JPS631449Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dielectric coaxial resonator used in distributed constant filters and the like.

Conventionally, filters in the several 100 MHz range have used LC resonant circuits or coaxial resonators, but these were structurally unstable or complex, had unsatisfactory characteristics, and were difficult to adjust. There were problems such as the high cost and the inability to reduce costs.

For this reason, as shown in Figures 1 and 2,
Holes 12, 12 are formed in the dielectric block 11, inner conductors 13, 13 are formed on the inner peripheral surfaces of the holes 12, 12, and four outer surfaces 14 of the dielectric block 11 surrounding the holes 12, 12 are formed. , 14 and 1
Outer conductors 16, 16 and 17, 17 are formed on 5, 15, respectively, and these inner conductors 13, 13 and outer conductor 1
6, 16 and 17, 17 are short-circuited by a shorting conductor 18 formed on one end face of the dielectric block 11, and the inner conductors 13, 13 and the outer conductors 16, 1 are short-circuited.
6 and 17, 17 and the dielectric block 11 interposed between them constitute a pair of 1/4 wavelength resonant units, and a cavity 19 is provided between these resonant units for adjusting the degree of dielectric coupling. In order to electrostatically couple the above-mentioned resonant unit to an external circuit not connected to the resonant unit, a dielectric unit 22, 22, which is formed by coating the conductive wires 21, 21 with a dielectric material, is inserted into the above-mentioned holes 12, 12.
There is a distributed constant type filter inserted in each.

Incidentally, in the above-mentioned distributed constant type filter, the corner portions 23, . . . , 23 of the dielectric block 11 are at right angles. Therefore, dielectric block 1
1, chips may occur in the corner portions 23, .
There was a problem that the Q of the resonance unit decreased.

The present invention was devised to solve the above problem, and its purpose is to round the corners of the dielectric block of a dielectric coaxial resonator to eliminate chipping of the dielectric block, and to prevent the inside of the dielectric block from being chipped. The aim is to increase the Q of the resonator by eliminating disturbances in the electromagnetic field.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In this invention, as shown in FIG.
In a distributed constant filter having exactly the same configuration as shown in the figure, the outer surface 14 of the dielectric block 11',
The corner portion 23 including 14 and 15, 15,...
..., 23 is rounded.

The radius of curvature R of the above roundness is the dielectric block 1
If the thickness of 1' is L, it is preferable to select so that R/L=0.2 to 0.5. R/L is 0.2
If it is smaller, it will have no effect. When R/L exceeds 0.5, disturbances in the electromagnetic field begin to occur as in the conventional case.

By doing the above, since the dielectric block 11' has rounded corners 23, . . . , 23, chips and the like will not occur in the dielectric block 11'.

Furthermore, the electromagnetic field within the dielectric block 11 is
As shown in the figure, both the electric field 31 and the magnetic field 32 are almost symmetrical with respect to the dielectric unit 22, and there is almost no disturbance, and the Q of the resonant unit is improved by about 10% compared to the conventional one. Note that although the above embodiments are based on the case where a 1/4 wavelength resonator is used, the present invention can also be implemented using a 1/2 wavelength resonator.

As is clear from the above detailed description, in the present invention, the corner portions of the dielectric block in the dielectric coaxial resonator are rounded, so that chipping does not occur at the corner portions of the dielectric block. Therefore, it is easy to mold the dielectric block with a mold, improving molding efficiency, and at the same time, the disturbance of the electromagnetic field within the dielectric block is reduced, making it possible to increase the Q of the resonator.

Further, by rounding the corners of the dielectric block, there is an advantage that the material used for the dielectric block can be reduced.

[Brief explanation of the drawing]

1 and 2 are a vertical cross-sectional view and a plan view of a conventional distributed constant filter, respectively, FIG. 3 is a plan view of an embodiment of a distributed constant filter according to the present invention, and FIG. 4 is a plan view of a conventional distributed constant filter. FIG. 2 is an explanatory diagram of an electromagnetic field within a dielectric block of a distributed constant type filter. 11, 11'...dielectric block, 12...hole,
13... Inner conductor, 16, 17... Outer conductor, 18...
... Short circuit conductor, 23 ... Corner part, 31 ... Electric field,
32...Magnetic field.

Claims (1)

[Scope of utility model registration request] In a dielectric coaxial resonator, a cylindrical hole is formed in a dielectric block, an inner conductor is formed on the inner peripheral surface of the hole, and outer conductors are formed on four outer surfaces of the dielectric block surrounding the hole. A dielectric characterized in that the corner portions of the dielectric block are each rounded, and the ratio R/L of the radius of curvature R of these roundness and the thickness L of the dielectric block is in the range of 0.2 to 0.5. Body coaxial resonator.