EP0324512B1 - Filtre diélectrique - Google Patents

Filtre diélectrique Download PDF

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Publication number
EP0324512B1
EP0324512B1 EP89102782A EP89102782A EP0324512B1 EP 0324512 B1 EP0324512 B1 EP 0324512B1 EP 89102782 A EP89102782 A EP 89102782A EP 89102782 A EP89102782 A EP 89102782A EP 0324512 B1 EP0324512 B1 EP 0324512B1
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EP
European Patent Office
Prior art keywords
dielectric
resonators
conductive
resonator
filter according
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EP89102782A
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German (de)
English (en)
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EP0324512A2 (fr
EP0324512A3 (en
Inventor
Atsushi Oki Electric Industry Co. Ltd. Fukasawa
Kenichiro Oki Electric Industry Co. Ltd. Hosoda
Takuro Oki Electric Industry Co. Ltd. Sato
Tatumasa Electric Industry Co. Ltd. Yoshida
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Oki Electric Industry Co Ltd
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Oki Electric Industry Co Ltd
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Priority claimed from JP7656682A external-priority patent/JPS58194403A/ja
Priority claimed from JP57076565A external-priority patent/JPS58194402A/ja
Application filed by Oki Electric Industry Co Ltd filed Critical Oki Electric Industry Co Ltd
Priority claimed from EP83104137A external-priority patent/EP0093956B1/fr
Publication of EP0324512A2 publication Critical patent/EP0324512A2/fr
Publication of EP0324512A3 publication Critical patent/EP0324512A3/en
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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
    • H01P1/205—Comb or interdigital filters; Cascaded coaxial cavities
    • H01P1/2056—Comb filters or interdigital filters with metallised resonator holes in a dielectric block

Definitions

  • the present invention relates to a high frequency dielectric filter, in particular, relates to a novel structure of a bandpass filter of dielectric waveguide type, which is suitable for use especially in the range from the VHF bands to the comparatively low frequency microwave bands.
  • the present filter relates particularly to such a filter having a plurality of resonator rods each coupled electrically and/or magnetically with the adjacent resonators, and can be conveniently installed in a mobile communication system.
  • Such kind of filters must satisfy the requirements that the size is small, the energy loss in a high frequency is small, the manufacturing process is simple, and the characteristics are stable.
  • Fig.1A shows the perspective view of a conventional interdigital filter, which has been widely utilized in the VHF bands and the low frequency microwave bands.
  • the reference numerals 1-1 through 1-5 are resonating rods which are made of conductive material, 2-1 through 2-4 are gaps between adjacent resonating rods, and 3 is a case.
  • the items 3-1 through 3-3 are conductive walls of said case 3.
  • a cover of the case 3 is not shown for the sake of the simplicity of the drawing.
  • a pair of exciting antennas 4 are provided for the coupling of the filter with an external circuit.
  • each illustrated resonating rod 1-1 through 1-5 is selected as to be substantially equivalent to one quarter of a wavelength, and one end of the resonating rods are short-circuited alternately to the confronting conductive walls 3-1 and 3-2, while the opposite ends thereof are free standing.
  • a magnetic flux distributes so that the density of the magnetic flux is maximum at the foot of the resonator, and is zero at the top of the resonator, while the electrical field distributes so that said field is maximum at the top of the resonator and the field at the foot of the resonator is zero. Therefore, when a pair of resonators are mounted on a single conductive plane, those resonators are coupled with each other magnetically and electrically, and the magnetic coupling is performed at the foot of the resonators, and the electrical coupling is performed at the top of the resonators.
  • an interdigital filter arranges the resonators alternately on a pair of confronting conductive walls.
  • the two adjacent resonators are electrically coupled with each other as shown in Fig.1B, where the magnetic flux M which has the maximum value at the foot of the resonator does not contribute to the coupling of the two resonators since the foot of the first resonator 1-1 located far from the foot of the second resonator 1-2, and so, only the electrical field E contributes to the coupling of the two resonators.
  • said interdigital filter has the disadvantage that the manufacture of the filter is cumbersome and subsequently the filter is costly, since each of the resonating rods are fixed alternately to the confronting two conductive walls to obtain a high enough coupling coefficient between each of the resonating rods.
  • Fig.2 shows the perspective view of another conventional filter, which is called a comb-line type filter, and has been utilized in the VHF bands and the low frequency microwave bands.
  • the reference numerals 11-1 through 11-5 are conductive resonating rods with one end thereof left free standing while opposite and thereof short-circuited to the single conductive wall 13-1 of a conductive case 13.
  • the length of each resonating rod 11-1 through 11-5 is selected to be a little shorter than a quarter of a wavelength.
  • the resonating rod acts as inductance (L), and capacitance (C) is provided at the head of each resonating rod for providing the resonating condition.
  • said capacitance is accomplished by the dielectric disks 11a-1 through 11a-5 and the conductive bottom wall 13-2 of the case 13.
  • the gaps 12-1 through 12-4 between each of the resonating rods, and the capacitance between the dielectric disks 11a-1 through 11a-5, and the bottom wall 13-2 provide the necessary coupling between each of the resonating rods.
  • a pair of antennas 14 are provided for the coupling between the filter and external circuits.
  • the resonating rods 11-1 through 11-5 are fixed on the single bottom wall 13-1 and the manufacturing cost can be reduced as far as this point is concerned, but there is the shortcoming in that the manufacture of the capacitance (C) with an accuracy of, for instance, several %, is rather difficult, resulting in no cost merit. Therefore, the advantage of a comb-line type filter is merely that it can be made smaller than an interdigital filter.
  • the material of the dielectric body for the use of a high frequency filter is ceramics for obtaining the small high frequency loss, and it is difficult to manufacture the ceramics with the complicated structure to cover the interdigital electrodes of Fig.1A, or the combination of the disks and the rods of Fig.2. If we try to fill the housing with plastics, the high frequency loss by plastics would be larger than the allowable upper limit.
  • a dielectric filter which has a plurality of dielectric resonators has been known.
  • a dielectric filter has the shortcoming that the size of each resonator is rather large even when the dielectric constant of the material of the resonators is the largest possible.
  • each resonator has a circular center conductor (31-1 through 31-5), and the cylindrical dielectric body (31a-1 through 31a-5) covering the related center conductor, and each of the resonators are fixed on the single conductive plane 33-1 of the housing 33, leaving the air gaps (32-1 through 32-4) between the resonators.
  • the items 34 are antennas for coupling the filter with external circuits.
  • the case 33 has the closed conductive walls having the walls 33-1, 33-2, and 33-3 (upper cover wall is not shown).
  • the structure of the filter of Fig.3A has the advantage that the length L of a resonator is shortened due to the presence of the dielectric body covering the conductor, and the resonators are coupled with each other although the resonators are fixed on a single conductive plane due to the presence of the dielectric bodies covering the center conductors.
  • the two resonators are coupled magnetically by the amount equal to the decrease of the electrical coupling. That decrease of the electrical coupling is caused by the leak of the electrical field at the border between the dielectric surface and the air, due to the presence of the air gap 32-1.
  • the leak of the electric field to an upper and/or bottom conductive wall increases with the length (x) between the two resonators, or the decrease of the electrical coupling increases with the length (x). Therefore, the overall coupling between resonators which is the difference between the magnetic coupling and the electrical coupling increases with the length (x) so long as that value (x) is smaller than the predetermined value (x0). When the length (x) exceeds that value (x0), the absolute value of both the electrical coupling and the magnetic coupling becomes small, and so the total coupling decreases with the length (x).
  • the filter of Fig.3A has the disadvantage that the leak (p) of the electrical field to an upper and/or bottom wall is considerably affected by the manufacturing error of both the housing and the dielectric cover. That is to say, the small error of the gap between the upper and/or bottom wall and the dielectric cover, and/or the small error of the size of the dielectric cover provides much error for the characteristics of the filter. Further, the filter is sometimes unstable since the resonators are fixed only at one end of them.
  • the dielectric filter in Figs.3A through 3C has the disadvantages that the length of conductive rods 31a-1 through 31a-5 must be very accurate, and the small error in the length of those conductive rods provides much error in the characteristics of the filter, and that the spurious characteristics of the filter are not enough.
  • Document EP-A1-0038996 discloses a dielectric filter according to the preamble of Claim 1 with a dielectric body surrounding inner conductors. Slits are provided between two adjacent resonators which slits operate as an air gap for effecting the coupling between the resonators. Furthermore, elongate conductive means are arranged between two resonators surrounded by a dielectric body each.
  • Document DE-A-2805965 discloses a dielectric filter in which slits or holes are provided within the dielectric body.
  • the present dielectric filter is based upon the dielectric filter of Figs. 3A through 3C in which a plurality of resonators with a conductive rod enclosed with a dielectric body are positioned on the common conductive wall of the conductive housing, and a pair of antennas are provided at both the extreme ends of the resonators to couple the filter with external input and output circuits.
  • An air gap is provided between two adjacent resonators for effecting the coupling between them.
  • the thickness of the dielectric body surrounding a conductive rod is enough to hold almost all the electromagnetic energy in the resonator except for the energy for coupling the resonator with the adjacent resonator.
  • a conductive rod may be replaced by an elongated hole plated with conductive material provided in a dielectric body.
  • the present dielectric filter has at least the following three improvements as compared with the structure of Figs. 3A through 3C.
  • Fig.4 shows the main portion of the filter in which the reference numeral 41 is a common dielectric body, 42 is a linear hole provided in said dielectric body 41 so that each hole is parallel to one another, and the surface of the holes is plated with conductive material.
  • the length of the hole 42 is approximately 1/4 wavelength, but said length is a little shorter than said 1/4 wavelength.
  • the hole plated with conductive material works as a conductive rod of a resonator.
  • the numeral 43 is a groove provided between the conductive rods or the holes 42. Said groove operates as an air gap 32-1 through 32-4 in Fig.3A.
  • the width and the depth of said groove 43 are W and D, respectively.
  • Fig.5 shows the enlarged cross section of the present filter
  • Fig.6 is an equivalent circuit of the filter of Fig.5, in which L1 is self inductance for unit length of a conductive rod, L12 is mutual inductance for unit length of two conductive rods, C1 is self capacitance between a conductive rod and a conductive housing for each unit length of a conductive rod, and C12 is mutual capacitance between two adjacent conductive rods for unit length of a conductive rod.
  • the coupling coefficient K T between the 1/4 wavelength resonators 52a and 52b is the sum of the magnetic coupling coefficient K L and the static coupling coefficient K C , and is shown by the following equation.
  • the suffix (i) in the equation (1) shows the structure of Fig.5 which has grooves and means inhomogeneous since the dielectric body is not uniform because of the presence of grooves. The structure with no groove is called homogeneous .
  • the values L 1(i) , and L 12(i) in the equation (1) are equal to self inductance L 1(h) , and mutual inductance L 12(h) , respectively, for unit length of a resonator in a homogeneous structure in which a dielectric body is completely filled with dielectric material without grooves.
  • the above relationship means that the magnetic coupling coefficient does not depend upon the presence of grooves, since the permeability of a dielectric body is 1.
  • Said values L 1(h) and L 12(h) are expressed by the equations (2) and (3), respectively, in which self capacitance C 1(h) , mutual capacitance C 12(h) for unit length of a resonator in homogeneous structure are used.
  • ⁇ r , ⁇ 0, ⁇ 0 are the dielectric constant of the dielectric body, the dielectric constant of space, and the space permiability, respectively.
  • K T(i) The coupling coefficient K T(i) between two adjacent resonators in the structure of Fig.5 is derived from the above equations (1), (2) and (3), and the result is shown in the equation (4).
  • the magnetic coupling coefficient K L is independent from the structure of the dielectric body whether or not it is inhomogeneous (having grooves) or homoneneous (without grooves).
  • the values C 1(i) and C 12(i) in the equation (4) are equal to C 1(h) and C 12(h ), respectively, and the magnetic coupling coefficient K L is equal to the static coupling coefficient K C . Therefore, the total coupling coefficient of the filter is almost zero, and no filter is obtained.
  • Fig.7 shows the modification, being in similar way disclosed in DE-A-2805965, of the structure of Fig.5, in which a single central groove 73 is provided between the resonators 72a and 72b, instead of a pair of grooves 53 in Fig.5.
  • the coupling coefficient between resonators is adjusted by the length L and the width W of the groove 73.
  • Fig.8 is another modification, in which at least one conductive rod 85 is provided between the resonators.
  • Those conductive rods 85 effect to adjust the coupling coefficient between the resonators by adjusting the thickness and/or the number of the rods.
  • Those rods also effects to improve the spurious characteristics of the filter.
  • Fig.9 shows an antenna structure for coupling the filter with an external circuit.
  • the numeral 95 is a recess provided in the dielectric body
  • 96 is an electrode provided at the bottom of the recess 95. The coupling between the resonator with the rod 52a and the antenna (95, 96) is accomplished through the capacitance between the electrode 96 and the conductive rod 52a.
  • Fig.10 is another modification of the present filter, in which a linear inner hole 104 is provided for increasing the coupling coefficient between the resonators 102a and 102b.
  • the external grooves 103a and 103b are also provided to couple the resonators.
  • the effect of the grooves in the above embodiments is to decrease the mutual capacitance C 12(i) between resonators in the equation (4), and to decrease the static coupling coefficient K C .
  • the magnetic coupling coefficient K L does not depend upon the presence of the grooves.
  • the grooves increase the total coupling coefficient K T which is the difference between the static coupling coefficient and the magnetic coupling coefficient.
  • the filter with the desired bandwidth is designed with the proper coupling coefficients between each of the resonators.
  • the operational mode of the electro-magnetic wave in the resonators of the present filter is close to the TEM mode which is the operational mode of a coaxial cable. Since the coupling coeffient of the filter in the embodiments of Figs.4 through 10 is adjustable by adjusting merely the width and the depth of the grooves, the filter with the desired bandwidth is obtained easily. Since the dielectric body is a single bulk body common to all the resonators, the structure of the filter is simple, and assembling process is simplified.
  • Fig.11A shows a part of the perspective view of the present filter, in which the reference, numeral 111 is a dielectric body for composing a plurality of resonators, 112 is a conductive housing, 113 is a conductive rod with the length approximately 1/4 wavelength provided in the dielectric body 111, 114 is a thin opaque dielectric plate provided at the free end of the resonators, 115 is a conductive layer attached on said dielectric plate 114, 118 is a groove provided on the dielectric body 111 for providing the coupling between the resonators.
  • Fig.11B is the cross section at the line A-A of Fig.11A.
  • the numeral 116 is the extension of the center conductor 113 on the top of the dielectric body 111
  • 115 is a conductive layer provided on the dielectric plate 114 so that said layer 115 confronts with the extended portion 116 of the center conductor 113.
  • Said conductive layer 115 is electrically coupled with the housing 112, or grounded.
  • a center conductor 113 of a resonator is provided by plating conductive film of the inner surface of the hole in the dielectric body 111.
  • the conductive layer 115, the dielectric plate 114, and the conductive portion 116 compose a capacitor, which is coupled with the resonator, and facilitates the fine adjusting of the resonating frequency of the resonator.
  • the length of the conductor rod 113 is a little shorter than 1/4 wavelength.
  • the free end of the resonator at which the capacitor is coupled has the maximum electric field, and the magnetic field is maximum at the other end of the resonator, as described in accordance with Fig.1B.
  • the reference numeral 117 is the cut out portion on the conductive layer 115.
  • the coupling between two adjacent resonators is provided by the presence of the groove 118 as is the case of the embodiment of Fig.4.
  • the earth current flows in the conductive layer 115.
  • the deterioration of the non-loaded Q u of the resonator by said earth current is prevented if the area of the conductive layer 115 is larger than the cross section of the center rod 113.
  • Said non-load Q u is also deteriorated by the displacement current in the dielectric plate 114. Therefore, in order to prevent the deterioration of the non-load Q u of the resonator by the displacement current, the loss in that dielectric plate 114 must be very small.
  • One example of the material of the dielectric plate 114 for that small loss is alumina (Al2O3).
  • the capacitance is provided between the conductive layer 115 and the extended portion 116 of the center rod 113. Due to the presence of the conductive layer 115 which covers the top of the resonator, the electric field in the resonator does not leak in the direction arrowed by Y. Therefore, the drift of the resonating frequency by opening or closing a cover 119 of the filter is prevented.
  • the resonating frequency of each resonator is adjusted by adjusting the capacitance between the electrodes 115 and 116.
  • the adjustment of the capacitance for adjusting the resonating frequency is accomplished by trimming the area of the outer electrode 115 by using a laser beam.
  • the resonating frequency of the resonator is adjusted without changing or adjusting the resonator itself or the conductive rod 113.
  • the grounded conductive layer 115 is trimmed by using a laser beam as shown in Fig.11C, in which the conductive layer 115 is made of opaque alumina (Al2O3).
  • the electrode 115 is cut by the length (x) as shown in Fig.11C, in which the reference numeral 117 is the cut out trace of a laser.
  • Fig. 12 shows the experimental result of the trimming of the electrode.
  • the horizontal axis shows length (x) of Fig.11C
  • vertical axis shows the frequency shift ⁇ f0 of the resonator (left side), and the un-loaded Q u of the resonator (right side).
  • the allowable error of the resonating frequency in this kind of filter is ⁇ 0.02% in general, therefore, when the center frequency of the filter is 800 MHz, that allowable error is ⁇ 160 KHz.
  • the dielectric plate 114 is opaque for the wavelength of a laser beam so that a laser beam does not deteriorate the dielectric body 111 by illuminating the same directly. If the dielectric body 111 of the resonator is illuminated by a strong laser beam directly, the ceramics (for instance M g T i O3 type ceramics) is deteriorated since T i in ceramics is changed to something like an alloy, and the dielectric loss of the dielectric body increases. In case of alumina, the thickness of the dielectric plate 114 must by thicker than 1.6 mm in order to protect the dielectric body 111 from a laser beam.
  • the trimming is accomplished by illuminating the electrode with a laser beam from the outside of the resonator.
  • a laser beam may provide a hole on a conductive plate, instead of cutting the same.
  • the dielectric plate 114 may be separated for each of the resonators, although the embodiment of Fig.11a shows a single continuous elongated dielectric plate common to all the resonators.
  • Fig.11D shows another alternative, in which the inner conductor 113 does not pass through the dielectric body 111, and said dielectric body 111 has the dielectric wall 111a on which the conductive layer 115 is attached.
  • Fig.11E shows still another alternative, in which a conductive layer 115 is separated to a plurality of cells 115a which are electrically coupled with one another by thin lead lines 115b plated on a dielectric plate.
  • the trimming of the capacitance is accomplished merely by cutting the thin lead lines 115b.
  • Fig.11F is still another modification of the filter of Fig.11A, and the feature of the filter of Fig.11F is that no dielectric plate 114 is provided and a trimming electrode 122 is attached directly on the dielectric body 111. And, said trimming electrode 122 and the ground electrode 120 provide the capacitance between them.
  • the reference numeral 121 shows the trimmed portion of the trimming electrode 122.
  • Two alternatives for the trimming are possible as shown in Figs.11G and 11H.
  • a pair of ground electrodes 120 confront with the electrode 122 which is coupled with the inner conductor 113, and the ground electrodes 120 is trimmed to adjust the resonating frequency of the resonator.
  • Fig.11H no ground electrode is provided, but the center electrode 122 has the flange 123, which is trimmed to adjust the resonating frequency.
  • the modifications in Figs.11F through 11H have no opaque dielectric plate 114. Therefore, a trimming operation can not be carried out by using a laser beam since a laser beam would deteriorate a dielectric body of a resonator, but the trimming operation is accomplished by mechanically cutting a trimming electrode.
  • the undesired mode in the present filter includes spurious of the coaxial mode, and the spurious of the waveguide mode.
  • the frequency of the spurious of the coaxial mode may be higher than 3f0 (where f0 is the resonating frequency) when the ratio D/d (where D is the external diameter of a dielectric body, and d is the inner diameter of a dielectric body) is properly designed.
  • the frequency of the spurious of the waveguide mode depends upon the dimentions of the housing of the filter, and the resonating wavelength is obtained by the following formula.
  • ⁇ 0 2 ⁇ w / (m/H)2+(n/D)2+(a/L)2
  • ⁇ w is the equivalent dielectric constant of the dielectric body
  • m is the number of the wavelength along the height H of a resonator
  • n is the number of the wavelengths along the height of the housing
  • s is the number of the wavelengths along the length (L) of the housing (see Fig.16).
  • the frequency of the spurious of the waveguide mode according to the above equation may be less than 2f0, which deteriorates the attenuation characteristics of the filter.
  • Figs.13A and 13B show two embodiments, in which the numeral 131 is the conductive housing, 132 is the dielectric body, 133 is the inner conductor, 134 is an input/output terminal, 136 is a conductive film attached on the dielectric body, and 137 is a conductive rod provided in the grooves between the resonators.
  • the conductive film or the conductive rod extends perpendicular to the inner conductor of the resonator, and the both the ends of the conductive film or the conductive rods are grounded to the housing 131.
  • the diameter of the conductive rod 137 is 0.8 - 1.6 mm, and 2 - 4 number of conductive rods are positioned around the middle of the height H of the resonator.
  • Fig.14 shows the effect of the conductive film or the conductive rod of the filter in which the center frequency is 800 MHz band.
  • the theoritical spurious resonating frequency of the TE101 mode is 1.468 GHz, which approximately coincides with the experimental spurious frequency 1.56 GHz.
  • the spurious level decreases as the number of the conductive rods increases as shown in Fig.14(b). That is to say, the electric field by the waveguide mode TE101 decreases as the number of the conductive rods increases.
  • Fig. 15 shows that the effect of the conductive rods depends upon the position of the same.
  • the diameter of the conductive rods is 1.2 mm, and three conductive rods arranged with the duration of 20 mm are used.
  • the position (1) means that three conductive rods are positioned at the portion (1) which is close to the free standing end of the resonator
  • the position (3) means that three conductive rods are positioned around the middle of the height (H) of the resonator
  • the position (2) is between the position (1) and the position (2).
  • the position (3) which is close to the middle of the resonator is the best for attenuating the undesired spurious mode.
  • the duration between the position (1) and the position (3) is about 4 mm, and the attenuation at the position (1) is worse by 10 dB as compared with that of the position (3).
  • Fig.16 shows the perspective view of the present dielectric filter which has all the three features of the present invention.
  • the dielectric body 111 with the grooves 118 are positioned in the housing 112, and the inner conductor 113 is provided by plating the inner surface of the hole in the dielectric body 111 with the conductive material.
  • the opaque dielectric plate 114 is attached at the top of the free standing end of the resonators, and the conductive layer 115 for trimming is attached on the surface of the dielectric plate 114.
  • An input/output antenna is not shown in Fig.16.
  • the conductive rods 137 are arranged in the grooves so that those conductive rods are perpendicular to the inner conductor 113, and those conductive rods are positioned approximately at the middle of the height H inner conductor 113.

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Claims (14)

  1. Un filtre diélectrique comprenant :
    (a) un boîtier conducteur (112),
    (b) au moins deux résonateurs fixés dans ledit boîtier (112),
    (c) un moyen d'entrée pour coupler un résonateur d'extrémité desdits au moins deux résonateurs à un circuit externe, et un moyen de sortie pour coupler l'autre résonateur d'extrémité desdits au moins deux résonateurs à un circuit externe,
    (d) chaque résonateur comprenant un conducteur interne linéaire allongé (113), une extrémité duquel est fixée communément au fond dudit boîtier (112), et l'autre extrémité duquel est autosupportante, un corps diélectrique (111) entourant les conducteurs internes (113),
    (e) l'épaisseur dudit corps diélectrique (111) entourant lesdits conducteurs internes (113) étant suffisante pour maintenir toute l'énergie électromagnétique dans le corps diélectrique à l'exception de l'énergie pour coupler deux résonateurs adjacents, et le rapport D/d du diamètre externe D sur le diamètre interne d du corps diélectrique (111) étant convenablement choisi pour réaliser de petites caractéristiques parasites,
    (f) un interstice d'air (118) est prévu entre les résonateurs adjacents,
    (g) ledit corps diélectrique (111) entourant les conducteurs internes (113) est un corps volumineux commun à tous les résonateurs,
    (h) un condensateur est prévu à l'extrémité libre du conducteur interne (13, 123) de chaque résonateur pour régler finement la fréquence de résonance desdits résonateurs,
       caractérisé en ce que
    (i) ledit corps diélectrique (111) entourant lesdits conducteurs internes (113) a des rainures (118) formant lesdits interstices d'air, chacun desquels étant localisé entre deux résonateurs adjacents, respectivement, lesdites rainures (118) étant disposées sur au moins une surface latérale dudit corps diélectrique (111),
       lesdites rainures (118) s'étendant parallèlement aux et le long de la longueur totale desdits conducteurs internes, et
    (j) ledit condensateur comprenant au moins une couche conductrice (115, 116, 120, 122, 123) à l'extrémité autosupportante du corps diélectrique (111), l'ajustement de la capacité pour régler la fréquence de résonance étant réalisé par usinage de la surface de ladite couche conductrice.
  2. Un filtre diélectrique conforme à la revendication 1, comprenant en outre un moyen conducteur allongé (136, 137) ménagé dans ladite rainure (118) de sorte que ledit moyen conducteur allongé soit perpendiculaire au conducteur interne (113) de chacun desdits résonateurs.
  3. Un filtre diélectrique conforme à la revendication 1, dans lequel ledit condensateur a une plaque diélectrique opaque (114) et une paire d'électrodes (115, 116) liées à deux faces de ladite plaque diélectrique (114), une électrode (116) est électriquement couplée à un conducteur interne (113) de chacun desdits résonateurs, et une autre électrode (115) est mise à la terre par le boîtier (112), et ladite dernière électrode est soumise pour être usinée par un faisceau laser afin de régler la capacité du condensateur.
  4. Un filtre diélectrique conforme à la revendication 3, dans lequel ladite électrode (115) est séparée d'une pluralité de cellules (115a), chacune desquelles est couplée électriquement à une autre.
  5. Un filtre diélectrique conforme à la revendication 3, dans lequel ladite plaque diélectrique (114) est prévue comme une partie du corps diélectrique volumineux (111) de sorte qu'une portion diélectrique mince (111a) soit prévue entre l'électrode (115) et le bout du conducteur interne (113) (Fig. 11D).
  6. Un filtre diélectrique conforme à la revendication 1, dans lequel un couvercle (119) dudit boîtier (112) en face de ladite électrode (115) est transparent afin qu'un usinage de l'électrode (115) par un faisceau laser soit effectué par un faisceau laser externe.
  7. Un filtre diélectrique conforme à la revendication 1, dans lequel la couche conductrice (120, 122, 123) est liée à l'extrémité autosupportante du corps diélectrique.
  8. Un filtre diélectrique conforme à la revendication 7, dans lequel ladite couche conductrice est composée d'une première couche (122) couplée à un conducteur interne (113) d'un résonateur, et d'une seconde couche couplée au boîtier (112), et la seconde couche est soumise à usinage.
  9. Un filtre diélectrique conforme à la revendication 7, dans lequel ladite couche conductrice a une couche (123) couplée à un conducteur interne (113), ladite couche (123) est soumise pour être usinée, et la capacité est prévue entre ladite couche (123) et le boîtier (112).
  10. Un filtre diélectrique conforme à la revendication 2, dans lequel ledit moyen conducteur allongé est un film conducteur (136).
  11. Un filtre diélectrique conforme à la revendication 2, dans lequel ledit moyen conducteur allongé est une tige conductrice (137).
  12. Un filtre diélectrique conforme à la revendication 2, dans lequel ledit moyen conducteur allongé (136, 137) est prévu autour de la portion médiane de la hauteur (H) d'un résonateur.
  13. Un filtre diélectrique conforme à la revendication 1, dans lequel ledit corps diélectrique est en céramique de type MgTiO₃.
  14. Un filtre diélectrique conforme à la revendication 3, dans lequel ladite plaque diélectrique (114) est en albumine.
EP89102782A 1982-05-10 1983-04-27 Filtre diélectrique Expired - Lifetime EP0324512B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP7656682A JPS58194403A (ja) 1982-05-10 1982-05-10 誘電体フイルタ
JP76565/82 1982-05-10
JP57076565A JPS58194402A (ja) 1982-05-10 1982-05-10 誘電体フイルタ
JP76566/82 1982-05-10
EP83104137A EP0093956B1 (fr) 1982-05-10 1983-04-27 Filtre diélectrique

Related Parent Applications (1)

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EP83104137.1 Division 1983-04-27

Publications (3)

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EP0324512A2 EP0324512A2 (fr) 1989-07-19
EP0324512A3 EP0324512A3 (en) 1989-07-26
EP0324512B1 true EP0324512B1 (fr) 1994-11-02

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EP89102782A Expired - Lifetime EP0324512B1 (fr) 1982-05-10 1983-04-27 Filtre diélectrique

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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2283856B (en) * 1990-04-05 1995-09-20 Gen Electric Microwave component having tailored operating characteristics and method of tailoring
GB2284095B (en) * 1990-04-05 1995-09-20 Gen Electric Microwave component having tailored operating characteristics and method of tailoring
US11862835B2 (en) * 2020-08-13 2024-01-02 Cyntec Co., Ltd. Dielectric filter with multilayer resonator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1228011B (de) * 1963-07-02 1966-11-03 Siemens Ag Durchstimmbares Bandfilter fuer sehr kurze elektromagnetische Wellen
US4179673A (en) * 1977-02-14 1979-12-18 Murata Manufacturing Co., Ltd. Interdigital filter
US4288530A (en) * 1979-10-15 1981-09-08 Motorola, Inc. Method of tuning apparatus by low power laser beam removal
JPS5657302A (en) * 1979-10-15 1981-05-19 Murata Mfg Co Ltd Microwave device using coaxial resonator
IT1119942B (it) * 1979-11-05 1986-03-19 Cselt Centro Studi Lab Telecom Linea di trasmissione derivata per l'adattamento di circuiti a micro striscia
US4386328A (en) * 1980-04-28 1983-05-31 Oki Electric Industry Co., Ltd. High frequency filter
FR2509536A1 (fr) * 1981-07-07 1983-01-14 Thomson Csf Filtre hyperfrequence comportant des couplages entre troncons de ligne et des moyens de reglage

Also Published As

Publication number Publication date
EP0324512A2 (fr) 1989-07-19
EP0324512A3 (en) 1989-07-26

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