Antenna module and communication device

Abstract

An antenna module and a communication device, the antenna module includes a substrate, a radiating portion and a grounding portion. The substrate includes opposite first and second surfaces. The radiating portion is located on the first surface of the substrate. The radiating 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 two-dimensional axial directions of the radiating portion respectively. Two adjacent ones of the four slot holes are symmetrical to each other. The grounding portion is located on the second surface of the substrate.

Description

Technical Field

[0001] This case concerns the field of communications, particularly antenna modules and communication devices. Background Technology

[0002] In Radio Frequency Identification (RFID) technology, RFID readers effectively identify RFID tags and acquire their information for use in workplaces such as retail and warehousing. RFID readers are typically implemented using a communication device and have a built-in antenna. This antenna is generally either circularly polarized or linearly polarized. Circularly polarized antennas can receive wireless signals from RFID tags in multiple directions, making them suitable for scenarios where RFID tags are positioned in multiple different directions. Linearly polarized antennas are widely used because they can polarize and match the RFID tag, thus increasing the read / write distance between the RFID reader and the tag. However, because circularly polarized antennas cannot polarize and match the RFID tag optimally, they reduce the read / write distance and have poor communication quality. On the other hand, linearly polarized antennas have better communication quality when receiving wireless signals in the polarized direction of the RFID tag. However, because linearly polarized antennas have poor communication quality when receiving wireless signals in the non-polarized direction of the RFID tag, they are not suitable for scenarios where RFID tags are positioned in multiple different directions. Therefore, how to ensure good communication quality and long read / write distance for antennas even when RFID tags are in multiple different directions has become an urgent issue to be addressed. Summary of the Invention

[0003] In view of the above, this invention provides an antenna module and a communication device. The antenna module includes a substrate, a radiating portion, and a grounding portion. The substrate includes a first surface and a second surface facing each other. The radiating portion is located on the first surface of the substrate. The radiating portion 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. Two adjacent slots are symmetrical to each other. The grounding portion is located on the second surface of the substrate.

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

[0005] In one embodiment of the present invention, the four slots are located around a point where the two-dimensional axes intersect.

[0006] In one embodiment of the present invention, the intersection of the two-dimensional axes is a center point of the radiating portion.

[0007] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are both between 8 mm and 25 mm.

[0008] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are both between 10 mm and 20 mm.

[0009] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are between 14 mm and 17 mm, respectively.

[0010] In one embodiment of the present invention, the lengths of the four slots are each a quarter wavelength of the frequency band in which the radiating part operates.

[0011] In one embodiment of the invention, the aspect ratio of each slot 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 radiating section, and a grounding section. The substrate includes a first surface and a second surface facing each other. The radiating section is located on the first surface of the substrate. The radiating section includes a first feed point, a second feed point, and four slots. The first feed point and the second feed point are located along the two-dimensional axis of the radiating section. Two adjacent slots are symmetrical to each other. The grounding section is located on the second surface of the substrate. The transceiver module is coupled to the first feed point and the second feed point.

[0013] In one embodiment of the present invention, the distance between the first feed point and an intersection point of the two-dimensional axis is the same as the distance between the second feed point and the intersection point of the two-dimensional axis.

[0014] In one embodiment of the present invention, the four slots are located around a point where the two-dimensional axes intersect.

[0015] In one embodiment of the present invention, the intersection of the two-dimensional axes is a center point of the radiating portion.

[0016] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are both between 8 mm and 25 mm.

[0017] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are both between 10 mm and 20 mm.

[0018] In one embodiment of the present invention, the distance between the first feed point and the intersection of the two-dimensional axis and the distance between the second feed point and the intersection of the two-dimensional axis are between 14 mm and 17 mm, respectively.

[0019] In one embodiment of the present invention, the lengths of the four slots are each a quarter wavelength of the frequency band in which the radiating part operates.

[0020] In one embodiment of the invention, the aspect ratio of each slot is between 44 and 13.3.

[0021] In summary, based on some embodiments, the antenna module of this invention supports the operating bandwidth of the frequency bands specified by relevant radio frequency identification (RFID) protocols. The frequency bands specified by RFID protocols are, for example, FCC (Federal Communications Commission) bands (approximately between 902 MHz and 928 MHz). The antenna module of this invention can transmit vertically polarized and horizontally polarized signals to the RFID tag, thereby improving read / write efficiency, increasing identification range, extending read / write distance, reducing signal dead zones, and enhancing adaptability to environments with varying RFID tag positions and orientations. Attached Figure Description

[0022] Figure 1 This is a three-dimensional schematic diagram of the antenna module in the first embodiment of this case;

[0023] Figure 2 This is a top view of the antenna module in the first embodiment of this case;

[0024] Figure 3 This is a bottom view of the antenna module of the first embodiment of this case;

[0025] Figure 4 These are schematic diagrams of communication devices and their applications according to some embodiments of this case;

[0026] Figure 5A and Figure 5B This is a schematic diagram of the antenna module and its application according to the first embodiment of this case;

[0027] Figure 6 This is a schematic diagram of the return loss of the antenna module in the first embodiment of this case;

[0028] Figure 7 This is a schematic diagram of the mutual coupling isolation between the first feed point and the second feed point of the antenna module in the first embodiment of this case;

[0029] Figure 8A This is a radiation field diagram of the communication signal generated in the XZ plane after the antenna module of the first embodiment of this case is excited through the first feed point;

[0030] Figure 8B This is a radiation field diagram of the communication signal generated in the YZ plane after the antenna module of the first embodiment of this case is excited through the first feed point;

[0031] Figure 9A This is a radiation field diagram of the communication signal generated in the XZ plane after the antenna module of the first embodiment of this case is excited through the second feed point;

[0032] Figure 9B This is a radiation field diagram of the communication signal generated in the YZ plane after the antenna module of the first embodiment of this case is excited through the second feed point;

[0033] Figure 10A This is a current distribution diagram of the antenna module in the first embodiment of this case after being excited through the first feed point;

[0034] Figure 10B This is a current distribution diagram of the antenna module in the first embodiment of this case after being excited through the second feed point;

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

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

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

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

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

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

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

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

[0043] Figure 19This is a top view of the antenna module in the second embodiment of this case;

[0044] Figure 20 This is a top view of the antenna module in the third embodiment of this case;

[0045] Figure 21 This is a schematic diagram of the return loss of the antenna module in the first to third embodiments of this case;

[0046] Figure 22 This is a schematic diagram of the mutual coupling isolation between the first feed point and the second feed point of the antenna module in the first to third embodiments of this case;

[0047] Figure 23 This is a schematic diagram of the antenna gain of the antenna module in the first to third embodiments of this case;

[0048] Figure 24 This is a top view of the antenna module in the fourth embodiment of this case;

[0049] Figure 25 This is a top view of the antenna module in the fifth embodiment of this case;

[0050] Figure 26 This is a schematic diagram of the return loss of the antenna module in the first embodiment and the fourth to fifth embodiments of this case;

[0051] Figure 27 This is a schematic diagram of the mutual coupling isolation between the first feed point and the second feed point of the antenna module in the first embodiment and the fourth to fifth embodiments of this case;

[0052] Figure 28 This is a schematic diagram of the antenna gain of the antenna module in the first embodiment and the fourth to fifth embodiments of this case.

[0053] [Symbol Explanation]

[0054] 10: Antenna Module

[0055] 20:Substrate

[0056] 21: First Surface

[0057] 23: Second Surface

[0058] 25:Ontology

[0059] 30: Radiation section

[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: Grounding part

[0069] 100:Communication device

[0070] 200: Transceiver Module

[0071] 300: Radio Frequency Tag

[0072] HS: Horizontal polarization signal

[0073] VS: Vertical polarization signal

[0074] P: Intersection point

[0075] L1~L58: Curves Detailed Implementation

[0076] Reference Figure 1 , Figure 2 and Figure 3 . Figure 1 This is a three-dimensional schematic diagram of the antenna module 10 in the first embodiment of this case. Figure 2 This is a top view of the antenna module 10 in the first embodiment of this case. Figure 3 This is a bottom view of the antenna module 10 according to the first embodiment of this invention. The antenna module 10 includes a substrate 20, a radiating portion 30, and a grounding portion 40. The substrate 20 includes a first surface 21 and a second surface 23 facing each other. The radiating portion 30 is located on the first surface 21 of the substrate 20. The grounding portion 40 is located on the second surface 23 of the substrate 20. Thus, the radiating portion 30 and the grounding portion 40 are separated from each other. Specifically, both the first surface 21 and the second surface 23 of the substrate 20 have conductive layers. The radiating portion 30 is formed by processing the conductive layer of the first surface 21 of the substrate 20, and the grounding portion 40 is formed by processing the conductive layer of the second surface 23 of the substrate 20. The aforementioned processing includes printing, etching, and other processing methods. In some embodiments, the substrate 20 further includes a body 25 located between the first surface 21 and the second surface 23. The body 25 is, for example, a dielectric with a dielectric constant of 4.4. Thus, the radiating portion 30 and the grounding 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 plate, which enables the reduction of the thickness of the antenna module 10, thereby miniaturizing the antenna module 10 to make it easier to install.

[0077] like Figure 2 As shown, the radiating section 30 includes a first feed point FD1, a second feed point FD2, and four slots (i.e., first slot ST1, second slot ST2, third slot ST3, and fourth slot 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 of a communication device (described in detail later). The first feed point FD1 and the second feed point FD2 are located in the two-dimensional axes of the radiating section 30. Specifically, the first feed point FD1 is located in the first dimension (e.g., the X-axis, i.e., the horizontal axis) of the two-dimensional axes of the radiating section 30, and the second feed point FD2 is located in the second dimension (e.g., the Y-axis, i.e., the vertical axis) of the two-dimensional axes of the radiating section 30. The first feed point FD1 and the second feed point FD2 receive the same feed signal from the signal source alternately. Thus, the radiating portion 30 of the antenna module 10 alternately transmits a first-dimensional polarized signal (e.g., a horizontally polarized signal) through the first feed point FD1 and a second-dimensional polarized signal (e.g., a vertically polarized signal) through the second feed point FD2. Through two-dimensional polarized signals (i.e., the first-dimensional and second-dimensional polarized signals), communication quality, communication efficiency, communication range, communication distance, and signal dead zones can be improved. Specifically, through two-dimensional polarized signals, the antenna module 10 of this invention not only possesses the characteristic of a circularly polarized antenna capable of receiving wireless signals from multiple different directions, but also the characteristic of a linearly polarized antenna that increases communication distance.

[0078] like Figure 2 As shown, the four slots (i.e., the first slot ST1 to the fourth slot ST4) are separated from each other, and the two adjacent slots are symmetrical to each other. In some embodiments, the four slots are formed by removing a region of the conductive layer on the first surface 21 of the substrate 20, exposing the body 25 of the substrate 20 in the corresponding region. In this way, the antenna module 10 adjusts the current path and current distribution of the radiating part 30 through the resonance of the four slots and the radiating part 30, so that it operates within the operating bandwidth of the frequency band specified by the relevant radio frequency identification (RFID) protocol. The frequency band specified by the relevant RFID protocol is, for example, the FCC band (approximately between 902MHz and 928MHz). Furthermore, the mutual coupling between the first feed point FD1 and the second feed point FD2 of the antenna module 10 can also be reduced through the resonance of the four slots and the radiating part 30.

[0079] Reference Figure 4 , Figure 5A and Figure 5B . Figure 4 This is a schematic diagram of a communication device 100 and its application in some embodiments of this case. Figure 5A and Figure 5B This is a schematic diagram of the antenna module 10 and its application according to the first embodiment of this case. The communication device 100 includes the antenna module 10 and the 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) (specifically its internal core wires). The grounding portion 40 of the antenna module 10 (e.g., Figure 3 The reference ground terminal (not shown) of the main board of the communication device 100 is connected to the outer metal surface of the coaxial cable. The outer metal layer of the coaxial cable is separated from the inner core wire by an insulating layer. The communication device 100 is, for example, an RFID reader / writer for reading and writing RFID tags 300. The radiating portion 30 of the antenna module 10 is capable of transmitting communication signals to the RFID tag 300. For example, the radiating portion 30 of the antenna module 10 transmits a first-dimensional polarized signal (e.g., a horizontally polarized signal HS) through a first feed point FD1 and a second-dimensional polarized signal (e.g., a vertically polarized signal VS) through a second feed point FD2 to the RFID tag 300. By using two-dimensional polarized signals (i.e., first-dimensional polarized signals and second-dimensional polarized signals), the read / write quality, read / write efficiency, and read / write range can be improved (for example, the RFID tag 300 can be read / written by the communication device 100 regardless of whether it is positioned horizontally or vertically relative to the communication device 100), the read / write distance can be increased (for example, compared to linearly polarized antennas and circularly polarized antennas, the read / write distance of the antenna module 10 in this invention can reach at least 5m), and the signal dead zone can be reduced. In some embodiments, the read / write distance of the antenna module 10 in this invention in the horizontal direction can be nearly the same as the read / write distance in the vertical direction.

[0080] Reference Figure 6 This is a schematic diagram illustrating the return loss of the antenna module 10 in the first embodiment of this case. Curve L1 represents the return loss of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the ideal case (and also the return loss of the communication signal generated by the antenna module 10 after being excited through the second feed point FD2 in the ideal case). Curve L2 represents the return loss of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the actual case. Curve L3 represents the return loss of the communication signal generated by the antenna module 10 after being excited through the second feed point FD2 in the actual case. From Figure 6 As can be seen, through the structural design of the antenna module 10, the return loss is substantially less than -6 dB (decibels) as specified by the relevant radio frequency identification protocols in the desired operating frequency band (e.g., FCC band), thus exhibiting good antenna characteristics.

[0081] Reference Figure 7 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 embodiment of this invention. Curve L4 represents the degree of interference between the communication signal transmitted by the antenna module 10 through the first feed point FD1 and the communication signal received through the second feed point FD2 under ideal conditions (also representing the degree of interference between the communication signal transmitted by the antenna module 10 through the second feed point FD2 and the communication signal received through the first feed point FD1 under ideal conditions). Curve L5 represents the degree of interference between the communication signal transmitted by the antenna module 10 through the first feed point FD1 and the communication signal received through the second feed point FD2 under actual conditions. Curve L6 represents the degree of interference between the communication signal transmitted by the antenna module 10 through the second feed point FD2 and the communication signal received through the first feed point FD1 under actual conditions. From Figure 7 As can be seen, through the structural design of the antenna module 10, in the desired operating frequency band (e.g., FCC band), the interference level (i.e., mutual coupling level) between the first feed point FD1 and the second feed point FD2 is less than -25dB, 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), and has good mutual coupling isolation and stability.

[0082] Reference Figures 8A to 9B . Figure 8A This is a radiation field diagram of the communication signal generated in the XZ plane after the antenna module 10 of the first embodiment of this case is excited through the first feed point FD1. Figure 8B This is a radiation field diagram of the communication signal generated in the YZ plane after the antenna module 10 of the first embodiment of this case is excited through the first feed point FD1. Figure 9A This is a radiation field diagram of the communication signal generated in the XZ plane after the antenna module 10 of the first embodiment of this case is excited through the second feed point FD2. Figure 9BThis is a radiation pattern diagram of the communication signal generated in the YZ plane after the antenna module 10 of the first embodiment of this case is excited through the second feed point FD2. Here, the numbers on the circumference are in degrees, and the distance between the curve and the center of the circle in the radiation pattern corresponds to the gain, which is in dB. Curve L7 is the radiation pattern of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the main polarization direction (e.g., the horizontal polarization direction) of the XZ plane. Curve L8 is the radiation pattern of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the cross polarization direction (which is perpendicular to the main polarization direction, e.g., the vertical polarization direction) of the XZ plane. Curve L9 is the radiation pattern of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the main polarization direction of the YZ plane. Curve L10 is the radiation pattern of the communication signal generated by the antenna module 10 after being excited through the first feed point FD1 in the cross polarization direction of the YZ plane. Curve L11 represents the radiation pattern of the communication signal generated by antenna module 10 after being excited through the second feed point FD2, in the main polarization direction (e.g., vertical polarization direction) of the XZ plane. Curve L12 represents the radiation pattern of the communication signal generated by antenna module 10 after being excited through the second feed point FD2, in the cross-polarization direction of the XZ plane (perpendicular to the main polarization direction, e.g., horizontal polarization direction). Curve L13 represents the radiation pattern of the communication signal generated by antenna module 10 after being excited through the second feed point FD2, in the main polarization direction of the YZ plane. Curve L14 represents the radiation pattern of the communication signal generated by antenna module 10 after being excited through the second feed point FD2, in the cross-polarization direction of the YZ plane. From Figures 8A to 9B As can be seen, when the antenna module 10 is excited at different feed points, the signal in its corresponding main polarization direction is enhanced and approximately omnidirectionally radiated, while the signal in its corresponding cross polarization direction is suppressed. This can improve communication efficiency and quality and provide good signal transmission and reception capabilities.

[0083] Reference Figure 10A and Figure 10B . Figure 10A This is a current distribution diagram of the antenna module 10 in the first embodiment of this case after being excited through the first feed point FD1. Figure 10B This is a current distribution diagram of the antenna module 10 in the first embodiment of this case after being excited through the second feed point FD2. From Figure 10A It can be seen that when the first feed point FD1 is excited, the current flows along the X-axis, indicating that the excitation of the first feed point FD1 generates a horizontally polarized signal. From Figure 10BAs can be seen, when the second feed point FD2 is excited, the current flows along the Y-axis, indicating that the excitation of the second feed point FD2 generates a vertically polarized signal. Thus, the excitation of different feed points will stagger the current flow direction and reduce the 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] Reference Figure 11 This is a schematic diagram illustrating the return loss of an antenna module of a comparative example and an antenna module 10 of the first embodiment. The difference between the comparative example antenna module and the antenna module 10 of the first embodiment is that the comparative example antenna module does not have four slots (i.e., the first slot ST1 to the fourth slot ST4). Curve L15 represents the return loss of the communication signal generated by the comparative example antenna module after being excited through the first feed point FD1 (which is also the return loss of the communication signal generated by the comparative example antenna module after being excited through the second feed point FD2). Curve L16 represents the return loss of the communication signal generated by the antenna module 10 of the first embodiment after being excited through the first feed point FD1 (which is also the return loss of the communication signal generated by the antenna module 10 of the first embodiment after being excited through the second feed point FD2). From... Figure 11 As can be seen, in the comparative example, the return loss in the desired operating frequency band (e.g., the FCC band) is greater than -6dB as specified by the relevant radio frequency identification (RFID) protocol. In contrast, the antenna module 10 of the first embodiment of this invention, through its four slots, achieves a return loss in the desired operating frequency band (e.g., the FCC band) that is less than -6dB as specified by the relevant RFID protocol, thus exhibiting superior antenna characteristics.

[0085] Reference Figure 12This diagram illustrates the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module of the comparative example and the antenna module 10 of the first embodiment. The difference between the comparative example antenna module and the antenna module 10 of the first embodiment is that the comparative example antenna module does not have four slots (i.e., the first slot ST1 to the fourth slot ST4). Curve L17 represents the interference level of the communication signal transmitted by the comparative example antenna module through the first feed point FD1 to the communication signal received through the second feed point FD2 (also the interference level of the comparative example antenna module through the second feed point FD2 to the communication signal received through the first feed point FD1). Curve L18 represents the interference level of the communication signal transmitted by the first feed point FD1 to the communication signal received through the second feed point FD2 (also the interference level of the first embodiment antenna module 10 through the second feed point FD2 to the communication signal received through the first feed point FD1). from Figure 12 As can be seen, in the comparative example, the interference level (i.e., mutual coupling level) between the first feed point FD1 and the second feed point FD2 is greater than -30dB in the desired operating frequency band (e.g., the FCC band). Compared to the comparative example, the antenna module 10 of the first embodiment of this case, through four slots, makes the interference level between the first feed point FD1 and the second feed point FD2 less than -25dB in the desired operating frequency band (e.g., the FCC band), 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), and has good mutual coupling isolation and stability.

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

[0087] Reference Figure 13 This is a schematic diagram illustrating the return loss of the antenna module 10 according to the first embodiment of this case. Since the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is the same as the distance between the second feed point FD2 and the intersection point P of the two-dimensional axis, only the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis will be used for explanation here. Curve L19 represents the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 11 mm. Curve L20 represents the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 14 mm. Curve L21 represents the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 17 mm. Curve L22 represents the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 20 mm. Curve L23 represents the return loss of the antenna module 10 when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 23 mm. From Figure 13 As can be seen, when the distance between the first feed point FD1 and the intersection point P of the two-dimensional axis is 11mm, 14mm, 17mm, 20mm or 23mm, the return loss of the antenna module 10 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.

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

[0089] In some embodiments, the lengths of the four slots (i.e., the first slot ST1 to the fourth slot ST4) are each a quarter wavelength of the frequency band in which the radiating portion 30 operates (specifically, the center frequency of the frequency band, i.e., the resonant frequency) 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 lengths of each slot are the same, and the widths of each slot are the same. In some embodiments, the width of each slot is inversely proportional to the resonant frequency of the antenna module 10. In some embodiments, the length of each slot is inversely proportional to the resonant frequency of the antenna module 10.

[0090] Reference Figure 14 This is a schematic diagram illustrating the return loss of the antenna module 10 according to the first embodiment of this case. Since all the slots have the same width, only the width of the first slot ST1 will be described here. Curve L24 represents the return loss of the antenna module 10 when the width of the first slot ST1 is 1 mm. Curve L25 represents the return loss of the antenna module 10 when the width of the first slot ST1 is 2 mm. Curve L26 represents the return loss of the antenna module 10 when the width of the first slot ST1 is 3 mm. From... Figure 14 As can be seen, when the width of the first slot ST1 is 1mm, 2mm or 3mm, the return loss of the antenna module 10 is substantially less than -6dB as specified by the relevant radio frequency identification protocol in the desired operating frequency band (e.g., FCC band), thus exhibiting good antenna characteristics.

[0091] Reference Figure 15This is a schematic diagram illustrating the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the first embodiment of this case. Since the width of each slot is the same, only the width of the first slot ST1 will be described here. Curve L27 represents the degree of interference between the communication signal emitted by the antenna module 10 through the first feed point FD1 and the communication signal received through the second feed point FD2 when the width of the first slot ST1 is 1 mm (also representing the degree of interference between the communication signal emitted by the antenna module 10 through the second feed point FD2 and the communication signal received through the first feed point FD1 when the width of the first slot ST1 is 1 mm). Curve L28 represents the interference level of the communication signal transmitted by the antenna module 10 through the first feed point FD1 to the communication signal received through the second feed point FD2 when the width of the first slot ST1 is 2mm (also, the interference level of the communication signal transmitted by the antenna module 10 through the second feed point FD2 to the communication signal received through the first feed point FD1 when the width of the first slot ST1 is 2mm). Curve L29 represents the interference level of the communication signal transmitted by the antenna module 10 through the first feed point FD1 to the communication signal received through the second feed point FD2 when the width of the first slot ST1 is 3mm (also, the interference level of the communication signal transmitted by the antenna module 10 through the second feed point FD2 to the communication signal received through the first feed point FD1 when the width of the first slot ST1 is 3mm). From Figure 15 It can be seen that when the width of the first slot ST1 is 1mm, 2mm or 3mm, the interference level between the first feed point FD1 and the second feed point FD2 basically meets the relevant specifications of the radio frequency identification protocol in the desired operating frequency band (e.g. FCC band). The more lenient specifications are, for example, interference level less than -15dB, and the more stringent specifications are, for example, interference level less than a standard value, which is in the range of -20dB to -30dB. It has good mutual coupling isolation and stability.

[0092] Reference Figure 16 This is a schematic diagram illustrating the return loss of the antenna module 10 according to the first embodiment of this case. Since all the slots have the same length, only the length of the first slot ST1 will be described here. Curve L30 represents the return loss of the antenna module 10 when the length of the first slot ST1 is 40 mm. Curve L31 represents the return loss of the antenna module 10 when the length of the first slot ST1 is 42 mm. Curve L32 represents the return loss of the antenna module 10 when the length of the first slot ST1 is 44 mm. From... Figure 16As can be seen, when the length of the first slot ST1 is 40mm, 42mm or 44mm, the return loss of the antenna module 10 is substantially less than -6dB as specified by the relevant radio frequency identification protocol in the desired operating frequency band (e.g., FCC band), thus exhibiting good antenna characteristics.

[0093] Reference Figure 17 This is a schematic diagram illustrating the mutual coupling isolation between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the first embodiment of this case. Since the lengths of each slot are the same, only the length of the first slot ST1 will be used for explanation here. Curve L33 represents the degree of interference between the communication signal emitted by the antenna module 10 through the first feed point FD1 and the communication signal received through the second feed point FD2 when the length of the first slot ST1 is 40mm (also representing the degree of interference between the communication signal emitted by the antenna module 10 through the second feed point FD2 and the communication signal received through the first feed point FD1 when the length of the first slot ST1 is 40mm). Curve L34 represents the interference level of the communication signal transmitted by the antenna module 10 through the first feed point FD1 to the communication signal received through the second feed point FD2 when the length of the first slot ST1 is 42mm (also, the interference level of the communication signal transmitted by the antenna module 10 through the second feed point FD2 to the communication signal received through the first feed point FD1 when the length of the first slot ST1 is 42mm). Curve L35 represents the interference level of the communication signal transmitted by the antenna module 10 through the first feed point FD1 to the communication signal received through the second feed point FD2 when the length of the first slot ST1 is 44mm (also, the interference level of the communication signal transmitted by the antenna module 10 through the second feed point FD2 to the communication signal received through the first feed point FD1 when the length of the first slot ST1 is 44mm). From Figure 17 It can be seen that when the length of the first slot ST1 is 40mm, 42mm or 44mm, the interference level between the first feed point FD1 and the second feed point FD2 basically meets the relevant specifications of the radio frequency identification protocol in the desired operating frequency band (e.g. FCC band). The more lenient specifications are, for example, interference level less than -15dB, and the more stringent specifications are, for example, interference level less than a standard value, which is in the range of -20dB to -30dB. Thus, it has good mutual coupling isolation and stability.

[0094] In some embodiments, the size of the radiating portion 30 is inversely proportional to the resonant frequency of the antenna module 10. For example... Figure 2As shown, in some embodiments, the length W1 and width W2 of the radiating portion 30 are between 74 mm and 78 mm, respectively. In some embodiments, the length W1 of the radiating portion 30 is the same as its width W2.

[0095] Reference Figure 18 This is a schematic diagram illustrating the return loss of the antenna module 10 according to the first embodiment of this case. Here, an example is used where the length W1 of the radiating portion 30 is the same as its width W2, and only the length W1 of the radiating portion 30 will be described. Curve L36 represents the return loss of the antenna module 10 when the length W1 of the radiating portion 30 is 74 mm. Curve L37 represents the return loss of the antenna module 10 when the length W1 of the radiating portion 30 is 75 mm. Curve L38 represents the return loss of the antenna module 10 when the length W1 of the radiating portion 30 is 76 mm. Curve L39 represents the return loss of the antenna module 10 when the length W1 of the radiating portion 30 is 77 mm. Curve L40 represents the return loss of the antenna module 10 when the length W1 of the radiating portion 30 is 78 mm. From... Figure 18 As can be seen, when the length W1 of the radiating part 30 is 74mm, 75mm, 76mm, 77mm or 78mm, the return loss of the antenna module 10 is basically less than -6dB as specified by the relevant radio frequency identification protocol in the desired operating frequency band (e.g., FCC band), thus exhibiting good antenna characteristics.

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

[0097] Reference Figure 21 This diagram illustrates the return loss of the antenna module 10 in the first to third embodiments of this invention. Curve L41 represents the return loss of the antenna module 10 in the first embodiment. Curve L42 represents the return loss of the antenna module 10 in the second embodiment. Curve L43 represents the return loss of the antenna module 10 in the third embodiment. Figure 21As can be seen, regardless of whether the shape of the radiating part 30 of the antenna module 10 is cross-shaped, circular, or square, 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.

[0098] Reference Figure 22 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 to third embodiments of this invention. Curve L44 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 L45 represents the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the second embodiment of this invention. Curve L46 represents the interference level between the first feed point FD1 and the second feed point FD2 of the antenna module 10 in the third embodiment of this invention. From Figure 22 As can be seen, regardless of whether the shape of the radiating part 30 of the antenna module 10 is cross-shaped, circular, or square, 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). It has good mutual coupling isolation and stability, and enables the antenna module 10 to provide good radio frequency read and write capabilities.

[0099] Reference Figure 23 This diagram illustrates the antenna gain of the antenna module 10 in the first to third embodiments of this invention. Curve L47 represents the antenna gain of the antenna module 10 in the first embodiment. Curve L48 represents the antenna gain of the antenna module 10 in the second embodiment. Curve L49 represents the antenna gain of the antenna module 10 in the third embodiment. Figure 23 As can be seen, the radiating part 30 of the antenna module 10 has good antenna gain regardless of whether it is cross-shaped, circular or square.

[0100] Reference Figure 2 , Figure 24 and Figure 25 . Figure 24 This is a top view of the antenna module 10 in the fourth embodiment of this case. Figure 25 This is a top view of the antenna module 10 according to the fifth embodiment of this case. Figure 2As 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 28This diagram illustrates the antenna gain of the antenna module 10 in the first, fourth, and fifth embodiments of this invention. Curve L56 represents the antenna gain of the antenna module 10 in the first embodiment. Curve L57 represents the antenna gain of the antenna module 10 in the fourth embodiment. Curve L58 ​​represents the antenna gain of the antenna module 10 in the fifth embodiment. Figure 28 As can be seen, the shape of each slot in the antenna module 10, whether W-shaped, M-shaped, or arc-shaped, has good antenna gain.

[0104] In summary, based on some embodiments, the antenna module of this invention supports the operating bandwidth of the frequency bands specified by the relevant protocols for Radio Frequency Identification (RFID). The frequency bands specified by the relevant RFID protocols are, for example, the FCC bands (approximately between 902MHz and 928MHz). The antenna module of this invention can transmit vertically polarized signals and horizontally polarized signals to the RFID tag, thereby improving read / write efficiency, increasing identification range, extending read / write distance, reducing signal dead zones, and enhancing adaptability to environments with varying RFID tag positions and orientations.

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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