A multi-band FPC antenna

Abstract

The utility model discloses a kind of multi-band FPC antennas, including FPC substrate, first radiating oscillator and second radiating oscillator on FPC substrate, FPC substrate one end is provided with feed part;First radiating oscillator is electrically connected with feed part and extends along the length direction of FPC substrate, first radiating oscillator includes a pair of parallelly arranged first radiating unit and second radiating unit, and first coupling gap is provided between first radiating unit and second radiating unit;Second radiating oscillator includes sequentially connected connecting arm, left radiating arm and right radiating arm, connecting arm is connected with first radiating unit, left radiating arm and right radiating arm are symmetrically arranged in the transverse two sides of first radiating oscillator, and located in the space above first radiating oscillator.This application is coupled with the architecture of layering hetero-surface, symmetrically folded double radiating oscillator, combined with the fine structure design of multi-order bending, coupling gap, tuning slot, symmetric protruding part, systematically solves the problem of terminal built-in antenna miniaturization.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology, and in particular to a multi-band FPC antenna. Background Technology

[0002] Currently, walkie-talkies and video intercom integrated terminals, as mainstream short-range wireless communication devices, generally use metal coils and elastic springs as radiating carriers for their built-in transceiver antennas, which belong to the traditional discrete metal antenna configuration. From the perspective of overall device structure adaptation, coil and spring-type metal antennas are limited by their own radiation principle, requiring long physical traces and large radial volumes to meet the radiation requirements of the entire 700-2700MHz walkie-talkie communication frequency band. The antenna occupies a large amount of internal stacking space. Due to the size constraints of this type of antenna, the terminal shell cannot be made thinner or smaller. The redundancy of the internal structural layout is extremely low. The arrangement of components such as the shell, battery, and motherboard must passively accommodate the antenna size, which greatly limits the iteration of lightweight and compact structural design of walkie-talkie terminals and makes it difficult to adapt to the current industry trend of miniaturization and integration of portable communication terminals.

[0003] Furthermore, the internal metal antenna structures of current intercom terminals in the industry are highly homogenized, with most adopting monopole and spiral coil basic radiation topologies. The changes in topology are minimal, lacking substantial structural novelty. At the same time, existing antennas have not undergone dedicated coupling and impedance tuning optimization for bidirectional transmission and reception scenarios of intercom devices, and there are no differentiated breakthroughs in core performance indicators such as radiation gain and frequency band isolation. Terminal products are unable to form technological barriers and are easily replaced in the survival-of-the-fittest market environment of the communication terminal industry. Utility Model Content

[0004] This application provides a multi-band FPC antenna, which aims to solve the problem that existing built-in antennas cannot simultaneously meet the requirements of miniaturization, multi-band coverage and high performance.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: a multi-band FPC antenna, comprising an FPC substrate, a first radiating element and a second radiating element disposed on the FPC substrate.

[0006] With the wiring plane of the FPC substrate as the reference, the long side of the substrate is the length direction, the short side is the width direction, and the direction perpendicular to the wiring plane of the substrate and facing outward is the top.

[0007] The FPC substrate has a power feeding section at one end along its length.

[0008] The first radiating element is electrically connected to the feed section and extends along the length direction of the FPC substrate. The first radiating element includes a pair of parallel first radiating units and second radiating units, and a first coupling gap is provided between the first radiating units and the second radiating units.

[0009] The second radiating oscillator includes a connecting arm, a left radiating arm, and a right radiating arm connected in sequence. The connecting arm is connected to the first radiating unit. The left and right radiating arms are symmetrically arranged on both sides of the width direction of the first radiating oscillator and are located in the space above the first radiating oscillator.

[0010] Furthermore, the connecting arm is divided into a first horizontal segment and a first vertical segment by a first bending portion, and the second radiating unit is provided with a corresponding bending portion on the same straight line as the first bending portion. The corresponding bending portion divides the second radiating unit into a second horizontal segment and a second vertical segment, and the first vertical segment and the second vertical segment are coplanar.

[0011] Furthermore, the upper end of the first vertical segment is connected to a second bend, which is connected to the left radiating arm. The left radiating arm extends to the left and then bends back toward the first radiating oscillator. The right radiating arm extends to the right and then bends back toward the first radiating oscillator. The left and right radiating arms are arranged opposite to each other.

[0012] Furthermore, the first radiating unit has a first protrusion at its end, and the second radiating unit has a second protrusion extending in the width direction in the middle of the second horizontal section. The first protrusion and the second protrusion are symmetrically arranged along the first coupling gap.

[0013] Furthermore, the second radiating unit also includes a third bend connected to the second vertical section, and a tuning groove is provided between the third bend and the second radiating oscillator.

[0014] Furthermore, the width of the first radiating element is smaller than the width of the second radiating element.

[0015] Furthermore, a second coupling gap is provided in the middle of the left radiating arm, a third coupling gap is provided in the middle of the right radiating arm, and a notch or groove is provided between the roots of the left and right radiating arms that are close to each other.

[0016] Furthermore, the width of the second coupling gap is smaller than the width of the third coupling gap.

[0017] Furthermore, the first radiating oscillator is a mid-to-high frequency radiating oscillator in the 1710-2690MHz frequency band, and the second radiating oscillator is a low frequency radiating oscillator in the 700-960MHz frequency band.

[0018] Furthermore, the antenna is disposed on the surface of the FPC substrate by laser engraving.

[0019] The beneficial effects of this utility model are as follows: Through a layered, non-planar, symmetrically folded dual-radiating element coupling architecture, combined with a refined structural design of multi-stage bending, coupling gaps, tuning slots, and symmetrical protrusions, it systematically solves the industry pain point of the incompatibility between miniaturization of the terminal's built-in antenna, full coverage of high and low frequencies, and balanced radiation gain. Specifically, it achieves non-planar space reuse to meet the requirements of extreme miniaturization. This application suspends the second radiating element, which is responsible for the low-frequency operation of 700-960MHz, above the first radiating element of the mid-high frequency operation of 1710-2690MHz. It achieves a longitudinal stacked layout of high and low frequency elements by relying on the bending structure of the connecting arm, without occupying additional long and wide planar wiring area of ​​the FPC substrate, thus avoiding the defects of traditional parallel antenna substrates being too large and unable to adapt to the narrow installation space inside the narrow bezel terminal. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the multi-band FPC antenna in the embodiment of this utility model;

[0021] Figure 2 This is a structural schematic diagram of the multi-band FPC antenna from another perspective in an embodiment of this utility model;

[0022] Figure 3 This is a structural schematic diagram of the multi-band FPC antenna from another perspective in an embodiment of this utility model;

[0023] Figure 4 This is a voltage standing wave ratio (VSWR) diagram of the multi-band FPC antenna in this embodiment of the present invention.

[0024] Figure 5 This is a passive efficiency diagram of the multi-band FPC antenna in the embodiments of this utility model;

[0025] Reference numerals: 1-FPC substrate, 10-first radiating unit, 101-first coupling gap, 100-first protrusion, 11-second radiating unit, 1110-second protrusion, 111-second horizontal segment, 112-corresponding bending portion, 113-second vertical segment, 114-third bending portion, 1140-tuning groove, 12-connecting arm, 120-first horizontal segment, 121-first bending portion, 122-first vertical segment, 123-second bending portion, 13-left radiating arm, 130-second coupling gap, 14-right radiating arm, 140-third coupling gap, 141-notch groove, 2-spring piece, 20-feeding portion. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] This embodiment discloses a multi-band FPC antenna that is compatible with miniaturized wireless communication devices such as smartphones, smart wearables, and IoT terminals. It has the advantages of multi-band compatibility, compact size, stable radiation performance, and convenient assembly, effectively solving the technical defects of traditional FPC antennas such as single frequency band, large high and low frequency radiation interference, and poor adaptability.

[0028] Combination Figure 1 , Figure 2 and Figure 3 As shown, this multi-band FPC antenna includes an FPC substrate 1. The dimensions (length * width * thickness) of the FPC substrate 1 are 30.5mm * 28.5mm * 0.1mm. The dimensions of the FPC substrate 1 here are only an example and can be set according to the actual design. The dimensions are not limited.

[0029] To facilitate the description of the structure of this utility model, the following spatial coordinate system is defined: with the front wiring plane of the FPC substrate 1 as the reference, the long side direction of the FPC substrate 1 as the length direction (i.e., the y direction), the short side direction of the FPC substrate 1 as the width direction (i.e., the x direction), and the direction perpendicular to the wiring plane of the FPC substrate 1 and outward as the upward direction (i.e., the z direction).

[0030] In this embodiment, the antenna body is laser-engraved onto its surface. More specifically, the front wiring plane of the FPC substrate 1 is provided with a first radiating element and a second radiating element. A feed section 20 is provided at the negative end of the FPC substrate 1 along its y-direction. In this embodiment, the feed section 20 adopts an integrated FPC copper foil etching structure, eliminating the need for additional welding and assembly. This results in a robust structure, high production efficiency, and controllable dimensional accuracy. Furthermore, the feed section 20 uses a spring-loaded contact to achieve a flexible electrical connection with the terminal motherboard, reducing energy loss. During assembly, the elastic contact tip abuts against the motherboard pads, adapting to the assembly tolerances of the terminal equipment. This effectively solves the problems of poor soldering, desoldering, and poor shock resistance inherent in traditional welded feed systems, ensuring the electrical connection stability of the antenna during long-term operation and facilitating automated assembly.

[0031] The first radiating element is a mid-to-high frequency radiating element, responsible for covering the high frequency band of 1710-2690MHz. The first radiating element is directly electrically connected to the feed section 20 and extends along the y-direction of the FPC substrate 1. Specifically, the first radiating element consists of a pair of parallel first radiating elements 10 and second radiating elements 11. The two radiating elements are evenly spaced, and a narrow first coupling gap 101 is formed between the first radiating element 10 and the second radiating element 11. Through the electromagnetic coupling effect of the first coupling gap 101, the radiation efficiency of mid-to-high frequency signals is optimized, effectively expanding and deepening the resonance depth and impedance bandwidth of the 850-960 MHz low frequency band, thereby further improving the anti-interference and stability of this 4G antenna.

[0032] Furthermore, in this embodiment, the overall width of the first radiating unit 10 is smaller than the width of the second radiating unit 11. This differentiated width design breaks the frequency band limitations of traditional symmetrical radiating structures, allowing the first radiating element to adapt to the resonance requirements of multiple mid-to-high frequency bands, thus improving the reception and transmission stability of mid-to-high frequency signals. Simultaneously, a first protrusion 100 is integrally formed at the end of the first radiating unit 10, and the middle of the second radiating unit 11 extends in the x-direction to form a matched second protrusion 1110. The first protrusion 100 and the second protrusion 1110 are symmetrically distributed along the first coupling gap 101. This symmetrical protrusion structure allows for fine-tuning of the current distribution of the first radiating element, optimizing impedance matching, effectively reducing return loss of mid-to-high frequency signals, and preventing signal resonance shift.

[0033] The second radiating element is a low-frequency radiating element, responsible for covering the 700-960MHz low-frequency band. It works in conjunction with the first radiating element to achieve high and low frequency multi-band compatible coverage, meeting the multi-mode communication requirements of the equipment. Specifically, the second radiating element includes a connecting arm 12, a left radiating arm 13, and a right radiating arm 14 connected sequentially and integrally. The connecting arm 12 is connected to and electrically conductive with the first radiating unit 10, realizing the coordinated power supply between the low-frequency radiating element and the power supply structure.

[0034] The left radiating arm 13 and the right radiating arm 14 are arranged in a symmetrical structure, respectively positioned on the left and right sides of the first radiating element in the x direction, and are suspended above the first radiating element in the z direction. Through the spatial layering layout, electromagnetic interference between the low-frequency radiating element and the mid-to-high-frequency radiating element is completely avoided. High and low frequency signals are radiated independently and do not affect each other, which greatly improves the overall radiation performance of the antenna.

[0035] To adapt to the flexible bending assembly requirements of FPC and optimize space utilization, a first bending portion 121 is provided at the connecting arm 12. The first bending portion 121 divides the connecting arm 12 into a lower first horizontal segment 120 and an upper first vertical segment 122. The first horizontal segment 120 is arranged parallel to the plane of the FPC substrate 1, and the first vertical segment 122 extends upward perpendicular to the plane of the FPC substrate 1. Correspondingly, a corresponding bending portion 112 is provided on the second radiating unit 11, which is on the same straight line as the first bending portion 121. The corresponding bending portion 112 divides the second radiating unit 11 into a second horizontal segment 111 and a second vertical segment 113. The second horizontal segment 111 extends along the y-direction of the substrate, and the second vertical segment 113 extends upward perpendicular to the substrate (z-direction). The first vertical segment 122 and the second vertical segment 113 are completely coplanar. The coaxial bending and coplanar layout design ensures the regularity of the overall antenna structure, reduces assembly stress, and optimizes the current radiation path in the vertical direction, thereby improving the radiation uniformity of low-frequency signals.

[0036] The upper end of the first vertical segment 122 is integrally connected to a second bent portion 123, which extends laterally and is fixedly connected to the left radiating arm 13. Specifically, the left radiating arm 13 extends laterally to the left by a predetermined length and then folds back towards the direction of the first radiating element (i.e., the negative y-direction). The right radiating arm 14 extends laterally to the right by a predetermined length and also folds back towards the direction of the first radiating element (i.e., the negative y-direction), making the left and right radiating arms 13 and 14 relatively symmetrically arranged. This folded-back structure can significantly increase the radiation length of the low-frequency radiating element within a limited space, meeting the resonance requirements of long wavelengths in the low-frequency band, while simultaneously reducing the overall space occupied by the antenna and adapting to the miniaturized assembly requirements of the terminal.

[0037] The second radiating element also includes a third bend 114 connected to the second vertical section 113, and a tuning slot 1140 is provided between the third bend 114 and the second radiating element. The added third bend 114 and tuning slot 1140 can fine-tune the antenna resonant frequency, optimize impedance matching, widen the operating bandwidth, and reduce electromagnetic interference between radiating elements. At the same time, it is suitable for narrow assembly spaces and has a simple structure.

[0038] To further optimize the bandwidth and impedance matching performance in the low-frequency band, this embodiment provides a second coupling slot 130 at the middle position of the left radiating arm 13 and a third coupling slot 140 at the middle position of the right radiating arm 14. Through the electromagnetic coupling effect of the dual coupling slots, the low-frequency resonant point is fine-tuned, and the low-frequency operating bandwidth is broadened. The width of the second coupling slot 130 is smaller than the width of the third coupling slot 140. This non-uniform slot design corrects the current distribution deviation between the left and right radiating arms, solves the problem of uneven low-frequency radiation in symmetrical structures, and improves the uniformity of omnidirectional low-frequency signal radiation. Simultaneously, a notch / groove 141 is provided at the root positions of the left and right radiating arms 13 and 14, which can change the current transmission path at the root of the low-frequency oscillator, weakening electromagnetic coupling interference at the root of the oscillator, further optimizing low-frequency radiation efficiency, and reducing signal loss.

[0039] Combination Figure 4 , Figure 5 The antenna performance test spectrum shown in this embodiment indicates that the voltage standing wave ratio (VSWR) of the multi-band FPC antenna prepared in this embodiment is generally close to 1. The VSWR value is stable across the entire operating frequency band without significant abrupt changes, indicating excellent antenna impedance matching performance and low signal reflection loss. OTA laboratory testing achieved a VSWR <4.0 and an efficiency greater than 28% in the low-frequency band (700-960MHz) of 4G-LTE; and a VSWR <3.1 and an efficiency greater than 43% in the mid-to-high frequency band (1710-2690MHz) of 4G-LTE. Figure 4 The test results are quite satisfactory (VSWR<4.0), indicating that the antenna has a low input / output reflection coefficient and low energy loss from antenna radiation.

[0040] Meanwhile, the antenna's passive efficiency remains high in both high and low frequency operating bands, with low radiation loss and excellent signal reception and transmission performance. It can stably cover multiple communication bands, including low, medium, and high frequencies, fully meeting the multi-band usage requirements of civilian wireless communication equipment.

[0041] This embodiment achieves miniaturization, multi-band operation, low interference, and high stability of the antenna through a collaborative design of layered staggered layout, differentiated radiation structure, multi-coupling gap cooperation, and integrated flexible feeding structure. The structure is simple, easy to mass-produce, and adaptable to various assembly and usage scenarios of small wireless terminals. Within a small, concise, and lightweight FPC material (including minimal antenna copper area), a special antenna combination structure is designed, achieving the predetermined specifications of a small-size antenna structure. This significantly reduces R&D and production costs and shortens the mass production cycle of antenna products.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] In the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the meaning of the above terms in this application according to the specific circumstances.

[0044] In the description of this embodiment, the terms "upper," "lower," "front," and "rear," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first" and "second" are used only for distinction in description and have no special meaning.

[0045] The embodiments described above are merely illustrative of the implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A multi-band FPC antenna, comprising an FPC substrate, a first radiating element and a second radiating element disposed on the FPC substrate, characterized in that: With the wiring plane of the FPC substrate as the reference, the long side of the substrate is the length direction, the short side is the width direction, and the direction perpendicular to the wiring plane of the substrate and facing outward is the top. The FPC substrate has a power feeding section at one end along its length. The first radiating element is electrically connected to the feed section and extends along the length direction of the FPC substrate. The first radiating element includes a pair of parallel first radiating units and second radiating units, and a first coupling gap is provided between the first radiating units and the second radiating units. The second radiating oscillator includes a connecting arm, a left radiating arm, and a right radiating arm connected in sequence. The connecting arm is connected to the first radiating unit. The left and right radiating arms are symmetrically arranged on both sides of the width direction of the first radiating oscillator and are located in the space above the first radiating oscillator.

2. The multi-band FPC antenna according to claim 1, characterized in that: The connecting arm is divided into a first horizontal segment and a first vertical segment by a first bending portion. The second radiating unit is provided with a corresponding bending portion that is on the same straight line as the first bending portion. The corresponding bending portion divides the second radiating unit into a second horizontal segment and a second vertical segment. The first vertical segment and the second vertical segment are coplanar.

3. The multi-band FPC antenna according to claim 2, characterized in that: The upper end of the first vertical segment is connected to a second bend, which is connected to the left radiating arm. The left radiating arm extends to the left and then bends back toward the first radiating oscillator. The right radiating arm extends to the right and then bends back toward the first radiating oscillator. The left and right radiating arms are arranged opposite to each other.

4. The multi-band FPC antenna according to claim 2, characterized in that: The first radiating unit has a first protrusion at its end, and the second radiating unit has a second protrusion extending in the width direction in the middle of the second horizontal section. The first protrusion and the second protrusion are symmetrically arranged along the first coupling gap.

5. The multi-band FPC antenna according to claim 2, characterized in that: The second radiating unit also includes a third bend connected to the second vertical section, and a tuning groove is provided between the third bend and the second radiating oscillator.

6. The multi-band FPC antenna according to claim 1, characterized in that: The width of the first radiating element is smaller than the width of the second radiating element.

7. The multi-band FPC antenna according to claim 1, characterized in that: The left radiating arm has a second coupling gap in the middle, the right radiating arm has a third coupling gap in the middle, and a notch or groove is formed between the roots of the left and right radiating arms that are close to each other.

8. The multi-band FPC antenna according to claim 7, characterized in that: The width of the second coupling gap is smaller than the width of the third coupling gap.

9. The multi-band FPC antenna according to claim 1, characterized in that: The first radiating oscillator is a mid-to-high frequency radiating oscillator in the 1710-2690MHz frequency band, and the second radiating oscillator is a low frequency radiating oscillator in the 700-960MHz frequency band.

10. The multi-band FPC antenna according to claim 1, characterized in that: The antenna is mounted on the surface of the FPC substrate by laser engraving.

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