JP2023092915A - antenna device - Google Patents

Abstract

To enable transmission/reception in a wide angle range from a vertical direction to a low elevation angle direction.SOLUTION: An antenna device includes a ground plane, a first antenna portion having a plurality of first helical elements spirally wound at a first pitch angle with respect to the ground plane, and a second antenna portion having a plurality of second helical elements spirally wound at a second pitch angle with respect to the ground plane at a position surrounding the first antenna portion, and the winding direction of each first helical element of the first antenna portion and the winding direction of each second helical element of the second antenna portion are opposite to each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to an antenna device having a helical antenna, and can be applied to an antenna device having circularly polarized wave characteristics.

In recent years, technologies have been developed for stratospheric platforms that use flying objects as communication base stations.

The stratospheric platform always flies a flight relay station (HAPS: High Altitude Platform Station) into the stratosphere, and performs wireless communication with a ground station provided on the ground by the flight relay station. As a result, even in areas where communication was not possible until now, communication is possible via the flight relay station (HAPS), so a wide-area communication network can be constructed at a lower cost than satellite communication.

The stratospheric platform also enables a flight relay station (HAPS) 52 to relay wireless communications between an unmanned air vehicle 51, such as a drone, and a ground station 53, as illustrated in FIG. At this time, the flying object 51 such as a drone is not in a constant attitude during flight, and the flight relay station 52 is in a circular flight. A helical antenna device is desirable as the antenna device 511 of the aircraft 51.

A helical antenna described in Patent Document 1 is an antenna device for satellite communication. Patent Document 1 discloses a four-wire helical antenna, and describes that the directivity changes according to the number of turns, pitch angle, and radius of each helical antenna element.

JP-A-10-75114

By the way, as illustrated in FIG. 3, it is assumed that the flight relay station 52 covers a downward communication area with a depression angle α. In that case, depending on the positional relationship between the flight repeater station 52 and the aircraft 51, the antenna device 511 can transmit and receive circularly polarized waves in the vertical direction with respect to the horizontal plane, and transmit and receive circularly polarized waves in the low elevation direction. It is desirable to be able to send and receive. In other words, there is a demand for an antenna device capable of transmitting and receiving circularly polarized waves over a wide angular range from the vertical direction to the low elevation angle direction.

In order to solve such a problem, the antenna device of the present invention provides: (1) a base plate; and (3) a second antenna section having a plurality of second helical elements spirally wound at a second pitch angle with respect to the ground plane at a position surrounding the first antenna section. (4) The winding direction of each first helical element of the first antenna section and the winding direction of each second helical element of the second antenna section are opposite to each other.

According to the present invention, circularly polarized waves can be transmitted and received in a wide angle range from the vertical direction to the low elevation angle direction.

1 is a configuration diagram showing the configuration of an antenna device according to an embodiment; FIG. 1 is a configuration diagram showing the configuration of a communication system in a stratosphere platform; FIG. FIG. 4 is an explanatory diagram illustrating communication between a flight relay station of the stratospheric platform and an aircraft; 3 is a circuit configuration diagram showing a transmission/reception circuit of the antenna device according to the embodiment; FIG. 1 is a configuration diagram showing a model configuration of a four-wire helical antenna (No. 1); FIG. FIG. 10 is an explanatory diagram illustrating changes in antenna gain when the radius and pitch angle of the four-wire helical antenna are changed (Part 1); FIG. 2 is a configuration diagram showing a model configuration of a four-wire helical antenna (No. 2); FIG. 11 is an explanatory diagram illustrating changes in antenna gain when the radius and pitch angle of the four-wire helical antenna are changed (No. 2); FIG. 10 is a diagram showing the directivity when changing the pitch angle of the four-wire helical antenna; It is an explanatory view explaining an operation mode of an antenna device of an embodiment. It is a figure which shows the directivity when the operation mode of the antenna apparatus which concerns on embodiment is switched. It is a figure which shows the reflection characteristic of the antenna device which concerns on embodiment. It is a figure which shows the axial ratio characteristic of the antenna device which concerns on embodiment. It is a block diagram which shows the structure of the antenna device of deformation|transformation embodiment.

(A) Main Embodiments Hereinafter, embodiments of an antenna device according to the present invention will be described in detail with reference to the drawings.

This embodiment exemplifies a case where the present invention is applied to an antenna device mounted on a flying object such as a drone in a stratospheric platform using a flight relay station (HAPS), for example. In general, the stratosphere refers to a layer located approximately 10 to 50 km in the vertical structure of the earth's atmosphere.

The antenna device of the present invention can also be applied to flying objects other than drones, as long as it is required to transmit and receive circularly polarized waves over a wide angle range from the vertical direction to the low elevation angle direction.

(A-1) Configuration of Embodiment FIG. 1 is a configuration diagram showing the configuration of an antenna device according to an embodiment. FIG. 4 is a circuit configuration diagram showing a transmission/reception circuit of the antenna device according to the embodiment.

In FIG. 1 , the antenna device 10 of the embodiment has a plate-shaped base plate 11 , a first antenna section 12 and a second antenna section 13 .

[Main plate 11]
The ground plate 11 is a circular plate member and is a ground plate that functions as a ground. For example, in a stratospheric platform using an airborne repeater (HAPS), use of radio waves with a frequency of 5030 MHz to 5091 MHz is under consideration. The radius ra of the base plate 11 of the circular plate member can be (1/2)×λ, where λ is the wavelength of the radio wave to be used. For example, when the frequency of the radio waves to be used is 5060 MHz (that is, the wavelength λ of the radio waves to be used is about 59 mm), the radius ra of the ground plane 11 can be about 30 mm (=(1/2)×λ).

[First antenna section 12]
The first antenna section 12 has directivity in a low elevation angle direction, and is a four-wire helical antenna having four helical elements 12a to 12d. In other words, the first antenna section 12 is an array of four helical elements 12a to 12d. The helical elements 12a to 12d of the first antenna section 12 are also called "first helical elements".

Conductors such as metal wires and conductive strips can be applied to the helical elements 12a to 12d of the first antenna section 12. In this embodiment, conductor wires such as metals are used for the helical elements 12a to 12d. use. The length (electrical length) of each of the helical elements 12a to 12d can be determined according to the wavelength λ of the radio wave to be used. 4) x λ x n; n is a positive integer). In this embodiment, the case where n is "3" is illustrated. For impedance matching, the length of each helical element 12a-12d can be adjusted.

The lower ends of the helical elements 12a-12d of the first antenna section 12 are connected to corresponding terminals Port1-Port4 provided on the ground plane 11, respectively. As illustrated in FIG. 4, a wireless device 134 and a distributor/synthesizer 133 are provided on the lower surface (second surface) of the XY plane of the base plate 11 . Transmission/reception terminals 1 to 4 of the distributor/combiner 133 are connected to corresponding terminals Port1 to Port4, respectively.

In FIG. 4, for example, “φ” attached to the terminals Port1 to Port4 indicates the physical positions of the terminals Port1 to Port4 on the XY plane of the ground plane 11 as angles with respect to the X axis. For example, "Port 1" is indicated as "φ=0 deg (degrees)" because it is on the X axis on the XY plane. "Phase" attached to the terminals Port1 to Port4 indicates the phase of the signal transmitted or received by the corresponding helical element 12a to 12d.

In FIG. 4 , when transmitting a signal, radio equipment 134 outputs the signal to splitter/combiner 133 , and splitter/combiner 133 changes the phase of the input signal from radio equipment 134 to transmit/receive terminal 1 . Output to ~4. For example, in FIG. 4, the distributor/synthesizer 133 directly outputs the input signal to the transmission/reception terminal 1 connected to the terminal Port1. Further, a signal obtained by shifting the phase of the input signal by -90 degrees (-π/2 rad) is output to the transmission/reception terminal 2 connected to the terminal Port2, and the phase of the input signal is output to the transmission/reception terminal 3 connected to the terminal Port3. A signal shifted by -180 degrees (-π rad) is output, and a signal obtained by shifting the phase of the input signal by -270 degrees (-3π/2 rad) is output to the transmission/reception terminal 4 connected to the terminal Port4. In this way, the distributor/combiner 133 changes the phase of the input signal and gives the signal to each of the helical elements 12a-12d connected to each of the terminals Port1-4.

Conversely, when receiving signals, each of the helical elements 12a-12d gives the received radio signal to the splitter/synthesizer 133 via each of terminals Port1-4 and each of transmission/reception terminals 1-4. Distributor/synthesizer 133 outputs a signal obtained by synthesizing signals input from transmission/reception terminals 1 to 4 to radio device 134 .

Each of the helical elements 12a to 12d of the first antenna section 12 is helically wound with a predetermined pitch angle with respect to the first surface of the base plate 11 . The pitch angles of the helical elements 12a to 12d, which will be described later, are angles that provide good gain in the direction of low elevation angles. That is, the pitch angles of the helical elements 12a to 12d of the first antenna section 12 are made larger than the pitch angles of the helical elements 13a to 13d of the second antenna section 13. FIG. For example, the pitch angle of each of the helical elements 12a-12d can be 70 degrees or less, preferably about 60-65 degrees.

[Second antenna section 13]
The second antenna section 13 is an antenna having directivity in the vertical direction, and is a four-wire helical antenna having four helical elements 13a to 13d. In other words, the second antenna section 13 is also an array of four helical elements 13a to 13d. The helical elements 13a to 13d of the second antenna section 13 are also called "second helical elements".

The helical elements 13a to 13d of the second antenna section 13 can also apply conductors such as metal wires and conductive strips. use. The length (electrical length) of each of the helical elements 13a to 13d can be determined according to the wavelength λ of the frequency of the radio wave to be used. 1/4)×λ×n; n is a positive integer). In this embodiment, the case where n is "3" is illustrated. For impedance matching, the length of each helical element 13a-13d can be adjusted.

The lower ends of the helical elements 13 a to 13 d of the second antenna section 13 are connected to corresponding end sections 131 provided on the ground plane 11 .

As illustrated in FIG. 4, each termination unit 131 is connected to a switch unit (termination load switching unit) 132 that switches between the ground and the termination load ZL. The four end portions 131 are arranged on the first surface of the main plate 11 on a circle with a radius of r2 (r1<r2<ra) centered on the center point of the main plate 11 (90 degree intervals in FIG. 1). is installed in On the first surface of the ground plate 11, an inner circle with a radius of r1 (also referred to as a "first circle") and an outer circle with a radius of r2 (also referred to as a "second circle") are formed concentrically, The corresponding end portions 131 are located on extensions of lines passing through the center point of the ground plate 11 and the terminals Port1 to Port4 on the inner circle.

Each of the helical elements 13a to 13d of the second antenna section 13 is helically wound up at a predetermined pitch angle with respect to the first surface of the base plate 11 .

The pitch angle of each of the helical elements 13a to 13d of the second antenna section 13 will be described later.

The winding direction of each of the helical elements 13a to 13d of the second antenna section 13 is opposite to the winding direction of each of the antenna elements 12a to 12d of the first antenna section 12. FIG. The reason why the winding direction is reversed will be described later. Sometimes, a current may be induced in the second antenna section 13 and radio waves may be canceled. The current directions can be made substantially the same, and cancellation of radio waves can be avoided.

For example, the direction of rotation of circularly polarized waves is assumed to be right-handed circularly polarized waves (RHCP). When the Z-axis direction as viewed from the ground plane 11 is the traveling direction, right-handed rotation in the Z-axis direction is the same as the rotation direction of the right-handed circularly polarized wave, and left-handed rotation in the Z-axis direction is the rotation of the right-handed circularly polarized wave. direction and the opposite direction. In FIG. 1, the helical elements 12a to 12 of the first antenna section 12 are left-handed in the Z-axis direction, and the helical elements 13a-13 of the second antenna section 13 are right-handed in the Z-axis direction. The directions are opposite to each other. The winding directions of the first antenna section 12 and the second antenna section 13 may be opposite to each other, and the first antenna section 12 is clockwise and the second antenna section 13 is counterclockwise. may be

(A-2) Directivity of Antenna Section Next, the directivity of the first antenna section 12 and the second antenna section 13 of the antenna device 10 will be described with reference to the drawings.

Here, in order to explain using a general model of a four-wire helical antenna, it will be described as an "antenna unit 20".

In FIG. 5, the number of turns of each of the four helical elements 20a to 20d is 0.75, and each helical element 20a to 20d is left-handed with respect to the Z-axis direction (in the direction opposite to the direction of rotation of the circularly polarized wave). 1 shows the antenna section 20 when 6A to 6C are diagrams showing changes in gain of the antenna section 20 of FIG.

In FIG. 7, the number of turns of each of the four helical elements 20a to 20d is 0.75, and each helical element 20a to 20d is right-handed with respect to the Z-axis direction (the same direction as the rotation direction of circularly polarized waves). The antenna section 20 is shown when . 8A to 8C are diagrams showing changes in the gain of the antenna section 20 of FIG.

6 and 8, the horizontal axis indicates the value of the angle Θ [degrees] with respect to the Z-axis, and the vertical axis indicates the gain [dB] of the antenna section 20. FIG.

Unless otherwise specified, the frequency of the radio wave used is 5060 MHz (the wavelength λ of the radio wave used is about 59 mm), the radius ra of the ground plane 11 is 30 mm (=(1/2)×λ), and the circularly polarized wave is right-hand circularly polarized (RHCP).

5 and 7, an antenna section (four-wire helical antenna) 20 having four helical elements 20a to 20d is provided on the ground plane 11. As shown in FIG. When the wavelength of the radio wave to be used is λ, the length of each helical element 20a to 20d is ((1/4)×λ×n; for example, n=3).

Under such model conditions, changes in the gain of the antenna section 20 are observed when the radius r of the circle and the values of the pitch angles of the helical elements 20a to 20d are changed.

6A to 6C, the winding direction of each helical element 20a to 20d is opposite to the rotation direction of the circularly polarized wave, and the pitch angles are 63.3 degrees and 48.1 degrees. The respective gains of the antenna section 20 at 30 degrees and 30 degrees are compared. Then, when the radius r is 4 mm and the pitch angle is 63.3 degrees, it can be seen that the gain increases when the angle Θ with respect to the Z axis is around ±60 degrees. For this reason, the winding direction of each helical element 20a to 20d of the antenna section 20 is opposite to the direction of rotation of the circularly polarized wave, and the greater the pitch angle, the stronger the directivity of the antenna section 20 in the low elevation angle direction. know to have

In the case of the antenna device 10 shown in FIG. 1, the antenna section 12 has this characteristic and functions as a device for transmitting and receiving a circularly polarized wave in a low elevation angle direction.

Next, as shown in FIGS. 8A to 8C, the winding direction of each of the helical elements 20a to 20d is the same as the direction of rotation of the circularly polarized wave, and the pitch angle is 63.5. Each gain of the antenna section 20 at 3 degrees, 48.1 degrees, and 30 degrees is compared. Then, when the radius r is 8 mm and the pitch angle is 30 degrees, it can be seen that the gain is large in the vertical direction (the angle Θ with respect to the Z axis is near 0 degrees). Therefore, the winding direction of each of the helical elements 20a to 20d of the antenna section 20 is the same as the direction of rotation of the circularly polarized wave, and the smaller the pitch angle, the stronger the directivity of the antenna section 20 in the vertical direction. I understand.

In the case of the antenna device 10 shown in FIG. 1, the antenna section 13 has this characteristic and functions as a device for transmitting/receiving circularly polarized waves in the vertical direction.

As described above, the antenna device 10 of FIG. 1 includes the first antenna section 12 having strong directivity in the low elevation direction and the second antenna section 13 having strong directivity in the vertical direction. It can transmit and receive with circular polarization over a range of angles.

FIG. 9 is a diagram showing changes in gain when the pitch angle of the four-wire helical antenna is changed.

In FIG. 9 , the horizontal axis indicates the angle Θ [degrees] with respect to the Z-axis, and the vertical axis indicates the gain [dB] of the antenna section 20 .

In FIG. 9, the winding direction of each of the helical elements 20a to 20d is opposite to the direction of rotation of the circularly polarized wave, and the number of turns N is 0.5. Furthermore, the gain is shown when the pitch angle is changed to 28.5 degrees, 42.2 degrees, 53.1 degrees, 63.3 degrees, 72.6 degrees and 81.5 degrees.

In FIG. 9, when the pitch angle is 28.5 degrees, the direction in which the gain of the antenna section 20 is maximized is the vertical direction (the angle .THETA. with respect to the Z-axis is 0 degrees). As the pitch angle gradually increases, the direction of maximum gain shifts to the low elevation angle direction. However, when the pitch angles are 72.6 degrees and 81.5 degrees, the direction of the maximum gain does not change, and the gain value decreases. That is, for example, when the pitch angle is 53.1 degrees to 63.3 degrees, a large gain is exhibited when the angle Θ with respect to the Z axis is around ±60 degrees to ±80 degrees. In other words, it can be said that the antenna section 20 has the characteristic that the pitch angle of each of the helical elements 20a to 20d is 70 degrees or less, and the gain in the low elevation angle direction is high.

(A-3) Operation of Embodiment Next, the operation of the antenna device 10 according to the embodiment will be described with reference to the drawings.

In the following explanation of the operation, the case where the antenna device 10 transmits radio waves will be mainly described. obtain.

The model conditions here are as follows. The frequency of the radio waves used is 5060 MHz (that is, the wavelength λ of the radio waves used is about 59 mm), and the radius ra of the ground plane 11 is about 30 mm (=(1/2)×λ).

Also, as shown in FIG. 1, the antenna device 10 has a first antenna section 12 on an inner circle with a radius of 4 mm and a second antenna section 13 on an outer circle with a radius of 12 mm. Further, when the wavelength of the radio wave to be used is λ, the lengths of the helical elements 12a to 12d of the first antenna section 12 and the lengths of the helical elements 13a to 13d of the second antenna section 13 are approximately ((1 /4)×λ×n). The number of turns of the helical elements 12a to 12d of the first antenna section 12 is set to 0.75, and the number of turns of the helical elements 13a to 13d of the second antenna section 13 is set to 0.5.

FIG. 10 is an explanatory diagram illustrating operation modes of the antenna device 10 of the embodiment. FIG. 11 is a diagram showing directivity when the operation mode of the antenna device 10 according to the embodiment is switched.

FIG. 10A shows an operation mode in which the antenna device 10 radiates circularly polarized waves in the low elevation direction, and FIG. 10B shows an operation mode in which the antenna device 10 radiates circularly polarized waves in the vertical direction. is shown.

In the case of FIG. 10A, the switch section 132 is switched to the load ZL, and the helical elements 13a to 13d of the second antenna section 13 are connected to the load ZL (for example, 1 MΩ) (termination condition: Open), A signal is input from the distributor/combiner 133 to each of the helical elements 12 a to 12 d of the first antenna section 12 . That is, the current flows from the distributor/combiner 133 toward the tips (upper ends) of the helical elements 12 a to 12 d of the first antenna section 12 . In this case, since the second antenna section 13 is connected to the load ZL (for example, 1 MΩ), no current is induced in the second antenna section 13 . Therefore, only the first antenna section 12 operates, and as shown in FIG. 11A, the antenna device 10 has strong radiation directivity in the low elevation angle direction.

In the case of FIG. 10B, the switch section 132 is switched to the ground to connect the helical elements 13a to 13d of the second antenna section 13 to the ground (for example, 0Ω) (termination condition: short), and the first A signal is input to each of the helical elements 12 a to 12 d of the antenna section 12 from the distributor/combiner 133 .

Here, when a current is caused to flow from the distributor/synthesizer 133 toward the tips (upper ends) of the helical elements 12a to 12d of the first antenna section 12, the helical elements 12a to 12d of the first antenna section 12 Current flows while rotating around the axis of

When the first antenna section 12 and the second antenna section 13 are arranged close to each other, when power is supplied to the first antenna section 12 , a current may also be induced in the second antenna section 13 . At this time, in the directions of the currents flowing through the first antenna section 12 and the second antenna section 13, the directions of the components rotating about the Z-axis direction are substantially opposite to each other.

Therefore, if the winding directions of the first antenna section 12 and the second antenna section 13 are the same, the directions of the currents flowing from the distributor/combiner 133 to the tip of the helical element are also substantially opposite to each other. Therefore, the radiation from the first antenna section 12 and the radiation from the second antenna section 13 cancel each other out.

Therefore, in this embodiment, the winding directions of the helical elements 12a to 12d of the first antenna section 12 and the helical elements 13a to 13d of the second antenna section 13 are opposite to each other.

As a result, when the current flows from the distributor/combiner 133 to the tips of the helical elements 12a to 12d, the directions of current flow can be substantially the same, and the first antenna section 12 and the second antenna section 13 radiation canceling each other can be avoided. As a result, as shown in FIG. 11B, the antenna device 10 has strong radiation directivity in the vertical direction.

FIG. 12 is a diagram showing reflection characteristics of the antenna device 10 according to the embodiment.

Here, reflection characteristics are considered when the termination condition of the second antenna section 13 as a parasitic antenna is changed. For example, consider the S parameter S11 (input reflection coefficient indicating the ratio of the signal reflected at the input terminal to the signal input to the input terminal).

In FIGS. 12A and 12B, the vertical axis is S11 [dB] of the S parameter, and the horizontal axis is the operating frequency [GHz].

When the used frequency is 5060 MHz and the termination condition of the second antenna section 13 is set to open, the amount of reflection can be reduced to -10 dB or less as shown in FIG. 12(A). Also, when the termination condition of the second antenna section 13 is short, the amount of reflection can be reduced to -10 dB or less as shown in FIG. 12(B). In this way, the amount of reflection can be kept low even if the terminal load condition changes.

FIG. 13 is a diagram showing axial ratio characteristics of the antenna device 10 according to the embodiment.

13(A) and 13(B), the vertical axis represents the axial ratio AR (the ratio of the major axis to the minor axis of the electric wave in which the circularly polarized wave is elliptically distorted (elliptical polarized wave)) [dB]. , the horizontal axis is the angle Θ [degrees] with respect to the Z-axis. Here, it is assumed that the performance of the antenna device 10 that radiates circularly polarized waves is good when the axial ratio (AR) of elliptically polarized waves is 3 dB or less.

As shown in FIG. 13A, when the termination condition of the second antenna section 13 was set to Open, the axial ratio (AR) was 3 dB or less in the range of ±65 degrees. Further, as shown in FIG. 13B, when the termination condition of the second antenna section 13 was short, the axial ratio (AR) was 3 dB or less in the range of ±30 degrees.

The first antenna section 12 that radiates in a low elevation angle direction is required to have a low axial ratio over a wide angle range, and each of the helical elements 12a to 12d of the first antenna section 12 has a large number of turns. Thereby, the axial ratio of the first antenna section 12 can be lowered.

(A-4) Effect of Embodiment As described above, according to this embodiment, the first antenna section of the four-wire helical antenna and the first antenna section are surrounded on the ground plane, and a second antenna section of a four-wire helical antenna, wherein the winding directions of the helical element of the first antenna section and the second antenna section and the helical element are opposite to each other, so that the first antenna section Since the directions of currents flowing through the first antenna section and the second antenna section can be substantially the same when power is supplied, cancellation of radiation can be avoided.

Further, in this embodiment, by making the pitch angle of the first antenna section larger than the pitch angle of the second antenna section, the first antenna section can radiate in a low elevation angle direction, and the second antenna section can radiate. The antenna part can radiate in the vertical direction.

Furthermore, according to this embodiment, by setting the pitch angle of the first antenna section to 70 degrees or less, it is possible to suppress a decrease in the gain of the first antenna section.

Furthermore, according to this embodiment, the number of turns of the first antenna section that radiates in the low elevation direction is made larger than the number of turns of the second antenna, so that the first antenna section is wide. Axial ratio can be low in the angular range.

(B) Other Embodiments Although various modified embodiments have been mentioned in the embodiments described above, the present invention can also be applied to the following embodiments.

(B-1) In the above-described embodiment, each of the first antenna section 12 and the second antenna section 13 is a four-wire helical antenna, but the number of helical elements may be three. In addition, if possible, the number may be five or more.

(B-2) In the above-described embodiment, the terminals Port1 to Port4 of the first antenna section 12 on the inner circle and the terminal ends 131 of the second antenna section 13 on the outer circle are connected to each other. , for example, the case where the angles formed with respect to a straight line of φ=0 degrees on the XY plane (here, referred to as “initial line”) are the same, but the angles formed with respect to the initial line are not the same, The positions of the terminals Port1 to Port4 and the end portions 131 may be shifted from each other. That is, for example, the angle formed by each end portion 131 with respect to the starting line may be different from the angles of the terminals Port1 to Port4, and the four end portions 131 may be arranged at equal intervals on the outer circle.

The helical elements 12a to 12d of the first antenna section 12 are, for example, wound up along the outer shape of a cylindrical or columnar core material, and the helical elements 13a to 13d of the second antenna section 13 are It may be rolled up along the contour of the core material with different radii (or diameters). In this case, each of the helical elements 12a-12d and 13a-13d may be formed on the outer peripheral surface of a cylindrical or columnar core in a pattern using a conductor such as metal. Further, the core material is not limited to a cylindrical shape or columnar shape, and may be a polygonal prism or a hollow polygonal prism.

Furthermore, the “spiral winding” described in the claims means that one conductor is continuously spirally wound, or that a plurality of conductors are connected together (that is, a plurality of conductors are connected) and wound up. including being The latter can be applied to an antenna device in which substrates having helical elements formed in a pattern on the surface of the substrate are stacked in the Z-axis direction, and the helical element of one substrate is connected to the helical element of the substrate in the vertical direction. means. In other words, the present invention can also be applied to an antenna device in which a helical element is formed on each surface of a plurality of substrates and the helical elements of each substrate are connected by conductors to form a package.

(B-3) In the above-described embodiment, the first antenna section 12 is connected to the divider/combiner 133 and the second antenna section 13 is connected to the terminal load switching section 132 as an example. However, the circuit configuration in which the first antenna unit 12 and the second antenna unit 13 are connected is not limited to this. A circuit connected to a distributor/combiner and having the first antenna section 12 connected to the terminal load switching section 132 may be used.

(B-4) FIG. 14 is a configuration diagram showing the configuration of an antenna device 10A according to a modified embodiment.

As shown in FIG. 14, the antenna section 10A may connect the tips of the helical elements 12a to 12d of the first antenna section 12 with a conductive ring member 52. FIG. Similarly, the tips of the helical elements 13 a to 13 d of the second antenna section 13 may be connected by a conductive annular member 53 .

By connecting the tips of the helical elements 12a to 12d in the first antenna section 12 with the conductive ring member 52, the length (electrical length) of the helical elements 12a to 12d is increased by the length of the conductive ring member 52. However, it can be adjusted by performing impedance matching. The same applies to the second antenna section 13 as well.

DESCRIPTION OF SYMBOLS 10... Antenna apparatus, 11... Base plate, 12... 1st antenna part, 12a-12d... Helical element, 13... Second antenna part, 13a-13d... Helical element, Port1-Port4... Terminal, 131... Terminal part, 132...Switch unit (terminal load switching unit), 133...Distributor/synthesizer.

Claims (10)

a baseplate;
a first antenna section having a plurality of first helical elements spirally wound at a first pitch angle with respect to the ground plane;
a second antenna section having a plurality of second helical elements spirally wound at a second pitch angle with respect to the base plate at a position surrounding the first antenna section,
The winding direction of each of the first helical elements of the first antenna section and the winding direction of each of the second helical elements of the second antenna section are opposite to each other. Device. Axial directions of the first helical elements and the second helical elements are perpendicular to the first surface of the ground plane on which the first helical elements and the second helical elements are provided. is formed in
2. The antenna device according to claim 1, wherein the winding direction of each of the first helical elements or the winding direction of each of the second helical elements is opposite to the direction of rotation of circularly polarized waves to be transmitted and received. . 3. The antenna device according to claim 1, wherein the first pitch angle of each first helical element is larger than the second pitch angle of each second helical element. 4. The antenna device according to claim 1, wherein said first pitch angle is 70 degrees or less. The electrical length of each of the first helical elements and each of the second helical elements is (1/4)×λ×n (where n is a positive integer), where λ is the wavelength of radio waves to be used. The antenna device according to any one of claims 1 to 4, characterized in that. 6. The antenna device according to claim 1, wherein the number of turns of each of said first helical elements is greater than the number of turns of each of said second helical elements. a divider combiner that divides or combines signals to each of the first helical elements or each of the second helical elements;
7. The antenna device according to any one of claims 1 to 6, further comprising: a termination load control section that controls a termination load connected to each of the second helical elements or each of the first helical elements. 8. The antenna device according to claim 1, wherein said ground plane is a circular flat plate. 9. The antenna device according to claim 1, wherein directions of maximum gain of each of said first helical elements and each of said second helical elements are different. 10. The antenna device according to claim 7, wherein the terminal load control section makes the value of the load variable.

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