Communication antenna and radio communication device

Abstract

The present invention is provided with a plurality of basic units (110) each serving as a digital beam forming element array for performing communication in a prescribed frequency band and respectively handling a plurality of prescribed frequency bands that differ from each other at least in part of the frequency bands, the plurality of basic units (110) covering a wider frequency band than each of the plurality of prescribed frequency bands.

Description

Communication antenna and wireless communication device

[0001] TECHNICAL FIELD The technology described herein relates to communication antennas and wireless communication devices.

[0002] Regarding the coverage of mobile phone operators in each country, the population coverage rate may be high but the area coverage rate may be low.

[0003] For example, the coverage of mobile phone operators in Japan varies depending on the operator and frequency, but the population coverage rate is a maximum of approximately 99%, while the area coverage rate is a maximum of approximately 70%, meaning that at least 30% of the country's land area is uncovered.

[0004] Space Cellular Study Task Group, "Document 43-1, Space Cellular Study Task Group Report," Ministry of Internal Affairs and Communications, Information and Communications Council, February 3, 2021. Suematsu, Noriharu, Furuichi, Tomoyuki, and Tsukamoto, Satoshi, "Basic Study on the Configuration of a Satellite-Mounted Q / V-Band Direct Digital RF DBF Transceiver," Institute of Electronics, Information and Communication Engineers, IEICE Technical Report, July 2023.

[0005] However, when a natural disaster occurs or an event is held, a large number of users may gather in areas where mobile phone communications are not covered or where communication capacity is low, and stable communications may not be possible.

[0006] In one aspect, the technology described herein aims to provide a wireless communication device with wide area coverage.

[0007] In one aspect, a communication antenna includes a plurality of basic units, each of which corresponds to a plurality of predetermined frequency bands, at least some of which are different from each other, and each of which covers a frequency band wider than each of the plurality of predetermined frequency bands, and each of which has a digital beamforming element array as a basic unit for communication in the predetermined frequency band.

[0008] As one aspect, a wireless communication device that covers a wide area can be provided.

[0009] 11 is a block diagram schematically showing an example of the configuration of a wireless communication device in a first embodiment. FIG. 12 is a diagram showing an example of the configuration of a surface-divided DBF (Digital Beam Forming) antenna in the first embodiment. FIG. 13 is a table illustrating frequency allocation in the 8-antenna configuration shown in FIG. 2. FIG. 14 is a block diagram schematically showing an example of the configuration of a DSP (Digital Signal Processing) unit of the transmission system shown in FIG. 1. FIG. 15 is a diagram schematically showing an example of the configuration of an antenna module of the transmission system shown in FIG. 1. FIG. 16 is a diagram illustrating an example of the configuration of a one-surface 2048-element DBF antenna in a conventional example. FIG. 17 is a block diagram schematically showing an example of the configuration of an antenna module of the reception system shown in FIG. 1. FIG. 18 is a block diagram schematically showing an example of the configuration of a DSP unit of the reception system shown in FIG. 1. FIG. 19 is a diagram schematically showing an example of the arrangement of antenna elements in the antenna module shown in FIG. 1. FIG. 19 is a block diagram illustrating an example of the arrangement of basic units in a 5-antenna configuration in an embodiment. FIG. 10 is a table illustrating frequency allocation in the 5-antenna configuration shown in FIG. 11. FIG. 12 is a diagram schematically showing an example of beam coverage corresponding to the frequency allocation shown in FIG. 11. FIG. 13 is a diagram schematically showing an example of the configuration of an antenna module of the transmission system in a conventional example. Fig. 10 is a diagram showing a configuration example of a surface-divided DBF antenna in a second embodiment. Fig. 11 is a diagram showing a configuration example of an antenna module of a transmitting system in the second embodiment. Fig. 12 is a diagram showing a first example of arrangement of a DBF antenna on a satellite body in a third embodiment. Fig. 13 is a diagram showing a second example of arrangement of a DBF antenna on a satellite body in a third embodiment. Fig. 14 is a diagram showing a schematic arrangement example of a DSP unit on a satellite body in a third embodiment.

[0010] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments described below are merely examples, and are not intended to exclude various modifications and applications of techniques not explicitly stated in the embodiments. In other words, the present embodiments can be implemented with various modifications within the scope of the spirit thereof.

[0011] Furthermore, each drawing does not necessarily include only the components shown in the drawing, but may include other components. In the drawings below, parts with the same reference numerals indicate the same or similar parts unless otherwise specified.

[0012] [A] Embodiments [A-1] First Embodiment FIG. 1 is a block diagram that schematically shows an example of the configuration of a wireless communication device 1 in the first embodiment.

[0013] The wireless communication device 1 is attached to an artificial satellite located at an altitude of, for example, 1000 km, and communicates with a wireless communication terminal (not shown) on the ground, and includes a receiving unit 1a and a transmitting unit 1b as shown in Fig. 1. The wireless communication device 1 may cover, for example, the Q / V band, with a DL (Down Link) of 40 GHz and a UL (Up Link) of 50 Hz.

[0014] Although only one receiving unit 1a and one transmitting unit 1b are shown in FIG. 1, the wireless communication device 1 may include a plurality of receiving units 1a and a plurality of transmitting units 1b.

[0015] The receiving unit 1a includes a plurality of receiving antenna modules 12a and a DSP unit 13a. The transmitting unit 1b includes a plurality of transmitting antenna modules 12b and a DSP unit 13b. Details of the transmitting antenna module 12b will be described later using FIG. 5, and details of the transmitting DSP unit 13b will be described later using FIG. 4. Details of the receiving antenna module 12a will be described later using FIG. 7, and details of the receiving DSP unit 13a will be described later using FIG. 8. Note that, hereinafter, when there is no need to distinguish between the receiving antenna module 12a and the transmitting antenna module 12b, they will simply be referred to as "antenna module 12," and when there is no need to distinguish between the receiving DSP unit 13a and the transmitting DSP unit 13b, they will simply be referred to as "DSP unit 13."

[0016] Fig. 2 is a diagram showing an example of the configuration of the area-divided DBF antenna in the first embodiment. Fig. 3 is a table showing an example of frequency allocation in the eight-antenna configuration shown in Fig. 2.

[0017] In the example shown in FIG. 2, eight basic units 110 of an area-divided DBF antenna (hereinafter sometimes simply referred to as a "DBF antenna") are arranged. Each basic unit 110 may have 256 elements, which are four 8x8 antenna elements arranged together, and may be provided in each antenna module 12 shown in FIG. 1. Each basic unit 110 (antenna module 12) is connected to a DSP unit 13 and is assigned the numbers ANT1 to ANT8. The connection configuration between each basic unit 110 (antenna module 12) and the DSP unit 13 will be described later using FIG. 9.

[0018] The basic units 110 ANT1 to ANT8 shown in Figure 2 do not necessarily need to be placed adjacent to each other, but may be placed at a distance sufficient for the wavelength. By placing the units at a distance from each other, there is an advantage that the heat dissipation of the antenna module and the mounting become easier. This is particularly useful for equipment mounted on satellites and aircraft, where heat dissipation is difficult.

[0019] In the example shown in Fig. 3, frequencies are assigned to ANT1 through ANT8 by each basic unit 110 having the 256-element array shown in Fig. 2. Ch. 1 through 4 at 39 to 39.3 GHz correspond to ANT1, Ch. 5 through 8 at 39.4 to 39.7 GHz correspond to ANT2, Ch. 9 through 10 at 39.8 to 39.9 GHz correspond to ANT3, Ch. 11 through 12 at 40 to 40.1 GHz correspond to ANT4, Ch. 13 through 14 at 40.2 to 40.3 GHz correspond to ANT5, Ch. 15 through 16 at 40.4 to 40.5 GHz correspond to ANT6, Ch. 17 through 18 at 40.6 to 40.7 GHz correspond to ANT7, and Ch. 19 through 20 at 40.8 to 40.9 GHz correspond to ANT8. That is, ANT1 to ANT2 each have a frequency band of 400 MHz, and ANT3 to ANYT8 each have a frequency band of 200 MHz, so the total RF band is 2 GHz.

[0020] Although it is assumed that the above-mentioned basic units 110 are basically assigned different frequency channels, it is also possible to assign the same frequency channel to multiple basic units 110 in order to narrow the beam, increase the antenna gain, or increase the transmission output for a specific terrestrial service area, thereby improving the S / N ratio during terrestrial reception. In this case, if the basic units 110 to which the same frequency channel are assigned are arranged adjacent to each other with an interval of one wavelength or less, a better beam can be formed. Note that, for units to which different frequency channels are always assigned, it is preferable to arrange them at a distance of one wavelength or more from the standpoint of heat dissipation and module implementation.

[0021] A continuous frequency band may be assigned to one basic unit 110 among the plurality of basic units 110. Furthermore, two or more basic units 110 among the plurality of basic units 110 that may be assigned the same frequency channel may be arranged adjacent to each other at a distance of one wavelength or less. Furthermore, at least some two adjacent basic units 110 among the plurality of basic units 110 may be arranged at an interval of less than the wavelength of each element included in the digital beamforming element array, and may transmit or receive beams in the same frequency band.

[0022] FIG. 4 is a block diagram showing a schematic configuration example of the DSP unit 13b of the transmission system shown in FIG.

[0023] 4, the DSP unit 13b includes m modulators 131 (MOD), an m-input / n-output DBF calculation unit 132, n delta-sigma modulators 133, and a QSFP (Quad Small Form-factor Pluggable Module) module 134. Both m and n are natural numbers.

[0024] The m modulators 131 respectively modulate Tx data corresponding to Beams #1 to #m. The DBF calculation unit 132 performs DBF calculation on the signals output from the m modulators 131 and inputs the signals to n delta-sigma modulators 133 respectively. The n delta-sigma modulators 133 are associated with ANTs #1 to #n respectively, and perform delta-sigma modulation on the outputs from the DBF calculation unit 132. The QSFP module 134 converts the electrical signals into optical signals and outputs them to the antenna module 12 via optical fiber.

[0025] To achieve a beam width of about 7° and a beam scanning angle of ±45°, a minimum of 256 antenna elements is required, as shown in Figure 2. With the aim of creating a scalable configuration for the number of antenna elements, as well as a configuration that allows for miniaturization and cost reduction, one antenna module is configured with four antenna elements.

[0026] A commercially available QSFP module 134 for 100 GbE is used between the DSP unit 13b and the antenna module 12b. This E / O, O / E module transmits 25 Gbps over 4 channels using optical wavelength division multiplexing (WDM), and data transmission is possible using one optical fiber and one set of QSFP module 134 for four antenna elements for a 25 Gbps 1-bit modulated signal in the DSP unit 13b.

[0027] To realize 256 elements and 160 beams, m in Fig. 4 becomes 160 and n becomes 256, which requires a fairly large-scale DBF calculation in the DBF calculation unit 132. The number of 1-bit bandpass delta-sigma modulators 133 required is equal to the number of antenna elements, and the 1-bit string output from this delta-sigma modulator 133 must be as high speed as 25 Gbps.

[0028] The DSP unit 13b and the antenna module 12b each require 256 / 4 = 64 QSFP modules 134. A 256-element array antenna is constructed by arranging 64 antenna modules, each with four elements. Since the width of the QSFP module 134 is slightly wider than the width of a four-element antenna, a single QSFP module 134 can transmit data for eight elements using a 1-bit modulator with a speed of 12.5 Gbps per element, or instead of the QSFP module 134, components within the QSFP module 134 (e.g., a ROSA) can be directly mounted on the module board to achieve miniaturization. Similar effects can also be achieved with an optical fiber transmission system other than the QSFP module 134, or an electrical signal transmission system such as a coaxial cable.

[0029] FIG. 5 is a diagram schematically illustrating an example of the configuration of the antenna module 12b of the transmitting system shown in FIG.

[0030] 5, the antenna module 12b is composed of four elements corresponding to ANT#1 to ANT#4, and includes a QSFP module 121, a DAC / CDR 122 (Digital-Analog Converter / Clock Data Recovery), a BPF 123, an amplifier 127, a SPDT-SW 124 (Single-Pole Double-Throw Switch), a PA 125 (Power Amplifier), a 90 deg. HYB circuit 126, and a DBF antenna 11.

[0031] The QSFP module 121 converts optical signals received from the DSP unit 13b via optical fiber into electrical signals. The DAC / CDR 122 converts the digital signals output by the QSFP module 121 into analog signals and separates the clock and data. The BPF 123 is, for example, a spurious rejection filter that removes aliasing spurious signals when converting the digital signals back to analog signals. The amplifier 127 amplifies the signal in the band that passes through the BPF 123. The SPDT-SW 124 inputs the input from the amplifier 127 side to one of the two PAs 125 in the subsequent stage. The PA 125 amplifies the signal output from the SPDT-SW 124. The 90° HYB circuit 126 outputs a signal to the antenna 11 so that the two output signals have a 90° phase difference. The DBF antenna 11 emits a transmission beam.

[0032] Unlike analog phased array antennas that use phase shifters, the DBF antenna 11, which is based on an array antenna, has the advantage of being able to form multiple beams simultaneously. Since radar prefers beams that are as sharp as possible, it is common for the DBF antenna 11 to be configured with a single multi-element array antenna. If all antenna elements were to handle signals in the 2 GHz band and 120 beams, the DBF calculation scale of the DSP unit 13b would increase, and the calculation volume of the 1-bit bandpass delta-sigma modulator 133 would also increase.

[0033] FIG. 6 is a diagram showing an example of the configuration of a conventional DBF antenna 11 having 2048 elements on one surface.

[0034] In this embodiment, in order to reduce the load on the DSP unit 13b, the DBF antenna 11, which has a conventional one-plane configuration with 2048 elements as shown in Fig. 6, is divided into a multi-plane DBF antenna 11 as shown in Fig. 2. As a result, in order to match the transmission power per element, one plane of the divided configuration has 256 elements, and when configured on one plane, it is divided into 8 parts, resulting in a 256 x 8 = 2048 element configuration.

[0035] In the case of a split antenna, an independent DSP unit 13b is connected to each DBF antenna 11. The table shown in FIG. 3 shows the frequency band of the beam handled by each split DBF antenna 11. For example, ANT1 is responsible for 400 MHz of Ch1-Ch4 in the 2 GHz band. Splitting the antenna makes it possible to narrow the frequency band handled by each side, thereby reducing the amount of calculation required by the 1-bit bandpass delta-sigma modulator 133.

[0036] Regarding the number of beams, in the case of a single-surface configuration, 160 beams are supported, but in the case of eight-surface division, the number of beams per surface is 160 / 8=20 beams, and the amount of DBF calculation in the DSP unit 13b can also be reduced.

[0037] For example, in a single-plane 2048-element DBF antenna configuration, the amount of DSP calculations in the DBF calculation unit 132 is (2 GHz band × 160 beams × 2048 elements) × 1 ANT = 655,360 (au; arbitrary unit).On the other hand, in an eight-plane 256-element DBF antenna configuration, the amount of DSP calculations in the DBF calculation unit 132 is (400 MHz band × 20 beams × 256 elements) × 2 ANT + (200 MHz band × 20 beams × 256 elements) × 6 ANT = 10,240 (au).

[0038] Furthermore, in a single-plane 2048-element DBF antenna configuration, the DSP calculation volume in the delta-sigma modulator 133 is (2 GHz band × 2048 elements) × 1ANT = 4096 (au).On the other hand, in an eight-plane 256-element DBF antenna configuration, the DSP calculation volume in the delta-sigma modulator 133 is (400 MHz band × 256 elements) × 2ANT + (200 MHz band × 256 elements) × 6ANT = 206.2 (au).

[0039] In this case, by dividing the DBF antenna 11, the amount of calculation in the DBF calculation unit 132 can be significantly reduced to 1 / 64, and the amount of calculation in the 1-bit bandpass delta-sigma modulator 133 can be significantly reduced to approximately 1 / 20.

[0040] So far, we have shown a configuration using a 1-bit bandpass delta-sigma modulator as a transmission system, but this configuration can also be applied to a conventional transmission system configuration similar to that of the wireless communication device 1 shown in Fig. 1. For example, the delta-sigma modulator 133 in Fig. 4 can be removed, and the DAC / CDR 122 in Fig. 5 can be replaced with a multi-bit DAC and an up-converter (a frequency converter from IF (intermediate frequency) to RF). In this case, the reduction in DSP calculations is limited to the amount of DSP calculations performed by the DBF calculation unit 132 described above.

[0041] Fig. 7 is a diagram schematically illustrating an example of the configuration of the antenna module 12a of the receiving system shown in Fig. 1. Fig. 8 is a block diagram schematically illustrating an example of the configuration of the DSP unit 13a of the receiving system shown in Fig. 1.

[0042] 7, the antenna module 12a is composed of four elements corresponding to ANT#1 to #4, and includes a DBF antenna 11, a 90° HYB circuit 126, an LNA 128, an SPDT-SW 124, an amplifier 127, a BPF 123, an S / H (Sample / Hold) circuit 129, a 4ch / 4Gbps ADC+P / S (Analog Digital Converter + Parallel / Serial) 130, and a 100GbE QSFP 121.

[0043] 8, the DSP unit 13a includes n QSFP modules 134, an n-input / m-output DBF calculation unit 132, and m demodulators 135 (DEMODs). Both m and n are natural numbers. The same effect can be achieved with an optical fiber transmission system other than the QSFP modules 134, or an electrical signal transmission system such as a coaxial cable.

[0044] The surface division DBF may be used in the receiving system, and the DBF calculations in the DSP unit 13 can be reduced in the same way as the DBF calculations in the conventional transmitting system configuration.

[0045] The transmitter 1b includes a plurality of basic units 110 each configured as a DBF antenna 11 having a plurality of antenna elements, and a plurality of sets of transmitting antenna modules 12b connected to each of the plurality of basic units 110 to perform transmission processing on signals transmitted from the plurality of basic units 110. In addition, for each of the frequency bands associated with the plurality of basic units 110, a plurality of delta-sigma modulators 133 may be used to perform 1-bit band-pass delta-sigma modulation to transmit a beam.

[0046] The receiving unit 1a includes a plurality of basic units 110 each consisting of a DBF antenna 11 having a plurality of antenna elements, and a plurality of sets of receiving antenna modules 12a connected to each of the plurality of basic units 110 and performing receiving processing on signals received from the plurality of basic units 110.

[0047] For example, the diameter of each spot beam of the receiving and transmitting systems may be 50 km, the beam width may be a minimum of 6 degrees, and the beam steering angle may be 45 degrees. Furthermore, one frequency channel may be associated with one beam. For example, the RF bandwidth may be greater than 2 GHz, and the bandwidth of one channel may be switchable between 100 MHz, 200 MHz, and 400 Hz. The DBF antenna 11 may be a full DBF antenna for more flexible beamforming.

[0048] FIG. 9 is a diagram schematically showing an example of the arrangement of antenna elements in the antenna module 12 shown in FIG.

[0049] 9 , each of the receiving unit 1a and the transmitting unit 1b in the wireless communication device 1 is provided with four radiating surfaces of DBF antennas 11, each having 8×8 elements, arranged side by side, to form a basic unit 110. Each DBF antenna 11 may be connected to the DSP unit 13 by, for example, eight or sixteen optical fibers.

[0050] The BB (Broadband) bandwidth is a maximum of 400 MHz. For SC and 64QAM, the theoretical limit is 6 bits / Hz, meaning the theoretical upper limit for the transmission rate per beam is 2.4 Gbps. Japan's land area is approximately 380,000 km2, so if we assume a beam diameter of 100 km (assuming a 50 km radius and a satellite altitude of 1,000 km) and an overlay of 1 / 2, we get 380,000 x 2 (overlay) / (50 * 50 * π) = 97 ≒ 100 beams. If four antennas are used to cover the entire country (repeated use of four frequency bands), the data rate per antenna is 2.4 Gbps x 25 beams = 60 Gbps. Including one redundant antenna, five antennas provide a data rate of 300 Gbps.

[0051] The total number of ANTs is a variable parameter ranging from 3 to 7. If we assume 7+1 (redundant) ANTs, the speed per ANT is 2.4Gbps x 100 / 7 beams (approximately 14 beams) = 34.3Gbps, and with a total of 8 ANTs, the speed is approximately 274Gbps.

[0052] Taking into account error correction, guard bands, etc., it is expected that the nominal value will be half of the above capacity. If 1 ANT has 25 (14) beams and 30 (17.2) Gbps, then 1 satellite will have a capacity of 120 (120) Gbps, and if there is a 5-ANT configuration including 1 ANT for the redundant system (temporary beam), then it will be 150 (137) Gbps.

[0053] Fig. 10 is a block diagram illustrating an example of the arrangement of the base units 110 in a five-antenna configuration in the embodiment. Fig. 11 is a table illustrating an example of frequency allocation in the five-antenna configuration shown in Fig. 10.

[0054] In the example shown in Fig. 10, five basic units 110 shown in Fig. 9 are arranged. Each basic unit 110 is connected to the DSP unit 13 and is assigned the numbers ANT1 to ANT5. Note that each basic unit 110 may be connected to the DSP unit 13 via an optical fiber, similar to the example shown in Fig. 9.

[0055] Among the basic units 110 ANT1 to ANT5 shown in FIG. 10, the basic units 110 having consecutive numbers may be arranged in adjacent positions.

[0056] In the example shown in Fig. 11, frequencies are assigned to ANT1 to ANT5 by each basic unit 110 having the 256-element array shown in Fig. 10. Ch. 1 to 4 at 39 to 39.3 GHz correspond to ANT1, Ch. 5 to 8 at 39.4 to 39.7 GHz correspond to ANT2, Ch. 9 to 12 at 39.8 to 40.1 GHz correspond to ANT3, Ch. 13 to 16 at 40.2 to 40.5 GHz correspond to ANT4, and Ch. 17 to 20 at 40.6 to 40.9 GHz correspond to ANT5. In other words, ANT1 to ANT5 each have a frequency band of 400 MHz, so the total RF band is 2 GHz.

[0057] The wireless communication device 1 may include a plurality of basic units 110, each of which corresponds to a predetermined frequency band (e.g., a 100 MHz band, a 200 MHz band, or a 400 Hz band) and which are digital beamforming element arrays that perform communication in the predetermined frequency band. The plurality of basic units 110 cover a frequency band (e.g., a 2 GHz band) that is wider than the predetermined frequency band.

[0058] 11, the frequency bands corresponding to ANT1 to ANT5 do not overlap with each other, but some of the frequency bands corresponding to ANT1 to ANT5 may overlap with each other. This allows the system to be made redundant even if one of the basic units 110 becomes unavailable.

[0059] FIG. 12 is a diagram schematically illustrating an example of beam coverage corresponding to the frequency allocation shown in FIG.

[0060] The hatching in each circle of the beam coverage illustrated in FIG. 12 corresponds to the hatching in the assigned frequencies of ANT1 to ANT5 illustrated in FIG.

[0061] Adjacent beams may be set to different frequency channels by changing the ANT. For example, ANT5 may be used not only as a redundant system but also as a temporary beam during disasters or other events.

[0062] According to the above-described embodiment, it is possible to provide wireless communication that covers a wide range. Specifically, by arranging a plurality of DBF antenna basic units, it is possible to ensure scalability and redundancy according to communication capacity, and it is also possible to reduce the amount of calculations performed by the DSP unit of each DBF antenna unit, thereby reducing power consumption and heat generation.

[0063] Conventionally, DBF antennas are constructed with only a single-sided array. For millimeter waves, a high-gain antenna can be obtained even with a small aperture area, making it possible to split the antenna. However, a single-sided array can cause problems such as mounting, heat generation, and excessively high directional gain.

[0064] [A-2] Second Embodiment In the conventional example and the first embodiment described above, the basic unit 110 of the DBF antenna is capable of transmitting radio waves of either the right-handed or left-handed circularly circumferential system.

[0065] FIG. 13 is a diagram schematically illustrating an example of the configuration of a conventional transmitting antenna module 22c.

[0066] 13, the transmitting antenna module 22c is made up of four elements corresponding to ANT#1 to #4, and includes two QSFP modules 121, as well as four 90° HYB circuits 126 and four DBF antennas 11 corresponding to ANT#1 to #4, respectively. Each of the elements corresponding to ANT#1 to #4 includes two sets of DAC / CDRs 122 for right-handed and left-handed circular polarization, two sets of BPFs 123, and two sets of PAs 127 (power amplifiers).

[0067] The transmitting system antenna module 22c in the conventional example shown in Figure 13 is equipped with two sets of DAC / CDR 122, two sets of BPF 123, and two sets of amplifiers 127, one for right-hand rotation and one for left-hand rotation, respectively, so that the circuit size becomes large and there is a risk that it cannot be mounted on the satellite main body 3 (described later using Figures 16 to 18).

[0068] In the second embodiment, right-handed or left-handed circular polarization is assigned to each of the 256 element basic units 110 in the DBF antenna.

[0069] FIG. 14 is a diagram showing an example of the configuration of an area-divided DBF antenna in the second embodiment.

[0070] In the example shown in Fig. 14, eight DBF antenna basic units 110 are arranged, similar to the first embodiment shown in Fig. 2. Each basic unit 110 (antenna module 12) is connected to the DSP unit 13 and is assigned the number ANT1 to ANT8.

[0071] In the second embodiment, of the eight basic units 110, ANT1 to ANT4 (first group) are assigned to transmit right-handed circularly rotated radio waves, and ANT5 to ANT8 (second group) are assigned to transmit left-handed circularly rotated radio waves. Note that the number of basic units 110 assigned to transmit right-handed circularly rotated radio waves and the number of basic units 110 assigned to transmit left-handed circularly rotated radio waves can be changed in various ways.

[0072] By assigning right-hand or left-hand polarization to each 256-element basic unit 110, a polarization switching circuit or a dual polarization compatible circuit between the transmitter and receiver connected to the antenna is no longer necessary, making it possible to reduce the size of the wireless communication device 1, increase the output of the transmitter, and reduce noise in the receiver.

[0073] FIG. 15 is a diagram schematically illustrating an example of the configuration of a transmitting antenna module 12c according to the second embodiment.

[0074] In the second embodiment, the same wireless communication device 1 as that shown in Fig. 1 in the first embodiment may be used, except that in the transmission system of the wireless communication device 1 shown in Fig. 1, a transmission system antenna module 12c shown in Fig. 15 is used instead of the transmission system antenna module 12b.

[0075] 15, the antenna module 12c includes four elements corresponding to ANT#1 to ANT#4, and includes a QSFP module 121, a DAC / CDR 122, a BPF 123, a PA 127 (power amplifier), a 90 deg. HYB circuit 126, a resistor 126a, and a DBF antenna 11.

[0076] The resistor 126a may be, for example, a 50Ω isolation resistor, which prevents leakage of radio waves.

[0077] The transmitting antenna module 12c shown in Figure 15 does not include the SPDT-SW 124, as compared to the transmitting antenna module 12b shown in Figure 5 in the first embodiment. This allows for increased transmission output and improved power efficiency of the transmitter. Furthermore, the transmitting antenna module 12c shown in Figure 15 has a simpler circuit configuration than the transmitting antenna module 22c in the conventional example shown in Figure 13, making it possible to realize a smaller transmitting antenna module 12c.

[0078] In the second embodiment, the receiving system may be the same as the receiving system antenna module 12a shown in FIG. 1 in the first embodiment.

[0079] [A-3] Third Embodiment Figure 16 is a diagram showing a first example of the arrangement of DBF antennas on the satellite body 3 in the third embodiment. Figure 16(a) is a cross-sectional view of the satellite body 3, and Figure 16(b) is a front view thereof.

[0080] If the antenna gain is increased, the radiation pattern may become narrower and the beam may not be able to swing.

[0081] Therefore, in the example shown in Figure 16, even if the beam steering angle of the basic unit 110 of the 256-element DBF antenna is set to ±30°, by mounting the basic unit 110 on the satellite body 3 at an angle, it is possible to ensure coverage.

[0082] In Fig. 16(b), a total of nine basic units 110 (3 x 3) are arranged on one surface of the partially curved satellite body 3. The number of basic units 110 to be arranged may be changed in various ways. For example, the one basic unit 110 in the center in Fig. 16(b) may be omitted and eight basic units 110 may be arranged, or four basic units 110 may be arranged only at the four corners in Fig. 16(b).

[0083] As shown in FIG. 16A, for example, the beam steering angle may be set to −60 to 0° for the beam with symbol A1, −30 to +30° for the beam with symbol A2, and 0 to +60° for the beam with symbol A3.

[0084] 17A and 17B are diagrams showing a second example of the arrangement of DBF antennas on the satellite body 3 in the third embodiment, in which (a) of Fig. 17A is a cross-sectional view of the satellite body 3, and (b) of Fig. 17B is a front view thereof.

[0085] When each basic unit 110 is assigned to right-handed and left-handed circular polarization as in the second embodiment described above, the DBF antennas may be arranged as shown in FIGS. 17(a) and 17(b).

[0086] 17(a) and 17(b), on one surface of the satellite body 3 having a partially curved surface, a total of four right-handed circularly rotating transmitting basic units 110a (first group) are arranged at the midpoints of each of the four sides, a total of four left-handed circularly rotating transmitting basic units 110b (second group) are arranged at each of the four corners, one right-handed circularly rotating receiving basic unit 110c (third group) is arranged near the center, and one left-handed circularly rotating receiving basic unit 110d (fourth group) is arranged near the center. The numbers and positions of the right-handed circularly rotating transmitting basic units 110a, left-handed circularly rotating transmitting basic units 110b, right-handed circularly rotating receiving basic units 110c, and left-handed circularly rotating receiving basic units 110d may be changed in various ways.

[0087] Even when each basic unit 110 is assigned to right-handed and left-handed rotations as in the second embodiment, coverage can be ensured in the same manner as in the case shown in FIG.

[0088] Fig. 18 is a diagram schematically showing an example of the arrangement of the DSP unit 13 in the satellite main body 3 in the third embodiment. Fig. 18(a) shows an example in which one DSP unit 13 is provided for one basic unit 110, and Fig. 18(b) shows an example in which one DSP unit 13 is provided for multiple basic units 110.

[0089] 18A, the satellite main body 3 includes three DSP units 13 connected one-to-one to three basic units 110. Each basic unit 110 and each DSP unit 13 may be connected by an optical fiber. The number of basic units 110 and the number of DSP units 13 may be changed in various ways.

[0090] 18(b), the satellite body 3 includes one DSP unit 13 and one switch 4 for three basic units 110. The number of DSP units 13 may be more than one, as long as it is less than the number of basic units 110. The number of basic units 110 may also be changed in various ways.

[0091] The DSP unit 13 is connected to each basic unit 110 via a switch 4. The DSP unit 13 and the switch 4, and the switch 4 and the basic unit 110 may be connected by optical fiber. The switch 4 may be an optical switch or a circuit that turns each basic unit 110 on and off. Furthermore, when multiple DSP units 13 are available, the switch 4 may be a switch matrix (in other words, a crossbar switch).

[0092] According to the example of arrangement of the DSP unit 13 shown in (b) of Figure 18, when multiple basic units 110 for right-hand and left-hand circular polarization transmission are redundantly arranged as shown in Figure 17, antennas in low traffic areas are not used, thereby improving power efficiency, and the number of DSP units 13 can be reduced, thereby reducing the scale of the wireless communication device 1.

[0093] [B] Others The disclosed technology is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the embodiments. The configurations and processes of the embodiments can be selected or combined as needed.

[0094] In the above-described embodiment, the wireless communication device 1 is mounted on an artificial satellite, but the present invention is not limited to this. The wireless communication device 1 may also be used in a terrestrial system. In this case, the same effects as those of the above-described embodiment can be achieved.

[0095] In the above-described embodiment, the set of DBF antennas 11 configured with 256 elements is used as the basic unit 110, but this is not limited to this. The basic unit 110 may be configured with, for example, 64, 16, or 8 of the 256 elements shown in Fig. 9, or may be configured with any other number of elements, or may be configured with a number of elements greater than 256. Then, frequencies ANT1 to ANT5 shown in Fig. 10 or ANT1 to ANT8 shown in Fig. 2 may be assigned to each of the basic units 110 configured with various numbers of elements.

[0096] In the above-described embodiment, the transmitting antenna and the receiving antenna are configured separately, but the same effect can be achieved even in a transmitting / receiving antenna module in which an antenna is shared for transmission and reception.

[0097] 1: Wireless communication device 1a: Receiving section 1b: Transmitting section 11: DBF antenna 110, 110a to 110d: Basic unit 12a, 12b, 12c, 22c: Antenna module 121, 134: QSFP module 122: DAC / CDR 123: BPF 124: SPDT-SW 125, 127: PA 125a: Resistor 126: 90 deg. HYB circuit 128: LNA 129: S / H circuit 130: ADC+P / S 13a, 13b: DSP section 131: Modulator 132: DBF calculation section 133: Delta-sigma modulator 134: QSFP 135: Demodulator 3: Satellite main body 4: Switch

Claims

1. A communications antenna comprising a plurality of basic units, each of which is a digital beamforming element array that performs communications in a predetermined frequency band, corresponding to a plurality of predetermined frequency bands, at least some of which differ from each other in frequency band, and wherein the plurality of basic units cover a frequency band that is wider than each of the plurality of predetermined frequency bands.

2. The communication antenna according to claim 1, wherein a continuous frequency band is assigned to one of the plurality of basic units.

3. A communications antenna according to claim 1 or 2, wherein two or more basic units among the plurality of basic units that may be assigned the same frequency channel are arranged adjacent to each other at a distance of one wavelength or less.

4. A communication antenna according to claim 1 or 2, wherein a plurality of modulators are used to perform 1-bit bandpass delta-sigma modulation for each of the frequency bands associated with the plurality of basic units, thereby executing beam transmission processing.

5. A communications antenna according to claim 1 or 2, wherein a first group of said plurality of basic units transmits right-handed circularly polarized radio waves, and a second group of said plurality of basic units transmits left-handed circularly polarized radio waves.

6. A communications antenna according to claim 1 or 2, wherein at least some of the plurality of basic units are arranged at angles to one another in a planar direction of the basic units.

7. A wireless communication device comprising: a receiving section having a plurality of receiving system basic units, each of which is a digital beam forming element array that communicates in a predetermined frequency band, corresponding to each of a plurality of predetermined frequency bands that differ from each other in at least some frequency bands, and a plurality of sets of receiving antenna modules connected to each of the plurality of receiving system basic units and performing receiving processing on signals received from the plurality of receiving system basic units; and a transmitting section having a plurality of transmitting system basic units, each of which is a digital beam forming element array that communicates in the predetermined frequency band, corresponding to each of a plurality of predetermined frequency bands that differ from each other in at least some frequency bands, and a plurality of sets of transmitting antenna modules connected to each of the plurality of transmitting system basic units and performing transmitting processing on signals transmitted from the plurality of transmitting system basic units, wherein the plurality of receiving system basic units and the plurality of transmitting system basic units cover a frequency band wider than each of the plurality of predetermined frequency bands.

8. A wireless communication device according to claim 7, wherein a continuous frequency band is assigned to one receiving system basic unit among the plurality of receiving system basic units, and a continuous frequency band is assigned to one transmitting system basic unit among the plurality of transmitting system basic units.

9. A wireless communication device as described in claim 7 or 8, wherein two adjacent receiving system basic units among the plurality of receiving system basic units are arranged at intervals approximately the same as the intervals between each element included in the digital beam forming element array, and receive beams of the same frequency band, and two adjacent transmitting system basic units among the plurality of transmitting system basic units are arranged at intervals approximately the same as the intervals between each element included in the digital beam forming element array, and transmit beams of the same frequency band.

10. A wireless communication device according to claim 7 or 8, wherein the transmitting section further comprises a plurality of modulation sections that perform 1-bit bandpass delta-sigma modulation for each of the frequency bands associated with the plurality of transmitting system basic units.

11. A wireless communication device as described in claim 7 or 8, wherein a first group of the plurality of transmission system basic units transmits right-hand circularly-polarized radio waves, a second group of the plurality of transmission system basic units transmits left-hand circularly-polarized radio waves, a third group of the plurality of reception system basic units receives right-hand circularly-polarized radio waves, and a fourth group of the plurality of reception system basic units receives left-hand circularly-polarized radio waves.

12. The wireless communication device according to claim 7 or 8, wherein at least some of the plurality of transmission system basic units are arranged at angles to one another in a planar direction of the transmission system basic units.

13. A wireless communication device according to claim 7 or 8, further comprising a digital signal processing unit that inputs signals to the plurality of sets of transmitting antenna modules, and a switch, wherein the switch between the plurality of transmitting system basic units and the digital signal processing unit is switched to operate one of the plurality of transmitting system basic units.

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