvent être fortement atténués. D'autre part, la structure de chaque résonateur peut être ramenée à un schéma équivalent simple sous forme d'un dipôle ce qui facilite la détermination, par le calcul, des filtres. Un exemple de schéma équivalent est représenté à la figure 4. Sur ce schéma, le résonateur, formé par le conducteur 4a de la figure 1, est equivalent a une ligne formée par les conducteurs 20, 21, court-circuitée à une extrémité par un conducteur 24 et branchée à son autre extrémité aux bornes du condensateur 12. De même, le conducteur 4b est équivalent à une ligne formée par les conducteurs 22 et 23, court-circuitée à une extrémité par le conducteur 25 et branchée à son autre extrémité aux bornes du condensateur 12. De façon identique, les conducteurs 5a et 5b formant les branches du "U" du deuxième résonateur de la figure 1 sont équivalents a une ligne formée par les conducteurs 26, 27 court-circuitée à une extrémité par le conducteur 28 et connectée à son autre extrémité aux bornes du condensateur 13. Egalement le conducteur 5b est équivalent à une ligne formée par les conducteurs 29 et 30, court-circuitée à une extrémité par le conducteur 31 et connectée a son autre extrémité aux bornes du condensateur 13. Pour compléter le schéma équivalent, les résonateurs 4 et sont couplés au travers des inverseurs d'impédance 32, 33 et 34.As each resonator is connected by its two ends to ground, the radiating dipole that it forms, emits less energy than a dipole with the open ends of the prior art, so that the couplings between nonadjacent resonators are are found to be greatly attenuated. On the other hand, the structure of each resonator can be reduced to a simple equivalent diagram in the form of a dipole which facilitates the determination, by calculation, of the filters. An example of an equivalent diagram is shown in FIG. 4. In this diagram, the resonator, formed by the conductor 4a of FIG. 1, is equivalent to a line formed by the conductors 20, 21, short-circuited at one end by a conductor 24 and connected at its other end to the terminals of capacitor 12. Similarly, conductor 4b is equivalent to a line formed by conductors 22 and 23, short-circuited at one end by conductor 25 and connected at its other end to terminals of the capacitor 12. Similarly, the conductors 5a and 5b forming the branches of the "U" of the second resonator of FIG. 1 are equivalent to a line formed by the conductors 26, 27 short-circuited at one end by the conductor 28 and connected at its other end to the terminals of the capacitor 13. Also the conductor 5b is equivalent to a line formed by the conductors 29 and 30, short-circuited at one end by the conductor 31 and connected at its other end to the b ornes of the capacitor 13. To complete the equivalent diagram, the resonators 4 and are coupled through the impedance inverters 32, 33 and 34.

La figure 5 représente une réalisation d'un filtre coupe-bande à l'aide des résonateurs en "U" selon l'invention qui comporte une seule ligne d'accès 35 dont les deux extrémités constituent respectivement l'entrée et la sortie du filtre. Trois résonateurs 36, 37 et 38 sont disposés dans un même plan que la ligne 35 avec leurs branches parallèles à la ligne 35 et sont placés de part et d'autre de cette ligne.FIG. 5 represents an embodiment of a notch filter using the "U" resonators according to the invention which comprises a single access line 35 the two ends of which constitute the inlet and the outlet of the filter respectively . Three resonators 36, 37 and 38 are arranged in the same plane as line 35 with their branches parallel to line 35 and are placed on either side of this line.

A titre d'exemple, la figure 6 représente une courbe de transmission obtenue à l'aide d'un filtre passe-bande centré sur la fréquence 1852,5 MHz où l'on peut voir que jusqu'à 12 GHz le filtre reste insensible aux fréquences parasites.By way of example, FIG. 6 represents a transmission curve obtained using a bandpass filter centered on the frequency 1852.5 MHz where it can be seen that up to 12 GHz the filter remains insensitive at spurious frequencies.

Les exemples qui viennent d'être donnés de réalisations préférées de l'invention ne sont pas limitées aux filtres précédemment décrits, il va de soi qu'elle s'applique également à d'autres variantes de realisation pouvant être empruntées, notamment, des techniques de fabrication des microcircuits.The examples which have just been given of preferred embodiments of the invention are not limited to the filters described above, it goes without saying that it also applies to other alternative embodiments which can be borrowed, in particular, techniques manufacturing microcircuits.

On comprendra également que l'invention n'est pas non plus limitée au nombre de résonateurs utilisés, ni à la forme des résonateurs qui au lieu d'être en "U" peuvent revêtir une forme quelconque, en V, linéaire ou autre, ni au type de condensateurs utilisés. Les condensateurs pourront être indifféremment accordables, fixes ou formés par des condensateurs inter-digités gravés sur le substrat.It will also be understood that the invention is also not limited to the number of resonators used, nor to the shape of the resonators which, instead of being in "U" shape, can take any shape, in V, linear or otherwise, nor the type of capacitors used. The capacitors can be either tunable, fixed or formed by inter-digitized capacitors etched on the substrate.

Claims (9)

1. A microwave filter having portionwise linear resonators which are constituted by at least one conductor (4, 5) situated on the first plane surface (2) of a substrate of dielectric material whose second surface (3) parallel to the first surface is metallized so as to constitute an earth plane, the ends of each conductor being connected to the earth plane, characterized in that the length of each conductor (4, 5) is shorter than half the wavelength of the wave having the resonance frequency Fo of the resonator which it forms, and that the center of each conductor (4, 5) is also connected to the earth plane through at least one capacitor in order to tune each resonator to its resonance frequency Fo.
2. A microwave filter according to claim 1, characterized in that each conductor (4, 5) has an adjustable capacitance.
3. A microwave filter according to any one of claims 1 and 2, characterized in that the ends of a conductor are connected to the earth plane through metallized holes.
4. A microwave filter according to any one of claims 1 to 3, characterized in that each conductor is U-shaped.
5. A microwave filter according to claim 4, characterized in that it comprises coupling conductors (6, 7) also located on the first surface (2) of the substrate (1) and having directions approximately parallel to the direction of the branches of the U of each resonator, in order to apply the microwave signal to be filtered to at least one resonator and to supply the resulting filtered signal to the outside of the filter.
6. A filter according to any one of claims 1 to 5, characterized in that the conductors forming resonators (4, 5) and the coupling conductors (6, 7) are arranged to constitute a band-pass-filter.
7. A filter according to any one of claims 4 to 6, characterized in that the U-shaped conductors (4, 5) have reversed positions with respect to each other.
8. A filter according to any one of claims 4 and 5, characterized in that the U-shaped conductors (4, 5) are coupled through a single coupling conductor (35) in order to form a band cut-off filter.
9. A microwave filter according to any one of the preceding claims, characterized in that the plates (12a, 12b) of a capacitor are soldered one to its corresponding conductor (4, 5) and the other to the earth plane.
EP84400151A 1983-01-31 1984-01-24 Microwave filter with line-shaped resonators Expired EP0117178B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8301454A FR2540294B1 (en) 1983-01-31 1983-01-31 MICROWAVE FILTER WITH LINEAR RESONATORS
FR8301454 1983-01-31

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EP0117178A1 EP0117178A1 (en) 1984-08-29
EP0117178B1 true EP0117178B1 (en) 1987-10-14

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EP (1) EP0117178B1 (en)
JP (1) JPS59121904U (en)
DE (1) DE3466838D1 (en)
FR (1) FR2540294B1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3835480A1 (en) * 1988-10-18 1990-04-19 Fraunhofer Ges Forschung HIGH FREQUENCY BAND PASS FILTER

Families Citing this family (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2164804B (en) * 1984-09-17 1989-03-15 Stc Plc Filters for transmission systems
FR2572591B1 (en) * 1984-10-26 1987-12-18 Portenseigne Sa FILTER CELL AND CHANNEL FILTER COMPRISING AN ASSOCIATION OF SUCH CELLS
US4677693A (en) * 1985-01-25 1987-06-30 Alps Electric Co., Ltd. Frequency conversion circuit
FR2578104B1 (en) * 1985-02-27 1987-03-20 Alcatel Thomson Faisceaux BAND PASS FILTER FOR MICROWAVE
FR2589650A1 (en) * 1985-11-05 1987-05-07 Radiotechnique RESONANT MICROBAND LINE CIRCUIT
FR2613557A1 (en) * 1987-03-31 1988-10-07 Thomson Csf FILTER COMPRISING CONSTANT DISTRIBUTED ELEMENTS ASSOCIATING TWO TYPES OF COUPLING
FR2613538A1 (en) * 1987-03-31 1988-10-07 Thomson Csf Microwave filter
US4757287A (en) * 1987-10-20 1988-07-12 Gte Service Corporation Voltage tunable half wavelength microstrip filter
US5231349A (en) * 1988-05-20 1993-07-27 The Board Of Trustees Of The Leland Stanford Junior University Millimeter-wave active probe system
JPH02146801A (en) * 1988-11-28 1990-06-06 Fujitsu Ltd Band pass filter whose center frequency is variable
US6026311A (en) * 1993-05-28 2000-02-15 Superconductor Technologies, Inc. High temperature superconducting structures and methods for high Q, reduced intermodulation resonators and filters
US7231238B2 (en) 1989-01-13 2007-06-12 Superconductor Technologies, Inc. High temperature spiral snake superconducting resonator having wider runs with higher current density
CA1264073A (en) * 1989-02-09 1989-12-27 Protap Pramanick Microstripline interdigital planar filter
JPH0385903A (en) * 1989-08-30 1991-04-11 Kyocera Corp Band pass filter
GB2246670B (en) * 1990-08-03 1995-04-12 Mohammad Reza Moazzam Microstrip coupled lines filters with improved performance
US5406233A (en) * 1991-02-08 1995-04-11 Massachusetts Institute Of Technology Tunable stripline devices
JP2502824B2 (en) * 1991-03-13 1996-05-29 松下電器産業株式会社 Flat type dielectric filter
US5241291A (en) * 1991-07-05 1993-08-31 Motorola, Inc. Transmission line filter having a varactor for tuning a transmission zero
JPH06104608A (en) * 1992-09-24 1994-04-15 Matsushita Electric Ind Co Ltd Filter
US5392011A (en) * 1992-11-20 1995-02-21 Motorola, Inc. Tunable filter having capacitively coupled tuning elements
US5888942A (en) * 1996-06-17 1999-03-30 Superconductor Technologies, Inc. Tunable microwave hairpin-comb superconductive filters for narrow-band applications
US6350335B1 (en) 1999-02-16 2002-02-26 Lucent Technologies Inc. Microstrip phase shifters
US6127906A (en) * 1999-02-25 2000-10-03 Thin Film Technology Corp. Modular thin film distributed filter
EA200200529A1 (en) 1999-11-04 2002-10-31 Паратек Майкровэйв, Инк. MICROPOSED REJECTABLE FILTERS REJECTABLE BY DIELECTRIC PARAMETRIC DIODE
KR100367718B1 (en) * 1999-11-23 2003-01-10 에스지씨테크놀로지 주식회사 Microwave filter with serial U-type resonators
KR20010094784A (en) * 2000-04-06 2001-11-03 윤종용 Radio filter of combline structure with capacitor recompense circuit
WO2002041441A1 (en) 2000-11-14 2002-05-23 Paratek Microwave, Inc. Hybrid resonator microstrip line filters
EP1380067A1 (en) 2001-04-17 2004-01-14 Paratek Microwave, Inc. Hairpin microstrip line electrically tunable filters
US20030222732A1 (en) * 2002-05-29 2003-12-04 Superconductor Technologies, Inc. Narrow-band filters with zig-zag hairpin resonator
KR100675393B1 (en) * 2005-02-25 2007-01-29 삼성전자주식회사 Parallel coupled-line filter miniaturized by using lumped capacitors and grounding and fabrication method thereof
US7688162B2 (en) * 2006-11-16 2010-03-30 Harris Stratex Networks, Inc. Hairpin microstrip bandpass filter
TWI330903B (en) * 2007-08-13 2010-09-21 Ind Tech Res Inst Filtering circuit and structure thereof
US9270008B2 (en) * 2011-01-28 2016-02-23 The University Of Electro-Communications Transmission line resonator, bandpass filter using transmission line resonator, multiplexer, balanced-to-unbalanced transformer, power divider, unbalanced-to-balanced transformer, frequency mixer, and balance-type filter
US8933768B2 (en) * 2011-10-25 2015-01-13 Zih Corp. Structures for registration error compensation
CN106848505A (en) * 2017-01-11 2017-06-13 电子科技大学 Microstrip filter method for designing based on hybrid coupled
RU2684438C1 (en) * 2018-06-18 2019-04-09 Федеральное государственное автономное образовательное учреждение высшего образования "Сибирский федеральный университет" Strip-line filter
EP3853941A1 (en) * 2018-09-17 2021-07-28 European Space Agency A radio frequency pass-band filter
WO2020066621A1 (en) * 2018-09-28 2020-04-02 株式会社村田製作所 Bandpass filter, communication device, and resonator
RU2730395C1 (en) * 2019-11-25 2020-08-21 Федеральное государственное бюджетное образовательное учреждение высшего образования "Сибирский государственный университет науки и технологий имени академика М.Ф. Решетнева" (СибГУ им. М.Ф. Решетнева) Microstrip ultra-broadband filter

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2030362A1 (en) * 1969-02-07 1970-11-13 Licentia Gmbh

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1068673A (en) * 1952-06-28 1954-06-30 Csf Improvements to ladder type delay lines for traveling wave tubes or magnetrons
FR1123829A (en) * 1955-03-21 1956-09-28 Csf Alternate tubes with delay lines
DE1541990B2 (en) * 1967-10-12 1976-09-23 Siemens AG, 1000 Berlin und 8000 München MICROWAVE FILTER IN PRINTED CIRCUIT TECHNOLOGY
US3530411A (en) * 1969-02-10 1970-09-22 Bunker Ramo High frequency electronic circuit structure employing planar transmission lines
US3621367A (en) * 1969-11-26 1971-11-16 Rca Corp Frequency multiplier employing input and output strip transmission lines without spatially coupling therebetween
US3706948A (en) * 1971-02-18 1972-12-19 Motorola Inc Comb-line filter structure having reduced length and width
US3754198A (en) * 1972-03-20 1973-08-21 Itt Microstrip filter
US3745489A (en) * 1972-05-01 1973-07-10 Stanford Research Inst Microwave and uhf filters using discrete hairpin resonators
JPS53112348U (en) * 1977-02-15 1978-09-07
JPS5732635Y2 (en) * 1977-12-07 1982-07-17
JPS54141850U (en) * 1978-03-24 1979-10-02
JPS54143045A (en) * 1978-04-28 1979-11-07 Mitsubishi Electric Corp Microwave integrated circuit
US4262269A (en) * 1979-12-10 1981-04-14 Hughes Aircraft Company Q Enhanced resonator
JPS5778201A (en) * 1980-10-31 1982-05-15 Toshiba Corp High frequency filter
FR2510326A1 (en) * 1981-07-24 1983-01-28 Thomson Csf LINEAR RESONATOR PASSER FILTER OPEN TO THEIR TWO ENDS
FR2510325B1 (en) * 1981-07-24 1987-09-04 Thomson Csf SMALL DIMENSIONAL MICROWAVE FILTER WITH LINEAR RESONATORS
US4418324A (en) * 1981-12-31 1983-11-29 Motorola, Inc. Implementation of a tunable transmission zero on transmission line filters

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2030362A1 (en) * 1969-02-07 1970-11-13 Licentia Gmbh

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3835480A1 (en) * 1988-10-18 1990-04-19 Fraunhofer Ges Forschung HIGH FREQUENCY BAND PASS FILTER

Also Published As

Publication number Publication date
FR2540294A1 (en) 1984-08-03
EP0117178A1 (en) 1984-08-29
FR2540294B1 (en) 1985-10-04
JPS59121904U (en) 1984-08-16
DE3466838D1 (en) 1987-11-19
JPH0230883Y2 (en) 1990-08-21
US4578656A (en) 1986-03-25

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