JP3881144B2 - Tapered slot antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tapered slot antenna that can be used in mobile communication devices, small information terminals, and other wireless devices, and more particularly to a tapered slot antenna with reduced cross-polarization components in the D plane. .
[0002]
[Prior art]
FIG. 10 is a perspective view showing an example of a conventional tapered slot antenna. The tapered slot antenna 100 includes a substrate 120 and a metal film 130 provided on the substrate 120.
[0003]
The substrate 120 is made of a dielectric material such as polyimide and has a thickness of 10 to 100 μm. The metal film 130 is made of copper as a main material and has a thickness of 2 to 20 μm. The metal film 130 is formed with a tapered portion 14 in which the slot width of the slot line becomes wider with an inclination. Reference numeral 15 denotes an antenna opening.
[0004]
The tapered slot antenna 100 radiates radio waves in a direction parallel to the surface of the antenna (advancing direction of the slot line).
[0005]
Since the structure of the tapered slot antenna is the same as that of the slot line, a ground conductor is not required on the back surface unlike the micro slot line, so that it is easy to integrate with a uniplanar structure feeder line and matching circuit. Further, the tapered slot antenna has a wide usable frequency bandwidth and a high gain, and is therefore used in mobile communication devices, small information terminals, and other wireless devices.
[0006]
However, the tapered slot antenna 100 has a high D-plane cross polarization component of −6 to −9 dB. In addition, the designation of the surface of the tapered slot antenna will be described. As shown in FIG. 11, in the tapered slot antenna, the plane that includes the direction of radiating electromagnetic waves and is parallel to the substrate 120 is a plane perpendicular to the substrate 120. The plane that forms an angle of 45 ° with the H plane, the E plane, and the H plane is called the D plane. The cross polarization is a polarization in which the polarization plane of the electromagnetic wave is orthogonal to the polarization direction of the antenna.
[0007]
A method of reducing the cross polarization component of the D-plane of the tapered slot antenna is described in “PR Acharya, J. Johansson, and EL Kollberg,“ Slotline antenna for milliliter and submillimeter wave length ”, Proc. Microwave Conf., Budapest, Hungary, pp 353-358, Sep. 1990 ”. In this report, it is explained that the cross-polarization component of the D-plane can be reduced to -11 dB by configuring the tapered shape of the tapered slot antenna with three straight lines with different inclinations called BLTSA (Broken Linearly Tapered Slot Antenna). ing.
[0008]
However, in the above report, there is no explanation as to why BLTSA can reduce the cross polarization component of the D plane and under what conditions the cross polarization component of the D plane can be reduced. . Therefore, based on this report, it is difficult to make a tapered slot antenna in which the cross polarization component of the D plane is reduced.
[0009]
[Problems to be solved by the invention]
As described above, the conventional tapered slot antenna has a high cross-polarization component in the D plane, which may cause a problem depending on the application. For example, in a system in which the openings of two tapered slot antennas are arranged orthogonally while being directed in the same direction and two polarization components are received independently, if the cross polarization component of the D plane is high, the polarization is different. There is a problem that the two polarization components cannot be separated well because they have sensitivity. Also, the reason why the cross polarization component of the D-plane of the tapered slot antenna becomes high is not clear.
[0010]
The present invention has been made in view of the above points, and clarifies the reason why the cross polarization component of the D-plane of the tapered slot antenna is increased, and a tapered slot antenna capable of reducing the cross-polarization component of the D plane is provided. The purpose is to provide.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a tapered slot antenna according to claim 1 is configured such that the slot width of the slot line on the substrate becomes wide with an inclination, the substrate, the metal film provided on the substrate, and the substrate. A tapered slot antenna that radiates an electric field from an opening of the tapered portion, and has a phase opposite to a component perpendicular to the substrate of the electric field radiated from the opening. Electric field generating means for generating an electric field, the electric field generating means, Corrugated structure composed of a plurality of grooves periodically formed on both side ends parallel to the radiation direction of the electromagnetic wave of the metal film, and the radiation direction of the electromagnetic wave formed between the corrugated structure of the metal film and the tapered portion The corrugated structure is formed at a position within 0.65 wavelength from the tapered portion, and the groove depth of the corrugated structure is 0.15 wavelength or more. Features .
[0012]
That is, in the tapered slot antenna of the present invention, an electric field having an opposite phase to the component perpendicular to the substrate of the electric field radiated from the opening is generated within 0.65 wavelength from the taper. The component perpendicular to the substrate of the electric field radiated from is canceled out. As will be described later, according to the consideration of the inventors of the present invention, the component perpendicular to the substrate of the electric field radiated from the opening increases the cross polarization component of the D plane. Therefore, by generating a component that cancels this component, the cross polarization component of the D plane can be reduced.
[0016]
Also, In the tapered slot antenna of the present invention, a corrugated structure having a groove depth of 0.15 wavelength or more is formed on both side ends parallel to the electromagnetic wave radiation direction of the metal film, and an electromagnetic wave is formed between the corrugated structure and the tapered portion. A linear slit is formed in parallel with the radial direction. This corrugated structure can reduce the cross polarization component of the D plane, and since the corrugated structure is formed, the strength of the electric field that becomes stronger at the edge of the substrate can be suppressed by forming a slit.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a tapered slot antenna according to the present invention will be described in detail in the order of [Outline of the present invention], [Embodiment 1], and [Embodiment 2] with reference to the accompanying drawings.
[0018]
[Outline of the Invention]
The reason why the cross polarization component of the D-plane of the tapered slot antenna is increased by the study of the inventors of the present invention will be described with reference to FIGS. 12 is a view of the conventional tapered slot antenna 100 shown in FIG. 10 as viewed from the opening 15 side.
[0019]
When electromagnetic waves are radiated from the tapered slot antenna 100, the electromagnetic waves change from the transmission mode T of the slot line to the mode F of free space. 10 and 12 schematically show how this mode changes.
[0020]
As shown in FIG. 12, the electric field in the transmission mode T can be separated into components T1, T3, T4, T6 perpendicular to the substrate 120 and components T2, T5 horizontal to the substrate 120. As described above, since the transmission mode T of the slot line also includes components T1, T3, T4, and T6 perpendicular to the substrate, these components are radiated into free space and become cross polarization components.
[0021]
The components perpendicular to the substrate 120 are highly symmetrical with respect to the E plane (horizontal direction in FIG. 12) and the H plane (vertical direction in FIG. 12), so that the radiated electric fields cancel each other.
[0022]
For example, when observed on the E plane, the component T1 and the component T4 (or the component T3 and the component T6) are equal in magnitude and opposite in direction, and the distance from the observation point is also equal, so the radiated electric fields cancel each other. When observed on the H plane, the component T1 and the component T3 (or the component T4 and the component T6) are equal in magnitude and opposite in direction, and the distance from the observation point is also equal, so the radiated electric fields cancel each other. For this reason, there is no problem in the E and H planes because the cross polarization component is not so high.
[0023]
However, since the symmetry of the component perpendicular to the substrate 120 is broken on the D plane (in the direction of 45 ° in FIG. 12), the cross polarization component becomes high.
[0024]
Therefore, in the tapered slot antenna of the present invention, the cross polarization component of the D plane is reduced by intentionally generating an electric field component that cancels out the component perpendicular to the substrate of the electric field radiated from the opening.
[0025]
[Embodiment 1]
FIG. 1 shows a tapered slot antenna according to Embodiment 1 of the present invention. FIG. 1A is a perspective view of a tapered slot antenna of the present invention, and FIG. 1B is a top view of the tapered slot antenna of the present invention.
[0026]
As illustrated in FIG. 1, the tapered slot antenna 10 includes a substrate 12 and a metal film 13 provided on the substrate 12.
[0027]
The board | substrate 12 consists of dielectric materials, such as a polyimide (for example, brand name: Kapton), and thickness is 10-100 micrometers. Moreover, the metal film 13 is comprised by using copper as the main material, The thickness is 2-20 micrometers. The metal film 13 is formed with a tapered portion 14 in which the slot width of the slot line becomes wider with an inclination. Reference numeral 15 denotes an antenna opening.
[0028]
Corrugated structures 16 are formed in the portions of the metal film 13 at both ends of the substrate 12. It has been reported by the present inventors that the phase and intensity of the electric field at the end of the substrate can be controlled by forming a corrugated structure at the end of the tapered slot antenna (IEEE MTT-S IMS Dig. Pp. 533). 536 1998). The corrugated structure 16 can intentionally generate an electric field component that cancels out a component perpendicular to the substrate of the electric field radiated from the opening 15.
[0029]
FIG. 2 shows a partially enlarged view of the tapered slot antenna 10. As shown in this figure, the corrugated structure 16 includes a plurality of grooves 17 formed by periodically removing the metal film 13 into a rectangular shape. In the figure, d is the depth of the groove 17, w is the width of the groove 17, and p is the period of the groove 17. L is the length from the opening 15 to the end of the antenna.
[0030]
The tapered slot antenna 10 radiates radio waves in a direction parallel to the plane of the antenna (advancing direction of the slot line), and can be used for mobile communication devices, small information terminals, and other wireless devices.
[0031]
An experiment was conducted to determine parameters for reducing the cross polarization component of the D plane. For this experiment, 5 μm copper serving as the metal film 13 was laminated on 50 μm kapton serving as the substrate 12. Then, the basic structure of the antenna was 20 mm, the length of the opening was 5 mm, and three types of antennas d4cw04, d5cw04, and d5cw08 were prepared.
[0032]
Regarding the length L from the opening to the substrate edge, the antenna d4cw04 with d4 at the head is 2 mm (0.4 wavelength), and the antennas d5cw04 and d5cw08 with the head d5 are 2.5 mm (0.5 wavelength). did. Regarding the groove width w and period p, the antennas d4cw04 and d5cw04 with cw04 at the end have a width of 0.2 mm (0.04 wavelength), a period of 0.4 mm (0.08 wavelength), and finally cw08. The antenna d5cw08 with a width of 0.4 mm (0.08 wavelength) and a period of 0.8 mm (0.16 wavelength).
[0033]
Then, the depth D of the corrugated structure of the three antennas d4cw04, d5cw04, and d5cw08 was changed, and the intensity of the cross polarization component on the D plane was measured. The measurement was performed at 60 GHz (wavelength 5 mm). The result of this experiment is shown in FIG. In this figure, the vertical axis represents the intensity of the cross polarization component of the D plane, and the unit is dB. The horizontal axis represents the depth d of the groove, and the unit is wavelength.
[0034]
When the depth d of the groove is 0 (zero) to 0.04 wavelength, the intensity of the cross polarization component of the D plane is higher than −10 dB for all three antennas. When the groove depth d is 0.04 to 0.12 wavelength, the intensity of the cross-polarized wave component on the D-plane suddenly decreases for all three antennas, and is lowest at -17.5 dB for the antenna d4cw04. When the groove depth d is 0.12 to 0.2 wavelengths, the intensity of the cross polarization component of the D plane is also higher than −10 dB for all three antennas.
[0035]
As can be seen from FIG. 3A, the cross-polarized wave component of the D plane is particularly reduced when the groove depth d is 0.06 to 0.1 wavelength. Therefore, in the tapered slot antenna 10 according to Embodiment 1, the depth of the groove of the corrugated structure 16 is set to 0.04 to 0.12 wavelength, preferably 0.06 to 0.1 wavelength. Thereby, in the tapered slot antenna 10, the cross polarization component of the D plane is reduced. That is, the corrugated structure 16 inverts the phase of the electric field at the edge of the substrate to increase the strength, and the electric field having a phase opposite to the component perpendicular to the substrate of the electric field radiated from the opening 15 is tapered. It is generated in the vicinity, and the cross polarization component of the D plane can be reduced.
[0036]
Next, an experiment was performed to determine an optimum value of the length L from the opening to the substrate edge. For this experiment, 5 μm copper serving as the metal film 13 was laminated on 50 μm kapton serving as the substrate 12. The basic structure of the antenna is that the antenna length is 20 mm, the opening length is 5 mm, the groove depth d is 0.4 mm (0.08 wavelength) at both ends of the antenna, and the width w is 0.2 mm (0 .04 wavelength) and a corrugated structure having a period p of 0.4 mm (0.08 wavelength).
[0037]
And the length L from the opening part of this antenna to the board | substrate edge was changed, and the intensity | strength of the cross polarization component of D surface was measured. The measurement was also performed at 60 GHz (wavelength 5 mm). The result of this experiment is shown in FIG. Also in this figure, the vertical axis represents the intensity of the cross polarization component of the D plane, and the unit is dB. The horizontal axis represents the depth d of the groove, and the unit is wavelength. For comparison, the strength of the cross polarization component of the D plane of the conventional tapered slot antenna in which the corrugated structure is not formed at the end of the substrate is indicated by a dotted line, and the cross of the D plane of the tapered slot antenna of the present invention is shown. The intensity of the polarization component is represented by a solid line.
[0038]
In the tapered slot antenna of the present invention, the intensity of the cross polarization component of the D plane gradually decreases when the length L from the opening to the substrate end is 0.3 to 0.4 wavelength, and 0.4 It becomes a minimum value of about -17.5 dB in the vicinity of the wavelength, and gradually increases when the length L from the opening to the substrate end is 0.4 to 0.7 wavelength. However, in the conventional tapered slot antenna, the intensity of the cross polarization component on the D plane is substantially constant even when the length L from the opening to the substrate end changes. In addition, the intensity of the cross polarization component of the D plane of the tapered slot antenna of the present invention is the value of the cross polarization component of the D plane of the conventional tapered slot antenna regardless of the value of the length L from the opening to the substrate end. Lower than strength.
[0039]
As can be seen from FIG. 3B, the cross polarization component of the D plane is reduced when the length L from the opening to the substrate end is 0.6 wavelengths or less.
[0040]
By the way, generally, the radiation field of the tapered slot antenna spreads outward by about 0.4 wavelength from the tapered portion. In addition, it is considered that the corrugated structure 16 needs to be provided at a distance of at least 0.25 (1/4) wavelength in order to cancel each other by using electric fields of opposite phases. Accordingly, it is considered that the corrugated structure 16 shown in FIG. 1 may be provided within 0.65 wavelength from the tapered portion 14.
[0041]
The result shown in FIG. 3B proves the above condition. Therefore, in the tapered slot antenna 10 of the first embodiment, the length L from the tapered portion 14 to the corrugated structure 16 (from the opening portion). The length to the substrate end) is set to be within 0.65 wavelength. As shown in FIG. 3B, the characteristic deteriorates when the length L becomes 0.3 wavelength or less, so the lower limit of the length L is 0.3. Thereby, in the tapered slot antenna 10, the cross polarization component of the D plane is reduced.
[0042]
From these two experiments, the depth d of the groove 17 of the corrugated structure 16 formed at the end of the tapered slot antenna 10 is 0.04 to 0.12 wavelength, preferably 0.06 to 0.1 wavelength, When the length L from the opening 15 to the substrate edge is within 0.65 wavelengths, an electric field component that cancels out the component perpendicular to the substrate 12 of the electric field radiated from the opening 15 can be optimally generated. , The cross polarization component of the D plane can be reduced most.
[0043]
Next, an experiment was conducted in which a tapered slot antenna to which the invention of Embodiment 1 was applied was formed and the directivities of the E, H, and D planes were measured. For this experiment, 5 μm copper serving as the metal film 13 was laminated on 50 μm polyimide serving as the substrate 12. The antenna length was 20 mm, the length of the opening was 5 mm, and the length L from the opening to the substrate edge was 2.5 mm (0.5 wavelength). Further, the depth d of the groove at the end of the antenna is 0.4 mm (0.08 wavelength), the width w is 0.2 mm (0.04 wavelength), and the period p is 0.4 mm (0.08 wavelength). A corrugated structure was formed. The design frequency of this antenna was 60 GHz.
[0044]
FIG. 4A shows the directivity of the E plane, FIG. 4B shows the directivity of the H plane, FIG. 4C shows the directivity of the D plane, and FIG. 4D shows the cross polarization component of the D plane. Show directivity. In this figure, the vertical axis represents relative intensity, and the unit is dB. The horizontal axis represents the radiation angle of the antenna, and the unit is degrees. For comparison, FIG. 5 shows the directivity of a conventional tapered slot antenna in which the corrugated structure is not formed at the end of the substrate. 4A, FIG. 5A shows the directivity of the E surface, FIG. 5B shows the directivity of the H surface, FIG. 5C shows the directivity of the D surface, and FIG. 5D shows the D surface. The directivity of the cross polarization component of
[0045]
As shown in FIG. 5 (d), in the conventional tapered slot antenna, the cross polarization component of the D plane is as high as −9 dB, whereas in the tapered slot antenna of the present invention as shown in FIG. 4 (d), the D plane. The cross polarization component of -13 dB is as low as -13 dB.
[0046]
As described above, in the tapered slot antenna 10 of the first embodiment, the length L from the opening 15 to the substrate end is set to within 0.65 wavelength, and the depth d of the groove 17 is set to 0.04 to 0.12 wavelength. In addition, by forming a corrugated structure preferably having a wavelength of 0.06 to 0.1 at both ends of the substrate 12, an electric field component that cancels out a component perpendicular to the substrate 12 of the electric field radiated from the opening 15 is intended. Therefore, the cross polarization component of the D plane can be reduced.
[0047]
In the first embodiment, the shape of the groove 17 of the corrugated structure 16 is rectangular. However, it is possible to use a shape other than the rectangle as long as the above-described effect can be obtained. Not too long.
[0048]
[Embodiment 2]
FIG. 6 shows a tapered slot antenna according to Embodiment 2 of the present invention. 6A is a perspective view of the tapered slot antenna of the present invention, and FIG. 6B is a top view of the tapered slot antenna of the present invention.
[0049]
As shown in FIG. 6, the tapered slot antenna 20 includes a substrate 22 and a metal film 23 provided on the substrate 22.
[0050]
In the metal film 23, linear slits S <b> 1 and S <b> 2 are formed between the corrugated structure 16 and the tapered portion 14. Since the configuration other than the depth of the groove of the corrugated structure 16 and the linear slits S1 and S2 is the same as that of the tapered slot antenna 10 according to the first embodiment, the description thereof is omitted.
[0051]
FIG. 7 shows a partially enlarged view of the tapered slot antenna 20. As shown in this figure, the corrugated structure 16 includes a plurality of grooves 17 formed by periodically removing the metal film 23 into a rectangular shape. In addition, slits S <b> 1 and S <b> 2 are formed between the groove 17 of the corrugated structure 16 and the tapered portion 14 so as to be substantially parallel to the electromagnetic wave radiation direction and the end of the substrate 22.
[0052]
In the tapered slot antenna 10 according to the first embodiment, an electric field component that intentionally cancels a component perpendicular to the substrate of the electric field radiated from the opening is intentionally generated. Strength increases. Thus, when the strength of the electric field at the edge of the substrate is increased, in a configuration such as an antenna array in which a plurality of antennas are arranged, crosstalk between adjacent antennas is increased.
[0053]
Therefore, in the tapered slot antenna 20 according to the second embodiment, by forming linear slits S1 and S2 between the corrugated structure 16 and the tapered portion 14, the electric field strength at the edge of the substrate is suppressed. . In order to suppress the electric field strength at the substrate edge, it has been clarified by the present inventors that a corrugated structure having a groove depth of 0.15 wavelength or more may be provided at the substrate edge. Yes.
[0054]
FIG. 8 is a view of the tapered slot antenna 20 of FIG. 6 as viewed from the opening 15 side. T is a transmission mode of the slot line, and G is an electric field generated in the slit. T3 in the figure is a component perpendicular to the substrate 22 of the electric field generated by the transmission mode T, and G1 and G2 are components perpendicular to the substrate 22 of the electric field generated by the electric field G. Here, one slit S1, S2 will be described, but the same phenomenon occurs in the other slit S1, S2.
[0055]
As can be seen from this figure, the component T3 and the component G1 cancel each other, and the component T3 and the component G2 strengthen each other. However, although the component T3 and the component G1 are spatially close to each other, they cancel out the same phase. However, since the component T3 and the component G2 are spatially separated, a phase shift occurs and the components T3 and G1 are not completely intensified. For this reason, the strength of the electric field at the edge of the substrate can be suppressed, and the cross polarization component of the D plane can be reduced.
[0056]
Note that a plurality of slits may be provided as long as they satisfy the above-described functions, and the slits may not be strictly parallel to the electromagnetic wave radiation direction. In addition, as long as the same effect can be obtained, the slit is not limited to the above-described slit, and other patterns and combinations thereof may be used. Further, the number, thickness, and combination of slits may be suitable for the antenna used. Furthermore, although the shape of the groove 17 of the corrugated structure 16 is rectangular, it is needless to say that a shape other than the rectangle can be used as long as the same effect can be obtained.
[0057]
Next, an experiment was conducted in which a tapered slot antenna to which the invention of Embodiment 2 was applied was formed and the directivities of the E, H, and D planes were measured. For this experiment, 5 μm copper serving as the metal film 13 was laminated on 50 μm polyimide serving as the substrate 12. The antenna length was 20 mm, the length of the opening was 5 mm, and the length L from the opening to the substrate edge was 2.5 mm (0.5 wavelength). Further, the groove depth d at the end of the antenna is 0.8 mm (0.16 wavelength), the width w is 0.2 mm (0.04 wavelength), and the period p is 0.4 mm (0.08 wavelength). A corrugated structure was formed. Further, between the corrugated structure and the tapered portion, a linear shape having a width of 0.3 mm (0.06 wavelength) between 1.2 mm (0.24 wavelength) to 1.5 mm (0.3 wavelength) from the substrate end. A linear slit S1 having a width of 0.2 mm (0.04 wavelength) was formed between the slit S2 and 1.8 mm (0.36 wavelength) to 2.0 mm (0.4 wavelength) from the substrate end. The design frequency of this antenna was 60 GHz.
[0058]
9 (a) shows the directivity of the E plane, FIG. 9 (b) shows the directivity of the H plane, FIG. 9 (c) shows the directivity of the D plane, and FIG. 9 (d) shows the cross polarization component of the D plane. Show directivity. In this figure, the vertical axis represents relative intensity, and the unit is dB. The horizontal axis represents the radiation angle of the antenna, and the unit is degrees.
[0059]
As shown in FIG. 5 (d), in the conventional tapered slot antenna, the cross polarization component of the D plane is as high as −9 dB, whereas in the tapered slot antenna of the present invention as shown in FIG. The cross polarization component of the surface is as low as −13.2 dB.
[0060]
As described above, in the tapered slot antenna 20 of the second embodiment, a corrugated structure in which the depth d of the groove 17 is 0.15 wavelength is formed at both ends of the substrate 22, and between the corrugated structure 16 and the tapered portion 14. By forming a linear slit in the electric field, it is possible to intentionally generate an electric field component that cancels out a component perpendicular to the substrate 12 of the electric field radiated from the opening 15 and an electric field at the edge of the substrate. Can be prevented from becoming stronger. Further, when this tapered slot antenna 20 is used for an antenna array, it is possible to reduce the crosstalk between adjacent antennas, and therefore it can be suitably used for a configuration such as an antenna array in which a plurality of antennas are arranged. .
[0061]
【The invention's effect】
As described above, in the tapered slot antenna of the present invention (Claim 1), an electric field having an opposite phase to the component perpendicular to the substrate of the electric field radiated from the opening is 0.65 wavelength from the tapered portion. (Electric field generating means), it is possible to intentionally generate an electric field that cancels out a component perpendicular to the substrate of the electric field radiated from the opening. Can be reduced.
[0063]
The tapered slot antenna of the present invention (claims) 1 ), As a means for generating an electric field, a corrugated structure having a groove depth of 0.15 wavelength is formed at both ends parallel to the radiation direction of the electromagnetic wave of the metal film, and the electromagnetic wave is radiated between the corrugated structure and the tapered portion. By forming a linear slit parallel to the direction, it is possible to intentionally generate an electric field component that cancels out a component perpendicular to the substrate of the electric field radiated from the opening, and at the edge of the substrate. Since the strength of the electric field can be prevented from being increased, the cross polarization component of the D plane can be reduced, and crosstalk does not occur between adjacent antennas when used in a configuration such as an antenna array.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a tapered slot antenna according to a first embodiment of the present invention.
2 is a partially enlarged view of the tapered slot antenna of FIG. 1. FIG.
FIG. 3 is an explanatory diagram of a result of an experiment for obtaining a parameter for reducing a cross polarization component of a D plane.
4 is an explanatory diagram of directivities on the E, H, and D planes of the tapered slot antenna to which the invention of Embodiment 1 is applied. FIG.
FIG. 5 is an explanatory diagram of directivities on the E, H, and D planes of a conventional tapered slot antenna.
FIG. 6 is a configuration diagram of a tapered slot antenna according to a second embodiment of the present invention.
7 is a partially enlarged view of the tapered slot antenna of FIG. 6. FIG.
8 is an explanatory diagram showing an electric field distribution of the tapered slot antenna of FIG.
9 is an explanatory diagram of directivities on the E, H, and D planes of a tapered slot antenna to which the invention of Embodiment 2 is applied. FIG.
FIG. 10 is a perspective view of a conventional tapered slot antenna.
FIG. 11 is a conceptual explanatory diagram of an E plane, an H plane, and a D plane of a tapered slot antenna.
FIG. 12 is a principle explanatory diagram for explaining the reason why the cross polarization component of the D-plane of the tapered slot antenna increases.
[Explanation of symbols]
10,20 Tapered slot antenna
12,22 substrate
13,23 Metal film
14 Taper part
15 opening
16 Corrugated structure
17 Groove
S1, S2 slit
T transmission mode
F Free space mode

Claims (1)

A substrate, a metal film provided on the substrate, and a tapered portion formed so that a slot width of the slot line is inclined and widened on the substrate, and an electric field is formed from the opening of the tapered portion. In a tapered slot antenna that radiates
Electric field generating means for generating an electric field having an opposite phase to a component perpendicular to the substrate of the electric field radiated from the opening,
The electric field generating means is formed between a corrugated structure composed of a plurality of grooves periodically formed on both side edges parallel to the electromagnetic wave radiation direction of the metal film and between the corrugated structure of the metal film and the tapered portion. The corrugated structure is formed at a position within 0.65 wavelength from the tapered portion, and the groove depth of the corrugated structure is 0. A tapered slot antenna having 15 or more wavelengths .

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