Antenna device and communication system

Abstract

To provide an antenna device capable of improving area quality by obtaining a good CN ratio with a high-gain antenna.SOLUTION: An antenna device includes a leaky wave antenna, a high frequency unit, and a control unit. The leaky wave antenna has a row of elements. The row of elements has a plurality of unit elements arranged in series. Each of the unit elements has a capacitance portion and an inductance portion, and either one of the capacitance portion and the inductance portion is arranged in series with another adjacent unit element. The control unit uses a beam squint of the leaky wave antenna to transmit radio waves in different directions for each of two or more different frequencies.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an antenna device using a leaky wave antenna, and a communication system having the antenna device. [Background technology]

[0002] An example of beamforming is described in Patent Document 1. In beamforming, multiple wireless devices, variable phase shifters, and variable attenuators are connected to multiple antenna elements, and a high-gain beam is directed toward a terminal. It has good frequency efficiency because it obtains beams in the same direction across the frequency band. In addition, the high gain improves the carrier-to-noise ratio and provides good area quality. When using signals such as 28 GHz, there is a configuration in which a single radio uses only a phase shifter to perform beamforming. In this configuration, a beam ID is set and the beam is switched for each terminal on the time axis. Furthermore, as described in Patent Document 2, leaky wave antennas can also be used in communications. On the other hand, Patent Document 3 describes an electromagnetic wave irradiation device that uses an antenna reflector to squint a beam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-16077 [Patent Document 2] Patent No. 6345325 [Patent Document 3] Patent No. 3700005 Summary of the Invention [Problem to be solved by the invention]

[0004] In the structure described in Patent Document 1, the device configuration for beamforming becomes complicated, resulting in high costs. In addition, in leaky wave antennas, the beam direction changes depending on the frequency, which is called beam squint. A characteristic of leaky wave antennas is that as the frequency changes, the direction of maximum directivity changes due to beam squint. Suppression of this beam squint is also being considered. In particular, when a left-handed transmission line made of metamaterial is used, the effect of beam squint is remarkable. Patent Document 3 is based on the premise of circular polarization, which is difficult to achieve with linear polarization (reference 0041 of Patent Document 3), but even in the case of circular polarization, in order to change the amount of squint, adjustments must be made to the sub-reflector or multiple mirror surfaces (see paragraph 0045 of Patent Document 3), which makes the device configuration complicated and increases the cost. Therefore, an object of the present invention is to provide an antenna device capable of improving area quality by obtaining a good C / N ratio with a high gain antenna, and a base station system having the antenna device. Another object of the present invention is to provide an antenna device that achieves good time efficiency by deflecting a beam on the frequency axis, and a base station system having the antenna device. It is yet another object of the present invention to provide an antenna device and a base station system having the antenna device, which are capable of carrying out communications without reducing frequency efficiency even when terminals are distributed over a wide area. [Means for solving the problem]

[0005] In the present invention, a different viewpoint is taken from the conventional one, and the characteristic of being affected by beam squint is utilized to utilize the beam squint phenomenon due to the frequency of the leaky wave antenna for beamforming. In one example, a reference signal for monitoring the received power at a terminal is placed within the frequency band in use, and frequencies are assigned to the terminal based on the measured value. The antenna device according to claim 1 of the present invention comprises: The device has a leaky wave antenna, a high frequency section, and a control section. The leaky wave antenna has an array of elements, The element array is A plurality of unit elements arranged in series, Each unit element has a capacitance portion and an inductance portion, and either one of the capacitance portion or the inductance portion is arranged in series with another adjacent unit element; The control unit is connected to the high frequency unit and controls the directionality of the radio waves. The high frequency output section of the high frequency section is connected to the leaky wave antenna, The control unit is an antenna device characterized in that it utilizes beam squint of a leaky wave antenna to transmit radio waves in different directions for two or more different frequencies. The antenna device according to claim 2 of the present invention comprises: The antenna device according to claim 1, characterized in that the angle over which the transmission range of radio waves from the antenna device is viewed is 60 degrees or more due to the beam squint of the leaky wave antenna. The antenna device according to claim 3 of the present invention comprises: 3. The antenna device according to claim 1, wherein the leaky wave antenna is a left-handed leaky wave antenna having a metamaterial. The antenna device according to claim 4 of the present invention comprises: 4. The antenna device according to claim 1, further comprising two feeding points independent of each other, at both ends of the element array. The antenna device according to claim 5 of the present invention comprises: 5. The antenna device according to claim 1, wherein the leaky wave antenna is a dual-polarized antenna having two element rows and capable of handling two mutually orthogonal polarized waves. The antenna device according to claim 6 of the present invention comprises: The plurality of element rows are arranged in a direction substantially perpendicular to the direction of the beam squint to form an array. The antenna device described in any one of claims 1 to 5, characterized in that the control unit controls the beam squint and the multiple element arrays to transmit radio waves in the direction of the beam squint and in a direction approximately perpendicular to the beam squint. The antenna device according to claim 7 of the present invention comprises: The antenna device has a communication unit that transmits and receives communication signals to and from a communication terminal, The antenna device according to any one of claims 1 to 5, wherein the control unit transmits communication signals in different directions for two or more different frequencies by utilizing a beam squint of the leaky wave antenna. The antenna device according to claim 8 of the present invention comprises: having a reference signal in the communication signal; the reference signal includes monitor signals corresponding to two or more different frequencies; The antenna device according to claim 7, wherein the control unit controls the directivity of the communication signal by utilizing the monitor signal. The antenna device according to claim 9 of the present invention comprises: The communication terminal is a mobile terminal, 9. The antenna device according to claim 8, wherein the reference signal is placed in a demodulation reference symbol in a synchronization broadcast signal used in communication with a mobile terminal. The antenna device according to claim 10 of the present invention comprises: The communication terminal is a mobile terminal, The synchronization notification signal used for communication with mobile terminals is composed of a different frequency for each beam ID. The control unit assigns one mobile terminal to one of two or more beam IDs, The antenna device according to claim 8, wherein the reference signal is placed in a synchronization broadcast signal used in communication with a mobile terminal. The antenna device according to claim 11 of the present invention comprises: The communication terminal is a mobile terminal, The synchronization notification signal used for communication with mobile terminals is time-divided for each beam ID, The control unit assigns one mobile terminal to one of two or more beam IDs, The antenna device according to claim 8, wherein the reference signal is placed in a synchronization broadcast signal used in communication with a mobile terminal. A communication system according to claim 12 of the present invention comprises: A communication system comprising an antenna device according to any one of claims 7 to 11. With this configuration, the beam squint can be easily adjusted simply by changing the frequency without complicating the device configuration. In communications, firstly, a good C / N ratio can be obtained due to high antenna gain, which improves area quality. Secondly, by shifting the beam on the frequency axis, time efficiency is improved. Thirdly, when terminals are widely distributed, the terminals can grasp the entire frequency band, so frequency efficiency is not reduced. [Brief description of the drawings]

[0006] [Figure 1] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Diagram 2] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Diagram 3] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 4] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Diagram 5] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 6] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 7] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 8] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 9]1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 10] 1 shows an example of the configuration of an antenna device according to an embodiment of the present invention. [Figure 11] 2 shows an example of the configuration of a communication signal in an embodiment of the present invention. [Figure 12] 2 shows an example of the configuration of a communication signal in an embodiment of the present invention. [Figure 13] 2 shows an example of the configuration of a communication signal in an embodiment of the present invention. [Figure 14] 1 illustrates an example of the configuration of a communication system according to an embodiment of the present invention. [Figure 15] 1 illustrates an example of the configuration of a communication system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] FIG. 1 shows an example of the configuration of an antenna device 100 according to an embodiment of the present invention. As shown in FIG. 1, the antenna device 100 includes a leaky wave antenna 101, a high frequency section 150, and a control section 160. The high frequency unit 150 has a high frequency output unit 151. The high frequency output unit 151 is connected to the leaky wave antenna 101. The control unit 160 is connected to the high frequency unit 150 and controls the directivity of the radio waves.

[0008] As shown in FIG. 2, the leaky wave antenna 101 has an array of elements 110 . The element array 110 has a plurality of unit elements 111, 112, and 113 arranged in series. Although three unit elements are shown in Fig. 2, as will be easily understood by those skilled in the art, the number of unit elements included in the element array 110 may be other than three, and may be several tens to several hundreds. 3, the unit element 111 has a capacitance portion 111C and an inductance portion 111L. Either the capacitance portion 111C or the inductance portion 111L is disposed in series with another unit element 112 adjacent thereto.

[0009] As shown in FIG. 4, the control unit 160 uses the beam squint of the leaky wave antenna 101 to transmit radio waves in different directions for two or more different frequencies. Specifically, radio waves are transmitted in different directions corresponding to frequencies f1, f2, f3, f4, and f5.

[0010] FIG. 5 shows an example of the configuration of an antenna device 100 according to an embodiment of the present invention. Due to the beam squint of leaky wave antenna 101, the viewing angle of the transmission range of radio waves from antenna device 100 is 60 degrees or more. Specifically, the angle between the transmission direction or reception direction of the radio wave corresponding to frequency f1 and the transmission direction or reception direction of the radio wave corresponding to frequency fn is 60 degrees or more.

[0011] In one embodiment, leaky-wave antenna 101 is a left-handed leaky-wave antenna having metamaterial 103 . By using metamaterials, it is possible to widen the angular range of beam squint when the frequency band is kept constant.

[0012] 6 and 7 show an example of the configuration of an antenna device 100 according to an embodiment of the present invention. The antenna device 100 has two mutually independent power feeding sections 118, 119 at both ends of the element arrays 110, 120, 130, and 140. In this embodiment, the antenna device 100 has a communication section 170, and the control section 160 is provided within the communication section 170. Furthermore, the leaky wave antenna is disposed on the XY plane, and the element arrays 110, 120, 130, and 140 are aligned in the X direction. Specifically, high frequency section 150 has two high frequency output sections 151 and 152, which are connected to two power feed sections 118 and 119 provided at both ends of element arrays 110, 120, 130 and 140 of leaky wave antenna 101, respectively.

[0013] When power is fed from Input 1 of power feeding section 118, a beam squint occurs from the negative z-axis direction, i.e., the -z-axis direction, to the negative x-axis direction, i.e., the -x-axis direction, as the frequency goes from high to low. When power is fed from Input 2 of power feeding section 119, a beam squint occurs from the negative z-axis direction, i.e., the -z-axis direction, to the positive x-axis direction, i.e., the +x-axis direction, as the frequency goes from high to low. In this way, by setting antenna power feed points in both directions, radio waves can be transmitted to both the left and right sides of the front direction of the antenna. For example, when used for communication, both the left and right sides of the front direction of the antenna can be made into coverage areas.

[0014] FIG. 8 shows an example of the configuration of a leaky wave antenna 101 in an antenna device 100 according to an embodiment of the present invention. In this embodiment, two element arrays 110 and 120 are formed on a substrate 104 and connected to a hybrid circuit section 105. By using a hybrid circuit or the like, it becomes possible to share polarization. By using two orthogonal polarizations, for example, when used for communication, the number of lines can be doubled.

[0015] FIG. 9 shows an example of the configuration of a leaky wave antenna 101 in an antenna device 100 according to an embodiment of the present invention. The leaky wave antenna 101 includes multiple element arrays 110, 120, and 130. A plurality of element rows 110, 120, 130 are arranged in a direction substantially perpendicular to the direction of the beam squint to form an array 102.

[0016] The control unit 160 controls the beam squint and the multiple element arrays 110, 120, and 130 to transmit radio waves in the direction of the beam squint and in a direction substantially perpendicular to the beam squint. In this embodiment, the antennas are arrayed in a direction perpendicular to the beam squint of the leaky wave antenna 101, and beam control in the perpendicular direction is also possible. Furthermore, when used for communication, for example, the antenna gain is improved.

[0017] FIG. 10 shows an example of the configuration of an antenna device 100 according to an embodiment of the present invention. In this embodiment, the antenna device 100 includes a communication unit 170 that transmits and receives communication signals to and from a communication terminal 9 such as a mobile terminal. The control unit 160 utilizes the beam squint of the leaky wave antenna 101 to transmit communication signals in different directions for two or more different frequencies.

[0018] With reference to FIG. 4, an example of beam squint at five different frequencies f1 to f5 will be considered. If reference signals that correspond to f1 to f5 and allow the terminal's downlink reception power to be measured are placed, for example, a terminal in an area corresponding to f1 will have a high level at frequencies near f1 and will be weak at f2 to f5. By using this value to assign frequencies, it is possible to select the optimal beam for the terminal. As will be readily understood by those skilled in the art, any number of frequencies may be actually used, and a configuration in which appropriate frequencies are individually selected from continuously changing frequencies may also be used.

[0019] In one embodiment, the antenna device 100 includes a reference signal within the communication signal, and the reference signal includes monitor signals corresponding to two or more different frequencies. Then, the control unit 160 uses the monitor signal to control the directivity of the communication signal.

[0020] FIG. 11 shows an example of the configuration of a communication signal in one embodiment of the present invention. The area enclosed by the dashed rectangle is the basic structure of the SS / PBCH, which is 240 SCS. Also, only the demodulation reference symbols, that is, the DMRS blocks, are allocated across the entire frequency band. In other words, all frequencies are used. The communication terminal 9 is a mobile terminal. The reference signal is placed in a demodulation reference symbol in a synchronization broadcast signal used in communication with the mobile terminal. In this manner, the demodulation reference symbol in the synchronization notification signal used in communication with the mobile terminal includes a reference signal.

[0021] In this embodiment, the SS / PBCH used in a mobile phone system, that is, a DMRS block arranged in a synchronization / broadcast signal, is used as a reference signal. In other words, the DMRS block is configured to include a reference signal. SS / PBCH is a downlink signal block used in 5G for synchronization / notification between terminals and base stations.

[0022] Since it is made up of 240 subcarriers (hereafter sometimes abbreviated as SC), the bandwidth changes depending on the subcarrier spacing. For example, if the subcarrier spacing is 15 kHz, then 240SC = 15 kHz x 240 = 3.6 MHz, if the subcarrier spacing is 30 kHz, then 240SC = 30 x 240 = 7.2 MHz, and if the subcarrier spacing is 240 kHz, then 240SC = 240 x 240 = 57.6 MHz. However, conventional SS / PBCH has 240 SCs and only uses a portion of the available frequency band. For example, in the case of the Sub6 band, the maximum bandwidth of the SS / PBCH is usually 7.2 MHz within the 100 MHz utilization band, but in this embodiment, the 100 MHz utilization band is allocated only in the DMRS block, i.e., the 100 MHz portion of the utilization band is used only in the DMRS block.

[0023] FIG. 12 shows an example of the structure of a communication signal in one embodiment of the present invention. In this embodiment, the allocation is not limited to DMRS blocks, and SSB blocks that were previously set on the time axis are allocated on the frequency axis. Specifically, on the right side of the figure, the SSB block of beam ID1 (ID1SSB) and the SSB block of beam ID2 (ID2SSB) are arranged in that order along the frequency axis (vertical axis). Then, in each beam, synchronous power measurement is performed by SS / PBCH. The communication terminal 9 is a mobile terminal.

[0024] The synchronization notification signal used in communication with mobile terminals is composed of a different frequency for each beam ID. The control unit 160 assigns one mobile terminal to one of two or more beam IDs. The reference signal is placed in a synchronization broadcast signal used in communication with a mobile terminal. Then, ID1SSB, the SSB block of beam ID1, and ID2SSB, the SSB block of beam ID2, are transmitted at the same time at frequencies that match their respective transmission directions. With this configuration, allocation to terminals can be performed according to conventional beam selection rules simply by changing the conventional time-axis allocation to the frequency axis.

[0025] FIG. 13 shows an example of the configuration of a communication signal in one embodiment of the present invention. In this embodiment, in the SS / PBCH, SSB blocks are transmitted on the time axis for each beam ID. That is, the beamforming conditions are switched for each time, and a beam ID is assigned to each terminal. The communication terminal 9 is a mobile terminal.

[0026] The synchronization notification signal used in communication with mobile terminals is time-divided for each beam ID. The control unit 160 assigns one mobile terminal to one of two or more beam IDs. The reference signal is placed in a synchronization broadcast signal used in communication with a mobile terminal. Then, ID1SSB, the SSB block of beam ID1, and ID2SSB, the SSB block of beam ID2, are transmitted at different times and at frequencies that match their respective transmission directions.

[0027] FIG. 14 shows an example of the configuration of a base station system, which is a communication system 2 in an embodiment of the present invention. The communication system 2 includes any one of the antenna devices 100 described above.

[0028] In this embodiment, a TDD system is used, and the frequency bands for transmission and reception are the same. If the frequency bands for transmission and reception are the same, a full-duplex communication system or the like is also possible. Moreover, the communication signals use multi-carrier modulated signals such as OFDM.

[0029] FIG. 15 shows another example of the configuration of the communication system 2 in an embodiment of the present invention. The above-described communication system 2 is configured to be an efficient communication system 2 even in a situation where terminals are evenly placed in a wide-angle area, such as a stadium or a train station platform in Tokyo. As shown in FIG. 15, the communication area may be further expanded by using a reflectarray 201 or the like.

[0030] According to the above configuration, firstly, a good C / N ratio can be obtained by high antenna gain, so that the quality of the area can be improved. Secondly, when the beam is swung on the frequency axis, the time efficiency is good. Thirdly, when terminals are widely distributed, the terminals can grasp the entire frequency band, so the frequency efficiency is not reduced.

[0031] It goes without saying that the present invention is not limited to the above-mentioned embodiments, and includes various embodiments within the scope of the present invention. For example, the communication system includes not only a base station system but also a mobile communication system installed in a mobile object. The targets to which the communication system transmits or receives radio waves for communication are not limited to communication terminals, and may include other base stations and the like. [Explanation of symbols]

[0032] 100 Antenna device 101 Leaky Wave Antenna 102 Alley 103 Metamaterials 104 Substrate 105 Hybrid circuit section 110,120,130,140 Element row 2 111,112,113 unit element 111C Capacitance section 111L Inductance section 111G Ground 118,119 Power supply unit 150 High Frequency Section 151,152 High frequency output section 160 Control section 170 Communications Department 2. Communication Systems 201 Reflect Array 9. Communication terminals

Claims

1. The device has a leaky wave antenna, a high frequency section, and a control section. the leaky wave antenna has an array of elements; The element array is A plurality of unit elements arranged in series, the unit element has a capacitance portion and an inductance portion, and either the capacitance portion or the inductance portion is disposed in series with another adjacent unit element; The control unit is connected to the high frequency unit and controls the directivity of radio waves; a high-frequency output section of the high-frequency section is connected to the leaky wave antenna, The antenna device is characterized in that the control unit utilizes a beam squint of the leaky wave antenna to transmit radio waves in different directions for two or more different frequencies.

2. 2. The antenna device according to claim 1, wherein the angle over which the transmission range of radio waves from said antenna device is viewed due to the beam squint of said leaky wave antenna is 60 degrees or more.

3. 3. The antenna device according to claim 1, wherein the leaky wave antenna is a left-handed leaky wave antenna having a metamaterial.

4. 4. The antenna device according to claim 1, further comprising two mutually independent feeding sections at both ends of said element array.

5. 5. The antenna device according to claim 1, wherein the leaky wave antenna is a dual-polarized antenna having two of the element rows and capable of handling two mutually orthogonal polarized waves.

6. the plurality of element rows are arranged in a direction substantially perpendicular to the direction of the beam squint to form an array; 6. The antenna device according to claim 1, wherein the control unit controls a beam squint and the plurality of element rows to transmit radio waves in a direction of the beam squint and in a direction substantially perpendicular to the beam squint.

7. the antenna device has a communication unit for transmitting and receiving communication signals to and from a communication terminal; 6. The antenna device according to claim 1, wherein the control unit transmits communication signals in different directions for two or more different frequencies by utilizing a beam squint of the leaky wave antenna.

8. having a reference signal within the communication signal; the reference signal includes monitor signals corresponding to two or more different frequencies; 8. The antenna device according to claim 7, wherein the control unit controls a directivity of the communication signal by utilizing the monitor signal.

9. the communication terminal is a mobile terminal, 9. The antenna device according to claim 8, wherein the reference signal is arranged in a demodulation reference symbol in a synchronization broadcast signal used in communication with the mobile terminal.

10. the communication terminal is a mobile terminal, A synchronization report signal used in communication with a mobile terminal is composed of a different frequency for each beam ID, The control unit assigns one mobile terminal to one of two or more beam IDs, 9. The antenna device according to claim 8, wherein the reference signal is arranged in the synchronization notification signal used in communication with a mobile terminal.

11. the communication terminal is a mobile terminal, A synchronization notification signal used in communication with a mobile terminal is time-divided for each beam ID, The control unit assigns one mobile terminal to one of two or more beam IDs, 9. The antenna device according to claim 8, wherein the reference signal is arranged in the synchronization notification signal used in communication with a mobile terminal.

12. A communication system comprising an antenna device according to any one of claims 7 to 11.

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