Antenna module and communication device

Abstract

The utility model discloses an antenna module and a communication device. The antenna module comprises a substrate, a radiation part and a grounding part, the substrate comprises a first surface and a second surface which are opposite. The radiation part is located on the first surface of the substrate. The radiation part comprises a first feed-in point, a second feed-in point and four slotted holes. The first feed-in point and the second feed-in point are respectively located in the two-dimensional axial direction of the radiation part. Two adjacent slots of the four slots are symmetrical to each other. The grounding part is located on the second surface of the substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of communication, and more particularly to an antenna module and a communication device. BACKGROUND

[0002] In the field of radio-frequency identification (RFID), a radio-frequency reader can effectively identify a radio-frequency tag and acquire information thereof for application in a working environment in a professional field such as retail and warehousing. The radio-frequency reader is generally implemented by a communication device and internally built with an antenna. The antenna is generally a circularly polarized antenna or a linearly polarized antenna. The circularly polarized antenna can receive wireless signals from the radio-frequency tag in multiple directions, and thus can be applied to a scenario in which the radio-frequency tag is in multiple different directions. The linearly polarized antenna can improve the read-write distance between the radio-frequency reader and the radio-frequency tag due to its polarization matching with the radio-frequency tag, and thus is widely used. However, the circularly polarized antenna cannot be well polarization-matched with the radio-frequency tag, and thus reduces the read-write distance and has poor communication quality. On the other hand, the linearly polarized antenna has good communication quality when receiving wireless signals from the radio-frequency tag in a polarized direction. However, the linearly polarized antenna has poor communication quality when receiving wireless signals from the radio-frequency tag in a non-polarized direction, and thus cannot be applied to a scenario in which the radio-frequency tag is in multiple different directions. Therefore, how to make the antenna have good communication quality and a long read-write distance in a scenario in which the radio-frequency tag is in multiple different directions has become an urgent problem to be solved. SUMMARY

[0003] In view of the above, the present application provides an antenna module and a communication device. The antenna module includes a substrate, a radiation portion, and a ground portion. The substrate includes opposite first and second surfaces. The radiation portion is located on the first surface of the substrate. The radiation portion includes a first feed-in point, a second feed-in point, and four slot holes. The first and second feed-in points are located on a two-dimensional axis of the radiation portion. Two adjacent slot holes are symmetrical to each other. The ground portion is located on the second surface of the substrate.

[0004] In an embodiment of the present application, the distance between the first feed-in point and an intersection of the two-dimensional axis is the same as the distance between the second feed-in point and the intersection of the two-dimensional axis.

[0005] In an embodiment of the present application, the four slot holes are located around the intersection of the two-dimensional axis.

[0006] In an embodiment of the present application, the intersection of the two-dimensional axis is a center point of the radiation portion.

[0007] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 8mm and 25mm.

[0008] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 10mm and 20mm.

[0009] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 14mm and 17mm.

[0010] In an embodiment of the present application, the length of each of the four slot holes is one quarter of the wavelength of the frequency band operated by the radiation part.

[0011] In an embodiment of the present application, the length-width ratio of each slot hole is between 44 and 13.3.

[0012] The communication device includes an antenna module and a transceiver module. The antenna module includes a substrate, a radiation part, and a ground part. The substrate includes opposite first and second surfaces. The radiation part is located on the first surface of the substrate. The radiation part includes a first feeding point, a second feeding point, and four slot holes. The first and second feeding points are located in a two-dimensional axial direction of the radiation part. Two adjacent slot holes are symmetrical to each other. The ground part is located on the second surface of the substrate. The transceiver module is coupled to the first and second feeding points.

[0013] In an embodiment of the present application, the distance between the first feeding point and an intersection of the two-dimensional axial direction is the same as the distance between the second feeding point and the intersection of the two-dimensional axial direction.

[0014] In an embodiment of the present application, the four slot holes are located around an intersection of the two-dimensional axial direction.

[0015] In an embodiment of the present application, the intersection of the two-dimensional axial direction is a center point of the radiation part.

[0016] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 8mm and 25mm.

[0017] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 10mm and 20mm.

[0018] In an embodiment of the present application, the distance between the first feeding point and the intersection of the two-dimensional axial direction and the distance between the second feeding point and the intersection of the two-dimensional axial direction are respectively between 14 mm and 17 mm.

[0019] In an embodiment of the present application, the length of the four slot holes is one quarter of the wavelength of the frequency band operated by the radiation part.

[0020] In an embodiment of the present application, the aspect ratio of each slot hole is between 44 and 13.3.

[0021] In summary, according to some embodiments, the antenna module of the present application supports the operating bandwidth of the frequency band specified by the relevant protocol of wireless radio frequency identification. The frequency band specified by the relevant protocol of wireless radio frequency identification is, for example, the FCC (Federal Communications Commission) frequency band (about 902 MHz (million hertz) to 928 MHz). The antenna module of the present application can respectively transmit vertical polarization signals and horizontal polarization signals to radio frequency tags, thereby improving reading and writing efficiency, improving identification range, increasing reading and writing distance, reducing signal blind area, and enhancing adaptability to the position and direction of the radio frequency tag in a variable environment. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a perspective view of the antenna module of the first embodiment of the present application;

[0023] Figure 2 is a top view of the antenna module of the first embodiment of the present application;

[0024] Figure 3 is a bottom view of the antenna module of the first embodiment of the present application;

[0025] Figure 4 is a schematic view of a communication device and its application according to some embodiments of the present application;

[0026] Figure 5A and Figure 5B is a schematic view of the antenna module of the first embodiment of the present application and its application;

[0027] Figure 6 is a schematic view of the return loss of the antenna module of the first embodiment of the present application;

[0028] Figure 7 is a schematic view of the mutual coupling isolation between the first feeding point and the second feeding point of the antenna module of the first embodiment of the present application;

[0029] Figure 8A is a radiation field pattern diagram of the communication signal generated by the antenna module of the first embodiment of the present application after excitation through the first feeding point in the X-Z plane;

[0030] Figure 8B is a radiation pattern of a communication signal generated by the antenna module of the first embodiment of the present case in the Y-Z plane after excitation by the first feed point;

[0031] Figure 9A is a radiation pattern of a communication signal generated by the antenna module of the first embodiment of the present case in the X-Z plane after excitation by the second feed point;

[0032] Figure 9B is a radiation pattern of a communication signal generated by the antenna module of the first embodiment of the present case in the Y-Z plane after excitation by the second feed point;

[0033] Figure 10A is a current distribution diagram of the antenna module of the first embodiment of the present case after excitation by the first feed point;

[0034] Figure 10B is a current distribution diagram of the antenna module of the first embodiment of the present case after excitation by the second feed point;

[0035] Figure 11 is a schematic diagram of return loss of the antenna module of a comparative example of the present case and the antenna module of the first embodiment;

[0036] Figure 12 is a schematic diagram of mutual coupling isolation between the first feed point and the second feed point of the antenna module of a comparative example of the present case and the antenna module of the first embodiment;

[0037] Figure 13 is a schematic diagram of return loss of the antenna module of the first embodiment of the present case;

[0038] Figure 14 is a schematic diagram of return loss of the antenna module of the first embodiment of the present case;

[0039] Figure 15 is a schematic diagram of mutual coupling isolation between the first feed point and the second feed point of the antenna module of the first embodiment of the present case;

[0040] Figure 16 is a schematic diagram of return loss of the antenna module of the first embodiment of the present case;

[0041] Figure 17 is a schematic diagram of mutual coupling isolation between the first feed point and the second feed point of the antenna module of the first embodiment of the present case;

[0042] Figure 18 is a schematic diagram of return loss of the antenna module of the first embodiment of the present case;

[0043] Figure 19is a top view schematic diagram of an antenna module of a second embodiment of the present application;

[0044] Figure 20 is a top view schematic diagram of an antenna module of a third embodiment of the present application;

[0045] Figure 21 is a schematic diagram of return loss of the antenna modules of the first embodiment to the third embodiment of the present application;

[0046] Figure 22 is a schematic diagram of mutual coupling isolation between the first feed point and the second feed point of the antenna modules of the first embodiment to the third embodiment of the present application;

[0047] Figure 23 is a schematic diagram of antenna gain of the antenna modules of the first embodiment to the third embodiment of the present application;

[0048] Figure 24 is a top view schematic diagram of an antenna module of a fourth embodiment of the present application;

[0049] Figure 25 is a top view schematic diagram of an antenna module of a fifth embodiment of the present application;

[0050] Figure 26 is a schematic diagram of return loss of the antenna modules of the first embodiment and the fourth embodiment to the fifth embodiment of the present application;

[0051] Figure 27 is a schematic diagram of mutual coupling isolation between the first feed point and the second feed point of the antenna modules of the first embodiment and the fourth embodiment to the fifth embodiment of the present application;

[0052] Figure 28 is a schematic diagram of antenna gain of the antenna modules of the first embodiment and the fourth embodiment to the fifth embodiment of the present application.

[0053]

List of Symbols

[0054] 10: antenna module

[0055] 20: substrate

[0056] 21: first surface

[0057] 23: second surface

[0058] 25: body

[0059] 30: radiating portion

[0060] FD1: first feed point

[0061] FD2: second feed point

[0062] W1: length

[0063] W2: width

[0064] ST1: first slot

[0065] ST2: second slot

[0066] ST3: third slot

[0067] ST4: fourth slot

[0068] 40: ground portion

[0069] 100: communication device

[0070] 200: transceiver module

[0071] 300: radio frequency tag

[0072] HS: horizontally polarized signal

[0073] VS: vertically polarized signal

[0074] P: intersection

[0075] L1-L58: curve DETAILED DESCRIPTION

[0076] Referring to Figure 1 , Figure 2 and Figure 3 . Figure 1 is a perspective view of an antenna module 10 according to a first embodiment of the present application. Figure 2 is a top view of the antenna module 10 according to the first embodiment of the present application. Figure 3 is a bottom view of the antenna module 10 according to the first embodiment of the present application. The antenna module 10 includes a substrate 20, a radiating portion 30, and a ground portion 40. The substrate 20 includes a first surface 21 and a second surface 23 opposite to each other. The radiating portion 30 is located on the first surface 21 of the substrate 20. The ground portion 40 is located on the second surface 23 of the substrate 20. In this way, the radiating portion 30 and the ground portion 40 are separated from each other. Specifically, the first surface 21 and the second surface 23 of the substrate 20 each has a conductive layer. The radiating portion 30 is made by processing the conductive layer of the first surface 21 of the substrate 20, and the ground portion 40 is made by processing the conductive layer of the second surface 23 of the substrate 20. The processing includes printing processing, etching processing, or the like. In some embodiments, the substrate 20 further includes a body 25 between the first surface 21 and the second surface 23. The body 25 is, for example, a medium with a dielectric coefficient of 4.4. In this way, the radiating portion 30 and the ground portion 40 are separated from each other via the body 25. In some embodiments, the substrate 20 is, for example, an FR-4 substrate. In some embodiments, the substrate 20 is a single layer board, so that the thickness of the antenna module 10 can be reduced, and thus the antenna module 10 can be miniaturized to be easily installed.

[0077] As shown in Figure 2 , the radiating portion 30 comprises a first feed point FD1, a second feed point FD2, and four slot holes (i.e., a first slot hole ST1, a second slot hole ST2, a third slot hole ST3, and a fourth slot hole ST4). The first feed point FD1 and the second feed point FD2 penetrate the substrate 20. The first feed point FD1 is coupled to a signal source via a coaxial cable (not shown). The second feed point FD2 is coupled to a signal source via a coaxial cable (not shown). The signal source is, for example, a transceiver module (to be described later) of a communication device. The first feed point FD1 and the second feed point FD2 are respectively located in two-dimensional axial directions of the radiating portion 30. Specifically, the first feed point FD1 is located in a first dimension axial direction (e.g., an X axial direction, i.e., a horizontal axial direction) of the two-dimensional axial directions of the radiating portion 30, and the second feed point FD2 is located in a second dimension axial direction (e.g., a Y axial direction, i.e., a vertical axial direction) of the two-dimensional axial directions of the radiating portion 30. The first feed point FD1 and the second feed point FD2 alternately receive the same feed signal from the signal source. In this way, the radiating portion 30 of the antenna module 10 alternately transmits a first dimension polarized signal (e.g., a horizontally polarized signal) through the first feed point FD1 and a second dimension polarized signal (e.g., a vertically polarized signal) through the second feed point FD2. By the two-dimensional polarized signals (i.e., the first dimension polarized signal and the second dimension polarized signal), the communication quality, the communication efficiency, the communication range, the communication distance, and the signal blind area can be improved. Specifically, by the two-dimensional polarized signals, the antenna module 10 not only has the characteristic of receiving wireless signals from multiple different directions like a circularly polarized antenna, but also has the characteristic of improving the communication distance like a linearly polarized antenna.

[0078] As shown in Figure 2 , the four slot holes (i.e., the first slot hole ST1 to the fourth slot hole ST4) are separated from each other, and two adjacent ones of the four slot holes are symmetric to each other. In some embodiments, the four slot holes are respectively formed by removing a region of the conductive layer of the first surface 21 of the substrate 20, and exposing the body 25 of the substrate 20 of the corresponding region. In this way, the antenna module 10 adjusts the current path and the current distribution of the radiating portion 30 by the resonance of the four slot holes and the radiating portion 30, so as to operate in the operating frequency bandwidth of the frequency band specified by the relevant protocol of the wireless radio frequency identification. The frequency band specified by the relevant protocol of the wireless radio frequency identification is, for example, the FCC frequency band (about 902 MHz to 928 MHz). Furthermore, by the resonance of the four slot holes and the radiating portion 30, the mutual coupling effect between the first feed point FD1 and the second feed point FD2 of the antenna module 10 can be reduced.

[0079] Referring to Figure 4 , Figure 5A and Figure 5B . Figure 4 is a schematic diagram of a communication device 100 and applications thereof according to some embodiments.Figure 5A and Figure 5B is a schematic diagram of the antenna module 10 of the first embodiment and its application. The communication device 100 comprises the antenna module 10 and a transceiver module 200. The transceiver module 200 is coupled to the first feed point FD1 and the second feed point FD2 of the antenna module 10. In some embodiments, the transceiver module 200 is coupled to the first feed point FD1 and the second feed point FD2 of the antenna module 10 via a coaxial cable (not shown), in particular the inner core of the coaxial cable. The ground portion 40 of the antenna module 10 (as shown in Figure 3 ) is connected to a reference ground end (not shown) of a host board of the communication device 100 by the outer metal surface of the coaxial cable. The outer metal surface of the coaxial cable is separated from the inner core by an insulating layer. The communication device 100 is, for example, a radio frequency reader to read and write a radio frequency tag 300. The radiating portion 30 of the antenna module 10 is capable of transmitting communication signals to the radio frequency tag 300. For example, the radiating portion 30 of the antenna module 10 alternately transmits a first dimension polarized signal (e.g. a horizontal polarized signal HS) through the first feed point FD1 and a second dimension polarized signal (e.g. a vertical polarized signal VS) through the second feed point FD2 to the radio frequency tag 300. With the two dimension polarized signals (i.e. the first dimension polarized signal and the second dimension polarized signal), the read and write quality, the read and write efficiency, the read and write range (e.g. the radio frequency tag 300 can be read and written by the communication device 100 no matter it is set in a horizontal direction or a vertical direction relative to the communication device 100), the read and write distance (e.g. the read and write distance of the antenna module 10 of the present embodiment can reach at least 5m (meter) compared to linear polarized antenna and circular polarized antenna) and the signal blind area can be improved. In some embodiments, the read and write distance of the antenna module 10 of the present embodiment in the horizontal direction and the read and write distance in the vertical direction can be almost consistent.

[0080] Referring to Figure 6 , is a schematic diagram of the return loss of the antenna module 10 of the first embodiment. The curve L1 is the return loss of the communication signal generated by the antenna module 10 through the first feed point FD1 in an ideal situation (also the return loss of the communication signal generated by the antenna module 10 through the second feed point FD2 in an ideal situation). The curve L2 is the return loss of the communication signal generated by the antenna module 10 through the first feed point FD1 in a practical situation. The curve L3 is the return loss of the communication signal generated by the antenna module 10 through the second feed point FD2 in a practical situation. It can be seen from Figure 6 that with the structural design of the antenna module 10, the return loss is substantially less than -6dB (decibel) specified by the related protocol of wireless radio frequency identification in the desired operating frequency band (e.g. FCC frequency band), and the antenna module 10 has good antenna characteristics.

[0081] Referring to Figure 7 is a plot of the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment. Curve L4 is the degree of interference of the communication signal transmitted by the antenna module 10 of the ideal case through the excitation of the first feed point FD1 to the communication signal received through the excitation of the second feed point FD2 (also the degree of interference of the communication signal transmitted by the antenna module 10 of the ideal case through the excitation of the second feed point FD2 to the communication signal received through the excitation of the first feed point FD1). Curve L5 is the degree of interference of the communication signal transmitted by the antenna module 10 of the actual case through the excitation of the first feed point FD1 to the communication signal received through the excitation of the second feed point FD2. Curve L6 is the degree of interference of the communication signal transmitted by the antenna module 10 of the actual case through the excitation of the second feed point FD2 to the communication signal received through the excitation of the first feed point FD1. It can be seen from Figure 7 that through the structural design of the antenna module 10, the degree of interference (i.e. the degree of mutual coupling) between the first feed point FD1 and the second feed point FD2 is less than -25dB in the desired operating frequency band (such as the FCC frequency band), which basically meets the relevant specifications of the relevant protocols of wireless radio frequency identification (the more relaxed specifications are, for example, the degree of interference is less than -15dB, and the more stringent specifications are, for example, the degree of interference is less than a standard value, which is in the range of -20dB to -30dB), and has good mutual coupling isolation and stability.

[0082] Referring to Figure 8A to Figure 9B . Figure 8A is a plot of the radiation field pattern of the communication signal generated after the antenna module 10 of the first embodiment is excited through the first feed point FD1 in the X-Z plane. Figure 8B is a plot of the radiation field pattern of the communication signal generated after the antenna module 10 of the first embodiment is excited through the first feed point FD1 in the Y-Z plane. Figure 9A is a plot of the radiation field pattern of the communication signal generated after the antenna module 10 of the first embodiment is excited through the second feed point FD2 in the X-Z plane. Figure 9Bis the radiation pattern of the communication signal generated by the antenna module 10 of the first embodiment of the present application when excited by the second feed point FD2 in the Y-Z plane. Here, the numbers on the circumference are the degrees of the circumference, and the distance from the center of the curve to the gain in the radiation pattern corresponds to the gain (dB). Curve L7 is the main polarization direction (e.g., horizontal polarization direction) radiation pattern of the communication signal generated by the antenna module 10 when excited by the first feed point FD1 in the X-Z plane. Curve L8 is the cross-polarization direction (which is perpendicular to the main polarization direction, e.g., vertical polarization direction) radiation pattern of the communication signal generated by the antenna module 10 when excited by the first feed point FD1 in the X-Z plane. Curve L9 is the main polarization direction radiation pattern of the communication signal generated by the antenna module 10 when excited by the first feed point FD1 in the Y-Z plane. Curve L10 is the cross-polarization direction radiation pattern of the communication signal generated by the antenna module 10 when excited by the first feed point FD1 in the Y-Z plane. Curve L11 is the main polarization direction (e.g., vertical polarization direction) radiation pattern of the communication signal generated by the antenna module 10 when excited by the second feed point FD2 in the X-Z plane. Curve L12 is the cross-polarization direction (which is perpendicular to the main polarization direction, e.g., horizontal polarization direction) radiation pattern of the communication signal generated by the antenna module 10 when excited by the second feed point FD2 in the X-Z plane. Curve L13 is the main polarization direction radiation pattern of the communication signal generated by the antenna module 10 when excited by the second feed point FD2 in the Y-Z plane. Curve L14 is the cross-polarization direction radiation pattern of the communication signal generated by the antenna module 10 when excited by the second feed point FD2 in the Y-Z plane. As can be seen from Figure 8A to Figure 9B , when the different feed points are excited, the corresponding main polarization direction signal of the antenna module 10 is strengthened and approximates to an omnidirectional radiation, and the corresponding cross-polarization direction signal is suppressed, so as to improve the communication efficiency and communication quality and have good signal transceiving capability.

[0083] Referring to Figure 10A and Figure 10B . Figure 10A is the current distribution diagram of the antenna module 10 of the first embodiment of the present application when excited by the first feed point FD1. Figure 10B is the current distribution diagram of the antenna module 10 of the first embodiment of the present application when excited by the second feed point FD2. As can be seen from Figure 10A , when the first feed point FD1 is excited, the current flows along the X-axis direction, indicating that the excitation of the first feed point FD1 generates a horizontal polarization signal. As can be seen from Figure 10BAs can be seen, when the second feed point FD2 is excited, the current flows in the Y-axis direction, indicating that the excitation of the second feed point FD2 generates a vertically polarized signal. As such, the excitation of different feed points can stagger the current flow direction and reduce the degree of interference between the first feed point FD1 and the second feed point FD2, thereby improving the mutual coupling isolation and the stability of the antenna module 10.

[0084] Referring to Figure 11 FIG. 16 is a graph showing the return loss of the antenna module of the comparative example and the antenna module 10 of the first embodiment of the present application. Here, the difference between the antenna module of the comparative example and the antenna module 10 of the first embodiment of the present application is that the antenna module of the comparative example does not have the four slot holes (i.e., the first slot hole ST1 to the fourth slot hole ST4). The curve L15 is the return loss of the communication signal generated after the antenna module of the comparative example is excited through the first feed point FD1 (also the return loss of the communication signal generated after the antenna module of the comparative example is excited through the second feed point FD2). The curve L16 is the return loss of the communication signal generated after the antenna module 10 of the first embodiment of the present application is excited through the first feed point FD1 (also the return loss of the communication signal generated after the antenna module 10 of the first embodiment of the present application is excited through the second feed point FD2). As can be seen from FIG. 16, in the comparative example, the return loss in the desired operating frequency band (e.g., the FCC frequency band) is greater than -6 dB specified by the relevant protocol of the wireless radio frequency identification. Compared with the comparative example, the antenna module 10 of the first embodiment of the present application has the four slot holes, so that the return loss in the desired operating frequency band (e.g., the FCC frequency band) is less than -6 dB specified by the relevant protocol of the wireless radio frequency identification, and has good antenna characteristics. Figure 11

[0085] Referring to Figure 12 ​is a schematic diagram of the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment of the present case and the antenna module of a comparative example of the present case. Here, the difference between the antenna module of the comparative example and the antenna module 10 of the first embodiment of the present case is that the antenna module of the comparative example does not have the four slot holes (i.e., the first slot hole ST1 to the fourth slot hole ST4). The curve L17 is the interference level of the communication signal transmitted by exciting the first feed point FD1 of the antenna module of the comparative example to the communication signal received by exciting the second feed point FD2 (also the interference level of the communication signal transmitted by exciting the second feed point FD2 of the antenna module of the comparative example to the communication signal received by exciting the first feed point FD1). The curve L18 is the interference level of the communication signal transmitted by exciting the first feed point FD1 of the antenna module 10 of the first embodiment of the present case to the communication signal received by exciting the second feed point FD2 (also the interference level of the communication signal transmitted by exciting the second feed point FD2 of the antenna module 10 of the first embodiment of the present case to the communication signal received by exciting the first feed point FD1). It can be seen from Figure 12 the comparative example that the interference level (i.e., the mutual coupling level) between the first feed point FD1 and the second feed point FD2 is greater than -30 dB in the desired operating frequency band (e.g., the FCC frequency band). Compared with the comparative example, the antenna module 10 of the first embodiment of the present case has the four slot holes, so that the interference level between the first feed point FD1 and the second feed point FD2 is less than -25 dB in the desired operating frequency band (e.g., the FCC frequency band), substantially meeting the relevant specifications of the relevant protocols of wireless radio frequency identification (the less stringent specification is, for example, the interference level is less than -15 dB, and the more stringent specification is, for example, the interference level is less than a standard value, which is in the range of -20 dB to -30 dB), and has good mutual coupling isolation and stability.

[0086] As Figure 2As shown, in some embodiments, the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is the same as the distance between the second feed point FD2 and the intersection P of the two-dimensional axial, to balance the impedance matching of the two-dimensional polarized signal. That is, to make the impedance matching of the first dimension polarized signal of the antenna module 10 the same as the impedance matching of the second dimension polarized signal. In some embodiments, by adjusting the distance between the first feed point FD1 and the intersection P of the two-dimensional axial and the distance between the second feed point FD2 and the intersection P of the two-dimensional axial, the impedance matching of the two-dimensional polarized signal can be adjusted. In some embodiments, the distance between the first feed point FD1 and the intersection P of the two-dimensional axial and the distance between the second feed point FD2 and the intersection P of the two-dimensional axial are respectively between 8mm (millimeter) to 25mm. In other embodiments, the distance between the first feed point FD1 and the intersection P of the two-dimensional axial and the distance between the second feed point FD2 and the intersection P of the two-dimensional axial are respectively between 10mm to 20mm. In yet other embodiments, the distance between the first feed point FD1 and the intersection P of the two-dimensional axial and the distance between the second feed point FD2 and the intersection P of the two-dimensional axial are respectively between 14mm to 17mm.

[0087] Referring to Figure 13 FIG. 19 is a graph showing the return loss of the antenna module 10 of the first embodiment. Since the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is the same as the distance between the second feed point FD2 and the intersection P of the two-dimensional axial, only the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is described herein. The curve L19 is the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 11mm. The curve L20 is the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 14mm. The curve L21 is the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 17mm. The curve L22 is the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 20mm. The curve L23 is the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 23mm. As can be seen from FIG. 19, when the distance between the first feed point FD1 and the intersection P of the two-dimensional axial is 11mm, 14mm, 17mm, 20mm or 23mm, the return loss of the antenna module 10 is substantially less than -6dB specified by the relevant protocol of the wireless radio frequency identification, and the antenna module 10 has good antenna characteristics. Figure 13

[0088] As Figure 2 ​As shown, in some embodiments, the four slots (i.e., the first slot ST1 to the fourth slot ST4) are located around the intersection P of the two-dimensional axis. In some embodiments, the intersection P of the two-dimensional axis is the center point of the radiating portion 30 to balance the impedance matching of the two-dimensional polarized signal. In some embodiments, the first slot ST1 and the third slot ST3 are respectively located on both sides of the first feed point FD1, and the third slot ST3 and the fourth slot ST4 are respectively located on both sides of the second feed point FD2.

[0089] In some embodiments, the length of each of the four slots (i.e., the first slot ST1 to the fourth slot ST4) is one quarter of the wavelength of the frequency band (specifically, the center frequency of the frequency band, i.e., the resonant frequency point) operated by the radiating portion 30 to obtain better impedance matching. In some embodiments, the impedance matching of the antenna module 10 can be adjusted by adjusting the aspect ratio of each slot. In some embodiments, the aspect ratio of each slot is between 44 and 13.3. For example, the length of each slot is between 40 mm and 44 mm, and the width of each slot is between 1 mm and 3 mm. In some embodiments, the length of each slot is the same, and the width of each slot is the same. In some embodiments, the width of each slot is inversely proportional to the resonant frequency point of the antenna module 10. In some embodiments, the length of each slot is inversely proportional to the resonant frequency point of the antenna module 10.

[0090] Referring to Figure 14 is a schematic diagram of the return loss of the antenna module 10 of the first embodiment. Since the width of each slot is the same, only the width of the first slot ST1 is described here. The curve L24 is the return loss of the antenna module 10 when the width of the first slot ST1 is 1 mm. The curve L25 is the return loss of the antenna module 10 when the width of the first slot ST1 is 2 mm. The curve L26 is the return loss of the antenna module 10 when the width of the first slot ST1 is 3 mm. It can be seen from Figure 14 that when the width of the first slot ST1 is 1 mm, 2 mm, or 3 mm, the return loss of the antenna module 10 is substantially less than -6 dB specified by the relevant protocol of wireless radio frequency identification in the desired operating frequency band (e.g., the FCC frequency band), and has good antenna characteristics.

[0091] Referring to Figure 15Fig. 27 is a schematic diagram of the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment of the present application. Since the widths of the slots are the same, only the width of the first slot ST1 is described herein. The curve L27 is the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the first feed point FD1 to the communication signal received through the excitation of the second feed point FD2 (also the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the second feed point FD2 to the communication signal received through the excitation of the first feed point FD1) when the width of the first slot ST1 is 1 mm. The curve L28 is the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the first feed point FD1 to the communication signal received through the excitation of the second feed point FD2 (also the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the second feed point FD2 to the communication signal received through the excitation of the first feed point FD1) when the width of the first slot ST1 is 2 mm. The curve L29 is the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the first feed point FD1 to the communication signal received through the excitation of the second feed point FD2 (also the degree of interference of the communication signal transmitted by the antenna module 10 through the excitation of the second feed point FD2 to the communication signal received through the excitation of the first feed point FD1) when the width of the first slot ST1 is 3 mm. From the curves L27, L28 and L29, it can be seen that when the width of the first slot ST1 is 1 mm, 2 mm or 3 mm, the degree of interference between the first feed point FD1 and the second feed point FD2 substantially satisfies the relevant specifications of the relevant protocols of the wireless radio frequency identification (e.g. the degree of interference is less than -15 dB) in the desired operating frequency band (e.g. the FCC frequency band), and the mutual coupling isolation and stability are good. Figure 15 It can be seen that when the width of the first slot ST1 is 1 mm, 2 mm or 3 mm, the degree of interference between the first feed point FD1 and the second feed point FD2 substantially satisfies the relevant specifications of the relevant protocols of the wireless radio frequency identification (e.g. the degree of interference is less than -15 dB) in the desired operating frequency band (e.g. the FCC frequency band), and the mutual coupling isolation and stability are good.

[0092] Referring to Fig. 28, Figure 16 Fig. 30 is a schematic diagram of the return loss of the antenna module 10 of the first embodiment of the present application. Since the lengths of the slots are the same, only the length of the first slot ST1 is described herein. The curve L30 is the return loss of the antenna module 10 when the length of the first slot ST1 is 40 mm. The curve L31 is the return loss of the antenna module 10 when the length of the first slot ST1 is 42 mm. The curve L32 is the return loss of the antenna module 10 when the length of the first slot ST1 is 44 mm. From the curves L30, L31 and L32, it can be seen that when the length of the first slot ST1 is 40 mm, 42 mm or 44 mm, the return loss of the antenna module 10 substantially satisfies the relevant specifications of the relevant protocols of the wireless radio frequency identification (e.g. the return loss is less than -15 dB) in the desired operating frequency band (e.g. the FCC frequency band), and the return loss is good. Figure 16It can be seen that when the length of the first slot hole ST1 is 40 mm, 42 mm or 44 mm, the return loss of the antenna module 10 is substantially less than -6 dB specified by the relevant protocol of the wireless radio frequency identification in the operating frequency band (for example, the FCC frequency band) to be covered, and the antenna module 10 has good antenna characteristics.

[0093] Referring to Figure 17 is a schematic diagram of the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment. Since the lengths of the slot holes are the same, only the length of the first slot hole ST1 is described here. The curve L33 is the degree of interference of the communication signal transmitted by exciting the first feed point FD1 with the communication signal received by exciting the second feed point FD2 (also the degree of interference of the communication signal transmitted by exciting the second feed point FD2 with the communication signal received by exciting the first feed point FD1) when the length of the first slot hole ST1 is 40 mm. The curve L34 is the degree of interference of the communication signal transmitted by exciting the first feed point FD1 with the communication signal received by exciting the second feed point FD2 (also the degree of interference of the communication signal transmitted by exciting the second feed point FD2 with the communication signal received by exciting the first feed point FD1) when the length of the first slot hole ST1 is 42 mm. The curve L35 is the degree of interference of the communication signal transmitted by exciting the first feed point FD1 with the communication signal received by exciting the second feed point FD2 (also the degree of interference of the communication signal transmitted by exciting the second feed point FD2 with the communication signal received by exciting the first feed point FD1) when the length of the first slot hole ST1 is 44 mm. From Figure 17 It can be seen that when the length of the first slot hole ST1 is 40 mm, 42 mm or 44 mm, the degree of interference between the first feed point FD1 and the second feed point FD2 substantially satisfies the relevant specification (for example, the degree of interference is less than -15 dB, or the degree of interference is less than a standard value, which is in the range of -20 dB to -30 dB) of the relevant protocol of the wireless radio frequency identification in the operating frequency band (for example, the FCC frequency band) to be covered, and the antenna module 10 has good mutual coupling isolation and stability.

[0094] In some embodiments, the size of the radiation portion 30 is inversely proportional to the resonant frequency point of the antenna module 10. As Figure 2As shown, in some embodiments, the length Wl and the width W2 of the radiating portion 30 are between 74mm and 78mm. In some embodiments, the length Wl of the radiating portion 30 is the same as the width W2 thereof.

[0095] Referring to Figure 18 , is a graph showing the return loss of the antenna module 10 of the first embodiment. Here, the length Wl of the radiating portion 30 is the same as the width W2 thereof is exemplified, and only the length Wl of the radiating portion 30 is described. The curve L36 is the return loss of the antenna module 10 when the length Wl of the radiating portion 30 is 74mm. The curve L37 is the return loss of the antenna module 10 when the length Wl of the radiating portion 30 is 75mm. The curve L38 is the return loss of the antenna module 10 when the length Wl of the radiating portion 30 is 76mm. The curve L39 is the return loss of the antenna module 10 when the length Wl of the radiating portion 30 is 77mm. The curve L40 is the return loss of the antenna module 10 when the length Wl of the radiating portion 30 is 78mm. From Figure 18 , it can be seen that when the length Wl of the radiating portion 30 is 74mm, 75mm, 76mm, 77mm or 78mm, the return loss of the antenna module 10 is substantially less than -6dB specified by the relevant protocol of the wireless radio frequency identification, and the antenna module 10 has good antenna characteristics.

[0096] Referring to Figure 2 , Figure 19 and Figure 20 . Figure 19 , is a top view of the antenna module 10 of the second embodiment. Figure 20 , is a top view of the antenna module 10 of the third embodiment. As shown in Figure 2 , in the first embodiment, the shape of the radiating portion 30 of the antenna module 10 is cross-shaped to have better antenna gain. The four corners of the cross-shaped radiating portion 30 respectively have notches, and the notches can be square or rectangular. However, the present application is not limited thereto, and the shape of the radiating portion 30 can be any type. For example, as shown in Figure 19 , in the second embodiment, the shape of the radiating portion 30 is circular; and as shown in Figure 20 , in the third embodiment, the shape of the radiating portion 30 is square to have better impedance matching.

[0097] Referring to Figure 21 , is a graph showing the return loss of the antenna module 10 of the first embodiment to the third embodiment. The curve L41 is the return loss of the antenna module 10 of the first embodiment. The curve L42 is the return loss of the antenna module 10 of the second embodiment. The curve L43 is the return loss of the antenna module 10 of the third embodiment. From Figure 21It can be seen from FIG. 12 that the radiation part 30 of the antenna module 10 has good antenna characteristics, no matter in the case of cross shape, circular shape or square shape, the return loss is substantially less than -6dB specified by the relevant protocol of the wireless radio frequency identification in the desired operating frequency band (for example, the FCC frequency band).

[0098] Referring to Figure 22 FIG. 13 is a diagram of the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment to the third embodiment. The curve L44 is the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the first embodiment. The curve L45 is the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the second embodiment. The curve L46 is the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 of the third embodiment. It can be seen from FIG. 13 that the interference level (i.e., the mutual coupling level) between the first feed point FD1 and the second feed point FD2 of the antenna module 10 is less than -30dB, substantially satisfying the relevant specification (for example, the interference level is less than -15dB for a relatively relaxed specification, and the interference level is less than a standard value for a relatively strict specification, the standard value is in the range of -20dB to -30dB) of the relevant protocol of the wireless radio frequency identification, and has good mutual coupling isolation and stability, and makes the antenna module 10 provide good radio frequency reading and writing capability, no matter in the case of cross shape, circular shape or square shape. Figure 22

[0099] Referring to Figure 23 FIG. 14 is a diagram of the antenna gain of the antenna module 10 of the first embodiment to the third embodiment. The curve L47 is the antenna gain of the antenna module 10 of the first embodiment. The curve L48 is the antenna gain of the antenna module 10 of the second embodiment. The curve L49 is the antenna gain of the antenna module 10 of the third embodiment. It can be seen from FIG. 14 that the radiation part 30 of the antenna module 10 has good antenna gain, no matter in the case of cross shape, circular shape or square shape. Figure 23

[0100] Referring to Figure 2 , Figure 24 and Figure 25 . Figure 24 FIG. 15 is a top view diagram of the antenna module 10 of the fourth embodiment. Figure 25 FIG. 16 is a top view diagram of the antenna module 10 of the fifth embodiment. As Figure 2 ​​As shown, in the first embodiment, each slot of the antenna module 10 extends along the boundary of the radiating portion 30 in an M-shape (with its pointed end facing outward from the boundary of the radiating portion 30). However, this embodiment is not limited to this; each slot can extend in any direction with two adjacent slots symmetrical. For example, as... Figure 24 As shown, in the fourth embodiment, the radiating portion 30 is W-shaped, and its pointed end faces the inner side of the boundary of the radiating portion 30; as Figure 25 As shown, in the fifth embodiment, the radiating part 30 is arc-shaped, and the dot corresponding to the arc is the center point of the radiating part 30.

[0101] Reference Figure 26 This diagram illustrates the return loss of the antenna module 10 in the first, fourth, and fifth embodiments of this invention. Curve L50 represents the return loss of the antenna module 10 in the first embodiment. Curve L51 represents the return loss of the antenna module 10 in the fourth embodiment. Curve L52 represents the return loss of the antenna module 10 in the fifth embodiment. Figure 26 As can be seen, regardless of whether the shape of each slot of the antenna module 10 is W-shaped, M-shaped or arc-shaped, the return loss in the desired operating frequency band (e.g., FCC band) is basically less than -6dB as specified by the relevant radio frequency identification protocol, thus exhibiting good antenna characteristics.

[0102] Reference Figure 27 This diagram illustrates the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the first, fourth, and fifth embodiments of this invention. Curve L53 represents the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the first embodiment of this invention. Curve L54 represents the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the fourth embodiment of this invention. Curve L55 represents the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the fifth embodiment of this invention. From Figure 27 As can be seen, regardless of whether the shape of each slot of the antenna module 10 is W-shaped, M-shaped, or arc-shaped, the interference level (i.e., mutual coupling level) between the first feed point FD1 and the second feed point FD2 is less than -30dB, which basically meets the relevant specifications of the radio frequency identification protocol (a more lenient specification is, for example, an interference level of less than -15dB, and a more stringent specification is, for example, an interference level of less than a standard value, which is in the range of -20dB to -30dB), thus having good mutual coupling isolation and stability, and enabling the antenna module 10 to provide good radio frequency read and write capabilities.

[0103] Reference Figure 28Fig. 56 is a graph showing the antenna gain of the antenna module 10 of the first embodiment and the fourth to fifth embodiments. The curve L56 is the antenna gain of the antenna module 10 of the first embodiment. The curve L57 is the antenna gain of the antenna module 10 of the fourth embodiment. The curve L58 is the antenna gain of the antenna module 10 of the fifth embodiment. It can be seen from Fig. 56 that the shape of the slots of the antenna module 10 has good antenna gain in the case of W-shaped, M-shaped or arc-shaped. Figure 28

[0104] In summary, according to some embodiments, the antenna module of the present application supports the frequency bandwidth of the frequency band specified by the relevant protocol of the wireless radio frequency identification. The frequency band specified by the relevant protocol of the wireless radio frequency identification is, for example, the FCC frequency band (about 902-928 MHz). The antenna module of the present application can respectively transmit vertical polarization signals and horizontal polarization signals to the radio frequency tag, thereby improving the reading and writing efficiency, improving the identification range, increasing the reading and writing distance, reducing the signal blind area and enhancing the adaptability of the position and direction of the radio frequency tag in a variable environment.​

Claims

1. An antenna module, characterized in that, Include: A substrate, comprising a first surface and a second surface opposite to each other; A radiating portion, located on the first surface of the substrate, includes a first feed point, a second feed point, and four slots. The first feed point and the second feed point are respectively located along the two-dimensional axis of the radiating portion, and two adjacent slots are symmetrical to each other. The grounding portion is located on the second surface of the substrate.

2. The antenna module as described in claim 1, characterized in that, The distance between the first feed point and the intersection of the two-dimensional axis is the same as the distance between the second feed point and the intersection of the two-dimensional axis.

3. The antenna module as described in claim 1, characterized in that, The four slots are located around the intersection of the two-dimensional axes.

4. The antenna module as described in claim 2 or 3, characterized in that, The intersection of these two-dimensional axes is the center point of the radiating part.

5. The antenna module as described in claim 2, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are between 8 mm and 25 mm, respectively.

6. The antenna module as described in claim 5, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are both between 10 mm and 20 mm.

7. The antenna module as described in claim 6, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are between 14 mm and 17 mm, respectively.

8. The antenna module as described in claim 1, characterized in that, The lengths of the four slots are each a quarter wavelength of the frequency band in which the radiating element operates.

9. The antenna module as described in claim 1, characterized in that, The aspect ratio of each slot is between 44 and 13.

3.

10. A communication device, characterized in that, Include: Antenna module, comprising: A substrate, comprising a first surface and a second surface opposite to each other; A radiating portion, located on the first surface of the substrate, includes a first feed point, a second feed point, and four slots. The first feed point and the second feed point are respectively located along the two-dimensional axis of the radiating portion, and two adjacent slots are symmetrical to each other. A grounding portion is located on the second surface of the substrate; and The transceiver module is coupled to the first feed point and the second feed point.

11. The communication device as claimed in claim 10, characterized in that, The distance between the first feed point and the intersection of the two-dimensional axis is the same as the distance between the second feed point and the intersection of the two-dimensional axis.

12. The communication device as claimed in claim 10, characterized in that, The four slots are located around the intersection of the two-dimensional axes.

13. The communication device as claimed in claim 11 or 12, characterized in that, The intersection of these two-dimensional axes is the center point of the radiating part.

14. The communication device as claimed in claim 11, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are between 8 mm and 25 mm, respectively.

15. The communication device as claimed in claim 14, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are both between 10 mm and 20 mm.

16. The communication device as claimed in claim 15, characterized in that, The distance between the first feed point and the intersection point of the two-dimensional axis, and the distance between the second feed point and the intersection point of the two-dimensional axis, are between 14 mm and 17 mm, respectively.

17. The communication device as claimed in claim 10, characterized in that, The lengths of the four slots are each a quarter wavelength of the frequency band in which the radiating element operates.

18. The communication device as claimed in claim 10, characterized in that, The aspect ratio of each slot is between 44 and 13.3.

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