JPS60232702A - Microwave probe - Google Patents

Abstract

PURPOSE:To transmit/receive microwaves efficiently and to interrupt heat transmission effectively by holding a transmitting/receiving antenna and a conductive ring member with a prescribed interval each other. CONSTITUTION:A through hole 11a is formed on the center of a supporting member consisting of a heat insulating material, an SAM type coaxial contact plug 13 is arranged on an upper opening of the through hole 11a and its inner conductor is bent at its leading end and short-circuited with an external conductor to form a loop antenna 14. In this probe 1, a microwave sent from the antenna 14 is electromagnetically coupled with a ring member 15 efficiently and radiated from the lower half part of the member 15 into atmosphere almost without being attenuated. On the other hand, heat transmission of high temperature through a diaphragm A is effectively interrupted by the supporting member 11 consisting of the heat insulating member so as not to be reached the contact plug 13. Consequently, a coaxial cable or the like connected to the contact plug 13 is prevented from deterioration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a probe for receiving and transmitting microwaves, and is particularly directed to a thermally insulated structure thereof.

[Prior art]

In recent years, microwave circuits have become extremely compact as ICs due to the development of solid-state circuit elements and strip transmission lines, and as a result, attempts have been made to apply microwaves to various measurement fields other than communications. For example, U.S. Patent No. 4.384,4
．． No. 80 discloses a method and apparatus for transmitting microwaves into the combustion chamber of an engine and determining the top dead center position of a piston from the received waveform.

In such applications, it is necessary to install the above-mentioned microwave probe on the wall of the combustion chamber, which is at a high temperature of over 1000°C, and in the conventional probe structure, heat is conducted to the coaxial cable or circuit device connected to it. There was a bulge that caused its deterioration.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a microwave probe capable of efficiently receiving and transmitting microphone waves and effectively preventing heat transfer.

[Structure of the invention]

In the probe of the present invention, a support made of a heat-insulating material is fixed to a hole provided in a partition wall that partitions a high-temperature atmosphere, and a support made of a heat-insulating material is fixed to the other end located outside the partition wall. Anwono that receives and transmits microwaves toward one end
A conductive ring member is provided in the support body at a predetermined distance from the antenna, and a part of the conductive ring member projects into the atmosphere from the one end.

[Embodiment 1] In FIG. 1, A is a partition wall that seals off a high-temperature atmosphere, such as a cylinder wall of an engine, and is heated to a high temperature by the heat received from the atmosphere. A punch hole Δ1 is provided in a part of the partition wall A, and a threaded portion is formed on the circumferential surface of the punch hole A1. The microwave blower 11 according to the present invention is fixed in the hole Δ1.

That is, the probe 1 has a cylindrical support 11, and the support 11 is screwed into the hole Δ1 by a metal threaded ring 12 fitted around its outer periphery. The support 11 is made of a heat insulating material such as stabilized zirconia or refractory brick. A through hole 11a is formed in the center of the support 11, and a SAM type coaxial plug 13 having a known [i] is disposed at the upper opening of the through hole 11a. The inner conductor protruding from the lower surface of the coaxial plug 13 is bent at its tip and short-circuited to the outer conductor to form a loop antenna 14.

In the through hole 11a, a ring member 15 made of a metal conductor is disposed below the loop antenna 14 at a predetermined distance, and the ring member 15 and the coaxial plug 1 are disposed in the through hole 11a.
3 is a ceramic adhesive 16 (
In this example, it is held and fixed with "Sumiceram" manufactured by Sumitomo Kagaku Kuri Co., Ltd. In this state, the lower half of the ring member 15 is projected into the atmosphere. Note that the distance between the loop antenna 14 and the ring member 15 is determined by the adhesive 16.
It is determined by the dielectric constant of and the wavelength of the microwave used for measurement, and in this example, it is about 3 cm in free space (microwave frequency 100+-12).

In the probe 1 having the above structure, the microwaves sent out from the loop antenna 14 are efficiently electromagnetically coupled to the ring member 15, and are emitted into the atmosphere from the lower half of the ring member 15 without being attenuated. .

On the other hand, heat transfer from the high-temperature partition ff1A is effectively blocked by the support member 11 made of a heat insulating material and does not reach the coaxial plug 13. This prevents deterioration of the coaxial cable etc. connected to the coaxial plug 13.

[Example 2] In FIG. 2, a loop antenna 14 and a ring member 15
A dielectric resonator 17 serving as microwave relay means is arranged at a predetermined position between them. By transmitting and receiving microphone waves through the resonator 17, it is possible to increase the distance between the antenna 14 and the ring member 15, and it is also possible to effectively prevent heat transfer. .

Note that, in place of the resonator 17, a similar effect can be obtained even if another ring member that is the same as the ring member 15 is used.

In each of the above embodiments, the antepu 14, the ring member 15
If the resonator 17 can be embedded in the support 11, the adhesive 16 is not required.

Further, although the antenna 14 does not necessarily have to be a loop antenna, microwaves can be more efficiently received and transmitted using this antenna.

〔Effect of the invention〕

As described above, in the microwave amplifier of the present invention, the antenna connected to the microwave transmitting/receiving means and the conductive gel ring member electromagnetically coupled to the antenna are connected by a support made of a heat insulating material. It is made of 4M structure that is held at a predetermined distance from each other and can effectively prevent the transfer of heat to the antenna.It is installed on the combustion cavity wall of one engine and transmits fibrous waves into the combustion chamber. It exhibits excellent performance when used in applications such as.

[Brief explanation of drawings]

FIG. 7 and FIG. 2 respectively show a first iJ3 and a second embodiment of the present invention, and are sectional views of a microwave probe provided on a partition wall. △...Partition wall Δ1...Drilling hole 1...Probe 11...Support body 14...Antenna 15...Ring member

Claims (5)

[Claims] (1) A support made of a heat insulating material fixed to the partition wall so as to cover a hole provided in a partition wall that partitions a high-temperature atmosphere, and one end of which is exposed to the atmosphere through the hole, and an antenna that is embedded and fixed at the other end of the support and receives and transmits microwaves toward the one end; and a part of the antenna that is embedded and fixed at a predetermined distance from the antenna in the microwave propagation path within the support. and a conductive ring member projecting into the atmosphere from the one end. (2) The microwave oven according to claim 1, wherein the heat insulating material is an insulating ceramic. (3) The microwave probe according to claim 1, wherein a microwave relay means is provided in the support body between the antenna and the conductive ring member. (4) The microwave probe according to claim 3, wherein the microwave relay means is another conductive ring member that is the same as the conductive ring member. (5) The microwave probe according to claim 3, wherein the microwave relay means is a dielectric resonator.