Orthogonal circularly polarized antenna

Abstract

To realize high gain, beam scanning, and polarization plane control of linearly polarized waves by using an array antenna capable of achieving dual-use of orthogonal and circularly polarized waves in the quasi-millimeter wave band and above, as well as a linearly polarized wave array antenna realized by combining / distributing orthogonal circularly polarized waves.SOLUTION: An orthogonal circularly polarized antenna includes a plurality of composite right-handed and left-handed lines, and a right-handed line connecting the composite right-handed and left-handed lines. The composite right-handed and left-handed line is a metamaterial leaky wave antenna, and includes a plurality of unit cells connected in series to each other. The unit cells include a series capacitance and a parallel inductance. From among the composite right-handed and left-handed lines, the two composite right-handed and left-handed lines at the ends have a right-handed circularly polarized wave excitation portion to which power for right-handed circularly polarized wave radiation is input, and a left-handed circularly polarized wave excitation portion to which power for left-handed circularly polarized wave radiation is input.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a metamaterial antenna, and more particularly to an orthogonal circularly polarized antenna used in wireless power transmission systems, satellite communications, and mobile communications. [Background technology]

[0002] For devices that are difficult to constantly power via wires, such as mobile terminals and IoT (Internet of Things) sensor terminals, the application of wireless power transmission systems using high frequency bands over long distances of several meters or more is being considered. As of 2022, the allocation of a very high frequency of 24 GHz for wireless power transmission is being considered. At such high frequencies, loss due to spatial propagation increases, so to compensate for this, it is desirable to apply a phased array antenna system with high antenna gain and beam steering function to the antennas for the power transmission station. In order to maximize the power transmission efficiency in wireless power transmission, it is necessary to perfectly align the polarization planes of the antennas at the receiver (terminal) and the power transmitting station. If we assume that the installation conditions of the terminal (such as the direction seen from the power transmitting station and the installation angle of the terminal) are not constant, if the terminal and power transmitting station are circularly polarized antennas, the polarization planes can be aligned regardless of the installation conditions of the terminal. On the other hand, if the terminal and power transmitting station are linearly polarized antennas, and the polarization planes are orthogonal (for example, terminal: vertical polarization, power transmitting station: horizontal polarization), the power transmission efficiency will be 0%, resulting in a large loss in the system. Non-Patent Document 1 discusses an antenna system that controls the polarization plane of linearly polarized waves and aligns the polarization plane between transmission and reception. In this document, a patch antenna that can handle both right-handed and left-handed circularly polarized waves is used. By connecting a phase shifter to each circularly polarized port, and controlling and combining the amplitude constant and only the phase difference, the polarization plane of the linearly polarized wave can be changed. By providing the power transmission station with such a polarization plane control function, it is possible to maintain the efficiency of wireless power transmission at a maximum. Patent Document 1 shows a precedent example of circularly polarized antenna technology. Patent Document 1 describes a technology in which two excitation points are provided on each patch antenna, and circularly polarized waves are excited using a hybrid circuit. If power is fed from a resistively terminated port of the hybrid circuit, orthogonal circular polarization can be shared. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] Sano, Hashimoto, and Wada, "Cross-polarization reduction of Ku-band polarization-variable phased array," IEICE Technical Report AP2021-175, February 2022 [Patent Document 1] JP 2004-221965 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described in Non-Patent Document 1, in the case of controlling the plane of polarization of linearly polarized waves, a method using an orthogonal and circularly polarized antenna and controlling it only by the phase difference can keep the amplitude constant and has good power transmission efficiency. The conventional method for realizing an orthogonal circularly polarized antenna described in Non-Patent Document 1 and the like requires connection to a 90-degree hybrid circuit. If this configuration method is realized on, for example, a multilayer dielectric substrate, a layer for a power feed circuit including a hybrid circuit is required, resulting in complexity and high cost. The same problem occurs with configurations other than a multilayer substrate. In addition, since the structure of the power feed section including the hybrid circuit is large, this places a restriction on the determination of element spacing when configuring a circularly polarized phased array antenna system. Therefore, it is desirable to realize an antenna that can transmit orthogonal and circularly polarized waves without including a hybrid circuit and that is small in size. [Means for solving the problem]

[0005] The orthogonal circularly polarized antenna according to claim 1 of the present invention comprises: A plurality of composite right-handed / left-handed transmission lines; and a right-handed line connecting the composite right-handed and left-handed lines; Composite right-handed / left-handed transmission line: 1. A metamaterial leaky wave antenna, comprising: A plurality of unit cells connected in series with each other, The unit cell is A series capacitance connected in series in the composite right-handed / left-handed transmission line, and a parallel inductance connected in parallel to the composite right-handed / left-handed line; Among the composite right-handed / left-handed lines, the two composite right-handed / left-handed lines at the ends are further One of the composite right-handed and left-handed lines has a right-handed circularly polarized wave excitation section to which power for right-handed circularly polarized wave radiation is input at an end not connected to the right-handed line, The other composite right-handed / left-handed line is an orthogonal circularly polarized antenna, characterized in that it has a left-handed circularly polarized excitation section to which power for left-handed circularly polarized radiation is input at the end not connected to the right-handed line. An orthogonal circularly polarized antenna according to claim 2 of the present invention is the orthogonal circularly polarized antenna according to claim 1, characterized in that the composite right-handed / left-handed line has a straight portion and a bent portion that bends approximately 180 degrees. An orthogonal circularly polarized antenna according to claim 3 of the present invention is the orthogonal circularly polarized antenna according to claim 1, characterized in that the composite right-handed / left-handed line has a straight portion and a bent portion bent by an angle smaller than 180 degrees. The orthogonal circularly polarized antenna according to claim 4 of the present invention comprises: 2. The orthogonal circularly polarized antenna according to claim 1, comprising a lumped element connected to a series capacitance. The orthogonal circularly polarized antenna according to claim 5 of the present invention comprises: A phase shifter connected to at least one of a right-handed circularly polarized wave excitation unit and a left-handed circularly polarized wave excitation unit of the orthogonal circularly polarized antenna; and a synthesis distributor connected to the transfer device; 2. The orthogonal circularly polarized antenna according to claim 1, wherein the polarization plane is controlled by combining or dividing the right-handed circularly polarized wave and the left-handed circularly polarized wave in a combining / dividing device. The orthogonal circularly polarized antenna according to claim 6 of the present invention comprises: 6. An array antenna comprising a plurality of orthogonal circularly polarized antennas according to any one of claims 1 to 5. The orthogonal circularly polarized antenna according to claim 7 of the present invention comprises: 7. The array antenna according to claim 6, wherein the orthogonal circularly polarized antennas are arranged in a square. The orthogonal circularly polarized antenna according to claim 8 of the present invention comprises: 7. The array antenna according to claim 6, wherein the orthogonal circularly polarized antennas are arranged in a triangular pattern. The orthogonal circularly polarized antenna according to claim 9 of the present invention comprises: 7. The array antenna according to claim 6, wherein at least some of the orthogonal circularly polarized antennas are arranged in a substantially arc shape at different angles to one another to form a sequential array. With the above-mentioned configuration, the present invention, compared to the conventional technology, firstly, simplifies and reduces the cost of the power feed section by eliminating the need for a hybrid circuit, and secondly, the compact configuration including the power feed section makes it possible to realize complex array antenna configurations such as sequential arrays. Furthermore, the present invention, with the above-mentioned configuration, realizes a novel orthogonal / circularly polarized antenna that can achieve polarization plane control of linearly polarized waves at least equivalent to that of the conventional antenna. Other advantages of the present invention will be described in the detailed description of the invention. [Brief description of the drawings]

[0006] [Figure 1] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Diagram 2]1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Diagram 3] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 4] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Diagram 5] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 6] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 7] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 8] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 9] 4 shows S parameters in one embodiment of the present invention. [Figure 10] 4 illustrates the directivity of one embodiment of the present invention. [Figure 11] 4 illustrates the directivity of one embodiment of the present invention. [Figure 12] 1 shows an example of the configuration of an orthogonal circularly polarized array antenna in one embodiment of the present invention. [Figure 13] 1 shows an example of the configuration of an orthogonal circularly polarized array antenna in one embodiment of the present invention. [Figure 14] 1 shows an example of the configuration of an orthogonal circularly polarized array antenna in one embodiment of the present invention. [Figure 15] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 16] 1 shows an example of the configuration of an orthogonal circularly polarized antenna according to an embodiment of the present invention. [Figure 17] 4 shows the change in the polarization plane angle with respect to the excitation phase difference in one embodiment of the present invention. [Figure 18] 4 shows the change in maximum antenna gain with respect to the excitation phase difference in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] 1, 2 and 3 show an example of an orthogonal circularly polarized antenna 1 according to an embodiment of the present invention. The orthogonal circularly polarized antenna 1 utilizes the technology of a metamaterial leaky wave antenna using a composite right-handed and left-handed line 100 to which a series capacitance and a parallel inductance are added. Orthogonal circularly polarized antenna 1 includes a plurality of composite right-handed and left-handed lines 100, and a right-handed line 120 connecting composite right-handed and left-handed lines 100 together. Composite right-handed / left-handed transmission line 100 is a metamaterial leaky wave antenna, and includes a plurality of unit cells 101 connected in series with each other. The unit cell 101 includes a series capacitance 102 connected in series in the composite right-handed / left-handed line 100 , and a parallel inductance 104 connected in parallel to the composite right-handed / left-handed line 100 . Of the right-handed / left-handed composite line 100, the two right-handed / left-handed composite line 100 at the ends further have a right-handed circularly polarized excitation unit 150 to which power for right-handed circularly polarized radiation is input at the end not connected to the right-handed line 120, and the other right-handed / left-handed composite line 100 has a left-handed circularly polarized excitation unit 151 to which power for left-handed circularly polarized radiation is input at the end not connected to the right-handed line 120. This antenna can be realized in the 24 GHz band using only a multi-layer dielectric substrate with a very small number of layers, and does not require hybrid circuits, etc., and has a simple, low-cost structure that allows dual-polarization of orthogonal and circular polarization. In addition, since the structure, including the power feed section, is small, it is also suitable for use as an element in a phased array antenna with narrow element spacing, with the aim of improving beam scanning functionality.

[0008] Orthogonal circularly polarized antenna 1 in this embodiment is composed of multiple composite right-handed and left-handed lines 100. Composite right-handed and left-handed lines 100 are composed of multiple unit cells 101. Unit cells 101 have a series capacitance and a parallel inductance. Series capacitance 102 is composed of dielectric 140 sandwiched between two conductor surfaces 130 and 131. Parallel inductance 120 has an inductance line portion formed on two conductor surfaces 130, and is conductive with conductor surface 132 through conductor via 122. This inductance may be formed on conductor surface 131, or on both conductor surfaces 130 and 131.

[0009] In the orthogonal circularly polarized antenna 1 in this embodiment, composite right-handed and left-handed line 100 has straight portion 111 and bent portion 112 that bends by approximately 180 degrees. That is, composite right-handed and left-handed line 100 includes at least two straight portions 111 and one bent portion 112, and each is realized by arranging a plurality of unit cells 101. In this embodiment, for compact size, it is composed of three straight portions 111 and two bent portions 112, and the bent angle of each bent portion 112 is set to 180 degrees. Adjacent composite right-handed and left-handed transmission lines 100 are connected by right-handed transmission lines 120, which are connected by microstrip lines in Fig. 1. In this embodiment, for compactness, the number of composite right-handed and left-handed transmission lines 100 is set to two. High frequency excitation sources 150 and 151 are provided as right-handed circularly polarized wave excitation unit 150 and left-handed circularly polarized wave excitation unit 151 on both ends of orthogonal circularly polarized antenna 1100. In this embodiment, high frequency excitation source 150 radiates a right-handed circularly polarized wave, and high frequency excitation source 151 radiates a left-handed circularly polarized wave.

[0010] 4 and 5 show an example of the configuration of an orthogonal circularly polarized antenna 1 according to an embodiment of the present invention. In this embodiment, the orthogonal circularly polarized antenna 1 includes an additional capacitance 103 as a lumped element connected to a series capacitance 102. As in the orthogonal circularly polarized antenna 1 shown in Figures 4 and 5, the series capacitance 210 can be formed in the conductor in the same layer. In this embodiment, only a single gap is used, but the capacitance value may be increased by forming an interdigital capacitance structure. In this embodiment, the capacitance value of the series capacitance is smaller than that of the embodiment of Fig. 1, in which the area between the conductors can be increased. To compensate for this capacitance value, an additional capacitance 103 such as a chip capacitor may be added to the series capacitance 210 as a lumped constant element.

[0011] FIG. 6 shows an example of the configuration of an orthogonal circularly polarized antenna 1 according to an embodiment of the present invention. In the orthogonal circularly polarized antenna 1 in this embodiment, composite right-handed and left-handed line 100 has straight section 111 and bent section 112 that bends at an angle smaller than 180 degrees. That is, bent section 112 may be less than 180 degrees as in orthogonal circularly polarized antenna 1 shown in Fig. 6. In this embodiment, it is set to 90 degrees. As in the orthogonal circularly polarized antenna 1 shown in FIG. 7, three or more composite right-handed and left-handed lines 100 may be provided, and adjacent composite right-handed and left-handed lines 100 may be connected by right-handed line 120.

[0012] FIG. 8 shows an equivalent circuit 500 of the orthogonal circularly polarized antenna 1. The equivalent circuit 500 includes a composite right-handed and left-handed line 100 including series inductance 510 and parallel capacitance 520 as right-handed lumped elements, and series capacitance 530 and parallel inductance 540 as left-handed lumped elements, with a connection section between them using right-handed line 550, and high-frequency excitation sources 560 installed at both ends. In this figure, one right-handed line 550 is shown sandwiched between two units of composite right-handed and left-handed line 100 on each side, but it goes without saying that the number of units varies depending on the configuration. The principles of the orthogonal circularly polarized antenna 1 shown in FIG. 1 to FIG. 7 can all be expressed by the equivalent circuit in FIG. 8.

[0013] Fig. 9 shows the S parameters in the embodiment shown in Fig. 1 to Fig. 3. At 24.5 GHz, the reflection coefficient S11 corresponding to the high frequency excitation source 150 and the reflection coefficient S22 corresponding to the excitation source 151 show good performance of -10 dB or less. Also, the transmission characteristic S21 between the high frequency excitation sources 150 and 151 shows -20 dB or less at 24.5 GHz, which shows that the electrical characteristics are sufficient for an orthogonal circularly polarized antenna.

[0014] Figures 10 and 11 show the directivities in the embodiments shown in Figures 1 to 3. The directivities corresponding to the high frequency excitation source 150 and the directivities corresponding to the high frequency excitation source 151 realize right-handed circularly polarized waves and left-handed circularly polarized waves, respectively, and have the same shape, so that the performance desired for an orthogonal circularly polarized antenna is obtained.

[0015] FIG. 12 shows an array antenna 10 in one embodiment of the present invention. The array antenna 10 in this embodiment includes a plurality of any of the above-mentioned orthogonal circularly polarized antennas 1. It may also include a plurality of orthogonal circularly polarized antennas 1, which will be described later. In particular, in this embodiment, the orthogonal circularly polarized antenna 1 is arranged in a square. More specifically, in this embodiment, the orthogonal circularly polarized antenna 1 shown in Figures 1 to 3 are arranged in a square. For example, by arranging the antenna elements at intervals of 0.6 wavelengths or less, an orthogonal circularly polarized array antenna 10 with high antenna gain and a wide beam scanning angle can be realized.

[0016] FIG. 13 shows an array antenna 10 in one embodiment of the present invention. In the array antenna 10 of this embodiment, the orthogonal circularly polarized antennas 1 are arranged in a triangular arrangement. It goes without saying that the arrangement method is not limited to a square arrangement, and various arrangement methods such as a triangular arrangement and a circular arrangement can be applied.

[0017] FIG. 14 shows an array antenna 10 in one embodiment of the present invention. In the array antenna 10 of this embodiment, at least some of the orthogonal circularly polarized antennas 1 are arranged in an approximately arc shape at different angles to one another to form a sequential array. In the claims and the specification, the term "approximately arc shape" includes cases where at least some of the orthogonal circularly polarized antennas 1 are arranged in an approximately arc shape at different angles to one another in a square arrangement as shown in Fig. 14, and cases where they are similarly arranged in a triangular arrangement. In other words, "approximately arc shape" also includes cases where they are arranged in an "approximate circle". A sequential array is a configuration that can optimize the axial ratio performance by rotating the structure and adjusting the phase of each excitation source depending on the position of the antenna elements. In the example shown in this figure, a sequential array with a square arrangement is shown, but it goes without saying that sequential arrays can also be configured in the same way with other arrangement methods such as a triangular arrangement or a circular arrangement.

[0018] In order to improve the degree of freedom in designing array antenna 10 of FIGS. 12 to 14, it is desirable that the antenna element structure including the feeding portion is small in size. In particular, the sequential array in Figure 14 involves element structure rotation, that is, a configuration in which the elements are arranged in different directions from each other, and therefore needs to be particularly small, including the power feed section. However, the antenna of this embodiment does not require a power feed circuit including a hybrid circuit and can provide dual-polarized and orthogonal circular polarization, so that a dual-polarized sequential array can be constructed with a simpler configuration than conventional dual-polarized antennas.

[0019] 15 and 16 show the configuration of an orthogonal circularly polarized antenna in one embodiment of the present invention. The orthogonal circularly polarized antenna 1 in this embodiment has a phase shifter 201 connected to at least one of the right-handed circularly polarized excitation unit 150 and the left-handed circularly polarized excitation unit 151 of the orthogonal circularly polarized antenna 1, and a combining / distributing unit 202 connected to the phase shifter 201. Then, in combiner / distributor 202, the right-handed circularly polarized wave and the left-handed circularly polarized wave are combined or distributed to control the polarization plane. With this configuration, the orthogonal and circularly polarized antenna can function as a linearly polarized antenna. At the same time, it can also function as a circularly polarized antenna. Of course, it may be configured so that it can be switched between the two. In this embodiment, as shown in Figures 1 to 8, a phase shifter 201 is provided in one or both of the excitation sources of the orthogonal circularly polarized antenna 1, enabling phase adjustment. Also, a right-handed circularly polarized excitation unit and a left-handed circularly polarized excitation unit are connected by a combining distributor 202, and the circularly polarized waves are combined to perform linearly polarized radiation. Also, the angle of the polarization plane of the linearly polarized wave can be freely set by adjusting the phase of the phase shifter. Also, a variable attenuator 203 or the like may be provided for amplitude adjustment. The orthogonal circularly polarized antenna 1 shown in this figure as a linearly polarized antenna can be realized not only as a single antenna element but also as an array antenna 10. The array antenna 10 can be arranged in the same manner as shown in Figs. 12 to 14. It goes without saying that the phase shifter 201, the shifter 202, and the variable attenuator 203 are also used for beam scanning in the array antenna 10. In this manner, the array antenna 10 can be configured to include a plurality of orthogonal circularly polarized antennas 1. In this configuration, the orthogonal circularly polarized antennas 1 can be arranged in a square or triangular arrangement. Alternatively, in this configuration, at least some of the orthogonal circularly polarized antennas 1 can be arranged in a substantially arc shape at different angles to each other to form a sequential array.

[0020] Figure 17 shows the characteristics of the polarization plane angle versus the phase difference between the excitation sources in the orthogonal circularly polarized antenna 1 serving as the linearly polarized antenna shown in Figures 15 and 16. The polarization plane angle can be changed from 0 degrees to 180 degrees each time the phase difference is changed from 0 degrees to 360 degrees. From the principles of the polarization plane of linear polarization, it can be seen that any polarization plane angle can be accommodated, since polarizations with a difference of 180 degrees, for example 0 degrees and 180 degrees, can be regarded as the same.

[0021] Fig. 18 shows the antenna gain characteristics versus the phase difference between the excitation sources in the orthogonal circularly polarized antenna 1 as a linearly polarized antenna shown in Fig. 15 and Fig. 16. Even when the phase difference is changed from 0 degrees to 360 degrees, an almost constant antenna gain of 6 dBi is obtained, and it is clear that the rotation of the polarization plane has almost no effect on the antenna gain. In other words, there is no decrease in power transmission efficiency due to the rotation of the polarization plane.

[0022] With the above configuration, firstly, the power feed section can be simplified and reduced in cost by eliminating the need for a hybrid circuit, and secondly, the compact configuration including the power feed section makes it possible to realize complex array antenna configurations such as sequential arrays. Furthermore, the above configuration realizes a novel orthogonal and circularly polarized antenna that can achieve polarization plane control of linearly polarized waves at least equivalent to that of the conventional antenna. The present invention is not limited to the above-described embodiments, and may of course be embodied in various other forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0023] 1 Orthogonal circularly polarized antenna 10 Array Antenna 100 Composite right-handed / left-handed line 101 unit cell 102 Series Capacitance 103 Added Capacitance 104 Parallel Inductance 105 Parallel inductance line section 111 Straight section 112 Refraction 120 Right-handed track 130 Conductor surface 1 131 Conductor surface 2 132 Conductor surface 3 (ground) 133 Conductive via 140 Dielectric 150 Right-handed circularly polarized wave excitation section 151 Left-handed circularly polarized excitation section 201 Phase shifter 202 Synthetic distributor 203 Variable Attenuator 500 Equivalent circuit of orthogonal circularly polarized antenna 510 Series Inductance 520 Parallel Capacitance 530 Series Capacitance 540 Parallel Inductance 550 Right-hand track connection 560 High Frequency Excitation Source

Claims

1. An orthogonal circularly polarized antenna, A plurality of composite right-handed / left-handed transmission lines; and a right-handed line connecting the composite right-handed and left-handed lines, The composite right-handed / left-handed transmission line is 1. A metamaterial leaky wave antenna, comprising: A plurality of unit cells connected in series with each other, The unit cell comprises: a series capacitance connected in series in the composite right-handed / left-handed transmission line; and a parallel inductance connected in parallel to the composite right-handed / left-handed line; Among the composite right-handed and left-handed lines, two composite right-handed and left-handed lines at the ends are further one of the composite right-handed and left-handed lines has a right-handed circularly polarized wave excitation section to which power for right-handed circularly polarized wave radiation is input at an end portion not connected to the right-handed line, the other composite right-handed / left-handed line has a left-handed circularly polarized excitation section to which power for left-handed circularly polarized radiation is input at an end not connected to the right-handed line.

2. 2. The orthogonal and circularly polarized antenna according to claim 1, wherein the composite right-handed and left-handed line has a straight portion and a bent portion that is bent by approximately 180 degrees.

3. 2. The orthogonal circularly polarized antenna according to claim 1, wherein the composite right-handed / left-handed line has a straight portion and a bent portion bent at an angle smaller than 180 degrees.

4. 2. The orthogonal circularly polarized antenna of claim 1, further comprising a lumped element connected to said series capacitance.

5. A phase shifter connected to at least one of the right-handed circularly polarized wave excitation unit and the left-handed circularly polarized wave excitation unit of the orthogonal circularly polarized antenna; and a synthesis distributor connected to the transporter, 2. The orthogonal circularly polarized antenna according to claim 1, wherein the combiner / distributor combines or distributes right-handed circularly polarized waves and left-handed circularly polarized waves to control the plane of polarization.

6. 6. An array antenna comprising a plurality of orthogonal circularly polarized antennas according to claim 1.

7. 7. The array antenna according to claim 6, wherein the orthogonal circularly polarized antennas are arranged in a square.

8. 7. The array antenna according to claim 6, wherein the orthogonal circularly polarized antennas are arranged in a triangular array.

9. 7. The array antenna according to claim 6, wherein at least some of the orthogonal circularly polarized antennas are arranged in a substantially arc shape at different angles to one another to form a sequential array.

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