Patent Publication Number: US-2022224012-A1

Title: Patch antenna and array antenna comprising same

Description:
TECHNICAL FIELD 
     The present invention relates to a patch antenna and an array antenna having the same. More particularly, the present invention relates to a patch antenna and an array antenna having the same, which can be used as a radar for a vehicle since having a wide bandwidth and a wide beam width. 
     BACKGROUND ART 
     As an autonomous driving age has arrived, various kinds of sensors are mounted on vehicles, and a radar is one of such sensors. 
     Meanwhile, there are various kinds of radars to be mounted on vehicles. The radars are divided into a long range radar (LRR), a middle range radar (MRR), and a short range radar (SRR). The SRR, more specifically, ultra short range radars (USRRs), are used for corner radars of passenger cars or used on the sides of trucks or buses. 
     Such USRRs perform a blind spot detection (BSD) function to detect blind spots. Accordingly, the USRRs essentially require wide bandwidth and beam width, and more specifically, require a bandwidth ranging from 77 GHz to 81 GHz and a beam width of more than 150°. 
     However, the conventional USRRs of a patch antenna form, which use a single radiator (patch), have a limitation in bandwidth to act. Moreover, the conventional USRRs of a patch antenna form, which use a plurality of radiators, have a disadvantage in that it shows insignificant effect in bandwidth expansion since resonance of a main radiator and resonance of a parasitic element adjoin each other to expand a bandwidth. Furthermore, because resonance of the main radiator and resonance of the parasitic element adjoin each other, the beam width is about 100°. So, the conventional USRR is too inadequate to perform the BSD function. 
     In order to overcome the above disadvantages of the conventional USRR, the present invention relates to an advanced patch antenna and an array antenna having the same, which can provide a wide bandwidth and a wide beam width. 
     DISCLOSURE 
     Technical Problem 
     Accordingly, the present invention has been made in an effort to solve the above-mentioned problems occurring in the prior arts, and it is an object of the present invention to provide a patch antenna and an array antenna having the same, which can perfectly perform a BSD function of an ultra short range radars (USRRs) by showing e a wide bandwidth and a wide beam width. 
     It is another object of the present invention to provide a patch antenna and an array antenna having the same, which can show a bandwidth ranging from 77 GHz to 81 GHz and a beam width of more than 150° required for the USRR. 
     Technical objects to be achieved by the present invention are not limited to the above-described objects and other technical objects that have not been described will be evidently understood by those skilled in the art from the following description. 
     Technical Solution 
     To achieve the above objects, the present invention provides a patch antenna including: a substrate; a first radiator disposed on the substrate and having a first shape; a second radiator disposed on the substrate, being spaced apart from the first radiator at a predetermined distance, and having a second shape; and a power feeder which supplies a power feed signal to the first radiator, wherein the first radiator includes: a first outer peripheral portion formed straight in the horizontal direction and second outer peripheral portions vertically formed from both ends of the first outer peripheral portion. 
     According to an embodiment of the present invention, the first shape and the second shape are the same, and the first radiator and the second radiator differ from each other in size. 
     According to an embodiment of the present invention, the second outer peripheral portion includes: a second-first outer peripheral portion formed straight in the vertical direction; a second-second outer peripheral portion curved at one end of the second-first outer peripheral portion in the central direction of the first radiator; and a second-third outer peripheral portion formed straight at one end of the second-second outer peripheral portion in the horizontal direction. 
     According to an embodiment of the present invention, the patch antenna further includes a first via and a second via formed in an inner space of the second-second outer peripheral portion. 
     According to an embodiment of the present invention, the shortest distance between the first outer peripheral portion and the first via and the second via is less than the shortest distance between the first outer peripheral portion and the second-third outer peripheral portion. 
     According to an embodiment of the present invention, a distance between the center of the first via and the center of the second via is less than 2/λ. 
     According to an embodiment of the present invention, the power feeder is directly connected with the second-third outer peripheral portion or extends from the second-third outer peripheral portion to supply a power feed signal to the first radiator. 
     According to an embodiment of the present invention, the first radiator and the second radiator are equal in horizontal length, but differ from each other in vertical length. 
     According to an embodiment of the present invention, the first radiator operates in a first operating frequency band and is tuned to resonate in the first operating frequency band, and the second radiator operates in a second operating frequency band after the first operating frequency band and is tuned not to resonate in the first operating frequency band and the second operating frequency band. 
     According to an embodiment of the present invention, the predetermined distance ranges from 0.1 mm to 0.2 mm. According to an embodiment of the present invention, provided is an array antenna including: a plurality of patch antennas; and a common power feeder connected to power feeders of the plurality of patch antennas in order to supply power feed signals to the plurality of power feeders. 
     Advantageous Effects 
     The patch antenna and the array antenna having the same according to an embodiment of the present invention can provide both of a wide bandwidth and a wide beam width required for the USRR since adjusting differences in shape and size of the first radiator and the second radiator and a predetermined distance between the first radiator and the second radiator. 
     Additionally, the patch antenna and the array antenna having the same according to an embodiment of the present invention can show a bandwidth ranging from 77 GHz to 81 GHz and a beam width of more than 150° required for the USRR since a resonance band of the first radiator is expanded, differently from the conventional patch antenna that resonance of the main radiator and resonance of the parasitic element adjoin each other to expand the bandwidth and the beam width. 
     The effects of the present invention are not limited to the above-mentioned effects and further effects not described above will be clearly understood by those skilled in the art. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top view of a patch antenna according to a first preferred embodiment of the present invention. 
         FIG. 2  is a perspective view of the patch antenna according to the first preferred embodiment of the present invention. 
         FIG. 3  is a side elevation view of the patch antenna according to the first preferred embodiment of the present invention. 
         FIG. 4  is a top view of a first radiator. 
         FIG. 5  is a top view illustrating an example of a conventional patch antenna using a single radiator. 
         FIG. 6  is a graph showing a simulation result for band characteristics of the conventional patch antenna illustrated in  FIG. 5  and the patch antenna according to the first preferred embodiment of the present invention. 
         FIG. 7  is a graph showing a simulation result for beam widths of the conventional patch antenna illustrated in  FIG. 5  and the patch antenna according to the first preferred embodiment of the present invention. 
         FIG. 8  is a top view of an array antenna according to a second preferred embodiment of the present invention. 
     
    
    
     MODE FOR INVENTION 
     Advantages and features of the present invention, and a method to achieve them of the present invention will be obvious with reference to embodiments along with the accompanying drawings which are described below. Meanwhile, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. In the detailed description, the same reference numbers of the drawings refer to the same or equivalent parts of the present invention. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Terms used in the specification are provided for description of the exemplary embodiments, and the present invention is not limited thereto. In the specification, singulars in sentences include plural unless otherwise noted. It will be understood in the specification that the terms “comprises” and “comprising”, when used herein, specify the presence of constituent elements, but do not preclude the presence or addition of other constituent elements. 
       FIG. 1  is a top view of a patch antenna  100  according to a first preferred embodiment of the present invention,  FIG. 2  is a perspective view of the patch antenna  100  according to the first preferred embodiment of the present invention, and  FIG. 3  is a side elevation view of the patch antenna  100  according to the first preferred embodiment of the present invention. 
     The patch antenna  100  according to the first preferred embodiment of the present invention includes a substrate  5 , a first radiator  10 , a second radiator  20 , and a power feeder  30 . Of course, the present invention can further include general components required for achieving the objects of the present invention. 
     The substrate  5  may be a general antenna substrate. For instance, the substrate  5  may be one of known antenna substrates, such as a printed circuit board (PCB), or a flexible printed circuit board (F-PCB). Because an area of the substrate is associated with an area of the patch antenna  100 , it is not necessary to use an excessively wide substrate in order to miniaturize the antenna. Therefore, it is sufficient that the substrate  5  has an area enough to form the first radiator  10 , the second radiator  20 , and the power feeder  30  on one side thereof. 
     The first radiator  10  is made of a conductive material, is arranged on one side of the substrate  5  in a patch form, and has a first shape. 
       FIG. 4  is a top view of the first radiator  10 . Referring to  FIG. 4 , the first radiator includes: a first outer peripheral portion  10 - 1  formed straight in the horizontal direction; and second outer peripheral portions  10 - 2  formed at both ends of the first outer peripheral portion in the vertical direction. The first outer peripheral portion  10 - 1  and the second outer peripheral portions  10 - 2  are formed by areas divided according to the shape of the first radiator  10 . 
     Meanwhile, the two second peripheral portions  10 - 2  are vertically formed at both sides of the first peripheral portion  10 - 1  formed straight in the horizontal direction. Alternatively, a part formed at one end of the first peripheral portion  10 - 1  in the vertical direction may be named a second peripheral portion  10 - 2 , and a part formed at the other end of the first peripheral portion  10 - 1  in the vertical direction may be named a third outer peripheral portion (not shown), but for convenience of description, all of them will be called the second peripheral portion  10 - 2  in this description of the present invention. 
     The first outer peripheral portion  10 - 1  is formed at the upper end of the first radiator  10  when viewed from the top, and may be formed straight in the horizontal direction to have a predetermined length. Of course, the first outer peripheral portion  10 - 1  may be formed to have any one of different shapes through antenna tuning to adjust operating frequency band or resonance. For instance, the first peripheral portion  10 - 1  may be formed in a saw-toothed wheel shape having at least one groove, and in this instance, there is effect of extension of length. 
     The second outer peripheral portions  10 - 2  are formed at both ends of the first outer peripheral portion  10 - 1  in the vertical direction. In more detail, each of the second outer peripheral portions  10 - 2  includes: a second-first outer peripheral portion  10 - 2 - 1  formed straight in the vertical direction; a second-second outer peripheral portion  10 - 2 - 2  curved at one end of the second-first outer peripheral portion  10 - 2 - 1  in the central direction of the first radiator  10 ; and a second-third outer peripheral portion  10 - 2 - 3  formed straight at one end of the second-second outer peripheral portion  10 - 2 - 2  in the horizontal direction. 
     The second-first outer peripheral portions  10 - 21 - 1  are formed at the right and left sides like the first outer peripheral portion  10 - 1  when viewed from the top, and may be formed straight in the vertical direction to have a predetermined length. Of course, the second-first outer peripheral portions  10 - 21 - 1  may be formed to have any one of different shapes through antenna tuning to adjust operating frequency band or resonance. For instance, the second-first outer peripheral portions  10 - 2 - 1  may be formed in a saw-toothed wheel shape having at least one groove, and in this instance, there is effect of extension of length. 
     The second-second outer peripheral portions  10 - 2 - 2  are formed to be curved from one end of the second-first outer peripheral portion  10 - 2 - 1  in the central direction of the first radiator  10 . Here, the central direction of the first radiator  10  is indicated by a dotted line of  FIG. 4 , and means the direction that the power feeder  30  which will be described later is arranged. In this instance, that the second-second outer peripheral portions  10 - 2 - 2  are curved in the central direction of the first radiator  10  means that the second-second outer peripheral portions  10 - 2 - 2  are bent inwards. That is, viewed from the top, since the second-second outer peripheral portions  10 - 2 - 2  are formed at the left side and the right side, the second-second outer peripheral portion  10 - 2 - 2  formed at the left side is bent in the counterclockwise direction, and the second-second outer peripheral portion  10 - 2 - 2  formed at the right side is bent in the clockwise direction. 
     In the meantime, the second-second outer peripheral portions  10 - 2 - 2  are bent to have a predetermined curvature. So, if the curvature is large, since the second-second outer peripheral portions  10 - 2 - 2  are bent a lot, the second-second outer peripheral portions  10 - 2 - 2  get shorter. If the curvature is small, since the second-second outer peripheral portions  10 - 2 - 2  are bent less, the second-second outer peripheral portions  10 - 2 - 2  get longer. Therefore, it is possible to freely set the curvature of if the curvature is large, since the second-second outer peripheral portions  10 - 2 - 2  are bent a lot, the second-second outer peripheral portions  10 - 2 - 2  through antenna tuning to adjust operating frequency band or resonance. 
     A first via  12 - 1  and a second via  12 - 2  are formed in an inner space of the first radiator  10  having the second-second outer peripheral portions  10 - 2 - 2 . The first via  12 - 1  and a second via  12 - 2  are connected with the substrate  5  to perform a short circuit. 
     In this instance, a distance between the center of the first via  12 - 1  and the center of the second via  12 - 2  may be less than 2/λ, so that the patch antenna  100  according to the first preferred embodiment of the present invention can show a bandwidth ranging from 77 GHz to 81 GHz and a beam width of more than 150°. 
     The second-third outer peripheral portion  10 - 2 - 3  is formed straight at one end of the second-second outer peripheral portion  10 - 2 - 2  in the horizontal direction. Because the second-second outer peripheral portion  10 - 2 - 2  is formed based on the horizontal direction, the second-third outer peripheral portion  10 - 2 - 3  is shorter than the second-first outer peripheral portion  10 - 2 - 1 . However, the second-third outer peripheral portions  10 - 2 - 3  may be also formed to have any one of different shapes through antenna tuning to adjust operating frequency band or resonance. For instance, the second-third outer peripheral portions  10 - 2 - 3  may be formed in a saw-toothed wheel shape having at least one groove, and in this instance, there is effect of extension of length. 
     Till now, referring to  FIG. 4 , the shape of the first radiator  10  is described in detail. Hereinafter, referring to  FIGS. 1 and 2 , the second radiator  20  will be described. 
     The second radiator  20  is made of a conductive material, is arranged on one side of the substrate  5  in a patch form, and is spaced apart from the first radiator  10  at a predetermined interval to have a second shape. 
     Here, preferably, the second radiator  20  is made of the same conductive material as the first radiator  10  so as to simplify a manufacturing process, and one side of the substrate  5  is the same as the one side of the substrate  5  on which the first radiator  10  is arranged. 
     Meanwhile, description of the second radiator  20  is basically the same as the first radiator  10 . For instance, the second radiator  20  may includes components corresponding to the first outer peripheral portion  10 - 1 , the second outer peripheral portion  10 - 2 , which has the second-first outer peripheral portion  10 - 2 - 1 , the second-second outer peripheral portion  10 - 2 - 2 , and the second-third outer peripheral portion  10 - 2 - 3 , the first via  112 - 1 , and the second via  12 - 2  of the first radiator  10 . Repeated descriptions of the components of the second radiator  20  will be omitted. 
     In this instance, since the first radiator  10  and the second radiator  20  have the same shape, the first shape of the first radiator  10  and the second shape of the second radiator  20  are the same. However, because the first radiator  10  and the second radiator  20  are not in symmetric relation, the first radiator  10  and the second radiator  20  may differ from each other in size. 
     Referring to  FIG. 1 , a horizontal length of the first radiator  10  and a horizontal length of the second radiator  20  are equal to each other, but a vertical length D 1  of the first radiator  10  is longer than a vertical length D 2  of the second radiator  20 . However, as occasion demands, the vertical length D 1  of the first radiator  10  is more than the vertical length D 2  of the second radiator  20 . Therefore, the first radiator  10  and the second radiator  20  may differ from each other in size, vertical length, and area. 
     Meanwhile, the predetermined interval between the first radiator  10  and the second radiator  20  may be a slot ranging from 0.1 mm to 0.2 mm to perform antenna tuning to adjust operating frequency band or resonance. 
     The second radiator  20  is not directly supplied with a power feed signal for operation from a power feeder, but may be supplied with a power feed signal, which has been supplied to the first radiator  10  by the power feeder  30 , through electromagnetic coupling. In this instance, the power feed signal supplied to the first radiator  10  by the power feeder  30  is supplied to the second radiator  20  after passing the predetermined interval. 
     On the other hand, the second radiator  20  serves as a parasitic element in relationship with the first radiator  10 , and it is a matter related with the operating frequency band and resonance, and will be described referring to  FIGS. 6 and 7  in detail. 
     The power feeder  30  supplies a power feed signal to the first radiator  10 . 
     Here, the power feeder  30  is directly connected with the second-third outer peripheral portion  10 - 2 - 3  of the first radiator  10 , or is formed integrally with the first radiator  10  to extend from the second-third outer peripheral portion  10 - 2 - 3 . 
     As described above, the power feeder  30  directly supplies the power feed signal to the first radiator  10 , and the power feed signal supplied to the first radiator is supplied to the second radiator  20  through the electromagnetic coupling. 
     Till now, the configuration of the patch antenna  100  according to the first preferred embodiment of the present invention is described. According to the present invention, the patch antenna  100  can show wide bandwidth and beam width according to the shapes of the first radiator  10  and the second radiator  20 , a difference in size between the first radiator  10  and the second radiator  20 , and a distance between the first radiator  10  and the second radiator  20  so as to perfectly perform the BSD function of the USRR. Hereinafter, simulation results on characteristics in bandwidth and beam width will be described in detail. 
       FIG. 5  is a top view illustrating an example of a conventional patch antenna using a single radiator,  FIG. 6  is a graph showing a simulation result for band characteristics of the conventional patch antenna illustrated in  FIG. 5  and the patch antenna according to the first preferred embodiment of the present invention, and  FIG. 7  is a graph showing a simulation result for beam widths of the conventional patch antenna illustrated in  FIG. 5  and the patch antenna according to the first preferred embodiment of the present invention. In  FIGS. 6 and 7 , parts marked with—indicate the simulation result of the patch antenna  100  according to the first preferred embodiment of the present invention, and parts marked with A indicate the simulation result of the conventional patch antenna. A detailed description of the conventional patch antenna illustrated in  FIG. 5  will be omitted since the conventional patch antenna corresponds to known technology. 
     Referring to  FIG. 6 , the bandwidth of the convention patch antenna illustrated in  FIG. 5  ranges from 77.79 GHz to 80.4 GHz corresponding to m1 to m2, and the bandwidth of the patch antenna  100  according to the first preferred embodiment of the present invention ranges from 77.11 GHz to 81.06 GHz corresponding to m3 to m4. It is confirmed that the bandwidth of the patch antenna  100  according to the first preferred embodiment of the present invention is wider than that of the conventional patch antenna illustrated in  FIG. 5 . 
     In this instance, because the bandwidth of the convention patch antenna illustrated in  FIG. 5  ranges from 77.79 GHz to 80.4 GHz, the conventional patch antenna needs 0.79 GHz more in a zone of less than 77.79 GHz, and 0.6 GHz more in a zone of more than 08.4 GHz for covering the bandwidth, ranging from 77 GHz to 81 GHz, required for the USRR. 
     However, the bandwidth of the patch antenna  100  according to the first preferred embodiment of the present invention ranges from 77.11 GHz to 81.06 GHz. So, the patch antenna  100  according to the first preferred embodiment of the present invention provides a sufficient bandwidth in the zone of more than 81.06 GHz but is 0.11 GHz less in the zone of less than 77.11 GHz, but it is a value which is negligible. Finally, the patch antenna  100  according to the first preferred embodiment of the present invention can show a wide bandwidth which can wholly cover the bandwidth, 77 to 81 GHz required for the USRR. 
     Referring to  FIG. 7 , the beam width of the conventional patch antenna illustrated in  FIG. 5  is 133.2° corresponding to m2 to m3, and the beam width of the patch antenna  100  according to the first preferred embodiment of the present invention is 160.2° corresponding to m5 to m6. So, the beam width of the patch antenna  100  according to the first preferred embodiment of the present invention is wider than the beam width of the conventional patch antenna illustrated in  FIG. 5 . 
     In this instance, since the beam width of the conventional patch antenna illustrated in  FIG. 5  is 133.2°, the conventional patch antenna is 16.8° less for covering the beam width, 150°, required for the USRR. 
     However, because the beam width of the patch antenna  100  according to the first preferred embodiment of the present invention is 160.2°, the patch antenna  100  according to the first preferred embodiment of the present invention can fully cover the beam width, 150°, required for the USRR. 
     As described above, the patch antenna  100  according to the first preferred embodiment of the present invention can all of the bandwidth and the beam width required for the USRR. The first radiator  10  operates in a first operating frequency band and is tuned to resonate in the first operating frequency band, and the second radiator  20  operates in a second operating frequency band after the first operating frequency band and is tuned not to resonate in the first operating frequency band and the second operating frequency band. Here, a detailed tuning of the first radiator  10  and the second radiator  20  is achieved by adjusting the shapes of the first radiator  10  and the second radiator  20 , a difference in size between the first radiator  10  and the second radiator  20 , and a distance between the first radiator  10  and the second radiator  20 . So, the above is technical characteristics of the patch antenna  100  according to the first preferred embodiment of the present invention. Moreover, the conventional patch antenna expands the bandwidth and the beam width by adjoining resonance of the main radiator and resonance of the parasitic element with each other, but the patch antenna  100  according to the first preferred embodiment of the present invention shows advanced and new technical characteristics since expanding one resonant band according to one main radiator (the first radiator). 
       FIG. 8  is a top view of an array antenna  1000  according to a second preferred embodiment of the present invention. 
     The array antenna  1000  according to the second preferred embodiment of the present invention includes a plurality of patch antennas  100  and a common power feeder  300 . Of course, the present invention can further include general components required for achieving the objects of the present invention. 
     The plurality of patch antennas  100  are the patch antennas  100  according to the first preferred embodiment of the present invention, and repeated descriptions of the patch antennas  100  will be omitted. 
     The common power feeder  300  is connected with the power feeders  30  included in the patch antennas  100  according to the first preferred embodiment to supply power feed signals. Therefore, power feed signals are directly supplied to the power feeders  30 , and as described above, the power feed signals supplied to the power feeders  30  can be supplied to the second radiator  20 . 
     While the exemplary embodiments of the present invention have been described in more detail with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that the present invention can be implemented as other concrete forms without changing the inventive concept or essential features. Therefore, these embodiments as described above are only proposed for illustrative purposes and do not limit the present invention.