JPH06177639A - Frequency election plate - Google Patents

Abstract

PURPOSE:To attain a broad band for the frequency selection plate by using at least a member made of plural elliptic ring shaped conductor strips arranged at a prescribed interval and a dielectric sheet to support the conductor strips. CONSTITUTION:An elliptic ring shaped conductor strips 1, 5 held on dielectric sheets 2,4 are of the same shape. The major axis of the ellipse of each ring is in parallel with this paper and the minor axis is perpendicular to this paper and the rings are formed repetitively. The ratio of the major axis of the ellipse of each conductor ring of the frequency selection plate to the major axis is selected so that the projected shape of the elliptic ring onto a face perpendicular to the propagation direction of an electromagnetic wave having two frequency bands made incident into the frequency selection plate is circular. The circumferential length of the ellipse is selected almost the same as a circumferential length of a circular ring so as to be resonated at the same frequency as that for the circular ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency selective reflector which reflects an electromagnetic wave in one frequency band and transmits an electromagnetic wave in the other frequency band of electromagnetic waves in two frequency bands.

[0002]

2. Description of the Related Art FIGS. 4A and 4B are views showing the structure of a conventional frequency selection plate, in which FIG. 4A is a top view and FIG. 4B is a side view. In the figure, 11 and 15 are circular ring-shaped conductor strips, 12 is a dielectric sheet that holds the ring-shaped conductor strip 11, 13 is a spacer, and 14 is a circular ring-shaped conductor strip 15 (having the same shape as 11). It shows a dielectric sheet on the underside.

As shown in the figure, this frequency selection plate is
The upper and lower parts are symmetrical with respect to the spacer 13. A plurality of circular ring-shaped conductor strips 11 arranged at regular intervals are adhered to a dielectric sheet 12,
The dielectric sheet 12 and the dielectric sheet 14 to which the conductor strip 15 on the back surface is adhered are held at regular intervals via the spacer 13.

In some cases, the spacer is composed of a sandwich plate of Kevlar honeycomb cores, and the dielectric sheet 1
Gluing 2, 14 to both sides of the sandwich plate holds them at regular intervals.

The frequency selection plate having such a structure is used for spatially separating electromagnetic waves in two frequency bands.
FIG. 2 is a diagram for explaining the operation of the frequency selection plate 7. Two frequency bands F on the frequency selection plate 7 placed diagonally
_When the electromagnetic waves of ₁ and F ₂ are incident, those of frequency F ₁ which resonate in the ring are reflected by the frequency selection plate, and those of frequency F ₂ which do not resonate pass through the frequency selection plate. In this way, the electromagnetic waves in the two frequency bands are spatially separated.

Basically, frequency isolation is achieved even with one layer of dielectric sheet with conductor strips. As shown in FIG. 4, the reflection band can be widened by using a two-layer structure. Also, multiple bands can be reflected by multiplexing the rings.

[0007]

Since the conventional ring-shaped frequency selection plate as described above is easy to analyze, it has always been the case to use such a circular ring. Characteristic measurement values when this circular ring is used as shown in FIG. 2 are shown by a broken line A in FIG. As is clear from the figure, the conventional frequency selection plate using the circular ring has a problem that the reflected band is basically a narrow band.

In order to solve such conventional problems, it is an object of the present invention to realize a frequency selection plate capable of widening a reflection band.

[0009]

According to the invention, the aforesaid problems are solved by means of the patent claims.

That is, according to the present invention, the frequency selection is configured by using a plurality of elliptical ring-shaped conductor strips arranged at regular intervals and at least one member made of a dielectric sheet for holding the conductor strips. It is a plate.

[0011]

According to the frequency selection plate constituted by the elliptical ring-shaped conductor strip according to the present invention, the wide band of about 20% is widened as compared with the frequency selection plate constituted by the conventional circular ring-shaped conductor strip. Can be realized. Hereinafter, it will be described in more detail based on examples.

[0012]

FIG. 1 is a diagram showing an embodiment of the present invention.
(A) is a top view and (b) is a side view. In the figure, 1 and 5 are elliptical ring-shaped conductor strips,
2, 4 are dielectric sheets, and 3 is a spacer.

The elliptical ring-shaped conductor strips 1 and 5 held by the dielectric sheets 2 and 4 have the same shape. Then, this repeating pattern is formed on the basis of a ring whose elliptical major axis is parallel to the paper surface of FIG. 2 and whose minor axis is perpendicular to the paper surface. In this embodiment, the ratio of the major axis to the minor axis of the ellipse of the conductor ring of the frequency selection plate is such that when the shape is projected on a plane perpendicular to the traveling directions of electromagnetic waves of two frequency bands incident on the frequency selection plate. Selected to be circular.

The perimeter of the ellipse is approximately the same as the perimeter of the circular ring so that it resonates at the same frequency as that of the circular ring. The measurement result of the characteristic of the frequency selection plate when the elliptical ring is used is shown by a solid line B in FIG. In the figure, when the band of transmission loss is -15 dB, that is, the band of low reflection loss is compared with A and B, the frequency selection plate of the elliptical ring has a wider band characteristic than the frequency selection plate of the circular ring. You know that you have.

FIG. 3 is a comparison of characteristics in the case of one layer of the dielectric sheet with the conductor strips, but also with the dielectric sheet with the conductor strips having a two-layer structure to widen the reflection band. The characteristics per one layer of the dielectric sheet with a conductor strip, which is the basis thereof, are superior to those according to the present invention, so that a wider band characteristic can be obtained as in the case of one layer. Further, even in the case where a plurality of bands are reflected by multiplexing the rings, the one according to the present invention can similarly obtain a wider band characteristic.

[0016]

As described above, the frequency selection plate of the present invention has a plurality of elliptical ring-shaped conductor strips. As a result, there is an advantage that it is possible to achieve a wide band of more than 20% as compared with the conventional one having a circular ring-shaped conductor strip.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the operation of a frequency selection plate.

FIG. 3 is a diagram showing measurement results of characteristics of a frequency selection plate.

FIG. 4 is a diagram showing a configuration of a conventional frequency selection plate.

[Explanation of symbols]

 1,5 Elliptical ring-shaped conductor strips 2,4,12,14 Dielectric sheet 3,13 Spacer 7 Frequency selection plate 11,15 Circular ring-shaped conductor strip

Claims (1)

[Claims] 1. A plurality of elliptical ring-shaped conductor strips arranged at regular intervals, and at least one member composed of a dielectric sheet for holding the conductor strips are used. Frequency selection board.