Method and apparatus for beam steering using frequency modulation and phase shifting

Abstract

To provide a beam steering device for reducing a grating lobe of a phased array antenna.SOLUTION: In an array of a plurality of antenna elements, the antenna element is caused to rotate at a prescribed angle, and thereby grating lobes generating upon receiving a signal are caused not to mutually overlap. To this end, a beam steering device includes: a plurality of phase shifters that adjust and output a phase of the signal to be delivered to the antenna element, or receive the signal from the antenna element to adjust and output the phase; a signal processor that generates an IQ signal of a baseband waveform and outputs the generated IQ signal to the phase shifter, or extracts the IQ signal from the signal received from the phase shifter; and a control unit that performs time delay of the signal to be output for each of the plurality of antenna elements so that the signal is output in a prescribed beam direction via the plurality of antenna elements, and performs time delay so that the signal is received in the prescribed beam direction via the plurality of antenna elements.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a beam steering method and apparatus using frequency modulation and phase shift, and more particularly to a beam steering method and apparatus using frequency modulation and phase shift, in which, when receiving a signal through a beam steering device, an array of multiple antenna elements is rotated by a predetermined angle to prevent grating lobes generated when receiving a signal from overlapping with each other. [Background technology]

[0002] A phased array antenna works by arranging multiple antenna elements in one dimension or in space, and then electrically controlling the phase of each element via a phase shifter that adjusts the phase of each element, thereby enabling the direction of the synthesized beam to be quickly controlled. Controlling the phase of the antenna array without relying on mechanical drive when directing the beam has various advantages, such as enabling reliable, fast and accurate direction.

[0003] Due to these advantages, it is being used to improve the pointing speed of radar beams installed on fighter jets and ships, and in recent years its range of applications has been gradually expanding, including in the transmitting and receiving antennas of aircraft and satellite-mounted synthetic aperture radar (SAR), and as a relay technology for mobile communications.

[0004] FIG. 1 shows a schematic configuration diagram of a conventional phased array antenna. As shown in FIG. 1, a conventional phased array antenna includes M antenna elements 1, a phase shifter 2 for adjusting the phase of a signal input to each of the antenna elements 1, a transmitter 3 for generating an IQ signal in a baseband form to be transmitted to the phase shifter 2 and up-converting the frequency, and a controller 4 for controlling the transmitter 3 and the phase shifter 2 to output a beam in a desired direction.

[0005] In addition, the antenna element 1 can receive an external signal, and the received signal is received by the phase shifter 2 and the phase is adjusted according to the control of the controller 4. The adjusted signal is received by a receiver (not shown in the drawing) and an IQ signal is extracted.

[0006] In a beam steering device using such a phased array antenna, if a plurality of antenna elements 1 are arranged on a two-dimensional plane, the array elements of the phased array antenna can be expressed as follows:

[0007] JPEG0007648716000001.jpg58170

[0008] FIG. 2 is a diagram showing an example of a general beam pattern, and FIG. 3 is a diagram showing an example of a beam pattern according to d / λ. Referring to the drawings, (a) and (b) of FIG. 2 are diagrams showing beam patterns, i.e., antenna directivity. (a) shows a normal beam pattern in which only a main lobe 5 is formed without a grating lobe 6, while (b) shows a defective beam pattern in which grating lobes 6 are formed on both sides of the main lobe 5.

[0009] When grating lobes 6 occur in the beam pattern in this way, the steering beam is output in an undesired direction, the gain of the steering beam that should be output in the desired direction is reduced, and the beam is emitted in an undesired direction.

[0010] JPEG0007648716000002.jpg42170

[0011] Furthermore, in the case of (a) in Figure 3, which shows the beam patterns when d / λ=0.5 and when d / λ=0.7, when d / λ=0.5, no grating lobe 6 occurs and a main lobe 5 exists at 30°, but when d / λ=0.7, in addition to the main lobe 5 at 30°, a beam pattern with a grating lobe 6 exists at approximately -70° is obtained.

[0012] Furthermore, when d / λ=1.5 as in FIG. 3(b), the grating lobes 6 are present at approximately 40° and −40° even without beam steering.

[0013] In addition, in a phased array antenna using a wideband signal, as the beam steering angle increases, the gain of the steering beam decreases and the beam width becomes wider.

[0014] Furthermore, the size of the phased array antenna elements is limited by the risk of grating lobes, which means that the advantage of a larger antenna element area being larger, which in turn results in a larger antenna gain and potentially narrower main lobe beamwidth, cannot be realized.

[0015] Therefore, if the occurrence of grating lobes could be prevented even if the size of the antenna elements were increased, signals could be transmitted and received over longer distances without increasing the transmission power. Therefore, there is an urgent need to develop a beam steering device that can limit the occurrence of grating lobes. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Korean Registered Utility Model No. 20-0406784 Summary of the Invention [Problem to be solved by the invention]

[0017] The present invention has been made to solve the above problems, and an object of the present invention is to provide a beam steering method and apparatus using frequency modulation and phase shift, which rotates an array of multiple antenna elements by a predetermined angle when receiving a signal via a beam steering device, thereby preventing grating lobes generated when receiving a signal from overlapping each other.

[0018] Another object of the present invention is to provide a beam steering method and apparatus using frequency modulation and phase shift, which can minimize the influence of grating lobes by calculating the rotation angle at which the relative distance between grating lobes is maximized. [Means for solving the problem]

[0019] In order to solve the above problems, the present invention has the following features. The present invention includes a plurality of antenna elements which output a transmitted signal to the outside in a predetermined beam direction and receive a signal received from the outside; a plurality of phase shifters respectively connected to the plurality of antenna elements and adjusting a phase of a signal transmitted to the antenna elements and outputting the signal, or receiving a signal from the antenna elements and adjusting a phase of the signal, a signal processor which generates an IQ signal of a baseband waveform and outputs the IQ signal to the phase shifter, or extracts the IQ signal from a signal received from the phase shifter; and a controller which controls the plurality of antenna elements, the plurality of phase shifters, and the signal processor so that a signal is output or received in a predetermined beam direction, and the controller sets an arrangement of the plurality of antenna elements during transmission and an arrangement of the plurality of antenna elements during reception to be different from each other so that a grating lobe generated during transmission through the plurality of antenna elements and a grating lobe or a side lobe generated during reception do not overlap each other.

[0020] Here, when the main beam directivity angle during transmission is θ0, φ0, the control unit calculates a plurality of θ, which are directivity angles of grating lobes generated during transmission based on the following formulas (1) and (2): pq , φ pq , and a first grating lobe chart is generated by specifying a visible region where transmission is possible. The arrangement of the antenna elements during transmission is rotated from the center by a predetermined angle, and a plurality of grating lobe directional angles θ, φ are received for the main beam directional angles θ0 and φ0 by the predetermined angle. pq , φ pq is calculated based on the following formulas (1) and (2), a visible area in which signals can be received is identified to generate a second grating lobe chart, and an angle at which the relative distance between each grating lobe in the visible area of ​​the first grating lobe chart and each grating lobe in the visible area of ​​the second grating lobe chart is greatest is calculated.

[0021] JPEG0007648716000003.jpg29170

[0022] (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p=0 & q=0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

[0023] In addition, the arrangement of the multiple antenna elements is a rectangular array or a triangular array for both transmission and reception, or a rectangular array for either transmission or reception and a triangular array for the other.

[0024] Furthermore, when generating the first grating lobe chart and the second grating lobe chart, the control unit generates a plurality of grating lobe directivity angles (θ pq , φ pq ) and calculate the relative distance between grating lobes in the visible area.

[0025] In addition, the control unit performs a phase shift via a plurality of phase shifters and a time delay by frequency modulation of the signal processor on the calculated beam direction angle (θ0, φ0) of the main lobe output during transmission and the calculated beam direction angle (θ0, φ0) of the main lobe received during reception.

[0026] Further, the signal processor includes a transmitting unit that generates the IQ signal and transmits it to the phase shifter, and a receiving unit that extracts the IQ signal from the signal received from the phase shifter, and the transmitting unit includes an IQ signal generating unit that generates the IQ signal, a modulation signal generating unit that generates a modulation signal for modulating the frequency of the IQ signal in accordance with the control of the control unit, a carrier signal generating unit that generates a carrier signal, and a frequency modulation unit that combines at least two of the received IQ signal, the modulation signal, and the carrier signal in accordance with the control of the control unit to perform frequency modulation.

[0027] In addition, the control unit performs frequency modulation by at least one of the following: the frequency modulation unit combines the IQ signal and the modulation signal to perform frequency modulation; the frequency modulation unit combines the IQ signal with a carrier signal generated by modifying it to perform frequency modulation; and the frequency modulation unit combines the IQ signal multiplied by a sinusoidal function with the carrier signal to perform frequency modulation.

[0028] Meanwhile, a beam steering apparatus for a phased array antenna according to another embodiment of the present invention includes a plurality of antenna elements which output a transmitted signal to the outside in a predetermined beam direction and receive a signal received from the outside, a plurality of phase shifters respectively connected to the plurality of antenna elements and adjusting a phase of a signal transmitted to the antenna elements and outputting the signal, or receiving a signal from the antenna elements and adjusting a phase of the signal, a signal processor which generates an IQ signal of a baseband waveform and outputs the IQ signal to the phase shifters, or extracts the IQ signal from a signal received from the phase shifters, and a controller which controls the plurality of antenna elements, the plurality of phase shifters, and the signal processor so that a signal is output or received in a predetermined beam direction, and the controller sets a beam direction of a main lobe output during transmission and a beam direction of a main lobe output during reception to be different from each other by physical rotation so that a grating lobe generated during transmission through the plurality of antenna elements and a grating lobe generated during reception do not overlap each other.

[0029] Here, when the plurality of antenna elements are arranged in a rectangular array, the control unit may be configured to control the plurality of grating lobe directivity angles (θ pq , φ pq ) on a grating lobe chart, a specific grating lobe position (p, q) from among the grating lobes displayed on the grating lobe chart is selected, and the beam direction angle of the main lobe to be finally output is calculated based on the following equations (1) and (2). During reception, a grating lobe position (-p, -q) that faces the grating lobe position (p, q) during transmission and the origin of the grating lobe chart is selected, and the beam direction angle of the main lobe to be finally received is calculated based on the following equations (1) and (2).

[0030] JPEG0007648716000004.jpg29170

[0031] (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p=0 & q=0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

[0032] In addition, when the plurality of antenna elements are arranged in a triangular array, the control unit may be configured to, during transmission, adjust the plurality of grating lobe directivity angles (θ pq , φ pq ) on a grating lobe chart, a specific grating lobe position (p, q (here, one of p and q is 0)) is selected from the grating lobes displayed on the grating lobe chart, and the beam pointing angle of the main lobe to be finally output is calculated based on the following equations (1) and (2). During reception, a grating lobe position (-p, -q (here, one of p and q is 0)) that faces the grating lobe position at the time of transmission and the origin of the grating lobe chart is selected, and the beam pointing angle of the main lobe to be finally received is calculated based on the following equations (1) and (2).

[0033] JPEG0007648716000005.jpg29170

[0034] (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p=0 & q=0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

[0035] Furthermore, the control unit performs a phase shift via a plurality of phase shifters and a time delay by frequency modulation of the signal processor on the calculated beam direction angle (θ0, φ0) of the main lobe output during transmission and the calculated beam direction angle (θ0, φ0) of the main lobe received during reception.

[0036] The signal processor also includes a transmitting unit that generates the IQ signal and transmits it to the phase shifter, and a receiving unit that extracts the IQ signal from the signal received from the phase shifter, and the transmitting unit includes an IQ signal generating unit that generates the IQ signal, a modulation signal generating unit that generates a modulation signal for modulating the frequency of the IQ signal in accordance with the control of the control unit, a carrier signal generating unit that generates a carrier signal, and a frequency modulation unit that combines at least two of the received IQ signal, the modulation signal, and the carrier signal in accordance with the control of the control unit to perform frequency modulation.

[0037] Furthermore, the control unit performs frequency modulation by at least one of the following: the frequency modulation unit combines the IQ signal and the modulation signal to perform frequency modulation; the frequency modulation unit combines the IQ signal with a carrier signal generated by modifying it to perform frequency modulation; and the frequency modulation unit combines the IQ signal multiplied by a sinusoidal function with the carrier signal to perform frequency modulation. Effect of the Invention

[0038] According to the present invention, by rotating the arrangement of antenna elements differently during transmission and reception, the grating lobes or side lobes do not overlap with each other, and the rotation angle at which the relative distance between the grating lobes is maximized is calculated, thereby minimizing the effect of the occurrence of grating lobes. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 shows a schematic configuration diagram of a conventional phased array antenna. [Diagram 2] FIG. 1 is a diagram showing an example of a general beam pattern. [Diagram 3] FIG. 1 is a diagram showing an example of a beam pattern according to d / λ. [Figure 4] 1 is a block diagram illustrating a schematic configuration of a beam steering device according to an embodiment of the present invention. [Diagram 5] FIG. 10 is a diagram showing a grating lobe chart when antenna elements are arranged in a square array according to an embodiment of the present invention. [Figure 6] FIG. 2 is a diagram showing a grating lobe chart when antenna elements are arranged in a triangular arrangement according to an embodiment of the present invention. [Figure 7] 13 is a diagram showing a main lobe and a grating lobe when the arrangement of antenna elements during transmission is a square arrangement and the arrangement of antenna elements during reception is a triangular arrangement. FIG. [Figure 8] 11A and 11B are diagrams showing how a rotation angle is calculated when a plurality of antenna elements are arranged in a square array for both transmission and reception according to an embodiment of the present invention. [Figure 9] 11 is a diagram showing how a rotation angle is calculated when a plurality of antenna elements are arranged in a triangular arrangement both during transmission and reception according to an embodiment of the present invention. FIG. [Figure 10] 11 is a diagram showing how a rotation angle is calculated when a plurality of antenna elements are arranged in a square arrangement during transmission and in a triangular arrangement during reception according to an embodiment of the present invention. FIG. [Figure 11]1 is a block diagram showing a configuration of a signal processor according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For the purpose of explaining the invention, its operating advantages, and objects attained by the practice of the invention, reference will now be made to a preferred embodiment of the invention, which is illustrated and described with reference to the same.

[0041] First, the terms used in this application are merely used to describe a particular embodiment and are not intended to limit the present invention. A singular expression may include a plural expression unless otherwise clearly indicated in the context. In addition, in this application, terms such as "include" or "have" are intended to specify the presence of a feature, value, step, operation, component, part, or combination thereof described in the specification, and should not be understood to preclude the possibility of the presence or addition of one or more other features, values, steps, operations, components, parts, or combinations thereof.

[0042] In describing the present invention, if it is determined that a detailed description of related known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0043] FIG. 4 is a block diagram showing a schematic configuration of a beam steering device according to one embodiment of the present invention, FIG. 5 is a diagram showing a grating lobe chart when the antenna elements are arranged in a square array according to one embodiment of the present invention, and FIG. 6 is a diagram showing a grating lobe chart when the antenna elements are arranged in a triangular array according to one embodiment of the present invention.

[0044] FIG. 7 is a diagram showing the main lobe and grating lobe when the arrangement of antenna elements during transmission is a square arrangement and the arrangement of antenna elements during reception is a triangular arrangement, and FIG. 8 is a diagram showing how the rotation angle is calculated when the arrangement of multiple antenna elements is a square arrangement both during transmission and reception in one embodiment of the present invention.

[0045] Furthermore, Figure 9 is a diagram showing how a rotation angle is calculated when the arrangement of multiple antenna elements is a triangular arrangement both during transmission and reception in one embodiment of the present invention, Figure 10 is a diagram showing how a rotation angle is calculated when the arrangement of multiple antenna elements is a square arrangement during transmission and a triangular arrangement during reception in one embodiment of the present invention, and Figure 11 is a block diagram showing the configuration of a signal processor in one embodiment of the present invention.

[0046] Referring to the drawings, a beam steering apparatus 1000 for a phased array antenna according to an embodiment of the present invention includes a plurality of antenna elements 100 for outputting a transmitted signal to the outside in a predetermined beam direction and receiving a signal received from the outside, a plurality of phase shifters 200 respectively connected to the plurality of antenna elements 100 and adjusting the phase of a signal transmitted to the antenna element and outputting the signal, or receiving a signal from the antenna element and adjusting the phase and outputting the signal, a signal processor 300 for generating an IQ signal of a baseband waveform and outputting the IQ signal to the phase shifter, or extracting the IQ signal from a signal received from the phase shifter, and a control unit 400 for controlling the plurality of antenna elements 100, the plurality of phase shifters 200, and the signal processor 300 so that a signal is output or received in a predetermined beam direction.

[0047] Here, as shown in Figures 5 to 10, the antenna elements 100 are arranged in a plurality of arrays on a two-dimensional plane. In this case, the antenna elements 100 may be arranged in a rectangular array or a triangular array, and the arrangements of the antenna elements 100 during transmission and reception may be configured to be different from each other. Furthermore, each antenna element 100 is connected to a phase shifter 200 that shifts the phase of an input signal.

[0048] The antenna elements 100 receive signals from the phase shifter 200 and output them, respectively. At this time, the signals output from the plurality of antenna elements 100 are output in a predetermined beam direction while canceling or reinforcing each other. The control unit 400 outputs such a beam direction so that a main lobe is formed at a desired azimuth angle (φ) and altitude angle (θ).

[0049] The spacing between such antenna elements 100 is set to 1.5λ, where λ is the wavelength of the signal output by one example of the present invention in Figures 7 to 10, and it is preferable that the spacing between such antenna elements 100 is configured to be 0.5λ or more.

[0050] JPEG0007648716000006.jpg57170

[0051] JPEG0007648716000007.jpg38170

[0052] The signal processor 300 includes a transmitting unit 310 that generates the IQ signal and transmits it to the phase shifter 200, and a receiving unit 320 that extracts the IQ signal from the signal received from the phase shifter 200, where the transmitting unit 310 includes an IQ signal generating unit 311 that generates the IQ signal, a modulation signal generating unit 312 that generates a modulation signal for modulating the frequency of the IQ signal according to the control of the control unit 400, a carrier signal generating unit 313 that generates a carrier signal, and a frequency modulation unit 314 that combines at least two of the received IQ signal, the modulation signal, and the carrier signal according to the control of the control unit 400 to perform frequency modulation.

[0053] The transmitting unit 310 is composed of a digital type transmitting unit and an analog type transmitting unit, and in the digital type transmitting unit, a carrier signal (e.g., 2.5 GHz) generated by a carrier signal generating unit 313 is transmitted to a digital waveform synthesizer (DDS) and combined with an IQ signal generated by an IQ signal generating unit 311, and the combined IQ signal is combined with a modulation signal generated by the modulation signal generating unit 312 and transmitted to a digital-to-analog converter (DAC), and finally transmitted to the phase shifter 200.

[0054] Furthermore, the IQ signal is also called a quadrature signal or a complex signal as a baseband waveform, and can be composed of two components, I and Q.

[0055] Such an IQ signal can be defined as a two-dimensional signal whose value at a specific time can be expressed by one complex number. For example, the I signal and the Q signal can each be formed into a waveform of -225 to 225 MHz, and the modulated signal can be formed into a waveform of 400 to 850 MHz, for example.

[0056] Meanwhile, the controller 400 controls the antenna elements 100, the phase shifters 200, and the signal processor 300 so that a signal is output or received in a predetermined beam direction. According to an embodiment of the present invention, the controller 400 sets the arrangement of the antenna elements during transmission and the arrangement of the antenna elements during reception to be different from each other so that a grating lobe generated during transmission through the antenna elements 100 and a grating lobe generated during reception do not overlap each other.

[0057] As an example of setting the arrangement of such antenna elements to be different from each other, the control unit 400 may configure the arrangement of the antenna elements during reception to be configured in a direction rotated by a certain angle from the center of the antenna element arrangement relative to the arrangement of the antenna elements during transmission.

[0058] JPEG0007648716000008.jpg32170

[0059] Therefore, in one embodiment of the present invention, the arrangement of antenna elements during reception is rotated to prevent such grating lobes occurring during transmission and grating lobes occurring during reception from occurring at the same positions and overlapping with each other.

[0060] Such rotation can be performed in a range of 0° to 90° clockwise from the center of the multiple antenna elements 100, as shown in each of Figures 8 to 10 (a).As shown in Figures 8 to 10 (a), it is possible to calculate the rotation angle at which the relative distance between the grating lobe generated during transmission and the grating lobe generated during reception is the largest in the visible area where transmission and reception are possible on the grating lobe chart.

[0061] Since the influence of the grating lobes can be minimized as the relative distance between the grating lobes is maximized, it is most preferable that the control unit 400 calculates a rotation angle at which the relative distance between the grating lobes is maximized, and rotates the antenna elements clockwise based on the rotation angle during reception.

[0062] In order for the control unit 400 to rotate the array of a plurality of antenna elements in this manner, it is preferable that a rotation driver (not shown) that rotates the array of antenna elements 100 by a certain angle based on the center is provided on the plane on which the antenna elements 100 are provided. Thus, the control unit can control the rotation driver to rotate the array of antenna elements by the rotation angle at which the relative distance between the grating lobes is the largest, as described above.

[0063] In the process in which the control unit 400 calculates the rotation angle at which the relative distance between the grating lobes is the largest, first, when the beam direction angle of the main lobe during transmission is θ0, φ0, the multiple grating lobe direction angles θ generated during transmission based on the following equations (1) and (2) are calculated. pq , φ pq Calculate.

[0064] JPEG0007648716000009.jpg28170

[0065] Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p=0 & q=0 are excluded as they are the main beam), dx is the x-axis spacing between grating lobes on a grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on a grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.

[0066] Next, the control unit 400 defines a visible region in which transmission and reception are possible among the plurality of grating lobes calculated at the time of transmission, and calculates the plurality of grating lobe directivity angles (θ0, φ0) for all the directable main lobe beam directivity angles (θ0, φ0) as described above. pq , φ pq ) is calculated.

[0067] Furthermore, the control unit 400 sequentially rotates the array of the plurality of antenna elements 100 clockwise from the center in the range of 0° to 90°, and adjusts the plurality of grating lobe directivity angles θ generated during reception as described above. pq , φ pq Calculate.

[0068] In addition, a visible area is defined within the calculated plurality of grating lobes, and the relative distance between the grating lobe during transmission and the grating lobe during reception described above is calculated.

[0069] In this way, the maximum value of the relative distance between the grating lobe during transmission and the grating lobe during reception calculated for each rotation angle is found, and the rotation angle having that value is calculated. The rotation angle having the largest value calculated in this manner is 37° in FIG. 8, 41° in FIG. 9, and 26° in FIG.

[0070] Furthermore, in order to calculate the rotation angle having the largest value among the relative distances between the grating lobes during transmission and the grating lobes during reception, the control unit 400 calculates a plurality of θ θ , which are the directivity angles of the grating lobes generated during transmission based on the above-mentioned equations (1) and (2) when the main beam directivity angles during transmission are θ0 and φ0. pq , φ pq is calculated, the visible area where transmission is possible is identified, and a first grating lobe chart is generated.

[0071] Next, the arrangement of the multiple antenna elements during transmission is rotated by a predetermined angle from the center, and multiple grating lobe directional angles θ0 and φ0 that are received for the main beam directional angles are calculated by the predetermined angle. pq , φ pq is calculated based on the following equations (1) and (2), the visible area in which reception is possible is identified, and a second grating lobe chart is generated.

[0072] This makes it possible to calculate the rotation angle at which the relative distance between each grating lobe in the visible region of the first grating lobe chart and each grating lobe in the visible region of the second grating lobe chart is maximized.

[0073] On the other hand, the control unit 400 can perform a time delay by phase shifting via multiple phase shifters 200 and frequency modulation by the signal processor 300 on the calculated beam direction angle (θ0, φ0) of the main lobe output during transmission and the beam direction angle (θ0, φ0) of the main lobe received during reception.

[0074] Here, the signal processor 300 includes a transmitting unit 310 that generates the IQ signal and transmits it to the phase shifter 200, and a receiving unit 320 that extracts the IQ signal from the signal received from the phase shifter 200, and here, the transmitting unit 310 includes an IQ signal generating unit 311 that generates the IQ signal, a modulation signal generating unit 312 that generates a modulation signal for modulating the frequency of the IQ signal according to the control of the control unit 400, a carrier signal generating unit 313 that generates a carrier signal, and a frequency modulation unit 314 that combines at least two of the IQ signal, the modulation signal, and the carrier signal received according to the control of the control unit 400 to perform frequency modulation.

[0075] Furthermore, the control unit 400 can perform frequency modulation by at least one of the following: the frequency modulation unit 314 combines the IQ signal and the modulation signal to perform frequency modulation; the frequency modulation unit combines the IQ signal with a carrier signal generated by modifying it to perform frequency modulation; and the frequency modulation unit combines the IQ signal multiplied by a sinusoidal function with the carrier signal to perform frequency modulation. Of course, frequency modulation may be performed by a combination of these depending on the settings.

[0076] JPEG0007648716000010.jpg41170

[0077] JPEG0007648716000011.jpg30170

[0078] TIFF0007648716000012.tif19170

[0079] TIFF0007648716000013.tif67170

[0080] TIFF0007648716000014.tif18170

[0081] TIFF0007648716000015.tif44170

[0082] TIFF0007648716000016.tif30170

[0083] TIFF0007648716000017.tif34170

[0084] TIFF0007648716000018.tif25170

[0085] Thus, the control unit 400 can cause the phase shifter 200 and the signal processor 300 to perform phase shift and frequency modulation, respectively, to perform time delay, according to the calculated phase shift value and frequency modulation value.

[0086] In addition, the receiving unit 320 of the signal processor 300 may be composed of a carrier signal removal unit 321 that removes a carrier signal from the signal received from the phase shifter 200 in accordance with the control of the control unit 400, a modulation signal extraction unit 322 for extracting a modulation signal from the received signal, an IQ signal extraction unit 323 that extracts the IQ signal, and a frequency modulation unit 324 that synchronizes with the frequency modulation of the transmitting unit in accordance with the control of the control unit 400 and separates at least two of the IQ signal, the modulation signal, and the carrier signal from the signal received from the phase shifter 200.

[0087] The time delay due to the phase shift and frequency modulation of the control unit 400 is sufficient when the band of the transmitted and received signals is narrowband, and can be set to perform the phase shift and frequency modulation simultaneously when the signal is wideband.

[0088] Here, a narrowband signal refers to a signal whose bandwidth (B) is much smaller than the carrier frequency (fc), and a wideband signal refers to a signal whose bandwidth (B) is similar to but not smaller than the carrier frequency (fc).

[0089] Meanwhile, a beam steering apparatus 1000 for a phased array antenna according to another embodiment of the present invention includes a plurality of antenna elements 100 for outputting a transmitted signal to the outside in a predetermined beam direction and receiving a signal received from the outside, a plurality of phase shifters 200 respectively connected to the plurality of antenna elements 100 and adjusting the phase of a signal transmitted to the antenna element and outputting the signal, or receiving a signal from the antenna element 100 and adjusting the phase of the signal, a signal processor 300 for generating an IQ signal of a baseband waveform and outputting the IQ signal to the phase shifter 200, or extracting the IQ signal from a signal received from the phase shifter 200, and a control unit 400 for controlling the plurality of antenna elements 100, the phase shifter 200, and the signal processor 300 so that a signal is output or received in a predetermined beam direction.

[0090] Here, the control unit 400 sets the beam direction of the main lobe output during transmission and the beam direction of the main lobe output during reception to be different from each other so that a grating lobe generated during transmission through the multiple antenna elements 100 and a grating lobe generated during reception do not overlap each other.

[0091] For this purpose, when the antenna elements 100 are arranged in a rectangular array, the control unit 400 controls the grating lobe direction angles (θ pq , φ pq) on a grating lobe chart, a specific grating lobe position (p, q) from among the grating lobes displayed on the grating lobe chart is selected, and the beam direction angle of the main lobe to be finally output is calculated based on the following equations (1) and (2). During reception, a grating lobe position (-p, -q) that faces the grating lobe position (p, q) during transmission and the origin of the grating lobe chart is selected, and the beam direction angle of the main lobe to be finally received is calculated based on the following equations (1) and (2).

[0092] JPEG0007648716000019.jpg29170

[0093] Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p=0 & q=0 are excluded as they are the main beam), dx is the x-axis spacing between grating lobes on a grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on a grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.

[0094] In addition, when the antenna elements 100 are arranged in a triangular array, the control unit 400 controls the grating lobe directivity angles (θ) generated when the beam directivity angles of the output main lobe are θ0 and φ0 during transmission. pq , φ pq) on a grating lobe chart, a specific grating lobe position (p, q (here, one of p and q is 0)) is selected from the grating lobes displayed on the grating lobe chart, and the beam pointing angle of the main lobe to be finally output is calculated based on the above-mentioned equations (1) and (2). During reception, a grating lobe position (-p, -q (here, one of p and q is 0)) that faces the grating lobe position at the time of transmission and the origin of the grating lobe chart is selected, and the beam pointing angle of the main lobe to be finally received is calculated based on the above-mentioned equations (1) and (2).

[0095] Furthermore, the control unit 400 can perform a phase shift via a plurality of phase shifters 200 and a time delay by frequency modulation of the signal processor 300 on the calculated beam direction angle (θ0, φ0) of the main lobe output during transmission and the beam direction angle (θ0, φ0) of the main lobe received during reception.

[0096] Here, the signal processor 300 includes a transmitting unit 310 that generates the IQ signal and transmits it to the phase shifter 200, and a receiving unit 320 that extracts the IQ signal from the signal received from the phase shifter 200, and here, the transmitting unit 310 includes an IQ signal generating unit 311 that generates the IQ signal, a modulation signal generating unit 312 that generates a modulation signal for modulating the frequency of the IQ signal according to the control of the control unit 400, a carrier signal generating unit 313 that generates a carrier signal, and a frequency modulation unit 314 that combines at least two of the IQ signal, the modulation signal, and the carrier signal received according to the control of the control unit 400 to perform frequency modulation.

[0097] Furthermore, the control unit 400 can perform frequency modulation by at least one of the following: the frequency modulation unit 314 combines the IQ signal and the modulation signal to perform frequency modulation; the frequency modulation unit combines the IQ signal with a carrier signal generated by modifying it to perform frequency modulation; and the frequency modulation unit combines the IQ signal multiplied by a sinusoidal function with the carrier signal to perform frequency modulation.

[0098] In addition, the receiving unit 320 of the signal processor 300 may be composed of a carrier signal removal unit 321 that removes a carrier signal from the signal received from the phase shifter 200 in accordance with the control of the control unit 400, a modulation signal extraction unit 322 for extracting a modulation signal from the received signal, an IQ signal extraction unit 323 that extracts the IQ signal, and a frequency modulation unit 324 that synchronizes with the frequency modulation of the transmitting unit in accordance with the control of the control unit 400 and separates at least two of the IQ signal, the modulation signal, and the carrier signal from the signal received from the phase shifter 200.

[0099] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment described above. That is, a person having ordinary knowledge in the technical field to which the present invention belongs can make multiple changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications should be considered as equivalents within the scope of the present invention. [Explanation of symbols]

[0100] 100: Antenna element 200: Phase shifter 300: Signal processor 310: Transmitter 311: IQ signal generator 312: Modulation signal generator 313: Carrier signal generator 314: Frequency modulation section 320: Receiving unit 321: Carrier signal removal unit 322: Modulation signal extraction unit 323: IQ signal extraction section 324: Frequency modulation section 400: Control unit 1000: Beam steering device

Claims

1. A plurality of antenna elements for outputting a transmitted signal to the outside in a predetermined beam direction and for receiving a signal received from the outside; a plurality of phase shifters respectively connected to the plurality of antenna elements, for adjusting a phase of a signal transmitted to the antenna elements and outputting the adjusted phase, or for receiving a signal from the antenna elements and outputting the adjusted phase; a signal processor for generating an IQ signal having a baseband waveform and outputting the IQ signal to the phase shifter, or extracting the IQ signal from a signal received from the phase shifter; a control unit that controls the antenna elements, the phase shifters, and the signal processor so that a signal is output or received in a predetermined beam direction; Including, The control unit is An arrangement of the plurality of antenna elements during transmission and an arrangement of the plurality of antenna elements during reception are set to be different from each other so that a grating lobe generated during transmission through the plurality of antenna elements and a grating lobe or a side lobe generated during reception do not overlap each other, The control unit is calculating a plurality of directional angles θ pq , φ pq of grating lobes generated during transmission based on the following equations (1) and (2) when the main beam directivity angles during transmission are θ 0 , φ 0 , and generating a first grating lobe chart by identifying a visible region in which transmission is possible; rotates the array of the antenna elements during transmission by a predetermined angle from the center, calculates grating lobe directional angles θ pq , φ pq received with respect to main beam directional angles θ 0 , φ 0 by the predetermined angle based on the following formulas (1) and (2), identifies a visible region where reception is possible, and generates a second grating lobe chart; a beam steering device that calculates an angle at which a relative distance between each grating lobe in a visible region of the first grating lobe chart and each grating lobe in a visible region of the second grating lobe chart is greatest. (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p = 0 & q = 0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

2. The arrangement of the plurality of antenna elements is Both transmit and receive are rectangular or triangular arrays, or 2. The beam steering device according to claim 1, wherein one of the transmitting and receiving beams has a square array and the other has a triangular array.

3. The control unit is When generating the first grating lobe chart and the second grating lobe chart, The beam direction angle (θ ０ , φ ０ ) for multiple grating lobe directivity angles (θ ｐｑ , φ ｐｑ 3. The beam steering device of claim 2, further comprising: a first optical axis for calculating a distance between adjacent grating lobes in the visible region;

4. The control unit is The calculated beam direction angle of the main lobe output during transmission (θ ０ , φ ０ ) and the beam direction angle of the main lobe received during reception (θ ０ , φ ０ 4. The beam steering apparatus of claim 3, wherein the time delay is performed on the first input signal (1) by phase shifting the first input signal (1) through a plurality of phase shifters and frequency modulation by the signal processor.

5. The signal processor includes: a transmission unit that generates the IQ signal and transmits the IQ signal to the phase shifter; a receiving unit that extracts the IQ signal from a signal received from the phase shifter, The transmission unit is an IQ signal generating unit that generates the IQ signal; a modulation signal generating unit that generates a modulation signal for modulating a frequency of the IQ signal in response to control of the control unit; A carrier signal generating unit that generates a carrier signal; The beam steering device according to claim 4 , further comprising: a frequency modulation unit that performs frequency modulation by combining at least two of the received IQ signal, the modulated signal, and the carrier signal under control of the control unit.

6. The control unit is the frequency modulation unit performs frequency modulation by combining the IQ signal and the modulation signal; The frequency modulation unit performs frequency modulation by combining the IQ signal with a carrier signal generated by changing the IQ signal; and The frequency modulation unit performs frequency modulation by combining the IQ signal multiplied by a sinusoidal function and the carrier signal.

6. The beam steering apparatus of claim 5, further comprising:

7. A plurality of antenna elements for outputting a transmitted signal to the outside in a predetermined beam direction and for receiving a signal received from the outside; a plurality of phase shifters respectively connected to the plurality of antenna elements, for adjusting a phase of a signal transmitted to the antenna elements and outputting the adjusted phase, or for receiving a signal from the antenna elements and outputting the adjusted phase; a signal processor for generating an IQ signal having a baseband waveform and outputting the IQ signal to the phase shifter, or extracting the IQ signal from a signal received from the phase shifter; a control unit that controls the antenna elements, the phase shifters, and the signal processor so that a signal is output or received in a predetermined beam direction; The control unit is A beam direction of a main lobe output during transmission and a beam direction of a main lobe output during reception are set to be different from each other so that a grating lobe generated during transmission through the plurality of antenna elements and a grating lobe generated during reception do not overlap each other, The control unit is When the plurality of antenna elements are arranged in a rectangular array, At the time of transmission, when the beam direction angle of the output main lobe is θ 0 , φ 0 , the generated multiple grating lobe direction angles (θ pq , φ pq ) are displayed on a grating lobe chart, a specific grating lobe position (p, q) is selected from among the grating lobes displayed on the grating lobe chart, and the beam direction angle of the final output main lobe is calculated based on the following formulas (1) and (2): A beam steering device which, upon reception, selects a grating lobe position (-p, -q) that is opposed to the grating lobe position (p, q) upon transmission based on the origin of a grating lobe chart, and calculates the beam direction angle of the main lobe that is ultimately received based on the following equations (1) and (2). (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p = 0 & q = 0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

8. The control unit is The calculated beam direction angle of the main lobe output during transmission (θ ０ , φ ０ ) and the beam direction angle of the main lobe received during reception (θ ０ , φ ０ 8. The beam steering apparatus of claim 7, wherein the time delay is performed on the first and second inputs by phase shifting through a plurality of phase shifters and frequency modulation by the signal processor.

9. A plurality of antenna elements for outputting a transmitted signal to the outside in a predetermined beam direction and for receiving a signal received from the outside; a plurality of phase shifters respectively connected to the plurality of antenna elements, for adjusting a phase of a signal transmitted to the antenna elements and outputting the adjusted phase, or for receiving a signal from the antenna elements and outputting the adjusted phase; a signal processor for generating an IQ signal having a baseband waveform and outputting the IQ signal to the phase shifter, or extracting the IQ signal from a signal received from the phase shifter; a control unit that controls the antenna elements, the phase shifters, and the signal processor so that a signal is output or received in a predetermined beam direction; The control unit is A beam direction of a main lobe output during transmission and a beam direction of a main lobe output during reception are set to be different from each other so that a grating lobe generated during transmission through the plurality of antenna elements and a grating lobe generated during reception do not overlap each other, The control unit is When the plurality of antenna elements are arranged in a triangular array, During transmission, when the beam direction angle of the output main lobe is θ 0 , φ 0 , the generated multiple grating lobe direction angles (θ pq , φ pq ) are displayed on a grating lobe chart, a specific grating lobe position (p, q (where either p or q is 0)) is selected from the grating lobes displayed on the grating lobe chart, and the beam direction angle of the final output main lobe is calculated based on the following formulas (1) and (2): A beam steering device which, upon reception, selects a grating lobe position (-p, -q (where either p or q is 0)) that is opposed to the grating lobe position upon transmission based on the origin of a grating lobe chart, and calculates the beam direction angle of the main lobe that is ultimately received based on the following equations (1) and (2). (Here, p, q = -n, -(n-1), ..., -1, 0, 1, ..., n (n is a natural number) (however, p = 0 & q = 0 are excluded because they are the main beam), dx is the x-axis spacing between grating lobes on the grating lobe chart (x-axis antenna element spacing), dy is the y-axis spacing between grating lobes on the grating lobe chart (y-axis antenna element spacing), and λ is the beam wavelength.)

10. The control unit is The calculated beam direction angle of the main lobe output during transmission (θ ０ , φ ０ ) and the beam direction angle of the main lobe received during reception (θ ０ , φ ０ 10. The beam steering apparatus of claim 9, wherein the time delay is performed on the first input signal (11) by phase shifting through a plurality of phase shifters and frequency modulation by the signal processor.

11. The signal processor includes: a transmission unit that generates the IQ signal and transmits the IQ signal to the phase shifter; a receiving unit that extracts the IQ signal from a signal received from the phase shifter, The transmission unit is an IQ signal generating unit that generates the IQ signal; a modulation signal generating unit that generates a modulation signal for modulating a frequency of the IQ signal in response to control of the control unit; A carrier signal generating unit that generates a carrier signal; The beam steering device according to claim 10 , further comprising: a frequency modulation unit that performs frequency modulation by combining at least two of the received IQ signal, the modulated signal, and the carrier signal under control of the control unit.

12. The control unit is the frequency modulation unit performs frequency modulation by combining the IQ signal and the modulation signal; The frequency modulation unit performs frequency modulation by combining the IQ signal with a carrier signal generated by changing the IQ signal; and The frequency modulation unit performs frequency modulation by combining the IQ signal multiplied by a sinusoidal function and the carrier signal.

12. The beam steering apparatus of claim 11, further comprising:

Images