JP2006135415A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an antenna device operating an antenna by suppressing deterioration of radiation characteristics or the reduction phenomenon of an antenna gain even when a parasitic element is loaded. <P>SOLUTION: The antenna device is provided with: a driven element 10 having first/second conductors 11, 12 which are formed to the surface of a first dielectric substrate and have the same isosceles triangular shape; and feeders 13 which are respectively provided to the apex formed by equal sides of the isosceles triangle, in which the bottom sides of the isosceles triangles other than the equal sides of the isosceles triangles of the first/second conductors are arranged so as to be axisymmetrical to an axial line parallel to each bottom side with an air gap. The device is also provided with the parasitic element having third/fourth conductors 21, 22 which are formed to the surface of a second dielectric substrate hierarchically installed to the first dielectric substrate and have the same isosceles triangular shape as the first/second conductors 11, 12, in which the bottom sides of the isosceles triangles other than the equal sides of the isosceles triangles of the third/fourth conductors are arranged so as to be axisymmetrical to an axial line parallel to each bottom side with an air gap. A gap 23 or 24 is provided to each of the third/fourth conductors 21, 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna device having broadband characteristics.

  As a conventional antenna device, there is a bow tie antenna capable of reducing the antenna size (for example, see Patent Document 1). This antenna device can reduce the size of the antenna by making equal sides of a conductor having an isosceles triangle shape into a curved shape or a staircase shape.

JP 2002-135037 A (first page, FIG. 1)

  However, the prior art has the following problems. In general, a method of loading a non-excitation element is used to broaden the antenna. However, when a conventional antenna device is loaded with a non-excitation element in order to widen the band, the reflection characteristic from the power supply section improves, but the radiation characteristic deteriorates in a high frequency band, and the antenna gain decreases. There is a problem that occurs.

  The present invention has been made to solve such a problem, and an antenna device capable of operating an antenna while suppressing deterioration of radiation characteristics or a decrease in antenna gain even when a non-excitation element is loaded. The purpose is to obtain.

  The antenna device according to the present invention is formed on the surface of the first dielectric substrate, and includes the first conductor and the second conductor having the same isosceles triangle shape, and the first conductor and the second conductor. Power supply portions respectively provided at the vertices formed by equal sides of the isosceles triangle, and the bases of the isosceles triangles other than the equal sides of the first conductor and the second conductor with respect to an axis parallel to each base In an antenna device including an excitation element arranged with a gap so as to be axially symmetric, a first conductor is formed on a surface of a second dielectric substrate provided hierarchically with respect to the first dielectric substrate. And the third conductor and the fourth conductor having the same isosceles triangle shape as the second conductor, and the bases of the isosceles triangles other than the equal sides of the third conductor and the fourth conductor are the bases. With a gap so that it is axisymmetric with respect to an axis parallel to Further comprising a parasitic element that is obtained by providing a gap in each of the third conductor and the fourth conductor.

  According to the present invention, by providing a gap in each conductor constituting the non-excitation element, even when the non-excitation element is loaded, the antenna can be operated while suppressing the deterioration of the radiation characteristic or the decrease in the antenna gain. An antenna device that can be used can be obtained.

Hereinafter, preferred embodiments of an antenna device of the present invention will be described with reference to the drawings.
The antenna device of the present invention is characterized in that by loading a non-excitation element having a conductor having a gap structure, it is possible to widen the antenna band while suppressing deterioration of radiation characteristics or a decrease in antenna gain.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of an antenna device according to Embodiment 1 of the present invention. This antenna device includes an excitation element 10 formed on the surface of a first dielectric substrate (not shown), and a second dielectric substrate (shown in a hierarchy) installed on the first dielectric substrate. (Not shown) and a non-excitation element 20 formed on the surface.

  Further, the excitation element 10 is composed of a first conductor 11 and a second conductor 12 both having the same isosceles triangle shape. A power feeding unit 13 is provided at each vertex of the first conductor 11 and the second conductor 12, and a signal is input to the power feeding unit 13.

  The first conductor 11 and the second conductor 12 are opposed to each other with a gap so that the bases of the isosceles triangles other than equal sides are axisymmetric with respect to an axis parallel to each base, and the respective power feeding portions 13 face each other. Are formed on the surface of the first dielectric substrate. In addition, the dimension represented as L1 in FIG. 1 represents the dimension of the 1st conductor 11 and the 2nd conductor 12 which are arrange | positioned in this way.

  On the other hand, the non-excitation element 20 includes a third conductor 21 and a fourth conductor 22 both having the same isosceles triangle shape as the first conductor 11 and the second conductor 12. The third conductor 21 and the fourth conductor 22 have an equal side of each isosceles triangle with a gap so that the bases of the isosceles triangles other than equal sides are axisymmetric with respect to an axis parallel to each base. Are formed on the surface of the second dielectric substrate so as to face each other. In addition, the dimension represented as L2 in FIG. 1 represents the dimension of the 3rd conductor 21 and the 4th conductor 22 which are arrange | positioned in this way.

  Next, the operation will be described. In the configuration of FIG. 1, a signal input from the power feeding unit 13 propagates through the first conductor 11 and the second conductor 12 from the power feeding unit 13. Of the signals that propagate, the signal in the frequency band higher than the frequency at which the dimension L1 between the first conductor 11 and the second conductor 12 is approximately a half wavelength is used because the antenna has a self-complementary structure. It is matched and radiated without depending on the frequency.

  On the other hand, the signal having a frequency lower than the frequency at which the dimension L1 between the first conductor 11 and the second conductor 12 is approximately one-half wavelength has a sudden decrease in radiation resistance because the antenna has an insufficient electrical length. Not emitted. Therefore, such an antenna is a broadband antenna device that radiates in a frequency band higher than the frequency at which the dimension L1 between the first conductor 11 and the second conductor 12 is approximately a half wavelength.

  As the dimension L1 between the first conductor 11 and the second conductor 12, the dimension shown in the following equation (1) is required when the lower limit frequency of the use frequency band is f1. In addition, c in Formula (1) is the speed of light in free space.

  L1 = c / (2 × f1) (1)

  A radio wave radiated from the excitation element 10 formed on the surface of the first dielectric substrate is not formed on the surface of the second dielectric substrate arranged hierarchically with respect to the first dielectric substrate. The third conductor 21 and the fourth conductor 22 of the excitation element 20 are combined and emitted. Here, a case where no gap is provided in the non-excitation element 20 and a case where a gap is provided are compared. Here, the gap provided in the non-excitation element 20 corresponds to the first gap 23 provided in the third conductor 21 itself and the second gap 24 provided in the fourth conductor 22 itself.

  FIG. 2 is a diagram showing a current distribution on the non-excitation element 20 and an antenna radiation pattern when no gap is provided in the non-excitation element 20 according to the first embodiment of the present invention. FIG. 3 is a diagram showing a current distribution on the non-excitation element 20 and an antenna radiation pattern when a gap is provided in the non-excitation element 20 in the first embodiment of the present invention. 2 and 3 both show four frequencies f1 to f4, and the magnitude relationship of these frequencies is f1 <f2 <f3 <f4.

  As shown in FIG. 2, when no gap is provided in the non-exciting element 20, the current distribution on the non-exciting element 20 does not change greatly even if the frequency increases. For this reason, at a high frequency, the antenna operates like a two-element antenna with a wide element interval, so that the radiation characteristics are degraded.

  On the other hand, as shown in FIG. 3, when a gap is provided in the non-exciting element 20, the current distribution on the non-exciting element 20 increases as the frequency increases. For this reason, at a high frequency, the current distribution is not different from that of a two-element antenna having a wide element interval, so that the deterioration of the radiation characteristics is alleviated.

  FIG. 4 is a diagram showing gain frequency characteristics in the antenna front direction when no gap is provided in the non-excitation element 20 according to the first embodiment of the present invention and when a gap is provided. When the non-excitation element 20 is not provided with a gap, the radiation characteristic is deteriorated as described above, so that the gain is reduced in a high frequency band. On the other hand, when the non-excited element 20 is provided with a gap, the deterioration of the radiation characteristic is alleviated as described above, and thus it can be seen that the gain reduction in the high frequency band is alleviated.

  According to the first embodiment, in the antenna device in which a non-excitation element is loaded on the excitation element, a gap is provided in the non-excitation element, thereby suppressing deterioration in radiation characteristics and a decrease in antenna gain in a high frequency band. Thus, an antenna device having stable operating characteristics can be obtained.

Embodiment 2. FIG.
FIG. 5 is a configuration diagram of the antenna device according to Embodiment 2 of the present invention. In FIG. 5, the same reference numerals are given to the same or corresponding parts as those in FIG. 1 that is the configuration diagram of the first embodiment.

  The exciting element 10 and the non-exciting element 20 in the second embodiment are the first conductor 11, the second conductor 12, the third conductor 21, and the fourth conductor 22 each having an isosceles triangle shape. The base of the equilateral triangle has an arc shape. That is, in Embodiment 2, each conductor shape referred to as an isosceles triangle shape indicates a sector shape as shown in FIG.

  The basic operation is the same as that described in the first embodiment, and the radio wave radiated from the excitation element 10 is the third conductor of the non-excitation element 20 provided hierarchically with respect to the excitation element 10. 21 and the fourth conductor 22 are combined and emitted.

  According to the second embodiment, even when the excitation element and the non-excitation element are configured with the base of the isosceles triangle being arcuate, the radiation characteristics are deteriorated in the high frequency band and the antenna is provided by providing a gap in the non-excitation element. It is possible to suppress the phenomenon of lowering the gain and obtain an antenna device having stable operating characteristics. Further, compared with the antenna device of the first embodiment, although the size is increased, there is an advantage that a larger band can be obtained.

Embodiment 3 FIG.
FIG. 6 is a configuration diagram of the antenna device according to Embodiment 3 of the present invention. In FIG. 6, the same reference numerals are given to the same or corresponding parts as those in FIG. 1 that is the configuration diagram of the first embodiment.

  The exciting element 10 and the non-exciting element 20 of the third embodiment are the first conductor 11, the second conductor 12, the third conductor 21, and the fourth conductor 22 each having an isosceles triangle shape. The equal sides of the isosceles triangle are curved. That is, in Embodiment 3, each conductor shape referred to as an isosceles triangle shape refers to a shape having two curved sides as shown in FIG.

  The basic operation is the same as the operation described in the first and second embodiments, and the radio wave radiated from the excitation element 10 is the third of the non-excitation elements 20 provided hierarchically with respect to the excitation element 10. The first conductor 21 and the fourth conductor 22 are combined and emitted.

  At that time, the respective isosceles triangles corresponding to the dimension L1 of the first conductor 11 and the second conductor 12 and the dimension L2 of the third conductor 21 and the fourth conductor 22 in which the lower limit frequency of the antenna device is determined. By making the sides with equal curves be curved, the electrical length can be increased as compared with the case where the sides with equal isosceles triangles are linear, and as a result, the antenna dimensions can be reduced.

  According to the third embodiment, the same effect as in the first and second embodiments can be obtained by providing a gap in the non-excitation element. Furthermore, by making the equal sides of the isosceles triangles of the first conductor, the second conductor, the third conductor, and the fourth conductor that determine the lower limit frequency of the antenna into a curved shape, the electric length is increased, Antenna dimensions can be reduced.

Embodiment 4 FIG.
FIG. 7 is a configuration diagram of the antenna device according to the fourth embodiment of the present invention. In FIG. 7, the same reference numerals are given to the same or corresponding parts as those in FIG. 1 that is the configuration diagram of the first embodiment.

  The exciting element 10 and the non-exciting element 20 of the third embodiment are the first conductor 11, the second conductor 12, the third conductor 21, and the fourth conductor 22 each having an isosceles triangle shape. The equal sides of the isosceles triangle are stepped. That is, in the fourth embodiment, each conductor shape referred to as an isosceles triangle shape refers to a shape having two steps in a step shape as shown in FIG.

  The basic operation is the same as the operation described in the first to third embodiments, and the radio wave radiated from the excitation element 10 is the third of the non-excitation elements 20 provided hierarchically with respect to the excitation element 10. The first conductor 21 and the fourth conductor 22 are combined and emitted.

  At that time, the respective isosceles triangles corresponding to the dimension L1 of the first conductor 11 and the second conductor 12 and the dimension L2 of the third conductor 21 and the fourth conductor 22 in which the lower limit frequency of the antenna device is determined. By making the sides with equal curves be curved, the electrical length can be increased as compared with the case where the sides with equal isosceles triangles are linear, and as a result, the antenna dimensions can be reduced.

  According to the fourth embodiment, the same effect as in the first and second embodiments can be obtained by providing a gap in the non-excitation element. Further, the equal sides of the isosceles triangles of the first conductor, the second conductor, the third conductor, and the fourth conductor that determine the lower limit frequency of the antenna are stepped to form the third embodiment and Similarly, the electrical length can be increased and the antenna size can be reduced.

It is a block diagram of the antenna apparatus in Embodiment 1 of this invention. It is the figure which showed the electric current distribution and antenna radiation pattern on a non-excitation element when not providing a clearance gap in the non-excitation element in Embodiment 1 of this invention. It is the figure which showed the electric current distribution and antenna radiation pattern on a non-excitation element at the time of providing a gap in the non-excitation element in Embodiment 1 of this invention. It is the figure which showed the gain frequency characteristic in the antenna front direction when not providing a gap in the non-excitation element in Embodiment 1 of this invention, and when providing a gap. It is a block diagram of the antenna apparatus in Embodiment 2 of this invention. It is a block diagram of the antenna apparatus in Embodiment 3 of this invention. It is a block diagram of the antenna apparatus in Embodiment 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Excitation element, 11 1st conductor, 12 2nd conductor, 13 Feeding part, 20 Non-excitation element, 21 3rd conductor, 22 4th conductor, 23 1st gap | interval, 24 2nd gap | interval.

Claims (4)

A first conductor and a second conductor formed on the surface of the first dielectric substrate and having the same isosceles triangle shape;
A feeding section provided at each apex formed by an equal side of an isosceles triangle of the first conductor and the second conductor;
In an antenna apparatus including an excitation element in which bases of isosceles triangles other than equal sides of the first conductor and the second conductor are arranged with a gap so as to be axially symmetric with respect to an axis parallel to the bases. ,
A first dielectric substrate formed on the surface of a second dielectric substrate arranged hierarchically with respect to the first dielectric substrate and having the same isosceles triangle shape as the first conductor and the second conductor. 3 conductors and a fourth conductor,
A non-exciting element in which a base of an isosceles triangle other than equal sides of the third conductor and the fourth conductor is arranged with a gap so as to be axially symmetric with respect to an axis parallel to the base;
An antenna device, wherein a gap is provided in each of the third conductor and the fourth conductor. The antenna device according to claim 1,
The first and second conductors having the shape of an isosceles triangle formed on the surface of the first dielectric substrate, and the isosceles triangle formed on the surface of the second dielectric substrate. An antenna device characterized in that the bases of the isosceles triangles of the third conductor and the fourth conductor having a shape are arcuate. The antenna device according to claim 1 or 2,
The first and second conductors having the shape of an isosceles triangle formed on the surface of the first dielectric substrate, and the isosceles triangle formed on the surface of the second dielectric substrate. An antenna device, wherein an equal side of each of the isosceles triangles of the third conductor and the fourth conductor having a shape is formed into an arbitrary curved shape. The antenna device according to claim 1 or 2,
The first and second conductors having the shape of an isosceles triangle formed on the surface of the first dielectric substrate, and the isosceles triangle formed on the surface of the second dielectric substrate. An antenna device characterized in that equal sides of respective isosceles triangles of the third conductor and the fourth conductor having a shape are formed in an arbitrary step shape.

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