JPS6281583A - Apparatus for detecting moving object - Google Patents

Abstract

PURPOSE:To reduce the length of the title apparatus as a whole without lowering efficiency, by continuously forming the electromagnetic horn antenna connected to microwave Doppler sensor from a pyramidal horn part, a curved reflective part and a square opening part. CONSTITUTION:In a moving body detection apparatus constituted by combining a microwave Doppler sensor 1 and an electromagnetic horn antenna 6, at first, a pyramidal horn part 3 approximately converting the spherical wave from the Doppler sensor 1 to a plane wave is provided to the electromagnetic horn antenna 6 so as to continue to the Doppler sensor 1. Next, a curved reflective part 4 having a curvature reflecting the plane wave at a predetermined angle is provided so as to continue to said pyramidal form part 3 and a square opening part 5 is provided to the leading end of said reflective part 4. By this method,the length of the apparatus can be reduced as a whole and required antenna efficiency can be secured.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is used as an activation switch for detecting a moving object such as a human body and controlling the operation of a security alarm device or the opening/closing of an automatically opening/closing door. This invention relates to a moving object detection device.

<Conventional technology> Conventional moving object detection devices that have been put into practical use include those that use mud switches, those that utilize the De-7pler effect of radio waves or ultrasonic waves, and those that use a receiver to collect infrared light beams emitted from a projector. There are active infrared systems for monitoring, and passive infrared systems that utilize fluctuations in the radiated infrared flux based on the temperature difference between the background and the moving object. Among these, the one that utilizes the Doppler effect has a configuration in which a microwave Doppler sensor 1 and a pyramidal horn antenna 2 are combined, as shown in FIG.

A microwave Doppler sensor l is generally used with a low power of several mW to several tens of mW, and has a microwave oscillation section using a Gunn diode and a mixer diode that detects the Doppler signal built into it, and detects the inside of the detection area. Changes in frequency due to the passing of a moving object are detected using reflected received waves. Further, the pyramidal horn antenna 2 performs impedance matching between the microwave oscillation part of the Doppler sensor 1 and free space, and efficiently emits radiation with sharp directivity.

<Problems to be Solved by the Invention> By the way, since the pyramidal horn antenna 2 matches the impedance between the microwave oscillating part and the free space, its shape and dimensions are limited within the range naturally determined by the conditions of use. be done. In detail, pyramidal horn antenna 2
The length of the opening 2' and the opening area of the opening 2' are important factors in determining the directivity of radio waves. The efficiency (power gain) G of the horn antenna 2 has the following relationship, where λ is the wavelength of the microwave, A is the aperture area, and η is the aperture efficiency. Therefore, in order to increase the efficiency of the antenna 2, the aperture It is sufficient to increase the area A, but in order to increase the aperture area A, it is necessary to increase the length of the horn antenna 2. Generally, the length of the horn antenna 2 is designed to be at least three times the wavelength, and the opening angle thereof is designed to be about 20 to 40 degrees in order to easily convert it into a plane wave. For example, when using a 10.5 GHz microwave, the wavelength is 2.85 cm, so the length of the horn antenna 2 is designed to be 8.6 CI11 or more, which is about three times the wavelength.

Considering the entire device under the above conditions, if the length of the main body mechanism is added to the length of the Ho antenna 2 and the Doppler sensor 1, the entire device will be approximately 15 cm or more. It has a very elongated appearance. However, the installation location of this type of moving object detection device is often in conspicuous places such as the ceiling of a building, the upper part of a side wall, or the blind area of a door, and its shape is severely restricted from the viewpoint of interior design. There is a problem that the length cannot be shortened in order to obtain the required antenna efficiency. Moreover, since it has an elongated shape, it may be inconvenient to use depending on the installation location.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a moving object detection device that can secure a required antenna efficiency while having a horizontally elongated physique. It is something to do.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a moving object detection device that combines a microwave Doppler sensor and an electromagnetic horn antenna, in which the electromagnetic horn antenna 6 A pyramidal horn section 3 that approximately converts a spherical wave emitted from the Doppler sensor 1 into a plane wave, and a curved surface reflecting section 4 having a curved surface with a curvature that reflects the plane wave from the pyramidal horn section 3 at a predetermined angle. The gist of the present invention is that a rectangular opening 5 continuous with the curved reflecting portion 4 are integrally formed.

Effects> With the above configuration, the microwave radiated from the Doppler sensor is deflected in the radiation direction at an angle corresponding to the curvature of the curved reflecting portion, for example, 90° within the electromagnetic horn antenna. Therefore, it is possible to secure the required opening area and obtain the desired antenna efficiency without increasing the overall shape of the electromagnetic horn antenna.

<Example> Hereinafter, one embodiment of the present invention will be explained in detail.

1 to 4 each show an embodiment of the present invention, in which a Doppler sensor l is provided with a pyramidal horn portion 3 that is sufficiently shorter than the conventional pyramidal horn antenna 2, and a predetermined distance from this pyramidal horn portion 3 is provided. A curved reflecting section 4 having a fan-shaped cross section and curved at an angle of 90° with respect to the pyramidal horn section 3 by a curved surface with a curvature R.
are provided in succession, and an opening 5 having a predetermined opening area made of a rectangular framework extends from the curved reflection part 4, and the electromagnetic horn antenna is formed by the pyramidal horn part 31, the curved reflection part 4 and the opening 5. 6 are configured.

Ideally, the curved surface of the curved reflection section 4 should be a paraboloid of revolution in a parabolic antenna, but in a small antenna 6 like the one of the present invention, a curved surface with a simple arc-like curvature can also sufficiently achieve the desired result. Demonstrate function.

Furthermore, as shown in Figure 3, this curved surface is configured to reflect radio waves at the magnetic interface, which has good directivity between the electric and magnetic interfaces in the rectangular waveguide. Care has been taken to ensure that

The operation of the embodiment device having the above configuration will be explained as follows.
As shown by the broken line in FIG. 4, the microwave emitted from the microwave oscillating part 1' of the Doppler sensor 1 is radiated from the radio wave emitting part of the Doppler sensor 1, which corresponds to a rectangular waveguide, to the pyramidal horn part 3. This spherical wave is gradually converted into a plane wave (approximately) in the pyramidal horn section 3.The microwave thus converted into a plane wave propagates close to light, and the microwave is The microwave is reflected by the curved surface of the curved reflection section 4 whose curvature is designed by optically capturing it, and the radiation direction is deflected by 90 degrees. Since it has side lobes, the side lobes are attenuated at the opening 5 and radiated as a substantially perfect plane wave, and the opening 5 enhances the overall upward direction.

With the above configuration, the longitudinal dimension of the electromagnetic horn antenna 6 required to obtain the required antenna efficiency can be made smaller than that of the conventional straight pyramidal horn antenna 2. Therefore, there is greater freedom in interior design for installing this, and the appearance of the installed state is also good.

Note that the present invention is not limited to the above embodiments,
Of course, various embodiments can be considered based on the scope of the claims. For example, in the embodiment described above, the case where the radiation direction of the microwave is deflected by 90' by the curved reflection section 4 is explained, In terms of interior design, it may be inconvenient to make the direction of microwave radiation from the Doppler sensor 1 perpendicular to the radiated surface, so the curved reflection section 40
The curved surface can be formed to have a curvature that allows the radiation to be deflected at any angle with respect to the direction of emission and reception of the microwave.

In such a case, the microwave is converted into a plane wave in the pyramidal horn section 3 and propagates similar to light, so the relationship between the curved surface of the microwave oscillating section 1 and the radiated surface can be easily designed to match optically. .

<Effects of the Invention> As described above, according to the moving object detection device of the present invention, the electromagnetic horn antenna is provided with a curved reflector to deflect the radiation direction of the microwave radiated from the Doppler sensor to a required angle inside the antenna. Since the antenna has a bent configuration, it is possible to obtain a specified antenna efficiency while shortening the longitudinal dimension, which increases the flexibility in interior design when installing the antenna, and it is aesthetically pleasing. It has the advantage of being easy to install and easy to handle due to its miniaturization.

[Brief explanation of drawings]

1 to 4 show an embodiment of the moving object detection device of the present invention, in which FIG. 1 is a perspective view, FIG. 2 is a plan view, FIG. 3 is a front view, and FIG. 4 is a third view. FIG. 5 is a perspective view of the conventional device.

Claims (1)

[Claims] (1) A moving object detection device that combines a microwave Doppler sensor and an electromagnetic horn antenna, wherein the electromagnetic horn antenna includes a pyramidal horn portion that approximately converts a spherical wave emitted from the Doppler sensor into a plane wave; A moving object detection device that is integrally formed with a curved surface reflecting section having a curved surface having a curvature that reflects the plane wave from the pyramidal horn section at a predetermined angle, and a rectangular opening continuous to this curved surface reflecting section. .