JPS6332281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coaxial resonant line in which a dielectric material is interposed between an inner conductor and an outer conductor.

Conventionally, LC resonators and coaxial resonators have been used as resonators in the VHF or UHF bands. However, the former had insufficient selectivity characteristics, and the latter had drawbacks such as its large size.

In recent years, in the communication equipment field, there has been a demand for smaller and lighter systems as a whole, but while most components are becoming smaller and lighter, many resonators used in filters etc. are still being used. However, it was difficult to make the system smaller and lighter, so there was a delay in reducing the size and weight of the system. Therefore, reducing the size and weight of resonators used in filters and the like has been a challenge in this field.

In particular, as resonators used in the VHF band, coaxial resonators and helical resonators with a dielectric interposed between the inner and outer conductors are considered, but the former is quite large in size, while the latter can be made smaller. However, it has drawbacks such as being difficult to manufacture and having a low Q. Typically, coaxial resonators are 400MHz to 2GHz
Helical resonators are generally used at frequencies of several tens to 100 MHz.

The present invention has been made to eliminate the drawbacks of the conventional resonators described above, and includes a 1/4 wavelength coaxial resonator in which a dielectric material is interposed between the inner and outer conductors. By constructing the conductor rod in close contact with the inner peripheral surface, we aim to provide a stable, simple, compact, and high-Q resonant line, especially for frequencies from 100 to several hundred MHz.
It is useful as a resonator used in the VHF band.

The present invention will be explained below based on illustrated embodiments. FIGS. 1a and 1b are a top view and a longitudinal sectional view of an embodiment of the present invention. In the figure, 1 is a cylindrical (hollow) dielectric body, and an outer conductor 2 is tightly covered on the outer peripheral surface of the dielectric body 1. In reality, for example, it is plated or baked with copper or silver. A cylindrical magnetic body 3 having a cylindrical shape or a central hole so as to be in close contact with the inner peripheral surface of the dielectric body 1
is inserted, and the conductor rod 4 is inserted into the magnetic body 3 so as to be in close contact with the inside thereof. One terminal 4a of the conductor rod 4 is connected to a portion 2a of the outer conductor 2 near the lower end surface. The structure is such that the other terminal 4b of the conductor rod 4 and the portion 2b close to the upper end surface of the external conductor 2 are used as input/output terminals.

In operation, one end 4a of the conductor rod 4 is short-circuited,
This is the same as a 1/4 wavelength coaxial resonator in which the other end 4b is open and the periphery is shielded. Since the conductor bar 4 is surrounded by a magnetic material 3 and the surrounding area is covered by a dielectric material, there is a wavelength shortening effect and the length of the resonator is shortened, which is useful for use in the VHF band. .

Next, a more effective specific embodiment based on the basic structure of the present invention shown in FIG. 1 will be described with reference to FIGS. 2 and 3. Components having the same functions as those explained in FIG. 1 are given the same reference numerals.

Figures 2a and b show the structure of Figure 1 plus the dielectric 1.
A top view and a vertical cross-sectional view of a resonator having a structure in which the lower end surface of the resonator is covered with an outer conductor 2a are shown. By adopting such a structure, the shielding effect can be further improved.

Figures 3a and b show the structure of Figure 2 plus the dielectric 1.
Electrodes 4 for input/output terminals are placed along the inner peripheral surface on the upper end surface of the
A top view and a vertical cross-sectional view of a resonator equipped with a resonator are shown. One end 4b of the conductor rod 4 is connected to the electrode 5,
The electrode 5 and the outer conductor 2b are used as input/output terminals.
With this structure, the conductor bar 4, magnetic material 3, dielectric material 1, and external conductor 2 are fixed in close contact with each other, resulting in a simple and stable structure.

As is clear from the above description, the present invention has the following excellent features.

(1) A cylindrical magnetic material is placed inside a cylindrical dielectric material with an external conductor attached to its outer peripheral surface, and
By inserting a conductive rod inside the magnetic material, connecting one end to one end of the external conductor, and leaving the other end open, the wavelength shortening rate is higher than that of a normal coaxial dielectric resonator. The length becomes shorter and the Q becomes higher.

Further, by using a dielectric material and a magnetic material whose temperature coefficients are complementary to each other, it is possible to make the temperature coefficient of the resonator itself close to zero.

(2) In addition to the structure in (1) above, by covering the ground side end face of the dielectric with an external conductor, the shielding effect can be improved and stability can be achieved.

(3) In addition to the structure in (1) or (2) above, an electrode can be attached to the end face of the dielectric on the input/output terminal side, and one terminal of the conductor rod can be connected to the electrode. It's easier and more stable.

Note that the dielectric and magnetic conductor rods that are the constituent elements of the present invention do not necessarily have to be in a completely intimate relationship, and even if they are not in a close relationship, they can be indirectly brought into close contact by, for example, pouring resin or the like. It is needless to say that means for causing this to occur may be used and are included in the present invention.

[Brief explanation of drawings]

Fig. 1 a, b is a top view and a vertical sectional view showing an example of the basic structure of the present invention, Fig. 2 a, b and Fig. 3 a, b
1A and 1B are a top view and a vertical cross-sectional view, respectively, showing specific embodiments of the present invention. 1... Dielectric material, 2... External conductor, 3... Magnetic material, 4... Conductor bar, 4a, 4b... Terminal, 5...
electrode.

Claims (1)

[Scope of Claims] 1. A cylindrical dielectric body having an outer conductor attached to its outer circumferential surface, and a cylindrical body disposed inside the dielectric body such that its outer circumferential surface faces an inner circumferential surface of the dielectric. Alternatively, a cylindrical magnetic body having a center hole and a conductor rod inserted into the magnetic body are provided, one terminal of the conductor rod is connected to one end of the external conductor, and the other terminal of the conductor rod is connected to one end of the outer conductor. A resonant line characterized in that one terminal and the other end of the external conductor are input/output terminals. 2. A resonant line according to claim 1, characterized in that the outer circumferential surface of the dielectric and the end surface of the conductor bar connected to one terminal are covered with a conductor. 3. According to claim 1 or 2, an electrode is attached to the end face of the dielectric on the input/output terminal side, and the input/output terminal of the conductor rod is connected to the electrode. resonant line.