Patent Publication Number: US-2022224010-A1

Title: Antenna member and assembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. JP2021-004233 filed Jan. 14, 2021, the contents of which are incorporated herein in their entirety by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to an antenna member which is configured to be mounted on a circuit board. 
     Referring to FIG. 25, JPB6240040 (Patent Document 1) discloses an antenna member 900 which is configured to be mounted on a circuit board (not shown) and to be used as an antenna. The antenna member 900 has a split ring resonating portion 910, an impedance matching portion 920 and a feed portion 930. The split ring resonating portion 910 is provided with a facing portion 912 which forms a split 911. The split ring resonating portion 910 has a first side portion 914, a second side portion 916 and an upper portion 918. The second side portion 916 is positioned away from the first side portion 914 in a Y-direction. The upper portion 918 connects the first side portion 914 and the second side portion 916 with each other. 
     There is a requirement for an antenna member, such as the antenna member 900 of Patent Document 1, to be further miniaturized. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an antenna member which can be further miniaturized. 
     One aspect of the present invention provides an antenna member which is configured to be mounted on a circuit board and to be used as an antenna. The antenna member has a split ring resonating portion, an impedance matching portion and a feed portion. The split ring resonating portion is provided with a facing portion which forms a split. The split ring resonating portion has a first side portion, a second side portion and an upper portion. The second side portion is positioned away from the first side portion in a lateral direction. The upper portion connects the first side portion and the second side portion with each other. The feed portion is provided on at least one of the first side portion and the second side portion. The impedance matching portion is positioned above the feed portion in an up-down direction perpendicular to the lateral direction. The impedance matching portion couples the first side portion and the second side portion with each other. 
     The antenna member of the present invention is configured so that the impedance matching portion is positioned above the feed portion in the up-down direction perpendicular to the lateral direction and couples the first side portion and the second side portion with each other. Accordingly, the antenna member of the present invention is further miniaturized. In a case where the antenna member of the present invention is made from a sheet metal plate, a blank can be cut out from the sheet metal plate without any waste. Accordingly, the present invention is more effective in this case. 
     An appreciation of the objectives of the present invention and a more complete understanding of its structure may be had by studying the following description of the preferred embodiment and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front, perspective view showing an assembly according to a first embodiment of the present invention. 
         FIG. 2  is a rear, perspective view showing the assembly of  FIG. 1 . 
         FIG. 3  is a top view showing the assembly of  FIG. 1 . 
         FIG. 4  is a front view showing the assembly of  FIG. 1 . 
         FIG. 5  is a rear view showing the assembly of  FIG. 1 . 
         FIG. 6  is a side view showing the assembly of  FIG. 1 . 
         FIG. 7  is an upper, perspective view showing an antenna member which is included in the assembly of  FIG. 1 . 
         FIG. 8  is a lower, perspective view showing the antenna member of  FIG. 7 . 
         FIG. 9  is a front view showing the antenna member of  FIG. 7 . 
         FIG. 10  is a top view showing the antenna member of  FIG. 7 . 
         FIG. 11  is a bottom view showing the antenna member of  FIG. 7 . 
         FIG. 12  is a side view showing the antenna member of  FIG. 7 . 
         FIG. 13  is a front, perspective view showing an assembly according to a second embodiment of the present invention. 
         FIG. 14  is a rear, perspective view showing the assembly of  FIG. 13 . 
         FIG. 15  is a top view showing the assembly of  FIG. 13 . 
         FIG. 16  is a front view showing the assembly of  FIG. 13 . 
         FIG. 17  is a rear view showing the assembly of  FIG. 13 . 
         FIG. 18  is a side view showing the assembly of  FIG. 13 . 
         FIG. 19  is an upper, perspective view showing an antenna member which is included in the assembly of  FIG. 13 . 
         FIG. 20  is a lower, perspective view showing the antenna member of  FIG. 19 . 
         FIG. 21  is a front view showing the antenna member of  FIG. 19 . 
         FIG. 22  is a top view showing the antenna member of  FIG. 19 . 
         FIG. 23  is a bottom view showing the antenna member of  FIG. 19 . 
         FIG. 24  is a side view showing the antenna member of  FIG. 19 . 
         FIG. 25  is a front view showing an antenna member of Patent Document 1. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     First Embodiment 
     As shown in  FIG. 1 , an assembly  700  according to a first embodiment of the present invention comprises a circuit board  600  and an antenna member  100  which is mounted on the circuit board  600 . The circuit board  600  has a feed pattern (not shown) and a ground pattern (not shown). 
     As shown in  FIG. 1 , the antenna member  100  of the present embodiment is configured to be mounted on the circuit board  600  and to be used as an antenna. The antenna member  100  is made of metal. More specifically, the antenna member  100  is formed by punching out a blank from a single sheet metal plate, followed by bending the blank. 
     As shown in  FIG. 8 , the antenna member  100  of the present embodiment has a split ring resonating portion  200 , an impedance matching portion  300  and a feed portion  500 . 
     As shown in  FIG. 9 , the split ring resonating portion  200  of the present embodiment has a substantially rectangular shape in a plane perpendicular to a front-rear direction. In the present embodiment, the front-rear direction is an X-direction. Specifically, it is assumed that forward is a positive X-direction while rearward is a negative X-direction. The split ring resonating portion  200  has a first side portion  230 , a second side portion  240 , an upper portion  260  and a lower portion  400 . 
     As shown in  FIG. 9 , the first side portion  230  of the present embodiment extends in an up-down direction. In the present embodiment, the up-down direction is a Z-direction. Specifically, it is assumed that upward is a positive Z-direction while downward is a negative Z-direction. The first side portion  230  defines a left end of the split ring resonating portion  200  in a lateral direction. In the present embodiment, the lateral direction is a Y-direction. Specifically, rightward is a positive Y-direction while leftward is a negative Y-direction. In the lateral direction, the first side portion  230  is positioned away from and leftward beyond the second side portion  240 . 
     As shown in  FIG. 9 , the second side portion  240  of the present embodiment extends in the up-down direction. The second side portion  240  defines a right end of the split ring resonating portion  200  in the lateral direction. The second side portion  240  is positioned away from the first side portion  230  in the lateral direction. Specifically, in the lateral direction, the second side portion  240  is positioned away from and rightward beyond the first side portion  230 . As shown in  FIG. 8 , the second side portion  240  has a fixed portion  242 . 
     Referring to  FIGS. 2 and 8 , the fixed portion  242  of the present embodiment is fixed to the circuit board  600  when the antenna member  100  is mounted on the circuit board  600 . The fixed portion  242  defines a lower end of the antenna member  100  in the up-down direction. The fixed portion  242  extends downward from a lower end of the second side portion  240 . 
     As shown in  FIG. 9 , the upper portion  260  of the present embodiment defines an upper end of the split ring resonating portion  200  in the up-down direction. The upper portion  260  extends in the lateral direction. The upper portion  260  connects the first side portion  230  and the second side portion  240  with each other. More specifically, the upper portion  260  connects an upper end of the first side portion  230  and an upper end of the second side portion  240  with each other. The upper portion  260  electromagnetically connects the first side portion  230  and the second side portion  240  with each other. The upper portion  260  has a facing portion  220  and an upper frame portion  262 . 
     As shown in  FIG. 8 , the facing portion  220  of the present embodiment forms a split  210 . Specifically, the split ring resonating portion  200  is provided with the facing portion  220  which forms the split  210 . The facing portion  220  forms a capacitance of the antenna member  100 . The facing portion  220  has a front facing portion  222  and a rear facing portion  224 . The front facing portion  222  and the rear facing portion  224  face each other in the front-rear direction with a space left therebetween. The front facing portion  222  is positioned forward beyond the rear facing portion  224  in the front-rear direction. The split  210  is positioned between the front facing portion  222  and the rear facing portion  224  in the front-rear direction. 
     As shown in  FIG. 9 , the upper frame portion  262  of the present embodiment has a right portion  2622  and a left portion  2624 . The right portion  2622  extends rightward in the lateral direction from the front facing portion  222 . The right portion  2622  couples the front facing portion  222  and the second side portion  240  with each other. As shown in  FIG. 8 , the left portion  2624  extends leftward in the lateral direction from the rear facing portion  224 . The left portion  2624  couples the rear facing portion  224  and the first side portion  230  with each other. 
     As shown in  FIG. 8 , the lower portion  400  of the present embodiment extends from the second side portion  240  toward the first side portion  230 . The lower portion  400  is positioned between the first side portion  230  and the second side portion  240  in the lateral direction. The lower portion  400  is not coupled with the first side portion  230 . The lower portion  400  is positioned away from the impedance matching portion  300  in the up-down direction. The lower portion  400  is positioned below the impedance matching portion  300  in the up-down direction. 
     Referring to  FIG. 9 , a frame body, which is formed by the first side portion  230 , the second side portion  240 , the upper frame portion  262  and lower portion  400 , forms an inductance of the antenna member  100 . 
     As shown in  FIG. 8 , the feed portion  500  of the present embodiment consists of a first feed portion  510  and a second feed portion  520 . 
     As shown in  FIG. 9 , the first feed portion  510  of the present embodiment is provided on a lower end of the first side portion  230  in the up-down direction. Referring to  FIGS. 2 and 8 , when the antenna member  100  is mounted on the circuit board  600 , high-frequency AC power is supplied to the first feed portion  510  from a high-frequency source (not shown) via the feed pattern of the circuit board  600  as shown in  FIG. 2 . 
     Referring to  FIGS. 2 and 8 , the second feed portion  520  of the present embodiment is provided on an end portion of the lower portion  400 . More specifically, the second feed portion  520  is provided on a left end portion of the lower portion  400 . The lower portion  400  is positioned above the second feed portion  520  in the up-down direction. The second feed portion  520  is connected with the ground pattern of the circuit board  600  when the antenna member  100  is mounted on the circuit board  600 . Specifically, when the antenna member  100  is mounted on the circuit board  600 , the lower portion  400  is connected with a ground of the circuit board  600  only at the second feed portion  520 . However, the present invention is not limited thereto. Specifically, the whole of a lower end of the lower portion  400  may be brought into contact with the ground of the circuit board  600  when the antenna member  100  is mounted on the circuit board  600 . 
     As described above, the facing portion  220  forms the capacitance of the antenna member  100 , and the frame body, which is formed by the first side portion  230 , the second side portion  240 , the upper frame portion  262  and the lower portion  400 , forms the inductance of the antenna member  100 . Accordingly, the facing portion  220  and the frame body constitute an LC resonant circuit. In other words, the antenna member  100  has a split ring resonator which is formed by the first side portion  230 , the second side portion  240 , the upper portion  260  and the lower portion  400 . 
     As shown in  FIG. 9 , the impedance matching portion  300  of the present embodiment extends in the lateral direction. More specifically, the impedance matching portion  300  extends linearly in the lateral direction. The impedance matching portion  300  intersects with the up-down direction. More specifically, the impedance matching portion  300  is perpendicular to the up-down direction. The impedance matching portion  300  is positioned below the upper portion  260  in the up-down direction. The impedance matching portion  300  is positioned below the facing portion  220  in the up-down direction. The impedance matching portion  300  is positioned above the feed portion  500  in the up-down direction perpendicular to the lateral direction. The impedance matching portion  300  couples the first side portion  230  and the second side portion  240  with each other. The impedance matching portion  300  adjusts an impedance of the antenna member  100  by a distance from the impedance matching portion  300  to the lower portion  400  and/or by a length of a portion of the impedance matching portion  300  which faces the lower portion  400 . In other words, the impedance of the antenna member  100  of the present embodiment can be adjusted only by a relationship between the impedance matching portion  300  and the lower portion  400  which are components of the antenna member  100 . Thus, the adjusted impedance of the antenna member  100  has reduced variation as compared to an adjusted impedance of an antenna member whose impedance is influenced by the ground of the circuit board  600 . 
     Since the antenna member  100  of the present embodiment has the impedance matching portion  300 , the antenna member  100  can exhibit improved return loss characteristics as compared to an assumption where the antenna member  100  have no impedance matching portion  300 . 
     Second Embodiment 
     As shown in  FIG. 13 , an assembly  700 A according to a second embodiment of the present invention comprises a circuit board  600 A and an antenna member  100 A which is mounted on the circuit board  600 A. The antenna member  100 A of the present embodiment is configured to be mounted on the circuit board  600 A and to be used as an antenna. The circuit board  600 A has a feed pattern (not shown) and a ground pattern (not shown). 
     As shown in  FIG. 20 , the antenna member  100 A according the second embodiment of the present invention has a structure similar to that of the antenna member  100  (see  FIG. 8 ) of the aforementioned first embodiment except that the antenna member  100 A has no lower portion  400 . Accordingly, components similar to those of the first embodiment among components shown in  FIGS. 13 to 24  will be designated by the same reference numerals as those of the first embodiment. As for directions and orientations in the present embodiment, expressions same as those of the first embodiment will be used hereinbelow. 
     As shown in  FIG. 20 , the antenna member  100 A of the present embodiment has a split ring resonating portion  200 A, an impedance matching portion  300 A and a feed portion  500 A. 
     As shown in  FIG. 21 , the split ring resonating portion  200 A of the present embodiment has a substantially rectangular shape in a plane perpendicular to the front-rear direction. The split ring resonating portion  200 A has a first side portion  230 A, a second side portion  240 A and an upper portion  260 . As shown in  FIG. 20 , the split ring resonating portion  200 A is provided with a facing portion  220  which forms a split  210 . The facing portion  220  forms a capacitance of the antenna member  100 A. The upper portion  260 , the split  210  and the facing portion  220  of the present embodiment have structures same as those of the upper portion  260 , the split  210  and the facing portion  220  of the first embodiment. Accordingly, a detailed explanation thereabout is omitted. 
     As shown in  FIG. 21 , the first side portion  230 A of the present embodiment extends in the up-down direction. The first side portion  230 A defines a left end of the split ring resonating portion  200 A in the lateral direction. In the lateral direction, the first side portion  230 A is positioned away from and leftward beyond the second side portion  240 A. 
     As shown in  FIG. 21 , the second side portion  240 A of the present embodiment extends in the up-down direction. The second side portion  240 A defines a right end of the split ring resonating portion  200 A in the lateral direction. The second side portion  240 A is positioned away from the first side portion  230 A in the lateral direction. Specifically, in the lateral direction, the second side portion  240 A is positioned away from and rightward beyond the first side portion  230 A. As shown in  FIG. 20 , the second side portion  240 A has a fixed portion  242 A. 
     Referring to  FIGS. 14 and 20 , the fixed portion  242 A of the present embodiment is fixed to the circuit board  600 A when the antenna member  100 A is mounted on the circuit board  600 A. The fixed portion  242 A defines a lower end of the antenna member  100 A in the up-down direction. The fixed portion  242 A extends downward from a lower end of the second side portion  240 A. 
     As shown in  FIG. 20 , the feed portion  500 A of the present embodiment consists of a first feed portion  510 A and a second feed portion  520 A. 
     As shown in  FIG. 20 , the first feed portion  510 A of the present embodiment is provided on a lower end of the first side portion  230 A in the up-down direction. Referring to  FIGS. 14 and 20 , when the antenna member  100 A is mounted on the circuit board  600 A, high-frequency AC power is supplied to the first feed portion  510 A from a high-frequency source (not shown) via the feed pattern of the circuit board  600 A. 
     As shown in  FIG. 20 , the second feed portion  520 A of the present embodiment is positioned at a lower end of the fixed portion  242 A. Referring to  FIGS. 14 and 20 , the second feed portion  520 A is connected with the ground pattern of the circuit board  600 A when the antenna member  100 A is mounted on the circuit board  600 A. 
     As shown in  FIG. 21 , the impedance matching portion  300 A of the present embodiment extends in the lateral direction. More specifically, the impedance matching portion  300 A extends linearly in the lateral direction. The impedance matching portion  300 A intersects with the up-down direction. More specifically, the impedance matching portion  300 A is perpendicular to the up-down direction. The impedance matching portion  300 A is positioned below the upper portion  260  in the up-down direction. The impedance matching portion  300 A is positioned below the facing portion  220  in the up-down direction. The impedance matching portion  300 A is positioned above the feed portion  500 A in the up-down direction perpendicular to the lateral direction. The impedance matching portion  300 A couples the first side portion  230 A and the second side portion  240 A with each other. The impedance matching portion  300 A adjusts an impedance of the antenna member  100 A by a distance from the impedance matching portion  300 A to a ground of the circuit board  600 A and/or by a length of a portion of the impedance matching portion  300 A which faces the ground of the circuit board  600 A. 
     Since the antenna member  100 A of the present embodiment has the impedance matching portion  300 A, the antenna member  100 A can exhibit improved return loss characteristics as compared to an assumption where the antenna member  100 A have no impedance matching portion  300 A. 
     Referring to  FIG. 21 , a member, which is formed by the first side portion  230 A, the second side portion  240 A and an upper frame portion  262 , forms an inductance of the antenna member  100 A. As described above, the facing portion  220  forms the capacitance of the antenna member  100 A. Accordingly, the aforementioned member and the facing portion  220  constitute an LC resonant circuit. Referring to  FIG. 13 , the assembly  700 A has a split ring resonator which is formed by the first side portion  230 A, the second side portion  240 A, the upper portion  260  and the ground of the circuit board  600 A. 
     Although the specific explanation about the present invention is made above referring to the embodiments, the present invention is not limited thereto and is susceptible to various modifications and alternative forms. 
     Although each of the antenna members  100 ,  100 A of the aforementioned embodiments is configured so that the facing portion  220  is provided on the upper portion  260 , the present invention is not limited thereto. Specifically, the antenna member  100  may be modified so that the facing portion  220  is provided on the first side portion  230  or on the second side portion  240 . Similarly, the antenna member  100 A may be modified so that the facing portion  220  is provided on the first side portion  230 A or on the second side portion  240 A. However, considering a possibility of using its secondary resonance, it is desirable that the facing portion  220  is provided on the upper portion  260 . 
     Although each of the split ring resonating portion  200 ,  200 A of the aforementioned embodiments has the substantially rectangular shape in the plane perpendicular to the front-rear direction, the present invention is not limited thereto. Specifically, the split ring resonating portion  200  may have an arc shape, a polygonal shape or a shape which is a part of a polygonal shape. Similarly, the split ring resonating portion  200 A may have an arc shape, a polygonal shape or a shape which is a part of a polygonal shape. However, from a point of view of strength of the split-ring resonating portion  200 ,  200 A, the split-ring resonating portion  200 ,  200 A is preferred to have a rectangular shape or the substantially rectangular shape. 
     Although the impedance matching portion  300  of the aforementioned first embodiment extends linearly in the lateral direction, the present invention is not limited thereto. Specifically, the impedance matching portion  300  may be modified to be bulged forward or rearward. The aforementioned modification of the impedance matching portion  300  enables a reduction of a capacitance between the modified impedance matching portion  300  and the lower portion  400 . However, if the impedance matching portion  300  is too close to the facing portion  220 , antenna characteristics of the antenna member  100  is degraded. Accordingly, it is preferred that the impedance matching portion  300  is bulged forward or rearward while the impedance matching portion  300  is positioned away from the facing portion  220 . Additionally, from a point of view of strength of the impedance matching portion  300 , it is preferable that the impedance matching portion  300  extends linearly in the lateral direction similar to the present embodiment. 
     Although the feed portion  500  of the aforementioned first embodiment is provided on both of the lower end of the first side portion  230  and the end portion of the lower portion  400 , the present embodiment is not limited thereto. Specifically, the feed portion  500  should be provided on at least one of the first side portion  230  and the second side portion  240 . 
     Although the feed portion  500 A of the aforementioned second embodiment is provided on both of the lower ends of the first side portion  230 A and the fixed portion  242 A, the present embodiment is not limited thereto. Specifically, the feed portion  500 A should be provided on at least one of the first side portion  230 A and the second side portion  240 A. 
     While there has been described what is believed to be the preferred embodiment of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such embodiments that fall within the true scope of the invention.