JPH1048304A - Loop gap resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loop gap resonator in which the variable range of a resonance frequency can be made wide, even when the height of the resonator is made small so as to make a drop in a Q-value and a change in the resonance frequency small. SOLUTION: A loop gap resonator 11 is supported inside a shielding box 12 by fixation claws 13 which are made of, e.g. a fluororesin. In the loop gap resonator 11, the central part of a thin-sheet electrode having a prescribed width and a prescribed length is bent to be a loop shape, and both end parts of the electrode are bent and worked in the part of a gap 14 as gap extension electrodes 15 so as to protrude in parallel toward the outside of a loop part. The height HG of the gap extension electrodes 15 is formed to be larger than the height HL of the loop part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement of a loop gap resonator used in an electron spin resonance device.

[0002]

2. Description of the Related Art FIG. 1 shows a loop gap resonator and a resonance frequency adjusting mechanism described in Japanese Patent Publication No. 3-79670. As shown in FIG. 1, the loop gap resonator has a structure in which a loop-shaped electrode 1 is cut by a gap 2 parallel to an axis O of the loop, and is supplied through a coupling with an external antenna circuit. A wave current flows through the electrode 1. At this time, an LC resonator is configured such that the loop electrode 1 has the inductance L and the gap 2 has the capacitance C.

The resonance frequency of this loop gap resonator is basically determined by the loop length (diameter of the loop) and the size of the gap, that is, the shape. However, the resonance frequency is changed by disposing a sample inside the resonator. Would. Therefore, the resonator is provided with a resonance frequency adjusting mechanism so as to cope with such a change in the resonance frequency due to the sample.
That is, as shown in FIG. 1, a mechanism for changing the resonance frequency by changing the capacitance C by inserting the dielectric plate 3 into the gap 2. The resonance frequency can be changed continuously by moving the dielectric in the direction of the arrow to change the amount of dielectric inserted in the gap.

[0004]

In such a configuration, when a sample having a large dielectric loss such as a biological sample is inserted into the resonator, if the height (length in the axial direction) H of the loop gap resonator is large, It is unavoidable that the Q value of the resonator is greatly reduced due to the dielectric loss at a portion other than the relatively narrow portion to be measured, and the resonance frequency is greatly changed accordingly.

As a countermeasure, if the height H of the resonator is reduced, the reduction of the Q value and the change of the resonance frequency are reduced, but the variable range of the resonance frequency performed by inserting a dielectric into the gap is narrowed. .

The present invention has been made in view of the above points, and even if the height H of the resonator is reduced to reduce the Q value and reduce the change in the resonance frequency, the variable range of the resonance frequency is widened. It is an object of the present invention to provide a loop gap resonator that can perform the above operations.

[0007]

In order to achieve this object, the present invention provides a loop gap resonator having a loop portion and a gap portion, wherein the height of the gap portion is higher than the height of the loop portion in the axial direction. It is characterized by having been enlarged.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a sectional view showing an example of the loop gap resonator according to the present invention. In FIG. 2, the loop gap resonator 11 is supported and fixed in a shield box 12 by a fixing claw 13 made of, for example, a fluororesin. The loop gap resonator 11 bends a central portion of a thin plate electrode having a predetermined width and a predetermined length into a loop shape, and has both ends of a gap extension electrode 15 at a gap 14.
It is bent so as to protrude in parallel toward the outside of the loop.

A dielectric plate 16 is inserted into a gap formed between the gap extending electrodes 15. The dielectric plate 16 is fixed to the distal end of the support plate 17 with a screw or the like. The support plate 17 is advanced and retracted from the outside of the shield box 12 by the fine movement mechanism 18 so that the dielectric plate 16 is inserted into the gap. Is adjusted.

FIG. 3 shows a sectional view and a side view of only the loop gap resonator 11 drawn. As can be seen from the figure, the height of the gap extending electrode 15 in this resonator is made larger than the height HL of the loop portion.

With this configuration, even if the height of the loop portion into which the sample is inserted is reduced, the area of the gap portion facing the electrode is increased, and the amount of insertion of the dielectric can be varied greatly. Can be taken.

In the above embodiment, the dielectric is moved back and forth toward the center axis of the loop gap resonator.
Needless to say, it may be moved in a direction along the central axis as shown in FIG.

FIG. 4 shows an embodiment in which the present invention is applied to a loop gap resonator having no gap extension electrode.

[0014]

As described above in detail, according to the present invention, since the height of the gap portion is made larger than the height of the loop portion, the height H of the resonator is made smaller to lower the Q value and change the resonance frequency. , A loop gap resonator that can widen the variable range of the resonance frequency is realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a loop gap resonator described in Japanese Patent Publication No. 3-79670.

FIG. 2 is a sectional view showing an example of a loop gap resonator embodying the present invention.

3A and 3B are a cross-sectional view and a side view illustrating only the loop gap resonator 11 in the embodiment of FIG.

FIG. 4 is a diagram showing an example in which the present invention is applied to a loop gap resonator having no loop extension electrode.

[Explanation of symbols]

 Reference Signs List 11 loop gap resonator 12 shield box 13 fixing claw 14 gap 15 gap extension electrode 16 dielectric plate 17 support plate 18 fine movement mechanism

Claims (4)

[Claims] 1. A loop gap resonator comprising a loop portion and a gap portion, wherein the height of the gap portion is larger than the height of the loop portion in the axial direction. 2. The loop gap resonator according to claim 1, further comprising a resonance frequency adjusting mechanism for adjusting a resonance frequency by inserting a dielectric into the gap and moving the dielectric. 3. The loop gap resonator according to claim 2, wherein the dielectric is moved within the gap in a direction of a central axis of the loop gap resonator. 4. The loop gap resonator according to claim 2, wherein the dielectric is moved in a direction in which the distance from the center axis of the loop gap resonator changes within the gap.