JPS60178705A - Dielectric coaxial resonator - Google Patents

Abstract

PURPOSE:To attain miniaturization of a dielectric coaxial resonator and to perform the frequency control in a simple constitution, by forming a conductor on the inner and outer peripheral surfaces of a cylindrical dielectric element having a level difference part at the outer peripheral surface as well as at the short circuit part on an end surface of said element and having an electrical and mechanical connection between said conductor and a conductor of the outer peripheral part. CONSTITUTION:The metallization is applied to form a conductor 3 on both inner and outer peripheral surfaces as well as a short circuit part of a cylindrical dielectric element 1 having a level difference part 8 near an open end face 2 and excluding said face 2. A rotor 14 made of a dielectric disk is set at the upper part of a metallic electrode 11, and an approximately semicircular rotor electrode 13 and a dummy electrode 21 are formed at the upper part of the rotor 14 by a silver baking process, etc. Then the open terminal capacity of a resonator is produced between the electrode 14 and a stator electrode 12 formed to the electrode 11. The rotor 14 is revolved with revolutions of a shaft 18. Thus said open terminal capacity can be varied.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a filter 2 used in radio equipment in a high frequency band,
The present invention relates to a dielectric coaxial resonator that can be used as an oscillator.

Conventional Structures and Their Problems Examples of conventional coaxial resonators using dielectric materials are shown in FIGS. 1 to 3. Figures 1 and 2 show the most well-known pure liquid rectangular coaxial resonator, in which the inner, outer circumferential surface and short-circuited portions of one end of the cylindrical dielectric element 1 are plated or baked with silver. The electrode 3 is formed on the open end surface 2 of the dielectric element 1 where the electrode 3 is not formed, and an arc-shaped electrode 4 continuous with the external conductor 3a is provided to connect the dielectric layer 5. By varying the capacitance of the open end surface 2 of the element 1, the resonance frequency was varied.

However, as radio equipment in high-frequency band mobile communication systems is becoming smaller, conventional filters have a limit to how small they can be, making it difficult to use them. In other words, it is generally known that the larger the dielectric constant of the dielectric element 1, the smaller the size can be made in order to obtain resonance at the same frequency. There were also some difficult aspects.

Further, FIG. 3 shows a conventional example intended to improve the above-mentioned drawbacks of the conventional technique. 1 is a dielectric element, 6 is an internal conductor, 3 is an external conductor, and 7 is a dielectric element.
8 indicates a short circuit portion, 8 indicates a stepped portion, and 2 indicates an open end surface. By partially changing the line impedance with this structure, it is possible to significantly improve the spurious characteristics and obtain a great effect as a coaxial resonator. As the surface area of the open end surface 2 becomes smaller, it becomes difficult to obtain a large frequency adjustment width even if the frequency adjustment mechanism as described above is provided, and in order to make no force adjustment, it is necessary to improve the machining precision of the coaxial resonator. However, it had drawbacks such as being expensive.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the conventional drawbacks, to reduce the size of a dielectric coaxial resonator, and to solve frequency adjustment with a simple configuration.

Structure of the Invention In order to achieve this object, the present invention forms a conductor on the inner and outer circumferential surfaces of a cylindrical dielectric element having a stepped portion on the outer periphery and a short-circuited portion on one end surface, and A disc-shaped metal electrode with an arcuate surface formed on the open end surface and a through hole in the center is installed, and is electrically and mechanically connected to the conductor on the outer periphery to form a stator. A dielectric rotor with semicircular rotor electrodes is stacked on top of the electrodes, and a metal reinforcing plate with a current collector and a spring are rotated through a shaft to increase the capacitance of the open end surface. It is variable and adjusts the resonant frequency. With this configuration, the surface area of the open end face is expanded by providing a metal electrode, and the variable range when adjusting the resonance frequency can be increased. Even in a dielectric coaxial resonator with a stepped part, the resonance frequency adjustment mechanism can be adjusted. It will be easy to install.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 4 to 7. Note that in FIGS. 4 to 7, parts that are the same as those in the conventional example shown in FIGS. 1 to 3 are designated by the same numbers. In the figure, a stepped portion 8 is provided near the open end surface 2.
The short-circuited portion is metallized as a conductor 3 except for the open end surface 2. Furthermore, by employing a dip method for metallizing the stepped portion 8, the fear of peeling of the metal conductor can be eliminated. Next, the open end face 2 and the stepped portion 8 are made of a metal with good rollability such as brass, and the surfaces are coined into a substantially arc shape using a press machine, etc., thereby forming an arc-shaped recess 9 and forming the above-mentioned metal in the center. When a ring-shaped metal electrode 11 with a tapered portion 19 is inserted into the through-hole 1Q into which the open end surface 2 can be inserted and the ring-shaped metal electrode 11 is provided with a tapered portion 19 in the periphery thereof, soldering occurs through the conductor 3 on the outer periphery of the stepped portion 8 and the tapered portion 19. Alternatively, the conductive adhesive 2o is used to firmly connect electrically and mechanically. Next, the rotor 14 installed above the metal electrode 11 is made of a dielectric disk, and has a substantially semicircular rotor electrode 1 on the top.
3 and a dummy electrode 21 are formed by silver baking, etc. 1. A reinforcing plate 16 made of metal with a current collecting part 15 is arranged on the upper surface thereof, and a through hole for inserting the shaft provided in the center of the rotor 14 is inserted. The current collector 15 is brought into contact with the inner peripheral surface conductor 22 of the dielectric element 1 to establish electrical continuity with the rotor 14. A cap-shaped spring 17 is provided on the upper surface of the metal reinforcing plate 16 and has a terminal. positioned. Each member has a head 23 in the central through-hole, and a shaft 18 having an adjustment driver groove 24 is inserted into the head 23.

A fitting portion 25 that fits into a through hole provided at the center of the rotor 14 and the metal reinforcing plate 16 is provided in a part of the shaft 18 . Further, the tip of the shaft 18 is inserted into the through hole 26 of the spring 1 and is rotatably fixed.

By forming in this way, an open end capacitance of a resonator is formed between the rotor electrode 14 and the stator electrode 12 formed on the metal electrode 11, and the rotor 14 is rotated by rotating the shaft 18. Open end capacitance can be varied.

Effects of the Invention As described above, according to the dielectric coaxial resonator of the present invention, even if the open end face has a small diameter due to the provision of a stepped portion, the frequency can be adjusted with a simple mechanism, the size can be reduced, and it is also environmentally friendly. A dielectric coaxial resonator that does not have a resonant frequency that varies depending on conditions and has good productivity can be obtained.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing a conventional dielectric coaxial resonator, Fig. 2 is a sectional view of the same dielectric coaxial resonator, Fig. 3 is a sectional view of another conventional dielectric coaxial resonator, and Fig. 4 is a sectional view of another conventional dielectric coaxial resonator. The figures are an exploded perspective view showing a stator assembly of a dielectric coaxial resonator according to an embodiment of the present invention, FIG. 5 is a partial sectional view showing the stator assembly, and FIG.
The figure is a sectional view of the same embodiment, and FIG. 7 is an exploded perspective view of the same embodiment. 1...Dielectric element, 2...Open end surface, 3
......Outer conductor, 6...Inner conductor, 7
...Short circuit part, 8...Step part, 9...Circular recess, 10...Central through hole, 11...Metal electrode, 12...Curved stator Electrode, 13... Rotor electrode, 14... Rotor, 15... Current collector, 1
6...Metal reinforcing plate, 17...Spring, 18...Shaft, 19...Taper part, 20...Solder or conductive adhesive, 21 River... Dummy electrode, 22... Inner peripheral surface conductor, 23...
- Head, 24...driver groove, 25...fitting part, 26...through hole. Name of agent: Patent attorney Toshio Nakao and 1 other person□1
1. ,1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A conductor is formed at the short-circuited part of the outer peripheral surface and one end face of a cylindrical dielectric element, a step is provided near the open end on the opposite side of the short-circuited part, and an arc-shaped recess and a central part are formed in the step. A disk-shaped metal electrode with a through hole is fitted and installed in the stator electrode, and is electrically and mechanically connected to the conductor on the outer circumferential surface to form a stator electrode.A semicircular rotor electrode is placed on the stator electrode. A rotor made of a dielectric material and a metal reinforcing plate having a current collecting part are arranged, and the current collecting part of the metal reinforcing plate is brought into sliding contact with the rotor electrode and the inner peripheral surface conductor of the cylindrical dielectric element, A dielectric coaxial resonator characterized by being rotatably strung together via a spring and a shaft.