Patent Publication Number: US-2023155296-A1

Title: Antenna module

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 110142544, filed on Nov. 16, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND 
     Technical Field 
     The disclosure relates to an antenna module, and more particularly, to an antenna module with two antenna units. 
     Description of Related Art 
     Generally speaking, if two antennas are disposed on a small-sized plane without a matching circuit and a parasitic pattern located on different layers, it is difficult to achieve good performance on isolation between two antennas. 
     SUMMARY 
     The disclosure provides an antenna module, which has two antenna units and may have good isolation. 
     An antenna module in the disclosure includes two antenna units, two isolation members, and a grounding member. The two antenna units include two feeding ends, two first radiators extending from the two feeding ends, and two second radiators extending from the two feeding ends. The two isolation members are disposed between the two antenna units, and include two first portions adjacent to each other and two second portions adjacent to the two second radiators. The grounding member is disposed beside the two antenna units and the two isolation members, and the two second radiators and the two second portions are connected to the grounding member. A first slot is formed among each first radiator, the corresponding second radiator, and the grounding member. A second slot is formed between each first radiator and the corresponding second radiator. A third slot is formed between each second radiator and the corresponding second portion. A fourth slot is formed between the two first portions. The two antenna units and the two isolation members are mirrored by the fourth slot, and the two first portions have widths gradually changing along an extending direction of the fourth slot. 
     In an embodiment of the disclosure, the two first portions include two right triangle regions, and each of the second portions is connected to a corner of the corresponding right triangle region. 
     In an embodiment of the disclosure, the two right triangular regions include two beveled edges. The two second portions include two vertical edges connected to the two beveled edges. The two beveled edges and the two vertical edges collectively form an M shape. 
     In an embodiment of the disclosure, each of the first radiators includes a first section, a second section, and a third section that are sequentially connected. An opening is surrounded by the first section, the second section, and the third section. The second slot communicates with the opening. 
     In an embodiment of the disclosure, the second slot is formed between the second section and the second radiator, between the third section and the second radiator, and between the first section and the third section. 
     In an embodiment of the disclosure, an end of each of the second radiators away from the feeding end is connected to an end of the corresponding second portion away from the first portion, and the end of the second radiator and the end of the second portion are collectively connected to the grounding member. 
     In an embodiment of the disclosure, a width of a portion of the first section beside the opening is greater than a total width of the end of the second radiator and the end of the second portion. 
     In an embodiment of the disclosure, a total width of the end of the second radiator and the end of the second portion is greater than a width of the second section. 
     In an embodiment of the disclosure, each of the second sections includes a terminal away from the corresponding first section, and the terminal of one of the second sections faces the terminal of the other of the second sections. 
     In an embodiment of the disclosure, each of the second radiators includes a fourth section, a fifth section, a sixth section, and a seventh section that are sequentially connected. The fourth section extends from the feeding end. The seventh section is connected to the grounding member. The first slot is formed between the fourth section and the grounding member and between the fifth section and the seventh section. 
     In an embodiment of the disclosure, the third slot is formed between the seventh section and the corresponding second portion. 
     Based on the above, the two antenna units of the antenna module in the disclosure are disposed in the mirrored manner, and in each of the two antenna units, the first slot is formed among the first radiator, the corresponding second radiator, and the grounding member. The second slot is formed between the first radiator and the corresponding second radiator. The widths of the first slot and the second slot may be configured to adjust center frequencies and impedance matching of a high frequency band and a low frequency band. In addition, in the antenna module in the disclosure, the two isolation members are disposed between the two antenna units, so as to improve the isolation between the two antenna units. The third slot is formed between each second radiator and the corresponding second portion. The fourth slot is formed between the two first portions of the two isolation members. The third slot and the fourth slot may be configured to adjust the center frequency of the isolation between the two antenna units. The two first portions of the two isolation members have the widths changing along the extending direction of the fourth slot, which helps to improve the isolation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an antenna module according to an embodiment of the disclosure. 
         FIG.  2    is a schematic diagram of the antenna module of  FIG.  1    applied to an electronic device. 
         FIG.  3    is a schematic diagram of the antenna module of  FIG.  1    applied to another electronic device. 
         FIG.  4    is a plot diagram of frequency vs. VSWR of the antenna module of  FIG.  1   . 
         FIG.  5    is a plot diagram of frequency vs. isolation of the antenna module of  FIG.  1   . 
         FIG.  6    is a plot diagram of frequency vs. antenna efficiency of the antenna module of  FIG.  1   . 
         FIG.  7 A  is a radiation pattern of a left antenna unit of the antenna module of  FIG.  1    at a frequency of 2450 MHz in the XY plane. 
         FIG.  7 B  is a radiation pattern of a right antenna unit of the antenna module of  FIG.  1    at the frequency of 2450 MHz in the XY plane. 
         FIG.  8 A  is a radiation pattern of the left antenna unit of the antenna module of  FIG.  1    at a frequency of 5470 MHz in the XY plane. 
         FIG.  8 B  is a radiation pattern of the right antenna unit of the antenna module of  FIG.  1    at the frequency of 5470 MHz in the XY plane. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
       FIG.  1    is a schematic diagram of an antenna module according to an embodiment of the disclosure. Referring to  FIG.  1   , an antenna module  100  in this embodiment includes two antenna units  110  and  110 ′, two isolation members  120  and  120 ′, and a grounding member  130 . Patterns of the two antenna units  110  and  110 ′ are the same, and are symmetrically disposed on the left and right sides in a mirrored manner. Therefore, the two antenna units  110  and  110 ′ are only disposed in a left-right reversed manner. The two isolation members  120  and  120 ′ are disposed between the two antenna units  110  and  110 ′. The grounding member  130  is disposed beside the two antenna units  110  and  110 ′ and the two isolation members  120  and  120 ′, for example, a lower part of  FIG.  1   . 
     The two antenna units  110  and  110 ′ include two feeding ends (positions A 1 ), two first radiators  118  (positions A 1  to A 7 ) extending from the two feeding ends (the positions A 1 ), and two second radiators  119  (positions A 1  and B 1  to B 3 ) extending from the two feeding ends (the positions A 1 ). Since the patterns of the two antenna units  110  and  110 ′ are the same, and patterns of the two isolation members  120  and  120 ′ are the same, the left antenna unit  110  and the left isolation member 120  of  FIG.  1    are used for description below. 
     The first radiator  118  includes a first section  111  (the positions A 1  to A 4 ), a second section  112  (the positions A 4  to A 7 ), and a third section  113  (the positions A 5  to A 6 ) that are sequentially connected in a bending manner. An opening  0  is surrounded by the first section  111  (the positions A 1  to A 4 ), the second section  112  (the positions A 4  to A 7 ), and the third section  113  (the positions A 5  to A 6 ). 
     The second section  112  (the positions A 4  to A 7 ) includes a terminal (the position A 7 ) away from the first section  111  (the positions A 1  to A 4 ). According to  FIG.  1   , the terminal (the position A 7 ) of the second section  112  of the left antenna unit  110  faces to the right while the terminal (the position A 7 ) of the second section  112  of the right antenna unit  110 ′ faces to the left. That is to say, the two terminals (the positions A 7 ) face each other, and such a design may have a better antenna effect. 
     The second radiator  119  includes a fourth section  114  (the positions A 1  to B 1 ), a fifth section  115  (the positions B 1  to B 2 ), a sixth section  116  (the position B 2 ), and a seventh section  117  (the positions B 2  to B 3 ) that are sequentially connected in the bending manner. The fourth section  114  (the positions A 1  to B 1 ) extends from the feeding end (the position A 1 ), and the seventh section  117  (the positions B 2  to B 3 ) is connected to the grounding member  130  (positions G 1 , G 2 , G 2 , and G 1 ). 
     In addition, in this embodiment, a first slot S 1  is formed among the first radiator  118 , the second radiator  119 , and the grounding member  130 . Specifically, the first slot S 1  is formed between the fourth section  114  (the positions A 1  to B 1 ) and the grounding member  130  and between the fifth section  115  (the positions B 1  to B 2 ) and the seventh section  117  (the positions B 2  to B 3 ). The first slot S 1  may be configured to adjust a central frequency and impedance matching of a high frequency band ( 5500  to  6500  MHz). 
     A second slot S 2  is formed between the first radiator  118  and the second radiator  119 , and the second slot S 2  communicates with the opening  0 . Specifically, the second slot S 2  is formed between the position A 7  of the second section  112  and the position B 2  of the second radiator  119 , among the third section  113  (the positions A 5  to A 6 ), the fifth section  115  and the fourth section  114  of the second radiator  119 , and between the positions A 1  to A 3  of the first section  111  and the position A 6  of the third section  113 . 
     The second slot S 2  may be configured to adjust center frequencies and impedance matching of a low frequency band (2400 to 2484 MHz) and a double frequency band (5150 to 5500 MHz), and may be further configured to adjust the center frequency and impedance matching of the high frequency band (6500 to 7500 MHz). 
     In addition, the two isolation members  120  and  120 ′ are located between the two antenna units  110  and  110 ′, and separated from each other. The two isolation members  120  and  120 ′ include two first portions  122  (positions B 5  to B 8 ) adjacent to each other and two second portions  124  (positions B 4  to B 5 ) adjacent to the two second radiators. The two first portions  122  have widths gradually changing along an up-down direction in  FIG.  1   . Specifically, in this embodiment, the two first portions  122  (the positions B 5  to B 8 ) include two right triangle regions (the positions B 5  to B 7 ), and each of the second portions  124  is connected to a corner (the position B 5 ) of the corresponding right triangle region. 
     In this embodiment, the two right triangle regions (the positions B 5  to B 7 ) include two beveled edges  123 . The two second portions  124  include two vertical edges  125  connected to the two beveled edges  123 . The two beveled edges  123  and the two vertical edges  125  collectively form an M shape. Therefore, the two isolation members  120  and  120 ′ present a design of an M-shaped open loop. 
     In addition, the two second radiators  119  and the two second portions  124  are connected to the grounding member  130 . Specifically, an end (the position B 3 ) of the second radiator  119  away from the feeding end is connected to an end (the position B 4 ) of the corresponding second portion  124  away from the first portion  122 . The end (the position B 3 ) of the second radiator  119  and the end (the position B 4 ) of the second portion  124  are both connected to the grounding member  130  (the positions G 1  to G 2 ). 
     In this embodiment, a width W 1  of a portion of the first section  111  beside the opening O is greater than a total width W 3  of the end of the second radiator  119  at the position B 3  and the end of the second portion  124  at the position B 4 . The total width W 3  of the end of the second radiator  119  at the position B 3  and the end of the second portion  124  at the position B 4  is greater than a width W 2  of the second section  112  (the positions A 4  to A 7 ). Such a design facilitates the isolation between the two antenna units  110  and  110 ′ in low frequency bands, and the widths W 1 , W 2 , and W 3  may be fine-tuned, so as to adjust a frequency point and the isolation. 
     Furthermore, a third slot S 3  is formed between the second radiator  119  and the second portion  124 . Specifically, the third slot S 3  is formed between the seventh section  117  (the positions B 2  to B 3 ) of the second radiator  119  and the corresponding second portion  124  (the positions B 4  to B 5 ) of the isolation member  120 . In addition, a fourth slot S 4  is formed between the two first portions  122  of the two isolation members  120  and  120 ′. The third slot S 3  and the fourth slot S 4  may be configured to adjust the isolation between the two antenna units  110  and  110 ′ in the low frequency band and the high frequency band. According to  FIG.  1   , the two antenna units  110  and  110 ′ and the two isolation members  120  and  120 ′ are mirrored by the fourth slot S 4 . That is to say, the two antenna units  110  and  110 ′ and the two isolation members  120  and  120 ′ are located on the two sides of the fourth slot S 4  in the mirrored manner. 
     In this embodiment, the antenna module  100  may be disposed on a circuit board with a length L 1  of about 30 mm, a width L 2  of about 10 mm, and a thickness of about 0.4 mm. A length L 3  of the single antenna unit  110  is about 10 mm. Two positive ends of two coaxial transmission lines  10  are connected to the two feeding ends (the positions A 1 ), and two negative ends of the two coaxial transmission lines  10  are connected to the grounding member  130  (the position G 1 ). A conductor  20  (e.g., aluminum foil or copper foil) is connected to the grounding member  130  (the positions G 1 , G 2 , G 2 , and G 1 ), and the conductor  20  is connected to a system grounding plane (not shown). 
     In the antenna module  100  of this embodiment, with the structure of a symmetrical dual-feed antenna, through the first slot S 1 , the second slot S 2 , the third slot S 3 , the fourth slot S 4 , and the M-shaped open loop formed by the two isolation members  120  and  120 ′ extending from two grounding ends (the position B 3 ), the antenna module  100  may generate characteristics of the antenna such as dual frequency bands, good isolation, and support for Wi-Fi  6 E broadband (5150 to 7125 MHz). In addition, the antenna module  100  is small in size, and is suitable for large-sized or small-sized electronic devices. 
       FIG.  2    is a schematic diagram of the antenna module of  FIG.  1    applied to an electronic device. Referring to  FIG.  2   , in this embodiment, the antenna module  100  of  FIG.  1    is applied to an electronic device  30 . The electronic device  30  is, for example, a voltage transforming device of the Internet of Things. However, the electronic device  30  may also be an AP router, and a type of the electronic device  30  is not limited thereto. A length L 4  of the electronic device  30  is about 250 mm, and a width L 5  is about 80 mm. The antenna module  100  may be disposed at a position close to a short side of the electronic device  30 . 
       FIG.  3    is a schematic diagram of the antenna module of  FIG.  1    applied to another electronic device. Referring to  FIG.  3   , in this embodiment, an electronic device  40  applied to the antenna module  100  of  FIG.  1    is an upper body of a laptop computer. The upper body of the laptop computer may be provided with the two antenna modules  100  on upper left and right sides of a screen. 
       FIG.  4    is a plot diagram of frequency vs. VSWR of the antenna module of  FIG.  1   . It should be noted that in  FIG.  4    , VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ of the antenna module  100  of  FIG.  1    when a width W 4  of the fourth slot S 4  is not  0  are shown, and the VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ when the width W 4  of the fourth slot S 4  is  0  (i.e., the two first portions  122  of the two isolation members  120  and  120 ′ are adhered together) are shown. 
     The VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ of the antenna module  100  of  FIG.  1    (when the width W 4  of the fourth slot S 4  is not 0, e.g., 0.5 mm) are denoted by solid lines while the VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ when the width W 4  of the fourth slot S 4  is zero are denoted by dashed lines. 
     Referring to  FIG.  4   , in  FIG.  4   , it may be seen that the VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ denoted by the solid lines when the width W 4  of the fourth slot S 4  is 0.5 mm have better performance than the VSWR values of the left antenna unit  110  and the right antenna unit  110 ′ denoted by the dashed lines when the width W 4  of the fourth slot S 4  is 0 mm. 
       FIG.  5    is a plot diagram of frequency vs. isolation of the antenna module of  FIG.  1   . Similarly, in  FIG.  5   , a solid line denotes the isolation of the antenna module  100  of  FIG.  1   , and a dashed line denotes the isolation of the antenna module  100  when the width W 4  of the fourth slot S 4  is zero. Referring to  FIG.  5   , according to the solid line and the dashed line, the isolation may be below 15 dB. However, compared to the dashed line, the isolation, denoted by the solid line, at two frequency points of 2400 MHz and 2484 MHz in the low frequency band may go from −10.5 dB to −16 dB. The isolation at the two frequency points of 5150 MHz and 5500 MHz in the high frequency band may go from −13.5 dB to −18 dB and from −15 dB to −19 dB. 
       FIG.  6    is a plot diagram of frequency vs. antenna efficiency of the antenna module of  FIG.  1   . Referring to  FIG.  6   ,  FIG.  6    illustrates antenna efficiency of the left antenna unit  110  and the right antenna unit  110 ′ of the antenna module  100  of  FIG.  1   . The efficiency of the left antenna unit  110  and the right antenna unit  110 ′ may be at −3.8 to −4.1 dBi in the low frequency band (2400 to 2484 MHz) of Wi-Fi 2.4G, and may be at −3.4 to −4.9 dBi in the high frequency band (5150 to 5850 MHz) of Wi-Fi 5G, and may be at −3.1 to −5.2 dBi in the high frequency band (5925 to 7125 MHz) of Wi-Fi  6 E, which has characteristics of good antenna performance. 
       FIG.  7 A  is a radiation pattern of the left antenna unit of the antenna module of  FIG.  1    at a frequency of 2450 MHz in the XY plane.  FIG.  7 B  is a radiation pattern of the right antenna unit of the antenna module of  FIG.  1    at the frequency of 2450 MHz in the XY plane.  FIG.  8 A  is a radiation pattern of the left antenna unit of the antenna module of  FIG.  1    at a frequency of 5470 MHz in the XY plane.  FIG.  8 B  is a radiation pattern of the right antenna unit of the antenna module of  FIG.  1    at the frequency of 5470 MHz in the XY plane. 
     Referring to  FIGS.  7 A to  8 B , in this embodiment, radiation patterns of the left antenna unit  110  and the right antenna unit  110 ′ have power coverage toward -X-axis and X-axis directions, respectively, and a degree of mutual influence between the radiation patterns of the two antennas is small. Therefore, ECC thereof may be less than 0.1. 
     Based on the above, the two antenna units of the antenna module in the disclosure are disposed in the mirrored manner, and the first slot is formed among the first radiator, the second radiator, and the grounding member in each of the antenna units. The second slot is formed between the first radiator and the corresponding second radiator. The widths of the first slot and the second slot may be configured to adjust the center frequencies and impedance matching of the high frequency band and the low frequency band. In addition, in the antenna module in the disclosure, the two isolation members are disposed between the two antenna units, so as to improve the isolation between the two antenna units. The third slot is formed between the second radiator and the corresponding second portion. The fourth slot is formed between the two first portions of the two isolation members. The third slot and the fourth slot may be configured to adjust the center frequency of the isolation between the two antenna units. The two first portions of the two isolation members have the widths changing along an extending direction of the fourth slot, which helps to improve the isolation.