ANTENNA STRUCTURE

An antenna structure includes four antenna arrays spaced apart from each other. Each of the four antenna arrays has four antennas. A first phase difference between any two adjacent ones of the four antennas is 90 degrees, so that the four antennas can jointly generate a first circular polarization. The four antenna arrays have a common center point, one of the four antennas of each of the four antenna arrays adjacent to the common center point is defined as a shared antenna, and the four shared antennas jointly form a shared antenna array. A second phase difference between any two adjacent ones of the four shared antennas is 90 degrees, so that the four shared antennas can jointly generate a second circular polarization that has a same rotation direction as the first circular polarization.

FIELD OF THE DISCLOSURE

The present disclosure relates to a structure, and more particularly to an antenna structure.

BACKGROUND OF THE DISCLOSURE

A conventional antenna structure has a plurality of antennas that are each connected by two phase shifters, and the two phase shifters input 90-degree phase difference signals in a horizontal direction and a vertical direction of one of the antennas, so that each of the antennas can independently generate a circular polarization. In other words, the conventional antenna structure is based on the architecture of “each of the antennas independently generating a circular polarization,” so the conventional antenna structure requires a large quantity of phase shifters (e.g., when the antennas of the conventional antenna structure are arranged in a 32 by 32 array, the conventional antenna structure requires 2048 phase shifters). However, the phase shifter is a high cost component, so that the cost of the conventional antenna structure remains high.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacy, the present disclosure provides an antenna structure.

In one aspect, the present disclosure provides an antenna structure. The antenna structure includes a substrate and four antenna arrays. The four antenna arrays are disposed on the substrate and are spaced apart from each other. Each of the four antenna arrays includes four antennas. A first phase difference between any two adjacent ones of the four antennas is 90 degrees, so that the four antennas are configured to jointly generate a first circular polarization. The four antenna arrays have a common center point, one of the four antennas of each of the four antenna arrays adjacent to the common center point is defined as a shared antenna, and the four shared antennas jointly form a shared antenna array. A second phase difference between any two adjacent ones of the four shared antennas is 90 degrees, so that the four shared antennas are configured to jointly generate a second circular polarization that has a same rotation direction as the first circular polarization.

Therefore, in the antenna structure provided by the present disclosure, by virtue of “a first phase difference between any two adjacent ones of the four antennas in each of the four antenna arrays being 90 degrees, so that the four antennas are configured to jointly generate a first circular polarization,” and “a second phase difference between any two adjacent ones of the four shared antennas being 90 degrees, so that the four shared antennas are configured to jointly generate a second circular polarization that has the same rotation direction as the first circular polarization,” the antenna structure can effectively reduce a quantity of phase shifters used therein, thereby reducing costs.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Referring toFIG.1toFIG.10, the present disclosure provides an antenna structure100that is configured to be operated in a transmission frequency band. As shown inFIG.1andFIG.2, the antenna structure100includes a substrate1and four antenna arrays2that are disposed on the substrate1and are arranged adjacent to each other. Each of the four antenna arrays2can produce a first circular polarization, and the four antenna arrays2can jointly produce a second circular polarization that has the same rotation direction as the first circular polarization, so that a quantity of phase shifters as required by the antenna structure100is much smaller than that of a conventional antenna structure, and a gain value finally generated by the antenna structure100is greater than or equal to that of the conventional antenna structure. The following description describes the structure and connection relation of each component of the antenna structure100.

Referring toFIG.1andFIG.3, the four antenna arrays2are arranged in a 2 by 2 matrix, and the four antenna arrays2have a common center point CP1. Each of the four antenna arrays2includes four antennas21. The four antennas21are arranged in a 2 by 2 matrix, and have a sub-center point. In other words, the antenna structure100has sixteen antennas21arranged in a 4 by 4 matrix.

It should be noted that, in the present embodiment, a first separation distance D1is between two sub-center points CP2of any two adjacent ones of the four antenna arrays2, and the first separation distance D1is equal to 0.5 times the wavelength corresponding to the center frequency of the transmission frequency band. Moreover, a second separation distance D2is between the sub-central point CP2in each of the four antenna arrays2and the common central point CP1, and the first separation distance D1is preferably equal to the second separation distance D2, but the present distance is not limited thereto. In general, the first separation distance D1is preferably less than or equal to 10% of the second separation distance D2.

Referring toFIG.3andFIG.4, in each of the four antenna arrays2, a first phase difference between any two adjacent ones of the four antennas21is 90 degrees, so that the four antennas21are configured to jointly generate a first circular polarization by the first phase difference.

In a practical application, each of the four antenna arrays2further includes a first microstrip line22and a first phase shifter23. The first microstrip line22is connected to a first feeding point P21A of each of the four antennas21(by an electrically conductive post), the first phase shifter23is connected (e.g., by welding) to the first microstrip line22, and a first connection point is between the first phase shifter23and the first microstrip line22. Preferably, a position of the first connection point overlaps the sub-central point CP2, but the present disclosure is not limited thereto (e.g., the first connection point is located on one side of the sub-central point CP2).

The first microstrip line22has a first shortest path from the first connection point to two first feeding points P21A of two of the four antennas21in one of the four antenna arrays2, and the first microstrip line22has a second shortest path from the first connection point to two first feeding points P21A of another two of the four antennas21in one of the four antenna arrays2. A first difference is between the first shortest path and the second shortest path, and the first phase shifter23generates the first phase difference by the first difference. Accordingly, each of the four antenna arrays2can generate the first circular polarization through the first microstrip line22and the first phase shifter23.

In more detail, the first microstrip line22has a first body segment221and two first connection segments222. The first body segment221is connected to the first phase shifter23, the two first connection segments222are respectively connected to two ends of the first body segment221, and a width of the first body segment221is greater than a width of each of the two first connection segments222. In addition, one part of each of the two first connection segments222is preferably designed to be substantially U-shaped, and another part of each of the two first connection segments222is designed to be substantially L-shaped (or V-shaped). Accordingly, the first microstrip line22can generate the first difference when the antenna structure100has a minimal area, but the present disclosure is not limited thereto.FIG.6is a schematic view of a radiation pattern PHI generated by one of the antenna arrays2according to the present disclosure.

Referring toFIG.3andFIG.5, one of the four antennas21of each of the four antenna arrays2adjacent to the common center point CP1can be defined as a shared antenna, and the four shared antennas jointly form a shared antenna array W. A second phase difference between any two adjacent ones of the four shared antennas is 90 degrees, so that the four shared antennas are configured to jointly generate a second circular polarization that has the same rotation direction as the first circular polarization. In practice, in addition to having the first feeding point P21A, each of the four antennas21defined as one of the four shared antennas has a second feeding point P21B, and a phase difference between the first feeding point P21A and the second feeding point P21B is 90 degrees, so that the shared antenna array W is configured to generate the second circular polarization.

It should be noted that, in the present disclosure, a rotation direction of the second circular polarization needs to be consistent with a rotation direction of the first circular polarization (e.g., when the second circular polarization is left-handed, the first circular polarization of each of the four antenna arrays2is also left-handed), so as to avoid negative effects caused by mutual influence of signals (e.g., the buff value is weakened).

In a practical application, the shared antenna array W further includes a second microstrip line W24and a second phase shifter W25. The second microstrip line W24is connected to the second feeding point P21B of each of the four shared antennas (by an electrically conductive post), the second phase shifter W25is connected (e.g., by welding) to the second microstrip line W24, and a second connection point is between the second phase shifter W25and the second microstrip line W24. Preferably, a position of the second connection point overlaps the common center point CP1, but the present disclosure is not limited thereto (e.g., the second connection point is located on one side of the common center point CP1).

The second microstrip line W24has a third shortest path from the second connection point to two second feeding points P21B of two of the four shared antennas, and the second microstrip line W24has a fourth shortest path from the second connection point to two second feeding points P21B of another two of the four shared antennas. A second difference is between the third shortest path and the fourth shortest path, and the second phase shifter W25generates the second phase difference by the second difference. Accordingly, the shared antenna array W can generate the second circular polarization through the second microstrip line W24and the second phase shifter W25.

In more detail, the second microstrip line W24has a second body segment W241and two second connection segments W242. The second body segment W241is connected to the second phase shifter W25, the two second connection segments W242are respectively connected to two ends of the second body segment W241, and a width of the second body segment W241is greater than a width of each of the two second connection segments W242. In addition, one part of each of the two second connection segments W242is preferably designed to be substantially U-shaped, and another part of each of the two second connection segments W242is designed to be substantially L-shaped (or V-shaped). Accordingly, the second microstrip line W24can generate the second difference under architecture of the antenna structure100with the smallest area, but the present disclosure is not limited thereto.

It should be noted that the antenna structure100in the present embodiment is described as including the four antenna arrays2, but the present disclosure is not limited thereto. Specifically, the quantity of antenna arrays of the antenna structure can satisfy any M by N matrix arrangement (M and N are positive integers that are greater than or equal to 2). For example, in another embodiment of the present disclosure (not shown in the figures), the antenna structure100can also be adjusted to have six antenna arrays (e.g., in a 3 by 2 matrix arrangement), nine antenna arrays (e.g., in a 3 by 3 matrix arrangement), or ten antenna arrays (e.g., in a 5 by 2 matrix arrangement). For example, as shown inFIG.7andFIG.8, the nine antenna arrays2of an antenna structure100′ are arranged in a matrix of 3 by 3, and can generate a radiation pattern PH2as shown inFIG.8. In another example, as shown inFIG.9, when a plurality of antenna arrays2are arranged in a matrix of 16 by 16, the antenna structure can generate a radiation pattern PH3as shown inFIG.9.

It is worth mentioning that a phase difference between the shared antenna array W and each of the four antenna arrays2can be designed to be 45 degrees. For example, when a phase of the shared antenna array W is “1 W, 90°,” a phase of each of the four antenna arrays2may be “1 W, 0°,” or “1 W, 90°”. Or, when a phase of the shared antenna array W is “1 W, 135°,” a phase of each of the four antenna arrays2may be “1 W, 90°,” or “1 W, 180°”. Accordingly, the antenna structure100can achieve an ideal beamforming effect. For example, as shown inFIG.7andFIG.10, when the nine antenna arrays2of the antenna structure100′ are arranged in a matrix of 3 by 3 and a phase difference between the shared antenna array W and each of the four antenna arrays2is designed to be 45 degrees, the antenna structure100′ can generate a radiation pattern PH4as shown inFIG.10.

In addition, comparing with the conventional antenna structure, the antenna structure100in the present embodiment can save 75% of a quantity of phase shifters. For example, when a quantity of antennas used is 1024, a quantity of phase shifters in the antenna structure100of the present disclosure is 481, and a quantity of phase shifters in the conventional antenna structure is 2048. In other words, the antenna structure100can save about 75% of the quantity of phase shifters.

Based on the abovementioned disclosure, the antenna structure100can also be adjusted appropriately. For example, in another embodiment of the present disclosure (not shown in the figures), each of the antenna arrays2can have four first phase shifters23and a first connection line. The four first phase shifters23are respectively connected to the first feeding points P21A of the four antennas21, and each of the four first phase shifters23can send first feed signals that have different phases to the four antennas21through the first feeding points P21A. The first connection line is electrically coupled to the four first phase shifters23, and lengths of any part of the first connection line from the sub-central point CP2to any one of the first feeding points P21A are equal (e.g., the first connection line is H-shaped). The four antennas21can generate the first circular polarization by different phases of the four first feed signals.

In addition, the shared antenna array W can have four second phase shifters W25and a second connection line. The four second phase shifters W25are respectively connected to the second feeding points P21B of the four shared antennas, and each of the four second phase shifters W25can send second feed signals that have different phases to the four shared antennas through the second feeding points P21B. The second connection line is electrically coupled to the four second phase shifters W25, and lengths of any part of the second connection line from the common center point CPI to any one of the second feeding points P21B are equal (e.g., the second connection line is H-shaped). The four shared antennas can generate the second circular polarization by different phases of the four second feed signals.

Beneficial Effects of the Embodiment

In conclusion, in the antenna structure provided by the present disclosure, by virtue of “a first phase difference between any two adjacent ones of the four antennas in each of the four antenna arrays being 90 degrees, so that the four antennas are configured to jointly generate a first circular polarization,” and “a second phase difference between any two adjacent ones of the four shared antennas being 90 degrees, so that the four shared antennas are configured to jointly generate a second circular polarization that has the same rotation direction as the first circular polarization,” the antenna structure can effectively reduce a quantity of phase shifters used therein, thereby reducing costs.