JPH11234017A - Wideband antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the antenna having wideband frequency characteristic which is at a low attitude, so as to suppress an increase in air resistance to an aero moving body in movement and can sufficiently secure a margin band covering a shift of frequency characteristics of the antenna due to changes of environmental conditions. SOLUTION: This antenna, equipped with a feed point 13 at a necessary part of a planar conductor 1 stood on a metallic base 10, is so constituted that the path length between the feed point 13 and one point on the side edge part of the plane conductor 1 is different with the place of the side edge part by arranging the feed point 13 off the geometric center of the planar conductor 1, so that the frequencies excited by supplying currents to the feed point 13 and respective side edge parts are different, thereby making widening of the band possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a broadband antenna used in a radio communication apparatus, and more particularly, to a broadband frequency communication suitable for being mounted on an aeronautical mobile body or the like where a frequency drift easily occurs due to a change in environmental conditions. The present invention relates to a broadband antenna used for a device, a radar device, and the like.

[0002]

2. Description of the Related Art In an aeronautical mobile body such as an aircraft, a wireless device is indispensable as a communication means, and the aeronautical mobile body is required to be reduced in size even in a wireless communication device because the installation space is limited. . In the wireless communication device, since a space is used as a signal transmission path as is well known, an antenna is used to efficiently radiate a wireless communication signal to the space. The antenna of the wireless communication device in the aeronautical mobile body must satisfy the electrical characteristics required for the wireless communication device even under severe environmental conditions such as vibration, impact, and temperature change specific to the aeronautical mobile body. When two-way wireless communication is performed between a wireless communication ground station and an aeronautical mobile body, a performance that operates well at two frequencies assigned as a transmission frequency and a reception frequency is required. In the case where the two frequencies to be assigned are also used for a wireless communication device of an aeronautical mobile body, two frequencies that are relatively far from each other are often used according to a request from the wireless communication device. Generally, as described above, an antenna mounted on an aeronautical mobile body that flies at a high speed has a frequency characteristic lower or higher than a design value due to a temperature change in addition to vibration and impact. It is known that the frequency shifts to the frequency side, and as a result, the electrical performance value required by the wireless communication system mounted on the aeronautical mobile body is not satisfied. In order to solve this problem, a method of broadening the frequency characteristics of the antenna to a value greater than the required value of the wireless communication system mounted on the aeronautical mobile body and providing a margin for the frequency shift is generally used in the aeronautical mobile body. Has been adopted.

A monopole antenna is widely used as an antenna mounted on a conventional aeronautical vehicle. FIG. 6 is a sectional view showing the structure of an example of such a conventional monopole antenna. In the monopole antenna shown in this example, a linear conductor 101 having a length of 波長 wavelength, which is connected to a connector 103 through a through hole 102 provided in a metal base 100, is perpendicular to the metal base 100. It was installed. When a high-frequency signal from a transceiver (not shown) is input to the connector 103, the linear conductor 101 operates as a half-wavelength dipole antenna based on the mirror image (image) principle of the metal base 100. Radiates the high-frequency signal input into the space. Since the monopole antenna has a simple structure, it is less likely to be damaged by vibration, impact, and the like, and is therefore often used as an antenna mounted on an aeronautical vehicle. The frequency characteristics of this monopole antenna are such that it operates as a half-wavelength dipole antenna based on the above-described operation principle only at a single frequency, so that the antenna capability set in a narrow frequency range cannot be exhibited. The above operable frequency bandwidth is known to be 2-3%. Therefore, the conventional monopole antenna has been used in a wireless communication system having a required bandwidth of about 2 to 3%.

[0004]

However, in the above-described monopole antenna mounted on the conventional aeronautical mobile body, the antenna height is relatively high at 1/4 wavelength, so that the The air resistance of the
In addition to deteriorating the fuel efficiency of the aeronautical mobile unit, depending on an applied system such as a secondary radar transponder to be described later, the frequency band value required by the system cannot be satisfied. It was not possible to realize a wide band in consideration of the compensation for the shift. Specifically, for example, a monopole antenna is used as an antenna for an aeronautical mobile-mounted secondary radar transponder in which the operating frequency of the wireless communication device is an L-band frequency of 1.03 GHz (reception) and 1.09 GHz (transmission). Consider the case. In that case, as a frequency in designing the antenna, 1.06 GHz which is a center frequency between the transmission frequency and the reception frequency is used.
The height of the antenna is ４ of the wavelength of the frequency, so that the height is 70.8 mm. To enable reception at 1.03 GHz and transmission at 1.09 GHz, a specific band of the operating frequency (used frequency) 5.7% is required for (bandwidth / center frequency) performance. However, since the monopole antenna protrudes 70.8 mm from the surface of the aeronautical mobile body, it increases the air resistance when the aerial mobile body moves and uses a monopole antenna with a specific band performance of usually 2-3%. Then, it is impossible to realize the 5.7% fractional band performance required in the case of the above transmission / reception frequency,
Furthermore, it has never been possible to provide a margin band in the fractional band performance in order to cover the shift of the frequency characteristic due to the change in the environmental conditions described above. The present invention
The purpose of the present invention is to solve the problem related to the monopole antenna mounted on the conventional aeronautical mobile body as described above, and to reduce the air resistance during the movement of the aerial mobile body, to have a low attitude, and An object of the present invention is to provide an antenna having a wideband frequency characteristic capable of sufficiently securing a margin band covering a shift of the frequency characteristic of the antenna due to a change in environmental conditions.

[0005]

According to a first aspect of the present invention, there is provided a broadband antenna according to the present invention, wherein a feeding point is provided at a required portion of a planar conductor erected on a metal base. In the above, by disposing the feeding point at a position shifted from the geometric center of the planar conductor,
It is characterized in that the path length between the feeding point and one point on the edge of the planar conductor is different depending on the location of the edge, and since the path length differs depending on the location of the edge, The frequency excited by the current flowing through the feeding point and the respective edge portions is different, and a wider band is possible. In the broadband antenna according to the second aspect of the present invention, in the wideband antenna according to the first aspect, a part of the planar conductor that is in contact with the metal base is cut out at a constant width along the surface of the metal base. It is characterized in that it is configured to provide a cut-out portion, and by providing the cut-out portion, it is possible to resonate even at a frequency corresponding to the size of the cut-out portion, thereby enabling a wider band. In the broadband antenna according to the third aspect of the present invention, in the wideband antenna according to the first or second aspect, the second base plate having substantially the same shape as the planar conductor but different in the detailed dimensions of each part on the metal base. Characterized in that the plane conductors are erected at a parallel position having a predetermined distance from the plane conductors, and by providing the second plane conductors having different dimensions, it has resonance points at different frequencies, Broadband is possible. In the broadband antenna according to the fourth aspect of the present invention, in the wideband antenna according to the third aspect, a part of the second planar conductor that is in contact with the metal base is formed in a plane along the surface of the metal base. It is characterized in that it is configured to provide a cutout portion cut out at a constant width different from the cutout portion of the conductor, by providing a cutout portion of a different size to the second planar conductor of a different size,
Further, since resonance points are provided at different frequencies, a wider band can be achieved. In the broadband antenna according to the fifth aspect of the present invention, in the broadband antenna according to the third aspect, the metal base has substantially the same shape as the planar conductor and the second planar conductor, but details of each part are provided. A third or third or later planar conductor having dimensions different from each other is sequentially provided in parallel with the planar conductor at predetermined intervals, and different third or third or later planar conductors are provided. As a result, since resonance points are provided at different frequencies, it is possible to further increase the bandwidth. In the broadband antenna according to the sixth aspect of the present invention, in the broadband antenna according to the fifth aspect, a part of the third or third or later planar conductor in contact with the metal base is provided on a surface of the metal base. And a third or subsequent planar conductor, which is different from the notched portion of the planar conductor or the second planar conductor, is provided with a notched portion which is notched at a different constant width. By providing the cutouts in the third and subsequent planar conductors as well, since resonance points are provided at different frequencies, it is possible to further widen the band. According to a seventh aspect of the present invention, in the broadband antenna according to any one of the third to sixth aspects, between the planar conductor and the second planar conductor, or the second planar conductor. And between the third and third or subsequent planar conductors is filled with a dielectric material having a predetermined dielectric constant. By using a dielectric material having a high dielectric constant between the planar conductors, It is possible to reduce the size of the material and increase the strength by filling. In the wideband antenna according to the eighth aspect of the present invention, in the wideband antenna according to any one of the first to sixth aspects, the planar conductor, the second planar conductor, and the third or third planar conductor may be used. Subsequent planar conductors are characterized by being composed of a conductor foil formed on one or both sides or between layers of a single-layer dielectric substrate or a multilayer dielectric substrate erected on the metal base, and using a dielectric substrate. By doing so, in addition to shortening the dimension between the planar conductors and increasing the strength, it is possible to facilitate the manufacture. According to the broadband antenna according to the ninth aspect of the present invention, in the first aspect,
9. The broadband antenna according to any one of items 1 to 8,
The planar conductor, the second planar conductor, and the third or third or later planar conductor are characterized in that they are polygonal planar conductors, and are easy to manufacture and adjust, and are used materials. Can be reduced. According to a tenth aspect of the present invention, in the broadband antenna according to the ninth aspect, the polygonal planar conductor is a trapezoidal planar conductor. It is easier to manufacture and adjust than in the case of a square shape, and the amount of wasted material used can be reduced. In the broadband antenna according to claim 11 according to the present invention, in the broadband antenna according to any one of claims 1 to 10, the feeding point is configured such that a current excited from the feeding point to the planar conductor is the current. The feeding point and each part on the edge of the planar conductor are connected to the feeding line so as to be radially diffused by different path lengths. Frequency, and a wider band can be achieved. In the broadband antenna according to claim 12 of the present invention, claim 1
12. In the broadband antenna according to any one of items 11 to 11, the notch portion is configured such that, when power is supplied to the feeding point, an electric field or a magnetic current is excited in accordance with the size of the notch portion. It is characterized in that an electric field is excited in the notch, so that it is possible to cope with a frequency different from that in the case where there is no notch, and it is possible to widen the band.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of a broadband antenna according to the present invention, FIG.
FIG. 1B is a side view as viewed from the side A in FIG. 1A, and FIG. 1C is a side view as viewed from the side B in FIG. 1A. As shown in FIG. 1A, the broadband antenna according to the present embodiment has a first polygon shown in FIGS. 1B and 1C formed on both surfaces of a dielectric substrate 3 having a thickness d. Conductor 1 and second polygonal conductor 2 are connected to metal base 10
The center conductor 14a of the connector 14 provided on the non-antenna forming surface of the metal base 10
Through the first trapezoidal conductor 1 in the polygonal conductor 1
1 is connected to a feeding point 13 provided in a required portion. Here, the shapes and dimensions of the feeding element 1 and the parasitic element 2 in FIG. 1 will be described. As shown in FIG. 1B, the feeding element 1 has an upper side (ul1) × a bottom side (b).
l1) a first trapezoidal conductor 11 having dimensions of height (h1) and a cut of depth (n1) × width (W1) provided at the bottom of the first trapezoidal conductor 11 The first cutout 12 is formed by a notch. Similarly, the parasitic element 2 has an upper side (u) as shown in FIG.
l2) × the bottom (bl2) × height (h2), and the depth (n2) × width (W2) provided at the bottom of the second trapezoidal conductor 21 ), The first and second trapezoidal conductor dimensions and the first and second notch dimensions are set to be different from each other. The conductor foils formed on both surfaces of the dielectric substrate 3 are processed into the shapes shown in FIGS. 1B and 1C by, for example, a photoetching technique.

The operation of the broadband antenna shown in FIG. 1 according to this embodiment is as follows. When a high-frequency signal from a wireless communication circuit or the like (not shown) is input to the connector 14, the high-frequency signal guided through the central conductor 14 a of the connector 14 is supplied to the power supply provided on the first trapezoidal conductor 11. Input to point 13 to excite feed element 1. As a result, the current (excitation current) induced in the first trapezoidal conductor 11 radially diffuses from the feeding point 13 on the first trapezoidal conductor 11 and flows. Resonance occurs at a plurality of frequencies corresponding to the difference in path length, and as a result, resonance occurs over a wide frequency range. Further, since the high-frequency signal input to the feeding point 13 excites an electric field or magnetic current corresponding to the size of the notch in the notch 12 in FIG. It will resonate. Therefore, the power supply element 1 has the dimensions of the first trapezoidal conductor 11 and the first trapezoidal conductor 11.
Has a plurality of resonance points for various frequencies in accordance with the size of the notch 12 and the position of the feeding point 13, and thus operates as a broadband antenna having a wide frequency band. Next, the operation of the parasitic element 2 will be described. In the broadband antenna according to the present invention, since the parasitic element 2 is arranged close to the feed element 1, the feed element 1 is excited as described above. Then, the parasitic element is also excited by the capacitive coupling. Since the dimensions of the second trapezoidal conductor 21 and the second notch 22 constituting the parasitic element 2 are set to be different from those of the parasitic element 1, the parasitic element 2 is excited. In this case, a plurality of resonance frequencies different from the resonance frequency generated in the feed element 1 are generated by the same operation principle as the feed element 1 described above. Will have. From the above, the broadband antenna according to the present invention can be regarded as an antenna in which two types of broadband antennas are connected in parallel in principle.

As described above, the broadband antenna according to the present invention may be configured so that the current excited in the polygonal conductor forming the antenna is radially diffused from the feeding point by different path lengths. Any conductor shape can be used. Further, the shape of the notch may be determined so as to excite a magnetic current having a resonance frequency different from that generated by the current excited in the polygonal conductor. There is no need to consider the distance between the metal base 10 and the position where the notch is provided, but the position is not limited to the bottom of the trapezoidal conductor described above. Therefore, if two frequencies of the transmission frequency and the reception frequency required by the wireless communication system are given as the antenna operation frequency, the feed element 1 and the parasitic element 2 of the broadband antenna according to the present invention are changed according to the above-mentioned use environment. In consideration of the shift of the frequency characteristic, it may be designed to resonate at the transmission frequency and the reception frequency. However, as described above, the feeder element 1 and the parasitic element 2 are closely coupled because of their close proximity, and affect each other's resonance frequency.
The characteristics of the antenna in which these are combined change from the characteristics of the feed element 1 and the parasitic element 2 alone, and it is therefore difficult to uniquely determine the characteristics of the broadband antenna according to the present invention. Then, the inventor of the present invention has clarified that the broadband antenna according to the present invention has the following properties by performing a numerical analysis using a computer and an experiment using a prototype. The main resonance frequency in the broadband antenna of the present embodiment is determined substantially by the depths n1 and n2 of the first and second cutouts 12 and 22, and the frequency band is determined by the first and second trapezoidal conductor elements 1 and 2. 2 heights h1, h2 and each side ul1, bl1, ul2, bl2
Is determined by the dimensions. When the notches 12 and 22 were deepened (when n1 and n2 were increased), the resonance frequency tended to increase. In practice, since there is a demand to reduce the antenna height as much as possible, it is considered that the height h1 of the first trapezoidal conductor and the height h2 of the second trapezoidal conductor are set to the same size. However, even in that case, as described above, if the top sides ul1 and ul2 and the bottom sides bl1 and bl2 of the trapezoidal conductor are set to different lengths so that the diffusion path length of the excitation current in the trapezoidal conductor is different, As described above, there is no problem in the antenna characteristics because the antenna characteristics exhibit the wideband characteristics.

Next, as an example of the embodiment of the broadband antenna according to the present invention, an antenna design example when applied to a secondary radar transponder (responder) mounted on an aeronautical vehicle will be described. In this transponder, as in the example used for the problem to be solved by the above-described invention, transmission: 1.09 G
Hz, reception: operates at a frequency of 60 MHz, which is 1.03 GHz. Therefore, the antenna used (designed) also has a center frequency of 1.0
Operation in a 5.7% bandwidth is required for 6 GHz. In the above example, it is assumed that the operation is required in the ratio band of 5.7% from the calculation, but actually, the margin for the shift of the frequency characteristic due to the use environment is included in the ratio band. Because it is necessary,
It is considered that operation in a fractional bandwidth of about 0% is required.

FIG. 2 is a diagram showing one embodiment of antenna dimensions when the broadband antenna according to the present invention shown in FIG. 1 is applied to a transponder. FIG. 3 is a diagram showing a voltage standing wave ratio (VSWR) characteristic representing impedance matching between the antenna of FIG. 2 and a feeder line. As shown in FIG. 2, the antenna height in this embodiment is only 43 mm (0.17λ with respect to the wavelength λ of the center frequency), and the height of the conventional monopole antenna (（wavelength: 0.25λ).
Since the air resistance increases or decreases in relation to the projected area of the front surface with respect to the moving direction, the width (d) of the first and second trapezoidal conductors is reduced to about the same as the conventional monopole antenna. , Air resistance can be significantly reduced as compared with the conventional monopole antenna. Also,
In the case of the antenna dimensions shown in FIG. 2, the respective operating frequencies of the feed element 1 and the parasitic element 2 are close to each other, and as a result, the frequency characteristic becomes a V-shaped characteristic as shown in FIG. The following frequency bandwidth exhibits a wide band characteristic of 12.8%. Therefore, in the broadband antenna according to the present embodiment, the above-mentioned system requirement of 5.7%
Needless to say, since it has a performance of 10% or more of the bandwidth in consideration of the margin due to the use environment described above, even if the frequency characteristic of the VSWR shifts due to the use environment such as temperature fluctuation as described above, the required performance of the system is sufficient. Can be satisfied. Note that, in addition to the V-shaped characteristics shown in FIG. 3, the wide-band antenna according to the present invention can obtain a W-shaped characteristic in which an optimum value exists at two more distant frequencies depending on the application. . FIG. 4 is a diagram showing an embodiment of the shape and dimensions of the wideband antenna according to the present invention for obtaining the above-mentioned W-shaped characteristic. FIG. 5 is a diagram showing the return loss characteristic (VSWR characteristic in dB) of FIG. FIG.

In the embodiment of the antenna shape shown in FIG.
On the short-circuit side (the side connected to the metal base 10) of the widths w1 and w2 of the first and second cutouts 12 and 22, the width w1
1 and 2 is that the width is reduced to width w1-w3, and the width is reduced to width w2-w3.
This is most different from the antenna shape shown in FIG. Although the details of the effect of this narrowly deformed notch on the operation of the entire antenna have not been theoretically elucidated, the inventors of the present invention have conducted experiments using the antenna shown in FIG. As shown in the return loss characteristics of FIG.
A W-shaped characteristic having resonance frequencies at 0.9 GHz and around 1.1 GHZ separated by Hz was obtained. As described above, in the wideband antenna according to the present invention, the shape parameters of the antenna to be designed are appropriately selected based on the results of the above experiments and the like with respect to the characteristics such as the fractional band and the return loss required by the wireless communication system. By doing so, it is possible to obtain optimal characteristics for a wide range of frequencies,
It is possible to provide an antenna having a wideband characteristic capable of covering a shift in frequency characteristics depending on a use environment.
In the above-described embodiment of the present invention, the feed element 1 and the parasitic element 2 are formed on both surfaces of the dielectric substrate 3 by a photoetching technique or the like in consideration of mass productivity. The present invention is not limited to this embodiment. For example, the feeder element 1 and the parasitic element 2 are configured using a conductor plate, and these are arranged directly on the metal base 10 via air instead of the dielectric substrate 3. Alternatively, a configuration may be adopted in which a dielectric material having an arbitrary dielectric constant is filled therebetween. According to experiments and studies by the inventors, the antenna characteristics in such a case are not inferior to those using the dielectric substrate 3, and conversely, when they are arranged via air, the antenna characteristics of the dielectric substrate Since there is no loss (dielectric loss), the loss inside the antenna can be reduced. Therefore, it is more advantageous than the case where a dielectric substrate is used in terms of radiation efficiency and the like. Furthermore, in the above-described embodiment, a combination of one feed element and one parasitic element has been described. However, a plurality of parasitic elements may be arranged. With a configuration in which a feed element is disposed between the power supply elements or a configuration in which a parasitic element is further disposed between the feed element and the parasitic element, it is possible to realize a broadband antenna having a wider frequency band characteristic. is there. The shape of the planar conductor constituting the broadband antenna according to the present invention may be, for example, triangular or square because the current excited in the planar conductor may be radially diffused from the feeding point by different lengths from the feeding point. Alternatively, any planar shape including a circular shape may be used. If the conductor shape is a circle, the current to be excited is diffused radially with different path lengths from the feeding point by shifting the position of the feeding point from the center point of the circle of the circular conductor. It can be used as a constituent planar conductor. Further, in the present embodiment, a case where a trapezoidal conductor is used from among polygonal conductors as an example of a planar conductor will be described.
However, in order to increase the bandwidth of the antenna according to the present invention, it is effective to combine a plurality of parasitic elements with a feeding conductor (feeding element) having a feeding point as described above. .

[0012]

As described above, according to the broadband antenna of the present invention, the radiating element of the broadband antenna is fed to the trapezoidal conductor which is a planar conductor and to the planar conductor which is a feeding element of the broadband antenna. Is shifted from the geometric center, and a notch for generating an electric field (magnetic current) provided in the trapezoidal conductor is formed. A wideband antenna is formed by combining a power supply element and a power supply element, so that the antenna can be a low-profile wideband antenna compared to a conventional dipole antenna. As a result, air resistance is reduced and fuel efficiency of aeronautical vehicles is improved. And a wideband having a wideband frequency characteristic capable of sufficiently securing a margin band for covering a shift of the frequency characteristic of the antenna depending on a use environment. It is possible to provide a container.

[Brief description of the drawings]

FIGS. 1A to 1C are structural views showing one embodiment of a wideband antenna according to the present invention.

FIGS. 2A to 2C are diagrams illustrating embodiments of shape parameters when the wideband antenna of FIG. 1 according to the present invention is used for a secondary radar transponder.

FIG. 3 is a diagram showing VSWR characteristics of the embodiment of the wideband antenna according to the present invention shown in FIG. 2;

FIGS. 4A to 4C are diagrams illustrating examples of antenna shape parameters for obtaining a W-shaped VSWR characteristic using one embodiment of the wideband antenna according to the present invention.

FIG. 5 is a diagram showing return loss characteristics of the embodiment of the wideband antenna according to the present invention shown in FIG. 4;

FIG. 6 is a cross-sectional view illustrating a structure of a monopole antenna used as an antenna mounted on a conventional aeronautical vehicle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Feeding element, 2 ... Parasitic element, 3 ... Dielectric substrate, 10 ... Metal base, 11 ... First trapezoidal conductor, 12, 22 ... Notch part, 13 ... feeding point,
14 ... connector, 14a ... central conductor, 15 ...
.Through hole, 21... Second trapezoidal conductor

Claims (12)

[Claims] 1. An antenna having a feeding point at a required portion of a plane conductor erected on a metal base, wherein the feeding point is arranged at a position shifted from a geometric center of the plane conductor. A wideband antenna, wherein a path length between a point and a point on an edge of the planar conductor is different depending on a location of the edge. 2. The structure according to claim 1, wherein a part of the planar conductor that is in contact with the metal base is provided with a cutout having a predetermined width along the surface of the metal base. Broadband antenna. 3. A method according to claim 1, wherein a second plane conductor having substantially the same shape as the plane conductor but different in the detailed dimensions of each part is erected on the metal base at a parallel position having a predetermined distance from the plane conductor. The broadband antenna according to claim 1 or 2, wherein 4. A notch in which a portion of the second planar conductor in contact with the metal base is cut along a surface of the metal base with a constant width different from that of the planar conductor. The wideband antenna according to claim 3, wherein the antenna is configured. 5. A third or third or later planar conductor having substantially the same shape as the planar conductor and the second planar conductor, but having different detailed dimensions of each part, on the metal base.
4. The wideband antenna according to claim 3, wherein the planar conductor and the parallel conductor are respectively provided upright at predetermined positions in parallel at predetermined intervals. 6. A part of the third or third or later planar conductor that is in contact with the metal base is formed along a surface of the metal base and is different from a cutout of the planar conductor or the second planar conductor. 6. The broadband antenna according to claim 5, wherein each of the third and subsequent planar conductors is provided with a cutout portion having a different fixed width. 7. A space between a plane conductor and the second plane conductor, or a space between the second plane conductor and the third plane or between each plane conductor after the third plane is filled with a dielectric material having a predetermined dielectric constant. The broadband antenna according to any one of claims 3 to 6, wherein: 8. The planar conductor, the second planar conductor, and the third or third or later planar conductor are formed on one surface of a single-layer dielectric substrate or a multilayer dielectric substrate erected on the metal base. The broadband antenna according to any one of claims 1 to 6, wherein the antenna is formed of a conductive foil formed on both surfaces or between layers. 9. The planar conductor according to claim 1, wherein said planar conductor, said second planar conductor, and said third or third or subsequent planar conductor are polygonal planar conductors. A broadband antenna according to any one of the preceding claims. 10. The broadband antenna according to claim 9, wherein the polygonal planar conductor is a trapezoidal planar conductor. 11. The power supply point is configured such that a current excited from the power supply point to the plane conductor is radially diffused by a different path length between the power supply point and each part on an edge of the plane conductor. The broadband antenna according to any one of claims 1 to 10, wherein the antenna is connected to a feed line. 12. The notch according to claim 1, wherein when the power is supplied to the power supply point, an electric field or a magnetic current is excited corresponding to the size of the notch.
A broadband antenna according to the item.