POS machine miniaturization large bandwidth efficient antenna

Abstract

The scheme discloses a POS machine miniaturization large-bandwidth high-efficiency antenna, which uses a small antenna size to excite a low-frequency working mode of a mainboard, uses components such as a camera FPC and an NFC coil which are not conducive to the antenna to expand the frequency, realizes better low-frequency bandwidth, changes the disadvantage into an advantage, optimizes the shape of the antenna working at a high frequency and places the antenna at a suitable position to excite the NFC coil and the rear camera FPC to generate a low-frequency resonance, thereby expanding the antenna bandwidth to a low frequency enough to cover common low-frequency communication frequency bands, and finally realizes a very small space-occupied and very high-efficiency large-bandwidth antenna.

Description

Technical Field

[0001] This solution belongs to the field of POS machine antenna technology, and proposes a miniaturized, high-bandwidth, high-efficiency antenna suitable for POS machines. Background Technology

[0002] Antennas are one of the most important components in the field of wireless communication, primarily functioning to receive and transmit electromagnetic waves. With societal development and technological advancements, the frequency bands used for radio communication are constantly expanding.

[0003] As a multi-functional terminal device, the POS machine provides data services and management functions for goods and media transactions, and enables non-cash settlement. When used in the financial sector, components such as the card slot / reader, NFC reader, and dedicated camera on the POS machine enable secure, fast, and reliable non-cash settlement. When used for inventory management of goods / goods, the POS machine is also called an inventory counting machine; its NFC reader, dedicated camera, and laser head enable inventory counting and management of goods or goods. Compared to fixed POS machines with wired operation, wireless POS machines have advantages such as smaller size, easy mobility, portability, and diverse communication methods. Therefore, wireless POS machines, especially those supporting multiple communication bands, have a very broad and diverse application market.

[0004] A typical wireless POS machine generally includes all the necessary components: a card slot / reader, an NFC reader, a dedicated camera, and a print head. The NFC reader's NFC coil is usually wrapped around the paper tray. The print head is inserted into one side of the paper tray and connected to the machine's mainboard via an FPC (flexible printed circuit board). The dedicated camera is placed on the back of the paper tray, inside the NFC coil loop, and connected to the mainboard via the FPC. Different telecom operators around the world support different communication frequency bands. The standard 4G LTE communication frequency band is 700MHz to 2700MHz, while the current 5G frequency band has an even wider range. According to antenna wavelength theory, antenna size is inversely proportional to its operating frequency. Therefore, if a POS machine is to support the common communication frequency bands of all global operators, the standard LTE antenna may need to be as long as 100mm. The only suitable space in the POS machine to accommodate a standard LTE antenna of this length is the paper tray housing area, and this standard LTE antenna needs to be deployed almost entirely around the paper tray to cover 700MHz. In addition, the electromagnetic environment formed by the NFC coil, print head and camera FPC around the aforementioned paper slot is very complex, and the electromagnetic interference it generates will interfere with the electromagnetic radiation of the conventional LTE antenna itself, causing the antenna performance to deteriorate.

[0005] like Figure 1The image shows an example of a conventional antenna, which completely surrounds the paper slot housing and is relatively large. The return loss of this conventional antenna in the 500MHz-3000MHz range is as follows: Figure 2 As shown, its low-frequency bandwidth below 1GHz is relatively narrow and cannot fully cover the commonly used low-frequency band for LTE communication in the 700MHz-960MHz range; the efficiency of this antenna is as follows... Figure 3 As shown, due to its own poor return loss and the influence of NFC coils, camera FPCs, etc. that encroach on its clearance area, even though the return loss of this antenna is relatively good at some frequency points below 1GHz, its overall radiation efficiency is still very poor. Summary of the Invention

[0006] The purpose of this solution is to address the aforementioned problems by providing a miniaturized, high-bandwidth, high-efficiency antenna for POS machines that can achieve high bandwidth and reliable operation in complex electromagnetic environments.

[0007] To achieve the above objectives, the following technical solutions are adopted in this proposal:

[0008] A miniaturized, high-bandwidth, high-efficiency antenna for a POS machine includes a paper slot, a motherboard, an NFC coil, a rear-facing camera, and an antenna for mobile communication. The paper slot has an arc-shaped cover and a first side and a second side located on either side of the arc-shaped cover. The NFC coil wraps around the paper slot along the side lines and is connected to the motherboard circuit during the wrapping process. The rear-facing camera is located on the back of the paper slot and is connected to the motherboard circuit via an FPC. The antenna includes an antenna grounding arm and an antenna radiating arm. The antenna grounding arm is attached to the second side of the paper slot and extends from the second side along the paper slot to the motherboard and is connected to the motherboard ground structure. The antenna radiating arm is located on the side of the camera FPC away from the first side, and is partially attached to the arc-shaped cover and partially extends from the arc-shaped cover and is attached to the second side. The end of the antenna radiating arm away from the second side extends to the camera FPC. The extension of the antenna radiating arm to the camera FPC means that the positional relationship between the antenna radiating arm and the camera FPC can be close or overlapping, depending on the resonance position generated by the camera FPC. It should be noted that there is no electrical connection between the antenna radiating arm and the camera FPC.

[0009] In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for POS machines, the antenna grounding arm is attached to the second side of the paper slot and extends to the bottom of the arc-shaped cover on the second side, and then extends along the paper slot to the main board.

[0010] In the aforementioned miniaturized, high-bandwidth, and high-efficiency antenna for POS machines, the antenna radiating arm has a V-shaped structure composed of a first branch and a second branch. The first branch is attached to the arc-shaped cover of the paper slot, and the second branch extends from the arc-shaped cover to the second side of the paper slot. The end of the first branch away from the second side extends to the camera FPC.

[0011] In the aforementioned miniaturized, high-bandwidth, and high-efficiency antenna for POS machines, the portion of the antenna radiating arm located on the arc-shaped cover is positioned in the lower middle part of the arc-shaped cover near the second side.

[0012] In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for POS machines, the antenna is excited by a coaxial radio frequency line located on the motherboard, and the core wire of the coaxial radio frequency line is connected to the radiating arm, while the ground wire of the coaxial radio frequency line is connected to the grounding arm.

[0013] In the aforementioned miniaturized, high-bandwidth, and high-efficiency antenna for POS machines, the NFC coil, after being driven by the self-board, surrounds the paper slot to the top of the main board and extends to the main board, then returns to the paper slot and continues to surround the main board, thus forming an NFC coil structure surrounding the paper slot.

[0014] In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for POS machines, the coil extending to the middle of the motherboard is connected to the motherboard ground structure via a jumper structure.

[0015] In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for POS machines, the jumper structure extending to the middle of the coil on the motherboard is connected to the motherboard ground structure via a capacitor or inductor.

[0016] The NFC coil is a loop connected end-to-end. It starts on the motherboard and connects to the motherboard circuitry, then loops around the paper slot, returns to the top of the motherboard, extends back to the motherboard, then returns to the paper slot to continue looping, finally looping back to the motherboard and connecting to the motherboard circuitry. The jumper structure is located in the middle of the coil extending from the top of the motherboard to the motherboard. In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for the POS machine, the coaxial radio frequency line is located on the motherboard near the second side of the paper slot, and the NFC coil extending to the motherboard is located between the coaxial radio frequency line and the camera FPC.

[0017] In the aforementioned miniaturized, high-bandwidth, and high-efficiency antenna for POS machines, the rear camera is located on the back of the paper slot, inside the loop of the NFC coil.

[0018] In the aforementioned miniaturized, high-bandwidth, and high-efficiency antenna for POS machines, the end of the camera FPC furthest from the rear camera is connected to the motherboard via a vertical extension extending from the NFC coil.

[0019] In the aforementioned miniaturized, high-bandwidth, high-efficiency antenna for POS machines, the NFC coil is wrapped around the lower edge of the paper slot;

[0020] The camera FPC extends along the curved cover from the back of the paper slot to the main board in front of the paper slot;

[0021] The antenna is located inside the NFC ring and above the NFC surround area.

[0022] The advantages of this solution are:

[0023] 1. This solution uses a smaller antenna size to excite the motherboard's low-frequency operating mode. It utilizes components such as the camera FPC and NFC coil, which are not inherently antenna-friendly, to extend the frequency range and achieve better low-frequency bandwidth. This turns a disadvantage into an advantage by optimizing the shape of the high-frequency antenna and placing it in a suitable position to excite the NFC coil and the rear camera FPC to generate low-frequency resonance, thereby extending the antenna bandwidth to a sufficiently low frequency to cover commonly used low-frequency communication bands. Ultimately, this results in a large-bandwidth antenna that occupies very little space and is highly efficient.

[0024] 2. The antenna proposed in this solution is not easily affected by electromagnetic radiation from surrounding devices, and can achieve high bandwidth, high efficiency and reliable operation in the complex electromagnetic environment inside the POS machine.

[0025] 3. The antenna structure proposed in this solution is smaller in size than conventional antennas, and its small size gives it a cost advantage.

[0026] 4. The antenna structure proposed in this solution occupies little space inside the machine, making it easy to flexibly design its usage location and leaving most of the space for adding other functional components inside the machine. Attached Figure Description

[0027] Figure 1 This is a structural diagram of an existing POS machine.

[0028] Figure 2 The return loss of existing POS machine antennas in the 500MHz-3000MHz range;

[0029] Figure 3 This is a test diagram of the efficiency of existing POS machine antennas;

[0030] Figure 4 This is a schematic diagram of the POS machine in this solution;

[0031] Figure 5 This is a schematic diagram of the NFC coil extending to the middle of the motherboard and connected to the motherboard ground structure in the POS machine structure of this solution.

[0032] Figure 6 The return loss of the antenna in this scheme is within the 500MHz-6000MHz frequency band;

[0033] Figure 8 Efficiency test diagram of the antenna before adding jumper wires to this scheme;

[0034] Figure 7 The return loss of the antenna in the 500MHz-6000MHz frequency band after adding jumpers to this scheme;

[0035] Figure 9 The efficiency test diagram of the antenna after adding jumpers to this scheme is shown.

[0036] Reference numerals: Paper slot 11; Mainboard 12; NFC coil 13; Camera FPC 14; Antenna 15; Antenna grounding arm 151; Antenna radiating arm 152; Coaxial RF cable 16; Rear camera 17; Curved cover 18; First side 19; Second side 20; Jumper structure 21. Detailed Implementation

[0037] The present solution will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 4 As shown, this solution provides a miniaturized, high-bandwidth, high-efficiency antenna for a POS machine, including a paper slot 11, a motherboard 12, an NFC coil 13, a rear camera 17 and its camera FPC 14, and an antenna 15. FPC, also known as a flexible circuit board, refers to a flexible printed circuit board.

[0039] The paper tray 11 is used to hold paper for POS printing-related information. It is generally made of plastic and has a U-shaped main structure, including an arc-shaped cover 18 and a first side 19 and a second side 20 located on both sides of the arc-shaped cover 18. Figure 4 The right side, i.e., the first side 19, and the left side, i.e., the second side 20, can be arbitrarily transformed according to needs.

[0040] The motherboard 12 carries all the circuits of the POS machine. In this embodiment, the motherboard structure is 140mm long, 70mm wide, and 1.6mm thick. Its actual size can be adjusted according to the application requirements.

[0041] The NFC coil 13 can be in the form of a flexible circuit board, copper wire, metal spring, etc. It wraps around the paper slot 11 twice and is then connected to a suitable position on the main board 12. The circuit on the main board 12 controls and implements its NFC function. The winding direction and number of turns of the NFC coil 13 can be adjusted according to the relevant products.

[0042] The rear camera 17 is located on the back of the paper tray 11, inside the NFC coil 13 ring. It is connected to the POS machine's mainboard 12 via the camera FPC 14. The main function of the camera FPC 14 is to connect the rear camera 17 to the circuitry on the mainboard 12, referred to here as the mainboard circuitry. The main structure of the camera FPC 14 is a long, strip-shaped flexible metal circuit board. One end of it, along with the rear camera 14, is placed on the back of the curved cover 18 of the paper tray 11, while the other end is connected to the mainboard 12, where its specific functions are implemented by the relevant circuitry. The camera FPC of the rear camera, connected to the mainboard, extends into the vertical space of the NFC coil.

[0043] The above structure is similar to that of existing POS machines. Since both the NFC coil 13 and the camera FPC 14 of the rear camera 17 are made of metal, their presence encroaches on the clearance area on the paper slot 11 available for the antenna 15. At this point, the only usable space on the paper slot 11 is the area not covered by the NFC coil and camera FPC. The NFC coil 13 and camera FPC 14, as extensions of the motherboard, severely intrude on the antenna clearance area. Using conventional antenna designs, to achieve low-frequency up to 700MHz and high-frequency up to 6000MHz, covering most existing LTE and WIFI communication frequency bands, the antenna pattern needs to almost completely cover the paper slot area. Even then, it is difficult for conventional antennas to have good performance throughout the 700MHz-960MHz frequency band. The common approach is to design different antenna versions for different regions and operators, which obviously increases design costs and production control risks.

[0044] The antenna structure designed for the POS machine in this solution is as follows: Figure 4 As shown: Antenna 15 consists of an antenna grounding arm 151 and an antenna radiating arm 152. The antenna grounding arm 151 is attached to the left side 20 and the bottom of the arc-shaped cover 18 of the paper slot 11. The camera FPC is located near the right side 19 of the paper slot 11. The antenna radiating arm 152 is located between the antenna grounding arm 151 and the camera FPC. The portion of the antenna grounding arm 151 located on the second side 20 of the paper slot 11 can be designed in a figure-7 shape. One end of the antenna grounding arm 151 extends along the paper slot structure to the motherboard 12 area and connects to the ground structure of the circuit on the motherboard, which is referred to here as the motherboard ground structure. The connection method can be either placing a spring contactor on the motherboard 12 to elastically contact the grounding arm 151, or placing conductive foam to contact the grounding arm 151 on the motherboard. This connection method can be designed differently according to needs.

[0045] Most of the antenna radiating arm 152 is attached to the lower middle part of the arc-shaped cover 18 near the left side 20 of the paper slot 11, forming a general "V" shape. The first branch of the "V" shape extends to the left side 20 of the paper slot 11. The second branch of the "V" shape extends to the rear camera FPC, and the spacing is adjusted according to the resonant frequency during use. The antenna is excited by a coaxial RF cable 16, the core wire of which is connected to the antenna radiating arm 152, and the ground wire of which is connected to the antenna ground arm 151. The coaxial RF cable 16 is located on the side of the motherboard near the second side 20 of the paper slot, and the NFC coil extending to the motherboard is located between the coaxial RF cable 16 and the camera FPC 14.

[0046] This solution optimizes the location of the coaxial cable excitation access point and the dimensions of the radiating arm 152, enabling the antenna to exhibit good return loss and radiation performance in most LTE communication frequency bands within the 824MHz-6000MHz band. The electrical dimensions of the radiating arm 152 are much smaller than the wavelength corresponding to the low-frequency resonance, allowing this solution to excite the low-frequency radiation mode of the motherboard 12. Simultaneously, the radiating arm 152 is very close to the rear camera FPC 14. By adjusting the width and shape of the portion of the radiating arm near the camera FPC 14, the coupling strength between the radiating arm and the camera FPC 14 is controlled, achieving a tuning effect. In other words, by optimizing the gap between the radiating arm 152 and the camera FPC 14, as well as the structural dimensions of the radiating arm 152 near the camera FPC 14, this solution's antenna excites electromagnetic waves within the 700MHz-824MHz frequency band, resulting in a return loss of less than -6dB in this band, demonstrating good performance. This achieves the goal of rationally designing the antenna of this solution using the motherboard 12 and the rear camera FPC.

[0047] Preferably, in this design, the NFC coil 13 extends from the mainboard 12 around the paper slot 11 to above the mainboard 12, then returns to the paper slot 11 and continues to encircle the mainboard 12, forming an NFC coil 13 structure surrounding the paper slot 11. A jumper structure 21 connects the coil extending to the mainboard 12 to the mainboard ground structure at its midpoint. Figure 5 In the diagram, 21 refers to the jumper structure, and A and B are the start and end points of the NFC coil loop, respectively, which are connected to the motherboard circuit.

[0048] To demonstrate that the antenna structure implemented in the POS machine designed in this scheme has a large bandwidth and high efficiency, and to prove the necessity of the aforementioned jumper structure, tests were conducted on the structure of this scheme with and without jumpers:

[0049] Figure 6 and Figure 8The figures show the return loss and efficiency test results of this design without jumpers in the 500MHz-6000MHz range. As can be seen from the figures, the return loss of this design can basically cover the commonly used low-frequency band for LTE communication (700MHz-960MHz), and the antenna exhibits good radiation efficiency. However, a noticeable "dip" appears in the efficiency curve around the 824MHz frequency point, indicating a significant efficiency reduction at this frequency. This is because the NFC coil 13, an essential component of the POS machine, encroaches on the antenna's radiation clearance area. The presence of the NFC metal coil causes a new resonance at the 824MHz frequency point. Therefore, although the NFC coil 13 causes a new resonance at 824MHz with an S11 less than -6dB, this resonance results in an efficiency "dip" within a narrow band.

[0050] Figure 7 and Figure 9 The figures show the return loss and efficiency test results of the proposed structure with jumpers added in the 500MHz-6000MHz range. It can be seen that the efficiency around the 824MHz frequency point has been optimized, and the "pit" in the efficiency curve has disappeared. This demonstrates that the proposed solution, through a simple jumper structure, effectively solves the efficiency "pit" problem while preserving the resonance of the excited NFC coil, enabling the antenna structure to achieve both high bandwidth and high efficiency.

[0051] In addition, the jumper structure can be connected to the motherboard ground structure through a capacitor or inductor, thereby further tuning the resonance generated by the NFC coil 13 and optimizing performance.

[0052] Therefore, it can be seen that the antenna solution can be used in POS machines in poor electromagnetic environments. Even if necessary components in the POS machine, such as NFC metal coils and camera FPCs, affect the antenna clearance, it can still work normally. Moreover, components such as camera FPCs and NFC coils, which are not inherently good for antennas, can be used to extend the frequency range and achieve better low-frequency bandwidth.

[0053] In this design, the minimum gap between the antenna grounding arm 151 and the antenna radiating arm 152 serves as the feed point for the radio frequency (RF) signal, commonly known as the feed point. A coaxial cable is used for excitation at the feed point. The outer conductor of the coaxial RF cable 16 is soldered to the antenna grounding arm 151 at the feed point, and the inner conductor is soldered to the antenna radiating arm 152 at the feed point. The other end of the coaxial RF cable 16 is riveted to an RF connector for connecting the antenna 15 to the RF circuitry on the motherboard. The length and diameter of the coaxial RF cable 16 can be adjusted according to specific application requirements without affecting the antenna performance.

[0054] It should also be noted that the above embodiments only use LTE and Wi-Fi bands as examples to illustrate the actual performance of this antenna scheme. However, it is not difficult to see that this antenna scheme has a large bandwidth characteristic and can be easily extended to the 5G (RF1) band.

[0055] The above implementation method is only described with the simplest structure of this solution. In actual applications, relevant structural components can be added as needed.

[0056] The specific embodiments described herein are merely illustrative examples of the spirit of this solution. Those skilled in the art to which this solution pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this solution or exceeding the scope defined by the appended claims.

Claims

1. A POS machine miniaturization, large bandwidth, high efficiency antenna, comprising a paper slot (11), a main board (12), an NFC coil (13), a rear camera (17), and an antenna (15) for mobile communication, the paper slot (11) has an arc-shaped cover surface (18) and a first side surface (19) and a second side surface (20) on both sides of the arc-shaped cover surface (18), the NFC coil (13) surrounds the paper slot (11) along the side surface connecting direction of the paper slot (11) and is connected to the main board circuit during the surrounding process, the rear camera (17) is located on the back of the paper slot (11) and is connected to the main board circuit through a camera FPC (14), characterized in that: The antenna (15) includes an antenna grounding arm (151) and an antenna radiating arm (152). The antenna grounding arm (151) is attached to the second side (20) of the paper groove (11) and extends from the second side (20) along the paper groove (11) to the main board (12) and is connected to the main board ground structure. The antenna radiating arm (152) is located on the side of the camera FPC (14) away from the first side (19). The antenna grounding arm (151) is attached to the second side (20) of the paper groove (11) and extends to the bottom of the arc-shaped cover (18) on the second side (20), and then extends along the paper groove (11) to the main board (12). The antenna radiating arm (152) has a V-shaped structure consisting of a first branch and a second branch. The first branch is attached to the arc-shaped cover (18) of the paper slot (11), and the second branch extends from the arc-shaped cover (18) to the second side (20) of the paper slot (11). The end of the first branch away from the second side (20) extends to the camera FPC (14) to generate low-frequency resonance.

2. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 1, characterized in that: The portion of the antenna radiating arm (152) located on the arc-shaped cover (18) is positioned in the lower middle part of the arc-shaped cover (18) near the second side (20).

3. A miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 1 or 2, characterized in that: The NFC coil (13) extends from the self-board (12) around the paper slot (11) to above the main board (12) and then extends to the main board (12), and then returns to the paper slot (11) to continue to surround the main board (12), thus forming an NFC coil (13) structure surrounding the paper slot (11).

4. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 3, characterized in that: The NFC coil (13) extends to the middle position of the coil of the motherboard (12) and is connected to the motherboard ground structure through a jumper structure (21).

5. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 4, characterized in that: The NFC coil (13) extends to the jumper structure (21) at the middle position of the coil of the motherboard (12) and is connected to the motherboard ground structure through a capacitor or inductor.

6. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 5, characterized in that: The antenna (15) is excited by a coaxial radio frequency line (16) located on the motherboard (12), and the core wire of the coaxial radio frequency line (16) is connected to the radiating arm, and the ground wire of the coaxial radio frequency line (16) is connected to the grounding arm. The coaxial radio frequency line (16) is located on the side of the motherboard near the second side (20) of the paper slot, and the NFC coil extending to the motherboard is located between the coaxial radio frequency line (16) and the camera FPC (14).

7. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 1, characterized in that: The rear camera (17) is located on the back of the paper slot (11), inside the loop of the NFC coil (13); The end of the camera FPC (14) away from the rear camera (17) is connected to the motherboard (12) through the vertical space extending from the NFC coil (13).

8. The miniaturized, high-bandwidth, high-efficiency antenna for a POS machine according to claim 1, characterized in that: The NFC coil (13) is wrapped around the lower edge of the paper slot (11); The camera FPC (14) extends along the arc-shaped cover (18) from the back of the paper tray (11) to the main board (12) in front of the paper tray (11). The antenna (15) is located inside the NFC ring and above the NFC surrounding area.

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