This application claims priority of Application No. 111126130 filed in Taiwan on 12 Jul. 2022 under 35 U.S.C. § 119; the entire contents of all of which are hereby incorporated by reference.
The present invention relates to an integrated antenna device having high gain and able to achieve multi-beam scanning of an active array antenna, particularly to an integrated antenna device, which utilizes the multifocal focusing feature of a transmission array to obtain multi-beams having almost the same gain in beam scanning, and which can decrease the units of an active army antenna, and produce multiple scannable beams simultaneously.
One objective of the present invention is to provide an integrated antenna device having high gain and able to perform beam scanning, wherein the integrated antenna device achieves high gain with fewer antennas and reduces the scanning loss.
One objective of the present invention is to provide an integrated antenna device to produce multiple beams scanning simultaneously in different directions.
One objective of the present invention is to provide an integrated antenna device for multiple LEO satellite tracking.
According to one embodiment, the integrated antenna device of the present invention comprises a curved-surface transmitting array and a feeder array antenna. The curved-surface transmitting array has a plurality of focuses for feeding to homogenize the radiation gain thereof The feeder array antenna is arranged between the curved-surface transmitting array and the plurality of focuses, which can be partitioned into several subarrays with each subarray excited by a plurality of beamforming networks (BFNs). Each BFN can be excited by a plurality of active RF modules and has a single port to the converted to an intermediate frequency (IF) band to be handled by a DSP (Digital signal processing) processor. Through the DSP coordinative computations, the subways can be operated into a standing-along group by combining the DSP computations of all subarrays or be operated by combining some adjacent subarrays to produce multi-beams pointing to different directions through the curved-surface transmitting arrays. The active RF module of the feeder array antenna (or each grouping of several subarrays) controls the feeder array antenna to emit a first-order beams and controls the directions of the first-order beams. The curved-surface transmitting array is used to focus the first-order beams to generate second-order beams with high gain. The rearranging of the beamforming feed excitation weight of the active RF module matches with the refocusing of the plurality of focuses to make the whole integrated antenna device have a beam scanning mechanism. The refocusing feature of the curved-surface transmitting array may enhance the gain of a wide-angle scanning beam and reduce scanning loss. The curved-surface transmitting array has a plurality of array units of various signal phases and determines the gain of the second-order beam. When the grouping of subarrays is employed, multi-beams are produced. The curved-surface transmitting array's plurality of array units may enhance the multiple beams simultaneously.
The integrated antenna device of the present invention uses the feeder array antenna to generate the first-order beam and implement beam scanning and then uses the curved-surface transmitting array to focus the first-order beam and generate the high-gain second-order beam. When the feeder array antenna is partitioned into subarrays processed by different DSP processors, the grouping of different subarrays may produce different beams, where the curved-surface transmitting array can focus the first-order beams and generate the high-gain second-order beams.
Therefore, it is unnecessary to increase the size of the feeder array antenna to accommodate more feeder antennas to enhance the gain of the beam because the curved transmitting array can enhance the radiation gains. Therefore, the present invention can decrease cost and reduce power consumption, and can perform multi-beam steering in interleaved directions. From a backward viewpoint, for a given gain of antenna scanning, the feeder array antenna of the present invention can maintain almost the same antenna gain and beam width using much fewer array units than the conventional array antenna. When the beam direction changes, the portion of the feeder array antenna moves to a different focus point area. Thus, the rest of the feeder array antenna at other focus points can be used to produce other beams. By alternatively changing the portions of feeder array antenna, multi-beams can be produced and scanned alternatively to differently directions.
Because the curved-surface transmitting array has a plurality of focuses, the second-order beams of different directions may have almost the same gain during beam scanning. Therefore, the present invention can decrease scanning loss or even enhance the gain of wide-angle beams to achieve a longer transmitting distance. Multiple beams can be produced simultaneously, which can be scanned simultaneously in a coordinative fashion to track different directions, such as tracking different LEO satellites.
The feeder array antenna 34 is arranged between the curved-surface transmitting array 32 and the plurality of focuses 322, 324 and 326. The feeder array antenna 34 includes a plurality of feeder antennas 344 in parallel and an active RF (Radio Frequency) module 346. The feeder antennas 344 of the feeder array antenna 34 may be but are not limited to be patch antennas. The layout of the feeder array antenna 34 may be a plane or a curved surface. The active RF module 346 of the feeder array antenna 34 is a control circuit for controlling the feeder antennas 344. The active RF module 346 of the feeder array antenna 34 controls the coefficients of each feeder antenna 344 to generate a first-order beam (radiation waveform) 342 and controls the direction of the first-order beam 342. The first-order bean 342 matches with the phase changes of the array units of the curved-surface transmitting array 32 to generate a focusing action. Through rearranging to generate the beamforming feed excitation weight of the active RF module 346, the first-order beam 342 may match with one of the plurality of focuses 322, 324 and 326, and the curved-surface transmitting array 32 refocuses the first-order beam 342 to make the whole integrated antenna device 30 have a beam scanning function. The beamforming feed excitation weight is used to adjust the phases and amplitudes of signals.
The feeder array antenna 34 generates the first-order beam 342 and performs beam scanning with appropriate amplitudes and phases, which is similar to the conventional array antenna 20 by equal-phase radiation field superpositions. The conventional array antenna uses linear phase change to excite neighboring feeder antennas 344. With the existence of the curved-surface transmitting array 32, the feeder antennas 344 of the present invention generate matching phases to acquire the greatest antenna gain, Which is different from the conventional array antenna. With the existence of the curved-surface transmitting array 32, the first-order beam 342, which is emitted by the feeder array antenna 34, has a virtual focus (not shown in the drawing) corresponding to one of the focuses 322, 324 and 326 of the curved-surface transmitting array 32. It is preferred that the virtual focus of the first-order beam 342 completely coincides with one of the focuses 322, 324 and 326. The curved-surface transmitting array 32 focuses the first-order beam 342 to generate a high-gain second-order beam 342′. For another direction of the beam, the virtual focus thereof appears among the focuses 322, 324 and 326. The practical focusing mechanism is stated as follows: turn on and excite the feeder antennas 344 of the feeder array antenna 34 in sequence to acquire the first-order beam 342; according to the intended direction of the beam, acquire the intensity and phase of the electromagnetic signal of each feeder array antenna 34 in the direction; acquire the excitation weight of the feeder array antenna 34 in the direction using the conjugate calculation of the intensity and phase of the electromagnetic signal; if beam scanning is being performed, change the directions of the selected signals in sequence to update the excitation weight of the array antenna.
The curved-surface transmitting array 32 includes a plurality of array units 328. The plurality of array units 328 has transmitting phases to change the phases of signals. The transmitting phases of the array units 328 are different according to the shapes, strictures and/or sizes of the array units 328. Through appropriately designing the shape and/or size of each array unit 328, the plurality of army units 328 may focus the first-order beam 342 to generate the second beam 342′ and determine the gain of the second-order beam 342′. The array units 328 may have regular or irregular shapes. The air ay units 328 may respectively have different shapes, as shown in
In one embodiment, the Steepest Decent Method (SDM) is used to design the transmitting phase of each array unit 328. For the details of the algorithm, please refer to a document in P.4008-4016, Vol. 6G, Issue 8, Aug. 2018, Transactions on Antennas and Propagation of IEEE:
“Synthesis and Characteristic Evaluation of Convex Metallic Reflectarray Antennas to Radiate Relatively Orthogonal Multibeams”. SDM can reduce the difficulty in designing the array unit 328 because it needn't use complicated equations. SDM is one of electromagnetic phase-only synthesis algorithms. The present invention may also use another electromagnetic optimization algorithm that can optimize the transmitting phases of the array units 328.
In one embodiment, it is an ordinary rule to arrange the plurality of array units 328 periodically. In other words, the distances between adjacent array units are identical. However, a non-periodic optimal arrangement, such as a hexagonal arrangement, may also be used without departing from the spirit of the present invention.
In one embodiment, the array units 328 in
In the integrated antenna device 30 of the present invention, the feeder array antenna 34 is used to generate the first-order beam 342 and implement beam scanning. In order to enhance the gain of the beam, the integrated antenna device 30 of the present invention uses the curved-surface transmitting array 32 to focus the first-order beam 342 and generate the high-gain second-order beam 342′. The second-order beam is a radiation beam representing the integrated antenna device 30. The characteristics of the second-order beam may be used to establish specifications of practical communication systems and applied to operations of practical communication systems. For a given gain, the feeder array antenna 34 of the present invention has smaller size, fewer feeder antennas and lower power consumption than the conventional array antenna 20 because of the high antenna gain production. In comparison with the conventional antenna device 10, the curved-surface transmitting array 32 of the present invention has a plurality of focuses. Therefore, the second-order beams 342′ respectively having different directions may have more consistent gains during beam scanning. This decreases scanning loss. The feeder array antenna 34 (the signal feeding element) of the present invention is disposed between the curved-surface transmitting array 32 and the focuses 322, 324 and 326. Therefore, the height/thickness of the integrated antenna device 30 of the present invention is smaller than a half of the height/thickness of the conventional antenna device 10.
In one embodiment, at least two groups 348 can simultaneously produce at least two first-order beams 342 in different directions.
In one embodiment, DSP processors 36 may dynamically adjust the group 348 in real time according to the position of the receiving device. For example, in
The feeder array antenna 34 of the present invention can be used as a single-army standing-alone. The feeder array antenna 34 may also be partitioned into a plurality of groups 348 which are operating independently, therefore the present invention does not need to change the focusing behaviors of the curved-surface transmitting array 32 for multi-beam production.
In
The present invention has been disclosed with embodiments hereinbefore. However, the embodiments described above are only to exemplify the present invention but not to limit the scope of the present invention. According to the technical contents disclosed above, the persons skilled in the art should be able to make equivalent modifications or variations without departing from the present invention. Therefore, any equivalent modification or variation made by the persons skilled in the art according to the technical contents of the present invention is to be also included by the scope of the present invention.
Number | Date | Country | Kind |
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111126130 | Jul 2022 | TW | national |