JPS63238703A - Method for adjusting frequency of coaxial tem resonator - Google Patents

Abstract

PURPOSE:To simply and surely correct resonance frequency in a higher direction by partially forming a groove on the end face of a dielectric substance which is an open end of a coaxial TEM resonator and allowing the resonator to resonate at a required frequency. CONSTITUTION:The coaxial TEM resonator is constituted of applying silver past components 4, 5 to the outer and inner peripheries 2, 3 of a cylindrical seramic dielectric substance having the inner and outer peripheries 3, 2 and rebaking them. In case of adjusting the resonance frequency of the resonator, a part of the opened end face of the dielectric substance is engraved to form the groove 7 and the shape, depth, number, position, etc., of the groove 7 are adjusted to obtain a required resonance frequency value. Consequently, the resonance frequency can be simply and surely adjusted in a higher direction.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to the invention of a method for producing a product, and particularly to a method for adjusting the frequency of a coaxial TEM resonator.

<Prior Art> Conventionally, filters used in the VEF band or UHF band include those using an LG resonator and those using a cavity resonator. However, the former has the disadvantage that sufficient selectivity characteristics cannot be obtained, and the latter has a large size.

In recent years, in the electronics field, there has been a strong desire to make systems smaller and lighter.While other components are being made smaller and lighter, filters are still being used in large numbers due to their importance. Because it is difficult to make the system smaller and lighter, it has been delayed in reducing the size and weight of the system. Therefore, reducing the size and weight of filters has been a top priority for engineers in this field. This is solved by providing a compact and high performance resonator. Further, if such a small and high-performance resonator is provided, it can be said to be preferable for devices other than filters using the resonator.

Some prior inventions have been made to overcome the above-mentioned drawbacks.

The present invention can be implemented mainly based on this prior invention, and prior to explaining the present invention, the prior invention will be explained first.

The main objective of this prior invention is to provide a coaxial TEM resonator with a small size.

Another object of this prior invention is to provide a coaxial 12M resonator with good productivity.

Another object of this prior invention is to provide a coaxial 12M resonator which is simple in structure and has excellent reliability.

Another object of this prior invention is to provide a coaxial 12 with excellent temperature characteristics.
The object of the present invention is to provide an M resonator.

Another object of this prior invention is to obtain the highest Q in such a coaxial 12M resonator.

Examples of this prior invention will be described below with reference to the drawings.

In FIG. 1, 1 is a cylindrical ceramic dielectric. The total length is set to 172 wavelengths or 1/4 wavelengths at the resonant frequency. As shown in FIG. 2, four coats of silver paste are applied to the outer circumferential surface 2 and inner circumferential surface 3 of the dielectric body 1 which has been fired in advance to form the outer conductor and the inner conductive shaft, respectively.
and 5, and re-fire. Repeat this until the required film thickness is achieved. Of course, any known conductive material other than silver that has excellent high frequency conductivity and excellent adhesion to the dielectric 1 may be used. In addition to coating and baking such a material, plating, vapor deposition, sputtering, printing, and even pressing a sheet made of such a material may be considered. As shown in FIG. 3, a rod-shaped dielectric 6 may be placed in the hole surrounded by the inner guide shaft to improve the strength. Alternatively, the entire rod including the inner shaft may be made of a metal rod.

The dielectric does not need to be a single piece, and a plurality of pieces may be combined depending on manufacturing issues.

In each of these examples, (the inner diameter of the outer conductor of the resonator)
When /(outer diameter of the inner guide shaft of the resonator) is set to approximately 3.6, Q takes the highest value. Also, if the temperature coefficient of the dielectric is appropriately selected,
Since the influence of the coefficient of linear expansion of the metal conductor is canceled out, a coaxial 12M resonator with excellent temperature characteristics can be provided.

As is clear from the above embodiments, the coaxial 12M resonator of this prior invention includes a dielectric material having an inner circumferential surface and an outer circumferential surface;
It has at least a film-like inner guide shaft provided on the inner peripheral surface, and a film-like outer conductor provided on the outer peripheral surface. In this way, since the dielectric material is interposed between the inner guide shaft and the outer conductor, the shape is smaller than that of a conventional cavity resonator even if the resonant frequency is the same. Furthermore, it is not necessary to manage the dimensions of both the inner conductive phase and the outer conductor, and only the dimensions of the dielectric material are required, resulting in excellent productivity. Furthermore, since there is no need for a structure to maintain the positional relationship between the inner guide shaft and the outer conductor, the structure is simplified and reliability is improved. In addition, by selecting the temperature coefficient of the dielectric material, it is possible to cancel the influence of the linear expansion coefficient of the inner guide shaft and outer conductor, and the size ratio of the inner diameter of the outer conductor/outer diameter of the inner guide shaft can be reduced to approximately 3. The highest Q can be obtained by selecting .6.

Incidentally, in such a coaxial 12M resonator, the resonant frequency is largely determined by the entire length as described above, but due to problems such as dimensional accuracy, the desired resonant frequency may not be obtained. To correct the resonant frequency to a higher value, the entire end face is usually shaved to shorten the overall length, as shown in FIG.

However, this process is cumbersome, and it has been desired to easily modify the resonance frequency to a higher value.

In addition, as a frequency adjustment method for a coaxial resonator, Japanese Patent Laid-Open No. 54
As disclosed in Publication No. 14655, a hole is provided in a coaxial resonator, and a dielectric rod is inserted into the hole to adjust the frequency to W.
There is a way to adjust it.

However, in this method, even if the dielectric constants of the dielectric intervening between the inner conductor and the outer conductor and the dielectric rod inserted into the hole are made equal, the dielectric constants of the dielectric rod inserted into the hole are the same. Since a combination of two methods was required: insertion and secure fixation in a predetermined position, a simpler and more reliable method was desired.

<Problems to be Solved by the Invention> Therefore, the main object of the present invention is to provide a frequency adjustment method for a coaxial 12M resonator that can easily and reliably modify the resonance frequency to a higher value.

In summary, this technique is a frequency adjustment method in which a groove is provided in the end face of a dielectric material, which is the open end, to adjust the resonance frequency to a desired value.

That is, in the present invention, grooves are partially formed in the end face of the dielectric, which is originally flat, and the shape, depth, number, position, etc. of the grooves are adjusted to achieve the target frequency. Although the final shape and the method disclosed in JP-A-54-14655 are similar at first glance, the process is completely different.

Embodiments The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 5 is a perspective view of one embodiment of the invention.

This FIG. 5 is the same as FIG. 2 except for the following points.

The present invention is applied when the resonant frequency of the resonator at hand is lower than a desired value. In other words, when a part of the open end surface of the dielectric 1 is hollowed out to form the groove 7, the resonant frequency increases. The shape, depth, number, position, etc. of the grooves 7 are determined appropriately so that the resonance frequency becomes a desired value.

As described above, according to the present invention, even if the axial dimensions of the resonators are not entirely similar, the resonant frequency can be easily modified by forming grooves on the dielectric surface located at the open end surface. can. This improves the yield rate and reduces costs.Furthermore, in the present invention, grooves are partially formed on the end face of the dielectric material, which is originally flat, so that the shape, depth, number, etc. of the grooves can be adjusted. Since adjustments are made to achieve the target frequency based on position, etc., the final shape may look similar at first glance compared to conventional ones, but the process is completely different.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a dielectric 1 of the prior invention, FIG. 2 is a perspective view of an embodiment of the prior invention, FIG. 3 is a sectional view of another embodiment of the prior invention, and FIG. 4 is a dielectric 1 of the prior invention. FREQUENCY ADJUSTMENT METHOD FIG. 5 is a perspective view of an embodiment of the present invention. 1...Ceramic dielectric 2...Outer peripheral surface 3...
・Inner peripheral surface 4.5...Silver paste 7・
Mizo Applicant's Representative Patent Attorney Kazu 1) Showa 2nd Figure 1J゛Figure 3

Claims (1)

[Claims] A coaxial TEM resonator has a dielectric having an inner circumferential surface and an outer circumferential surface, an inner guide shaft provided on the inner circumferential surface, and an outer conductor provided on the outer circumferential surface. A method for adjusting the frequency of a coaxial TEM resonator in which grooves are partially provided so that the resonator resonates at a desired frequency.