JPH10270907A - Coaxial dielectric filter - Google Patents

Abstract

(57) [Problem] To provide a coaxial dielectric filter whose electrical characteristics are unlikely to change or deteriorate even when a large impact is applied. SOLUTION: This coaxial dielectric filter is fixed to an input side with a cutoff waveguide 1, coaxial dielectric resonators 21 and 22 arranged coaxially at a distance in the cutoff waveguide. A rod-shaped input-side antenna 32, one end of which is supported by the input-side connector 31 and the other end of which is inserted into the input-side inner conductor of the resonator 21 through a sleeve 51 made of polytetrafluoroethylene, and Output connector fixed to
One end side is supported by 41 and the other end side is provided with a rod-shaped output-side antenna 42 inserted and arranged in the output-side inner conductor of the resonator 22 via a sleeve 52. In this coaxial dielectric filter, each antenna 32, 42
Since both ends of the antenna are supported at both ends by the connectors 31, 41 and the sleeves 51, 52, deformation of the antenna hardly occurs and electrical characteristics against impact are hardly deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial dielectric filter used for a microwave or quasi-microwave communication device, and more particularly to a filter whose electrical characteristics change or deteriorate even when a large impact is applied to the filter. The present invention relates to an improvement in a coaxial dielectric filter which is difficult to perform.

[0002]

2. Description of the Related Art FIG. 4 is an equivalent circuit diagram of a typical dielectric filter using a coaxial dielectric resonator. FIG. 5 is a diagram showing a conventional coaxial type dielectric filter using a capacitor. It is a top view showing the structure of a dielectric filter. In a typical coaxial dielectric filter, as shown in the equivalent circuit diagram of FIG. 4, between an input connector and a coaxial dielectric resonator,
Components such as capacitors (C1, C2, C3) (or inductors) are arranged between the coaxial dielectric resonators (between stages) and to obtain coupling between the coaxial dielectric resonators and the output connector. ing. In the coaxial dielectric filter according to the conventional example, the capacitor is formed by a technique such as thick film printing on a substrate of alumina or the like in order to obtain a desired coupling, and as shown in FIG. They are connected using leads. In FIG. 5, reference numeral a denotes a coaxial dielectric resonator, b denotes an input / output capacitor, c denotes an interstage capacitor, and d denotes a recessed housing part d 'which constitutes a part of a cutoff waveguide. A metal case, e indicates an input side connector, f indicates an output side connector, and g indicates a capacitor connection lead.

When a coaxial dielectric filter having a narrow pass band is to be manufactured as a dielectric filter, a capacitor having an extremely small capacitance is required. In the above-mentioned coupling method using a substrate made of alumina or the like, since it is extremely difficult to realize a capacitor or the like having a small capacity, there is a disadvantage that a coaxial dielectric filter having a narrow pass band width cannot be mass-produced.

Therefore, the present applicant has already proposed a coaxial dielectric filter whose structure is simplified by adopting a novel coupling method which does not use components such as capacitors (Japanese Patent Laid-Open No. Hei 8-88504). Reference).

That is, this coaxial dielectric filter is
As shown in FIGS. 6 (A) and 6 (B), a blocking waveguide composed of a housing portion d ′ provided in a metal case d and a metal lid d ″ for closing the open side of the housing portion d ′, At least two coaxial dielectric resonators a, a coaxially arranged at a distance in the cut-off waveguide, and an input connector e fixed to the input side of the cut-off waveguide; A rod-shaped input antenna i whose one end is supported by the input connector e and whose other end is inserted into the input inner conductor of the coaxial dielectric resonator a disposed on the input side; An output-side connector f fixed to the output side, and a rod-shaped one end of which is supported by the output-side connector f and the other end of which is inserted into the output-side inner conductor of the coaxial dielectric resonator a disposed on the output side. And an output-side antenna j.

Since the input side connector e and the output side connector f provided on the input side and the output side of the cutoff waveguide are not necessarily essential components, these connectors e and f are provided.
In the coaxial dielectric filter not provided with the antenna, support holes (not shown) are respectively provided on the input side wall surface and the output side wall surface of the cutoff waveguide, and the antennas i and i are provided in these support hole portions.
The antenna is supported by fitting the end of j.

The capacitance of the capacitors corresponding to C1 and C3 shown in FIG. 4 in the coaxial dielectric filter is such that the rod-shaped input antenna i supported by the input connector e is connected to the coaxial dielectric resonator. a by inserting the rod-shaped output-side antenna j supported by the output-side connector f into the output-side inner conductor of the coaxial dielectric resonator a. Obtained respectively. These capacitances can be changed by changing the insertion amounts of the rod-shaped input-side antenna i and the output-side antenna j inserted into the inner conductors of the coaxial dielectric resonators a and a. Since the areas of the inner conductors of the containers a and a and the antennas i and j that face each other change, they can be changed. For this reason, by changing the insertion amount of the rod-shaped input-side antenna i and output-side antenna j to be inserted into the inner conductor of each coaxial dielectric resonator a, a, the capacitor C1,
C3 can be adjusted.

A capacitor corresponding to C2 shown in FIG. 4 has an open end on the opposite side of the coaxial dielectric resonators a when the coaxial dielectric resonators a are disposed in the cut-off waveguide. It can be given by increasing the distance between the surfaces. The coupling amount is the same as that of the coaxial dielectric resonator a in the cutoff waveguide.
The distance between the coaxial dielectric resonators a, a is exponentially attenuated by increasing the interval of a, and the capacitor C2 between the coaxial dielectric resonators a, a is changed by changing the distance between the opposed coaxial dielectric resonators a. Can be adjusted.

As described above, according to the coaxial dielectric filter developed by the present applicant, the structure of the filter can be simplified because a novel coupling method that does not use components such as capacitors can be employed, and the number of components can be reduced. This has the advantage that a narrow band coaxial dielectric filter can be easily and inexpensively manufactured because the reduction can be achieved.

[0010]

By the way, the coaxial dielectric filter developed by the present applicant has the above-mentioned advantages, but one end of the input antenna i and the output antenna j is connected to the input connector e. And the output side connector f (when these connectors are not provided, support holes provided on the input side and output side wall surfaces of the cutoff waveguide), and the other ends are fixed. Therefore, if a large shock is applied to the coaxial dielectric filter for some reason and an external force acts on the input antenna i and the output antenna j, the other end of the input antenna i and the output antenna j that is not fixed is The coaxial dielectric resonators a may be deformed to change the amount of insertion into the inner conductor or the distance between the inner conductors. Inserted antennas other end coaxial dielectric resonator a within, was sometimes come into contact with the inner conductor of a.

For this reason, capacitors C1 and C shown in FIG.
3 has a problem that the electric characteristics of the coaxial dielectric filter are liable to change or deteriorate, for example, due to the fluctuation of the element 3 or the failure to function as a capacitor.

The present invention has been made in view of such a problem, and an object thereof is to provide a coaxial dielectric material whose electric characteristics are hardly changed or deteriorated even when a large impact is applied to a filter. To provide a filter.

[0013]

According to the first aspect of the present invention, there is provided a blocking waveguide, and at least two coaxial dielectric resonators disposed coaxially at a distance in the blocking waveguide. And an input side of a coaxial dielectric resonator, one end of which is supported by a support hole provided on the input side wall surface of the cut-off waveguide or an input side connector fixed to the input side and disposed on the input side. A rod-shaped input-side antenna having the other end inserted into the conductor, and a support hole provided on the output side wall surface of the blocking waveguide or an output-side connector fixed to the output side; And a rod-shaped output-side antenna having the other end inserted into the output-side inner conductor of the coaxial-type dielectric resonator disposed on the coaxial-type dielectric resonator. Antenna insertion site in inner conductor Fixing members made of a low-loss dielectric material are fitted respectively, and a part of the input-side antenna and a part of the output-side antenna are fitted respectively into the antenna introduction holes provided in these fixing members, and each is inserted through the fixing member. A part of each antenna is inserted into the inner conductor of the coaxial dielectric resonator, and both ends of each antenna are supported in a double-ended manner by a support hole or a connector and a fixing member of the blocking waveguide. It is characterized by the following.

According to the coaxial dielectric filter according to the first aspect of the present invention, the input antenna and the input side antenna are fixed to the inner conductor of the coaxial dielectric resonator via the fixing member made of a low-loss dielectric material. The end of the output-side antenna is inserted, and both ends of each antenna are supported in a double-supported manner by the support hole or connector of the blocking waveguide and the fixing member. Even if an external force acts on each antenna due to impact, deformation of the antenna is unlikely to occur.Therefore, the amount of insertion of each antenna into the inner conductor in each coaxial dielectric resonator changes, and the distance from the inner conductor fluctuates. In addition, contact with the inner conductor of the antenna can be avoided by the presence of the fixing member. For this reason, even if a large impact is applied to the coaxial dielectric filter for some reason, it has the advantage that its electrical characteristics are unlikely to change or deteriorate.

In the above technical means, the fixing member fitted into the antenna insertion portion of the inner conductor of the coaxial dielectric resonator and having the antenna introduction hole is a fluorine resin represented by polytetrafluoroethylene. In principle, the structure is arbitrary as long as it is made of a low-loss dielectric material such as acetal copolymer represented by "Duracon" (trade name of Celanese Corporation in the United States). In consideration of the workability of inserting the fixing member into the part, a fixing member having a flange portion locked at the entrance of the inner conductor is advantageous. Claim 2
The invention according to the above relates to an invention in which the configuration of the fixing member is specified for such a reason.

That is, the invention according to claim 2 is based on the coaxial dielectric filter according to the invention described in claim 1,
The fixing member is provided in a substantially disk-shaped flange portion, a convex portion protruding outward from the center and fitted into the inner conductor of the coaxial dielectric resonator, and provided at a central portion of the flange portion; The main part is constituted by a flange part and an antenna introduction hole penetrating the convex part.

Next, in this technical means, the above-mentioned cut-off waveguide is generally of a straight-line structure. It is also possible to apply a cut-off waveguide having a bent structure instead of a linear structure. The invention according to claim 3 relates to the invention in which the cutoff waveguide is specified.

That is, a third aspect of the present invention is based on the coaxial dielectric filter according to the first or second aspect of the present invention, wherein the cutoff waveguide has a bent portion, and the bent portion has a bent portion. At least two coaxial dielectric resonators are arranged coaxially at a distance from each other in a cutoff waveguide on both sides thereof.

In the case where the above-mentioned cut-off waveguide having a bent portion is applied in this technical means, in this cut-off waveguide, the propagation path length on the outer circumference side at the bent portion is the propagation path length on the inner circumference side. Be longer. And, as the bending angle of the bent portion becomes smaller, the difference between the propagation path length on the outer peripheral side and the inner peripheral side becomes larger, and accordingly, the attenuation amount of the electromagnetic wave propagated between the outer peripheral side and the inner peripheral side of the bent portion becomes different. Therefore, the characteristics as a filter may be slightly reduced as compared with a coaxial dielectric filter having a linear structure. The invention according to claim 4 relates to an invention that prevents such an adverse effect.

That is, the invention according to claim 4 is based on the premise of the coaxial dielectric filter according to claim 3 of the present invention.
The cross-sectional structure of the bending portion of the blocking waveguide is characterized in that the cross-sectional size on the outer peripheral side of the bending portion is set to be larger than the cross-sectional size on the inner peripheral side.

According to the coaxial dielectric filter according to the fourth aspect of the present invention, since the cross-sectional dimension on the outer peripheral side of the bent portion is larger than the cross-sectional size on the inner peripheral side, the amount of electromagnetic wave attenuation on the outer peripheral side of the bent portion is reduced. This can be set to be smaller than the amount of attenuation of the electromagnetic wave on the inner peripheral side. This is because the attenuation of the electromagnetic wave in the cutoff waveguide decreases as the cross-sectional size of the cutoff waveguide increases. Therefore, by setting the cross-sectional dimension on the outer peripheral side of the bent portion to be larger than the cross-sectional dimension on the inner peripheral side, it is possible to correct the difference in the amount of attenuation in the electromagnetic waves on the outer peripheral side and the inner peripheral side of the bent portion.

The cross-sectional structure of the bending portion of the blocking waveguide may be set such that the cross-sectional dimension on the outer peripheral side of the bending portion is larger than the cross-sectional size on the inner peripheral side. In the case where the housing is formed of a recess-shaped housing portion provided in the metal case and a metal lid or the like for closing the open side of the housing portion, the thickness dimension of the metal lid is appropriately set, and the outer peripheral side cross section at the bent portion is set. Is adjusted so that the height dimension is larger than the height dimension of the inner peripheral cross section. In addition, for a metal case having a recess-shaped accommodation portion, a thick metal body such as duralumin may be cut and formed, or a steel plate having a thickness of about 0.8 mm or silver plating or the like may be formed on the surface. This may be configured by bending the applied steel sheet. In addition, ABS resin, acrylonitrile resin, butadiene resin, styrene resin, etc. are injection molded into a case shape, and the surface of a plastic material is plated with nickel undercoat. The metal case may be constituted by a case made of metal.

Next, the invention according to claim 5 relates to an invention in which the configuration of a coaxial dielectric resonator is specified.

That is, a fifth aspect of the present invention is based on the coaxial dielectric filter according to the first to fourth aspects of the present invention, wherein the coaxial dielectric resonator has a cylindrical shape or a rectangular cylindrical shape. / 2 wavelength coaxial dielectric resonator.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

This coaxial dielectric filter is shown in FIG.
(B) As shown in FIG. 1 (B), two coaxial waveguides 1 having a linear structure and two coaxial dielectrics disposed coaxially at a distance from each other and electrically open at both ends thereof. Body resonators (１ ／ wavelength type resonators) 21 and 22, an input connector 31 fixed to the input side of the cutoff waveguide 1, one end of which is supported by the input connector 31, and A rod-shaped input-side antenna 32 having the other end inserted into the input-side inner conductor layer of the disposed coaxial dielectric resonator 21, and an output-side connector 41 fixed to the output side of the cutoff waveguide 1.
And a rod-shaped output-side antenna 42 having one end supported by the output-side connector 41 and the other end inserted into the output-side inner conductor layer of the coaxial dielectric resonator 22 disposed on the output side.
The main part is constituted by the above, and the antenna insertion portion in each inner conductor in the coaxial dielectric resonators 21 and 22 is provided with a sleeve 51 made of polytetrafluoroethylene shown in FIG. , 52 are fitted, and the antenna introduction holes 53, 54 of the respective sleeves 51, 52 are inserted.
The other end of each of the antennas 32 and 42 is fitted therein, and both ends of the antennas 32 and 42 are supported by the input connector 31 and the sleeve 51 and the output connector 41 and the sleeve 52 in a double-supporting manner. .

Further, the cutoff waveguide 1 is shown in FIGS.
As shown in FIG. 1B, an aluminum metal case 11 provided with a substantially rectangular accommodating portion 10 and an aluminum metal cover 1 for closing an upper opening of the metal case 11 are provided.
2 and coaxial dielectric resonators 21, 22
As shown in FIG. 1A, a rectangular cylindrical main body made of barium and titanium-based oxide ceramics, and thick-film silver provided on inner and outer peripheral surfaces of the cylindrical main body. The conductive layer made of paste (the conductive layer provided on the inner peripheral surface is referred to as an inner conductor layer, and the conductive layer provided on the outer peripheral surface is referred to as an outer conductor layer) constitutes a main part thereof, and both ends thereof are described above. So that it is electrically open.

Also, the sleeves 51 and 52 are
As shown in (C), substantially disk-shaped flange portions 55 and 56, and convex portions 57 and 5 having a circular cross section protruding outward from the center.
8 and antenna introduction holes 53, 54 provided at the center of the flanges 55, 56 and penetrating through the flanges 55, 56 and the protrusions 57, 58 to form a main part thereof. Type dielectric resonators (1/2 wavelength type resonators) 21, 22
The convex portions 57 and 58 are fixedly arranged so as to be fitted respectively into antenna insertion portions in the input side inner conductor and the output side inner conductor. Further, the input antenna 32 and the output antenna 42 are provided in the inner conductors of the coaxial dielectric resonators (１ ／ wavelength resonators) 21 and 22 via the sleeves 51 and 52.
, And both ends of the antennas 32 and 42 are connected to the input connector 31 and the sleeve 51 and the output connector 41 and the sleeve 52 as described above.
It has a structure that is supported by both ends.

In this coaxial dielectric filter, an input signal passes through an input antenna 32 and is passed through a coaxial dielectric resonator (（wavelength resonator) 21 disposed on the input side.
Is capacitively coupled to the inner conductor to excite the coaxial dielectric resonator 21. At this time, by the action of the sleeve 51 made of polytetrafluoroethylene, the input antenna 3
It is possible to keep a constant distance between 2 and the inner conductor of the coaxial dielectric resonator 21. Next, the excited resonance energy of the coaxial dielectric resonator 21 is transmitted from the open end on the opposite side to the coaxial dielectric resonator (１ ／ wavelength resonator) 22 disposed on the output side, and Are output via the output-side antenna 42.

In this coaxial dielectric filter, both ends of the input antenna 32 and the output antenna 42 are supported by the input connector 31 and the sleeve 51 and the output connector 41 and the sleeve 52 in a double-supporting manner. Since the antennas 32 and 42 are unlikely to be deformed even when a large impact is applied to the coaxial dielectric filter, each antenna 32 is inserted into the inner conductor of each of the coaxial dielectric resonators 21 and 22. , 42 does not change, and the distance between the inner conductor and the inner conductor does not change.
It is also possible to avoid contact of the inner conductors 2 and 42 with the inner conductor.

FIG. 2 shows a configuration of a coaxial dielectric filter according to another embodiment in which a cut-off waveguide having a bent structure is applied instead of the cut-off waveguide having a straight structure. FIG.

That is, this coaxial dielectric filter is:
As shown in FIG. 2, a cut-off waveguide 1 having a bent portion 100
And the blocking waveguides 1 on both sides of the bent portion 100.
The two coaxial dielectric resonators (1/1) are arranged coaxially at a distance and electrically open at both ends.
Two-wavelength resonators) 21 and 22, an input connector 31 fixed to the input side of the cut-off waveguide 1, and a coaxial dielectric whose one end is supported by the input connector 31 and arranged on the input side. A rod-shaped input-side antenna 32 having the other end inserted into the input-side inner conductor layer of the body resonator 21 via the sleeve 51 made of polytetrafluoroethylene, and fixed to the output side of the cutoff waveguide 1. Output side connector 41
The other end is inserted through the sleeve 52 made of polytetrafluoroethylene into the output-side inner conductor layer of the coaxial dielectric resonator 22 supported at one end by the output-side connector 41 and disposed at the output side. The main part is constituted by a rod-shaped output antenna 42 and both ends of the input antenna 32 and the output antenna 42 are supported by the input connector 31 and the sleeve 51 and the output connector 41 and the sleeve 52. The structure is supported by the formula.

As shown in FIG. 2, the cut-off waveguide 1 has a metal case 110 having a substantially U-shaped cross section and a substantially L-shaped plane, obtained by bending a plate-shaped duralumin. A substantially L-shaped duralumin metal lid (not shown) for closing the upper opening of the case 110 is provided.
The coaxial dielectric resonator (共振 wavelength resonator) 2
1 and 22 and the sleeves 51 and 52 are shown in FIG.
The same components as those shown in FIGS.

Also in this coaxial dielectric filter, the input signal passes through the input side antenna 32 and passes through the inner conductor of the coaxial dielectric resonator (１ ／ wavelength type resonator) 21 disposed on the input side. And the coaxial dielectric resonator 21 is excited. Next, the excited resonance energy of the coaxial dielectric resonator 21 is transmitted from the open end on the opposite side to the coaxial dielectric resonator (１ ／ wavelength resonator) 22 disposed on the output side, and Are output via the output-side antenna 42.

In the coaxial dielectric filter according to this embodiment, since the cut-off waveguide 1 having the bent portion 100 is applied instead of the cut-off waveguide having a linear structure, the length dimension of the filter is reduced. Can also be reduced. Therefore, when a component such as a microwave or quasi-microwave communication device is integrated in a package together with, for example, an electronic circuit and mounted on the device, the electronic device is placed in the space on the inner peripheral side of the bent portion 100 in the cutoff waveguide 1. By arranging components such as circuits, dead space can be eliminated, and there is an advantage that the above components can be significantly reduced in size.

Further, in this coaxial dielectric filter, both ends of the input side antenna 32 and the output side antenna 42 are supported by the input side connector 31 and the sleeve 51 and the output side connector 41 and the sleeve 52 in a double-supported manner. Therefore, similarly to the coaxial dielectric filter shown in FIGS. 1A and 1B, the antennas 32 and 42 are unlikely to be deformed even when a large impact is applied to the coaxial dielectric filter. From the respective coaxial dielectric resonators 21 and 22
The amount of insertion of each of the antennas 32 and 42 in the inner conductor in the above does not change, and the distance between the inner conductors does not fluctuate. It is also possible to avoid contact with the object.

FIG. 3 is a plan view of a coaxial dielectric filter to which the present invention has been applied to a coaxial dielectric filter in which an input connector and an output connector are not incorporated. The coaxial dielectric filter is substantially the same as the coaxial dielectric filter shown in FIG. 2 except that the antenna support method is different as follows.

That is, in this coaxial dielectric filter, the end portions of the antennas 32 and 42 are fitted into support holes (not shown) provided on the input side and the output side wall of the metal case 110 so that the antennas are fitted. The structure is supported. The antennas 32 and 42 exposed from the support holes of the metal case 110 are connected to appropriate connection portions of a circuit board on which the coaxial dielectric filter is incorporated.

In this coaxial dielectric filter, both ends of the input-side antenna 32 and the output-side antenna 42 are both supported by a support hole and a sleeve 51 and a support hole and a sleeve 52 (not shown). Due to the structure, similarly to the coaxial dielectric filter shown in FIG. 2, even if a large impact is applied to this filter, there is an advantage that its electric characteristics are hardly changed or deteriorated.

[0040]

EXAMPLE A coaxial dielectric filter shown in FIGS. 1A and 1B and having a center frequency of 2500 MHz and a 3 dB bandwidth of 3.2 MHz was manufactured.

The sleeves 51 and 52 fitted into the antenna insertion sites in the inner conductors of the coaxial dielectric resonators 21 and 22 have the structure shown in FIG. 1C and are made of polytetrafluoroethylene. Was applied. Beryllium copper is used as the material of the input side antenna 32 and the output side antenna 42.

The coaxial dielectric filter according to this embodiment and the coaxial dielectric filter according to the prior art having the same structure as that of the embodiment except that the sleeves 51 and 52 are not incorporated are MIL-STD883D. An impact test was performed based on (Mill Standard 883D).

As a result, the coaxial dielectric filter according to the conventional example can reduce the insertion loss of the filter from 10 dB to 11 dB by applying a shock of 100 G three times in each of three directions.
Has deteriorated.

On the other hand, in the coaxial dielectric filter according to the example, no deterioration in insertion loss was observed even when a shock of 500 G was applied three times in each of the three directions.

[0045]

According to the coaxial dielectric filter according to the first to fifth aspects of the present invention, the input side antenna is provided in each inner conductor of the coaxial dielectric resonator via a fixing member made of a low-loss dielectric material. And the end side of the output side antenna is inserted, and both ends of each antenna are supported by the supporting hole of the blocking waveguide or the connector and the fixing member in a double-supporting manner. Even if a large impact is applied and an external force acts on each antenna, it is difficult for the antenna to be deformed.Therefore, the insertion amount of each antenna into the inner conductor in each coaxial dielectric resonator may change, or the distance from the inner conductor may be reduced. It does not fluctuate, and the contact of the antenna with the inner conductor can be avoided by the presence of the fixing member.

For this reason, even when a large impact is applied to the coaxial dielectric filter for some reason, its electric characteristics are hardly changed or deteriorated.

[Brief description of the drawings]

FIG. 1A is a plan view of a coaxial dielectric filter according to an embodiment of the present invention with a lid removed, FIG. 1B is a front view of a coaxial dielectric filter provided with a lid, FIG. 1C is a schematic perspective view of a sleeve incorporated in the coaxial dielectric filter.

FIG. 2 is a plan view of a coaxial dielectric filter according to another embodiment with the lid removed.

FIG. 3 is a plan view of a coaxial dielectric filter according to another embodiment with the lid removed.

FIG. 4 is an equivalent circuit diagram of a typical dielectric filter using a coaxial dielectric resonator.

FIG. 5 is a plan view of a conventional coaxial dielectric filter using a capacitor, in which the lid is removed.

FIG. 6A is a plan view of a conventional coaxial dielectric filter without using a capacitor or the like in which a lid is removed, and FIG. 6B is a plan view of a conventional coaxial dielectric filter without using a capacitor or the like; FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cut-off waveguide 21 Coaxial dielectric resonator 22 Coaxial dielectric resonator 31 Input side connector 41 Output side connector 32 Input side antenna 42 Output side antenna 51 Sleeve (fixing member) 52 Sleeve (fixing member) 53 Antenna introduction Hole 54 Antenna introduction hole

Claims (5)

[Claims] 1. A blocking waveguide, at least two coaxial dielectric resonators disposed coaxially at a distance in the blocking waveguide, and provided on an input side wall surface of the blocking waveguide. A rod-shaped input antenna in which one end is supported by a support hole or an input connector fixed to the input side, and the other end is inserted into the input-side inner conductor of a coaxial dielectric resonator disposed on the input side. And an output side of a coaxial dielectric resonator having one end supported by a support hole provided on the output side wall surface of the cut-off waveguide or an output side connector fixed to the output side and arranged on the output side. A coaxial dielectric filter having a rod-shaped output antenna having the other end inserted into a conductor, wherein the coaxial dielectric resonator comprises a low loss dielectric material fixed to an antenna insertion site in each inner conductor in the inner conductor. Insert each member Each of the input-side antenna and the output-side antenna is fitted into an antenna introduction hole provided in the fixed member, and each antenna is inserted into the inner conductor of each coaxial dielectric resonator via the fixed member. , And both ends of each antenna are supported by a supporting member or a connector and a fixing member of the blocking waveguide in a double-supported manner. 2. The fixing member according to claim 1, wherein the fixing member has a substantially disk-shaped flange portion, a convex portion protruding outward from the center and fitted into an inner conductor of the coaxial dielectric resonator, and a center of the flange portion. 2. The coaxial dielectric filter according to claim 1, wherein a main part thereof is constituted by a flange portion and an antenna introduction hole penetrating the convex portion. 3. The cut-off waveguide has a bent portion, and at least two coaxial dielectric resonators are coaxially spaced apart from each other in the cut-off waveguides on both sides of the bent portion. 3. The coaxial dielectric filter according to claim 1, wherein the coaxial dielectric filter is arranged. 4. The cross-sectional structure of a bent portion of the blocking waveguide is set such that a cross-sectional dimension on an outer peripheral side of the bent portion is larger than a cross-sectional size on an inner peripheral side. Coaxial dielectric filter. 5. The coaxial dielectric resonator according to claim 1, wherein the coaxial dielectric resonator is a half-wavelength coaxial dielectric resonator having a cylindrical shape or a rectangular tube shape. Or the coaxial dielectric filter according to 4.