KR20190000787A - Antenna and array antenna - Google Patents

Abstract

Provided is an antenna capable of generating a circular polarized wave over a wide-band with less occurrence of spurious. The antenna (1) comprises: a ground conductor plate (114); an inner conductor plate (124); a reactance conductor plate (134); and a power supply conductor (14). The ground conductor plate, the inner conductor plate, and the reactance conductor plate are formed concentrically and layered on dielectric substrates (113, 123, 133), respectively. The inner conductor plate (124) is cut away from a periphery of a circular outer periphery, and a shape of the inner conductor plate is formed spatially and smoothly. Therefore, unnecessary (spurious) resonance electromagnetic fields can be suppressed. As a result, a spurious-free wide-band circular polarization antenna is realized.

Description

Antenna and array antenna [0002]

The present invention relates to an antenna and an array antenna.

A small microwave antenna is known in which a circular polarized wave is transmitted and received by supplying power from a single feeding element to a planar inner conductor.

The conventional circular polarization antenna is a stripline type and is composed of a resonator composed of a rectangular or circular planar inner conductor. A rectangular inner conductor plate is formed with a cut-out portion at a diagonal angle as seen from a plane (plane). Further, the circular inner conductor plate is formed with a cut-out portion in the vicinity of the center or in a rectangular shape in a plan view. By these cut-out portions, the planar inner conductor operates as two resonators having different lengths in the x-axis and y-axis directions, respectively. The planar inner conductor emits a circularly polarized wave in a band near the center frequency between two resonance frequencies.

As shown in Figs. 6 (a) and 6 (b), in the circular polarization antenna of this configuration, a number of spurious resonance modes appear near the center frequency of 10 GHz. That is, the conventional antenna for circular polarization can not transmit circularly polarized waves over a wide band.

Therefore, it is necessary to provide an antenna capable of transmitting a circularly polarized wave over a wide band with less occurrence of spurious signals.

Non-Patent Document 1 discloses a back feed type one-point power supply disc circular polarized antenna in which a slot is provided at the center or a peripheral portion of a disc element and is de-axially separated and fed to one point from the back surface of the antenna substrate to function as a circular polarized antenna have. Also, non-patent document 1 discloses a circular inner conductor plate having a rectangular cut-out portion at its rim.

Non-Patent Document 2 discloses a configuration method and radiation characteristic for an antenna system in which a rectangular microstrip antenna is excited by a coplanar line.

Patent Document 1 discloses a circularly polarized patch antenna in which a hexagonal power feeding element in which two vertexes of a quadrangular diagonal corner are cut out and a rectangularly non-powered element are coaxially arranged. However, any patent document does not disclose a configuration in which generation of spurious signals is small and a circular polarized wave can be generated over a wide band.

[Patent Document 1] Japanese Published Patent Application No. 2003-503724

[Non-Patent Document 1] Misao Haneishi et al., &Quot; Antenna for Microstrip Circular Polarization by Feeding a Single Feed Point with a Single Feed Point, " Journal of Japan Electromagnetic Engineering Society, Vol. J63-B, No. 6, pp. 559-565, 1980. [Non-Patent Document 2] Misato Haneishi et al., &Quot; Broadband microstrip antenna excited by coplanar line ", Journal of the Japan Institute of Electronics Information and Communication Engineers, Vol. J84-B, No. 7, pp.1358-1364, 2001.

An object of the present invention is to provide an antenna capable of generating a circular polarized wave over a wide band with less occurrence of spurious.

The grounding conductor plate, the inner conductor plate, and the reactance conductor plate each have a concentric concentric shape on the dielectric substrate. The ground conductor plate, the inner conductor plate, the reactance conductor plate, And the inner conductor plate is cut away from the outer periphery of the circular outer periphery and the power supply conductor is electrically connected to the inner conductor plate.

According to the present invention, it is possible to provide an antenna capable of generating a circular polarized wave over a wide band with less occurrence of spurious.

1 is a plan view showing an embodiment of the antenna according to the present invention.
2 is a partial cross-sectional view of the antenna.
3 is a plan view of the inner conductor plate of the antenna.
4 is a graph showing an axial ratio characteristic of the antenna. The axial ratio is an algebraic number of the amplitude ratio of the electric field between the x-axis and the y-axis of the circular polarized wave. In perfect circular polarization, the axial ratio is 1 and the logarithmic display is 0 dB. The axial ratio of 3 dB when the circularly polarized wave is deformed into the elliptically polarized wave is the criterion of the accepted standard.
5 is a plan view showing an array antenna formed by arranging a plurality of antennas made of an inner conductor plate and a reactance conductor plate on a common grounding conductor plate on a multilayer dielectric substrate.
Fig. 6 (a) is a graph showing the axial ratio characteristics of the antenna of the related art having a cut-out portion and a rectangular inner conductor seen in plan view, Fig. 6 (b) And Fig. 5 is a graph showing an axial ratio characteristic of an antenna of another related art having the antenna.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of antennas according to the present invention will be described with reference to the drawings.

● Antenna outline

In Fig. 1, the antenna 1 transmits and receives circular polarized waves by feeding power from a feeding point to a planar inner conductor.

● Configuration of antenna

As shown in Figs. 1 and 2, the antenna 1 includes a ground conductor plate 114, an inner conductor plate 124, a reactance conductor plate 134, and a feeder line 14. The ground conductor plate 114, the inner conductor plate 124 and the reactance conductor plate 134 are stacked in this order and fixed to each other with the dielectric substrates 113, 123, and 133 interposed therebetween.

The grounded conductor plate 114 is formed on the dielectric substrate 113. The size of the grounded conductor plate 114 is sufficiently larger than that of the inner conductor plate 124 and the reactance conductor plate 134.

The dielectric substrate 113 and the grounded conductor plate 114 have a first through hole 119 through which the feeder line 14 is inserted from the bottom of the grounded conductor plate 114 to the inner conductor plate 124 side .

As shown in Figs. 2 and 3, the inner conductor plate 124 constitutes two resonators as a conductive flat plate. The inner conductor plate 124 is cut along two straight lines parallel to each other at opposite positions of the circumference of the circular plate material so that two circular arcs 121 and 122 and two rectilinear sections 125, 126 are alternately connected. That is, the arc portion 121, the straight portion 125, the circular arc portion 122 and the straight portion 126 are connected in this order to constitute the outer periphery of the inner conductor plate 124. The circular portions 121 and 122 and the straight portions 125 and 126 are orthogonal to the plane of the inner conductor plate 124.

The inner conductor plate 124 is formed such that when the center of the conductor plate 124 in the plane is the origin O and the axis parallel to the straight section 125 is the y axis and the axis orthogonal to the y axis is the x axis, Axis and y-axis, respectively.

If the conductor constituting the resonator includes spatially sharply changed portions such as a right angle or an acute angle, the current and voltage are spatially disturbed and resonate in a plurality of unnecessary (spurious) modes. According to the inner conductor plate 124 of the present invention, the outer surface shape is smooth and does not include a right angle or an acute angle in its shape. Therefore, the antenna 1 simultaneously generates two resonance modes that are spatially and temporally orthogonal (that is, with a phase difference of 90 degrees) within a sufficiently wide frequency band around the center frequency without generating spurious signals. Therefore, the antenna 1 can generate circularly polarized waves in a wide band.

In FIG. 3, both ends of the straight line portions 125 and 126 are connected to the circular arc portions 121 and 122 to form angles. However, both ends of the straight portions 125 and 126 may be smoothly connected to respective adjacent sides while drawing circular arc smaller than the arc portions 121 and 122.

Instead of the linear portions 125 and 126, both ends of the circular arc portions 121 and 122 may be connected to each other by a smooth curved line symmetrical to each other. In other words, the inner conductor plate 124 may have a shape in which the outer periphery of the circular outer periphery is cut out to have a smooth curved line symmetrical to each other.

The distances from the origin O to the straight lines 125 and 126 are arbitrary and not limited to the shapes shown in FIG.

The dielectric substrate 123 disposed between the inner conductor plate 124 and the ground conductor plate 114 has a second through hole 129 communicating with the first through hole 119 .

The feeder line 14 is a coaxial cable in which the outer periphery of the power supply conductor is covered with an insulator. One end of the feed conductor of the feeder line 14 passes through the first through hole 119 and the second through hole 129 and passes through the strip line and the coaxial line to the feed point 15 on the inner conductor plate 124 Respectively. The other end of the power supply conductor of the feeder line 14 is connected to an external power supply circuit (not shown). The power transmitted from the external power feeding circuit is supplied to the internal conductor plate 124 through the feed line 14. [ The inner conductor plate 124 is excited by the electric power transmitted from the external power supply circuit.

Although the position of the feed point 15 is electrically equidistant to the resonance currents on the x and y axes, the actual position is determined by experimentation rather than theory. That is, the position of the feed point 15 is not limited to the position shown in Fig. It is also possible to feed two points on the x and y axes, respectively (two-point feed method). In the case of feeding two points, the feeding point 15 is divided into two points, and its position can be determined by experiment.

When the inner conductor plate 124 is excited by the power supplied through the feeder line 14, two resonance modes corresponding to the lengths along the x axis and the y axis of the inner conductor plate 124 appear. Then, the circularly polarized waves of the microwaves are generated in the x-y plane, and the circularly polarized waves are propagated toward the front side of the paper surface along the z-axis direction orthogonal to the x-y plane.

The reactance conductor plate 134 is a substantially circular conductive flat plate. The reactance conductor plate 134 is reactively coupled to the inner conductor plate 124 through a dielectric substrate 133 having substantially the same shape as the reactance conductor plate 134 in plan view. That is, the inner conductor plate 124 and the reactance conductor plate 134 constitute a reactance circuit in parallel with the two resonance circuits formed on the inner conductor plate 124. The reactance conductor plate 134 can enlarge the bandwidth of each of the two resonance circuits formed on the inner conductor plate 124 and increase the directional gain of the antenna 1.

The reactance conductor plates 134 may be cut along two straight lines parallel to each other at opposite positions of the circumference.

A plurality of reactance conductor plates 134 may be stacked on the inner conductor plate 124. The plurality of reactance conductors 134 are all stacked with the dielectric substrate 133 interposed therebetween. According to the configuration in which a plurality of reactance conductor plates 134 are laminated, a plurality of reactance circuits in parallel with two resonance circuits on the inner conductor plate 124 are formed.

The thicknesses of the dielectric substrates 113, 123, and 133 are arbitrary, respectively. The thicknesses of the dielectric substrates 113, 123, and 133 are appropriately determined depending on the desired characteristics of the antenna 1 and the like.

● The axial ratio characteristic of the antenna (1)

As shown in Fig. 4, the antenna 1 according to the present invention does not involve spurious in a band of 8 GHz to 12 GHz with respect to a center frequency of 10 GHz. It can also be seen that the antenna 1 has a bandwidth of 3 dB or less and a bandwidth of 7% or more at 10 GHz band. Spurious is not accompanied even in a band of not less than 5 GHz and not more than 8 GHz, and not more than 12 GHz and not more than 15 GHz.

As described above, according to the antenna 1, generation of spurious signals is small and circular polarization can be generated over a wide band. The antenna 1 is also applicable to a measuring device that transmits a radio wave toward a measured object, receives the radio wave reflected by the measured object, and measures the position of the measured object based on the received radio wave. Particularly, the antenna 1 is also applicable to a measuring device of the FMCW system requiring a broadband radio wave.

● Configuration of array antenna

As shown in Fig. 5, the array antenna 10 includes four inner conductor plates 124, four reactance conductor plates 134, and one ground conductor plate 21. As shown in Fig. Each conductor plate 124 and each reactance conductor plate 134 constitute an antenna together with one ground conductor plate 21, and these four antennas constitute a relay antenna. The four inner conductor plates 124 and the four reactance conductor plates 134 are disposed on the plane of one common ground conductor plate 21 at a predetermined distance from each other in plan view. In other words, the four inner conductor plates 124 and the four reactance conductor plates 134 share the ground conductor plate 21. The ground conductor plate 21, the inner conductor plate 124, and the reactance conductor plate 134 are stacked and fixed in this order with a dielectric substrate interposed therebetween.

The size of the plane of the ground conductor plate 21 is sufficiently larger than the sum of the sizes of the planes of the four inner conductor plates 124.

The origin O of the four inner conductor plates 124 is arranged so as to be located at the vertex of the square. In other words, the distances between the origin O of each of the four inner conductor plates 124 and the origin O of the adjacent inner conductor plates 124 are equidistant. Further, the inclination of the y-axis of the inner conductor plate 124 located at the diagonal, that is, the angles of the linear portions 125 and 126 in the plane is the same. The inclination of the y-axis of the adjacent inner conductor plate 124 may be line-symmetrical.

The number of inner conductor plates 124 and reactance conductor plates 134 provided in the array antenna 10 is arbitrary.

According to the array antenna 10, the directional gain and the bandwidth can be further improved by disposing a plurality of circular polarization antennas in the same plane.

1 antenna
114 grounded conductor plate
124 conductor plate
134 reactance conductor plate

Claims (7)

A ground conductor plate, an inner conductor plate, a reactance conductor plate, and a power supply conductor,
The ground conductor plate, the inner conductor plate, and the reactance conductor plate are formed in a layered manner concentrically on the dielectric substrate,
The inner conductor plate has a circular outer periphery of a portion thereof opposed to the outer periphery thereof,
And the power supply conductor is electrically connected to the inner conductor plate. A ground conductor plate, an inner conductor plate and a power supply conductor,
The ground conductor plate and the inner conductor plate are formed in layers on the dielectric substrate in a concentric manner,
The inner conductor plate has a round outer periphery cut away,
And the power supply conductor is electrically connected to the inner conductor plate. The method according to claim 1,
Wherein the plurality of reactance conductive plates are laminated, and each of the plurality of reactance conductive plates is laminated. 4. The method according to any one of claims 1 to 3,
Wherein the inner conductor plate is cut out into two straight lines in which the opposite ends of a circular outer periphery are parallel to each other. 4. The method according to any one of claims 1 to 3,
Wherein the inner conductor plate is cut out into a smooth curved line in which the outer periphery of the circular outer periphery is symmetrical to each other. 4. The method according to any one of claims 1 to 3,
Wherein two resonant circuits are formed on the inner conductor plate to generate a circular polarized wave in a direction orthogonal to the plane of the inner conductor plate. A ground conductor plate, a plurality of inner conductor plates, and a power supply conductor,
Wherein the plurality of inner conductor plates are arranged in parallel to the ground conductor plate at a predetermined distance from each other in plan view,
Wherein the inner conductor plate is the inner conductor plate according to any one of claims 1 to 3.

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