An antenna based on distributed doubly-fed technology and its terminal

Abstract

This invention relates to the field of antenna technology, specifically to an antenna and its terminal based on distributed double-fed technology. The antenna includes radiating stubs, a frequency-modulated inductor, and a feed network. The feed network includes a low-frequency feed port, a power divider, and a microstrip line phase shifter. The low-frequency feed port is connected to the input of the power divider, and the output of the power divider forms two feed branches, at least one of which is equipped with a microstrip line phase shifter. The two feed branches are respectively connected to two radiating stubs via the frequency-modulated inductor. The power divider and microstrip line phase shifter form a distributed double-fed system with a phase difference, enabling the two radiating stubs to excite two closely spaced resonant modes in the low-frequency band. With the impedance compensation of the frequency-modulated inductor, continuous broadband coverage is achieved, thus realizing low-frequency broadband operation within a relatively small physical size.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, specifically to an antenna and its terminal based on distributed doubly fed technology. Background Technology

[0002] As consumers' demands for mobile phone functionality continue to increase, the size of components such as LCD screens, camera modules, and batteries continues to grow, further compressing the available clearance area for antennas. Against this backdrop, low-frequency mobile phone antennas, especially those designed for 4G / 5G low-frequency bands, face even more prominent challenges in balancing structure and performance. Existing low-frequency mobile phone antennas mostly employ single-fed inverted L-structures or inverted F-structures, whose operating mechanism typically relies on quarter-wavelength resonance. Therefore, metal stubs often require considerable physical length, making effective arrangement difficult under limited clearance conditions. To expand bandwidth, existing technologies have also employed solutions that add parasitic stubs for improvement. However, in compact spaces, the coupling between the main stub and the parasitic stub is often significantly enhanced, easily leading to current reversal and subsequently creating local minima of radiation efficiency in certain frequency bands, which is detrimental to maintaining stable terminal communication performance.

[0003] Meanwhile, existing dual-fed antenna technology still has certain limitations in low-frequency miniaturized applications. For example, the invention patent "A mobile phone antenna and electronic device based on common-mode and differential-mode" (publication number: CN117748173A) discloses a parallel feeding method with phase difference, attempting to reduce or eliminate the efficiency minimum point through phase adjustment. Although this type of technical solution can improve the efficiency dip to some extent, it mainly focuses on optimizing radiation performance through phase adjustment and does not fundamentally get rid of the dependence of low-frequency antennas on long stub structures. Therefore, the overall physical length of the antenna is still relatively large, making it difficult to meet the requirements of multi-antenna integration and arrangement under ultra-narrow clearance conditions. Furthermore, in the low-frequency band, due to the more drastic changes in input impedance, it is usually difficult to simultaneously achieve impedance matching and multi-mode excitation by relying solely on phase shifters, thus making it difficult to achieve low-frequency wideband coverage under small size conditions.

[0004] Therefore, how to significantly shorten the physical length of the antenna while suppressing the low-frequency efficiency trap and maintaining good wideband operating characteristics in a very small headroom environment has become an urgent technical problem to be solved in the field of mobile phone low-frequency antenna design. Summary of the Invention

[0005] The purpose of this invention is to provide an antenna and its terminal based on distributed doubly fed technology to solve the technical problems mentioned in the background.

[0006] Based on the above ideas, the present invention provides the following technical solution:

[0007] An antenna and its terminal based on distributed doubly-fed technology, comprising:

[0008] It includes a radiating stub, a frequency modulation inductor, a frequency modulation inductor, and a feed network; the feed network includes a low-frequency feed port, a power divider, and a microstrip line phase shifter; the low-frequency feed port is connected to the input terminal of the power divider, and the output terminal of the power divider forms two feed branches, at least one of which is equipped with the microstrip line phase shifter, and the two feed branches are respectively connected to the radiating stub and the radiating stub via the frequency modulation inductor and the frequency modulation inductor;

[0009] The power divider and the microstrip line phase shifter form a distributed doubly fed circuit with a phase difference, so that the radiating stubs excite two resonant modes that are close to each other in the low-frequency band, and form a continuous broadband coverage under the impedance compensation of the frequency modulation inductor.

[0010] By combining a power divider, a microstrip line phase shifter, and frequency-modulated inductors on both branches with two radiating stubs, this invention achieves distributed doubly-fed excitation in the low-frequency band under small-size radiating stub conditions. This technical solution enables the two radiating stubs to form two resonant modes close to each other in the low-frequency band, and forms continuous broadband coverage under the impedance compensation of the frequency-modulated inductors, thus simultaneously meeting the low-frequency operating requirements and bandwidth requirements under small-size conditions.

[0011] Preferably, the power supply network further includes a matching network, which is disposed between the low-frequency power supply port and the power divider.

[0012] Setting up a matching network between the low-frequency feed port and the power divider helps to improve the impedance matching relationship between the feed network and the radiation structure, enabling the input signal to be coupled more effectively to the subsequent dual-branch feed structure, thereby providing more suitable input conditions for distributed doubly fed and subsequent dual-mode excitation.

[0013] Preferably, by adjusting the phase angle of the microstrip line phase shifter, the radiating stub and the radiating stub simultaneously excite the first resonant mode and the second resonant mode in the low-frequency band, and the center frequencies of the first resonant mode and the second resonant mode are close to each other, so as to form a continuous broadband covering the target low-frequency band.

[0014] By adjusting the phase angle of the microstrip line phase shifter, the two radiating stubs can simultaneously excite the first and second resonant modes in the low-frequency band, and bring the center frequencies of the two resonant modes closer to each other. This technique is beneficial for forming continuous broadband in the low-frequency band and is an important means for achieving low-frequency broadband coverage in this invention.

[0015] Preferably, the frequency-modulated inductor is used to compensate for the capacitive reactance effect caused by the reduction in the physical length of the radiating stub and the radiating stub, so that the radiating stub and the radiating stub achieve impedance matching under the condition that the physical size is much smaller than a quarter wavelength corresponding to the target frequency.

[0016] A frequency-modulated inductor is used to compensate for the capacitive reactance effect caused by the reduction in the physical length of the radiating stub, allowing the small-sized radiating stub, with a physical size much smaller than a quarter wavelength of the target frequency, to still achieve impedance matching. Therefore, this invention can maintain usable electrical performance in the low-frequency band while shortening the physical length of the radiating stub.

[0017] Preferably, the radiating stub and the radiating stub are metal inverted L-antenna stubs;

[0018] The antenna also includes a plastic frame, a main dielectric substrate, and a metal ground plane. The radiating stubs are disposed outside the plastic frame, and the metal ground plane is disposed outside the main dielectric substrate. The plastic frame is perpendicularly connected to the main dielectric substrate.

[0019] Setting the radiating stub as a metal inverted L antenna stub, and combining it with a plastic frame, a main dielectric substrate, and a metal ground plane to form a corresponding antenna arrangement structure, is beneficial for realizing the low-frequency small-size antenna structure required by this invention within the limited space of a mobile terminal, and provides a specific structural basis for the aforementioned distributed doubly fed, phase-shifted, and impedance compensation schemes.

[0020] Preferably, the plastic frame is an FR4 dielectric substrate, and the main dielectric substrate is a Rogers RO4003C dielectric substrate;

[0021] The thickness of the radiating branch and the radiating branch is 0.02 mm, the thickness of the plastic frame is 0.5 mm, the thickness of the main dielectric substrate is 0.8 mm, and the thickness of the metal floor is 0.02 mm.

[0022] Limiting the material and thickness parameters of the plastic frame, the main dielectric substrate, and each metal layer helps to form the antenna structure conditions corresponding to the embodiments, enabling the structural arrangement, power supply network setup, and low-frequency operation mode of the present invention to be realized on a relatively clear parameter basis.

[0023] Preferably, the power divider includes 25-ohm microstrip lines and 50-ohm microstrip lines.

[0024] Limiting the power divider to include 25-ohm and 50-ohm microstrip lines facilitates the construction of a specific implementation structure for the power divider, thereby distributing a single low-frequency feed signal to two feed branches and providing a structural basis for forming a distributed doubly fed system with phase difference.

[0025] Preferably, the width of the 25-ohm microstrip line is 5.5 mm, and the width of the 50-ohm microstrip line is 2.2 mm;

[0026] The length of each radial branch is 15mm, and the total length of the branches is 30mm.

[0027] The main dielectric substrate has dimensions of 75mm × 140mm, and the metal floor has dimensions of 74mm × 139mm.

[0028] When the phase shift angle of the microstrip phase shifter is 50 degrees, the corresponding length of the 50-ohm microstrip line is 28 mm; or, when the phase shift angle of the microstrip phase shifter is 45 degrees, the corresponding length of the 50-ohm microstrip line is 25 mm.

[0029] The technical solution of the present invention may include the following beneficial effects:

[0030] On the one hand, this invention introduces a frequency-modulated inductor into the frequency-modulated network to compensate for the capacitive reactance caused by the reduction in the physical length of the antenna radiating stubs. This allows the low-frequency antenna to still achieve impedance matching even with a physical size much smaller than a quarter wavelength of the target frequency, thus meeting the antenna miniaturization requirements under the limited clearance conditions of mobile terminals while ensuring low-frequency operating performance. On the other hand, this invention breaks through the limitation of traditional single-fed antennas that mainly rely on a single resonant point to achieve low-frequency coverage. By using a distributed double-fed structure in conjunction with phase-shift control, two small-sized radiating stubs excite two resonant modes that are close to each other in the low-frequency band, thereby compensating for the bandwidth loss caused by antenna miniaturization, forming continuous broadband coverage, and achieving a balance between small size and broadband performance. Attached Figure Description

[0031] Figure 1 This is a technical schematic diagram of the low-frequency small-size mobile phone antenna designed based on the distributed doubly fed antenna of the present invention.

[0032] Figure 2 This is a top view of the low-frequency, small-size mobile phone antenna designed based on the distributed doubly fed antenna of this invention.

[0033] Figure 3 This is a top anatomical view of the low-frequency, small-size mobile phone antenna designed based on the distributed doubly fed antenna of this invention.

[0034] Figure 4 A top view of a long-stubby single-fed inverted L-shaped mobile phone antenna in contrast to the present invention.

[0035] Figure 5 Top view anatomical diagram of a long-stub single-fed inverted L mobile phone antenna for comparison with the present invention.

[0036] Figure 6Comparison of antenna impedance for single-fed inverted L-shaped mobile phone antennas with long stubs, 15mm and 60mm stub lengths.

[0037] Figure 7 The current distribution of a single-fed inverted L-shaped mobile phone antenna with a stub length of 60mm at 0.9GHz.

[0038] Figure 8 A comparison of antenna impedance between a 60mm long single-fed inverted L mobile phone antenna with a 30mm total length of antenna stubs and the distributed dual-fed small-size inverted L antenna proposed in this invention.

[0039] Figure 9 The current distribution of the distributed doubly fed small-size inverted L antenna (total antenna stub length is 30mm) proposed in this invention is shown at 0.85GHz and 1GHz.

[0040] Figure 10 Impedance comparison of a 60mm long stub single-fed inverted L mobile phone antenna with a 30mm total stub length and a 60mm long segment of the antenna. This invention proposes a distributed dual-fed small-size inverted L antenna with the same matching conditions.

[0041] Figure 11 A comparison of S11 between a 60mm long stub single-fed inverted L mobile phone antenna and the distributed dual-fed small-size inverted L antenna (total antenna stub length of 30mm) proposed in this invention under the same matching conditions.

[0042] Figure 12 A comparison of system efficiency between a 60mm long stub single-fed inverted L mobile phone antenna and the distributed dual-fed small-size inverted L antenna (total antenna stub length of 30mm) proposed in this invention under the same matching conditions. Detailed Implementation

[0043] Example 1

[0044] like Figure 1 As shown, the technical protection points of this invention are mainly reflected in two aspects: First, by adjusting the phase angle of the phase shifter, the small-sized radiating stub simultaneously excites the first and second resonant modes in the low-frequency band, and makes the center frequencies of the first and second resonant modes close to each other, thereby forming a continuous broadband coverage of the target low-frequency band; Second, in order to compensate for the large reactance effect exhibited by the electrically small antenna under miniaturization conditions, a frequency-modulated inductor is introduced into the feed branch to compensate for the capacitive reactance caused by the reduction in the physical length of the radiating stub, and combined with the mode multiplexing formed by dual-port excitation, the physical length of the radiating stub is much smaller than a quarter wavelength corresponding to the target frequency. Therefore, under strictly limited physical dimensions, the antenna operating bandwidth can still be expanded, realizing the miniaturization design of low-frequency mobile phone antennas.

[0045] like Figure 2and Figure 3 As shown, the mobile phone antenna in this embodiment includes a small-sized radiating stub 1, a radiating stub 2, a plastic frame 6, a main dielectric substrate 7, a metal ground plane 8, and a feed network. Both radiating stubs 1 and 2 are small-sized metal inverted-L antenna stubs, each 15mm in length, for a total stub length of 30mm. The plastic frame 6 uses an FR4 dielectric substrate with a dielectric constant of 4.3, and the small-sized radiating stubs 1 and 2 are located outside the plastic frame 6. The main dielectric substrate 7 uses a Rogers RO4003C dielectric substrate with a dielectric constant of 3.55, and the metal ground plane 8 covers the outside of the main dielectric substrate 7. The plastic frame 6 is perpendicularly connected to the main dielectric substrate 7, thus forming an overall structure suitable for a plastic-framed mobile phone antenna. The feed network includes a low-frequency feed port 5, a matching network, a power divider 3, a microstrip line phase shifter 4, and frequency modulation inductors 9 and 10. The two small-sized radiating stubs are connected to the frequency modulation inductors 9 and 10 via microstrip lines, respectively. In other words, this embodiment uses a plastic-framed mobile phone antenna as a carrier, introduces a new resonance through distributed feeding and small-angle phase shifting technology, and achieves dual-mode operation with an extremely small dual stub.

[0046] In this embodiment, the power divider 3 includes a 25Ω microstrip line 3a and a 50Ω microstrip line 3b. According to the parameters set in the original disclosure, the width of the 25Ω microstrip line 3a is 5.5mm, and the width of the 50Ω microstrip line 3b is 2.2mm. Meanwhile, the main dielectric substrate 7 has dimensions of 75mm × 140mm, and the metal ground plane 8 has dimensions of 74mm × 139mm. For Embodiment 1, the phase shift angle of the microstrip line phase shifter 4 is 50 degrees, corresponding to a 50Ω microstrip line length of 28mm. The low-frequency signal is input through the low-frequency feed port 5, pre-adjusted by the matching network, and then enters the power divider 3. The power divider 3 distributes the signal to two feed branches, and after introducing a phase difference through the microstrip line phase shifter 4 in one branch, the signal is fed into two radiating stubs, thus forming a distributed double-fed system with a phase difference.

[0047] To provide a performance comparison with large-size inverted-L mobile phone antennas that resonate at low frequencies, such as Figure 4 and Figure 5As shown, a set of long-stub single-fed inverted-L mobile phone antennas is set as a control structure. The control antenna includes a large-size radiating stub 1, a plastic frame 6, a main dielectric substrate 7, a metal ground plane 8, a low-frequency feed port 5, and a matching network. The large-size radiating stub 1 is 60mm long. The plastic frame 6 also uses an FR4 dielectric substrate with a dielectric constant of 4.3. The main dielectric substrate 7 uses a Rogers RO4003C dielectric substrate with a dielectric constant of 3.55. The metal ground plane 8 covers the outside of the main dielectric substrate 7, and the plastic frame 6 is perpendicularly connected to the main dielectric substrate 7. Thus, under the premise that the dielectric environment, overall installation boundary, and matching conditions are basically the same, this embodiment and the control scheme form a comparison of two low-frequency antenna structures: a "small-size dual-stub distributed dual-feed" and a "long-stub single-feed".

[0048] like Figure 6 As shown, to illustrate the impact of the mode and size of a single-fed long-stub mobile phone antenna on its impedance, the impedances of single-fed antennas with stub lengths of 15mm and 60mm were compared. Figure 6 It can be seen that when the stub length of the single-fed antenna is 15mm, the antenna exhibits extremely high capacitive reactance characteristics. At this time, the physical length of the antenna is much smaller than the electrical length required for resonance, and the port mismatch state makes it difficult to achieve efficient power transmission over a wide bandwidth using only the matching circuit. However, when the stub length of the single-fed antenna is 60mm, the intersection of the antenna impedance and the real axis is close to 0.9GHz, at which point the antenna generates a resonance point near 0.9GHz. In other words, Figure 6 This reflects that traditional single-fed low-frequency antennas often require a relatively long radiating stub to achieve effective resonance around 0.9 GHz.

[0049] like Figure 7 As shown, to further illustrate the operating mode of a single-fed long stub antenna at 0.9 GHz, the current distribution of a 60 mm long single-fed long stub antenna at 0.9 GHz is illustrated. Figure 7 It can be seen that the antenna is operating in the quarter-wavelength mode of the stub at this time. This figure is consistent with... Figure 6 This further illustrates the dependence of traditional single-fed long-stub antennas on relatively long physical stubs when achieving low-frequency resonance.

[0050] like Figure 8 As shown, to illustrate the performance advantages of this invention over long-stubby single-fed inverted-L mobile phone antennas, the impedance of a 60mm long-stubby single-fed inverted-L mobile phone antenna and the distributed dual-fed small-size inverted-L antenna proposed in this invention were compared under the same matching conditions. Figure 8It can be seen that when the length of the single-fed stub is 60mm, the antenna has only one intersection point with the real axis near 0.9GHz, corresponding to a single resonant mode. However, when the distributed dual-fed technology of this invention is used to excite two short stubs, each 15mm long, the antenna exhibits a "knotting point" near 0.9GHz, corresponding to a dual-mode operating state. In other words, this invention does not rely on extending the length of the single stub to obtain low-frequency resonance, but rather constructs adjacent dual modes under relatively small physical size conditions by implementing dual-fed excitation with phase difference on two short stubs.

[0051] like Figure 9 As shown, to further illustrate the dual-mode generation of the distributed doubly-fed antenna near 0.9 GHz, the current distribution of the proposed distributed doubly-fed small-size inverted-L antenna at 0.85 GHz and 1 GHz is illustrated. Figure 9 It can be seen that at 0.85 GHz, the two stubs exhibit opposite current modes; at 1 GHz, the two stubs exhibit same current modes. Therefore, this invention does indeed form two adjacent but different modes near the low frequency range, and achieves broadbanding through mode proximity and superposition, which is consistent with... Figure 8 The dual-mode impedance characteristics shown corroborate each other.

[0052] like Figure 10 and Figure 11 As shown, to verify the broadband performance of the proposed solution under the same matching conditions, the impedance and S11 of the long-stub single-fed inverted-L mobile phone antenna and the distributed double-fed small-size inverted-L antenna proposed in this invention were compared. Figure 11 It can be seen that the -6dB impedance bandwidth of the distributed dual-fed small-size antenna is 114MHz, corresponding to the frequency band of 0.875-0.989GHz; the -6dB impedance bandwidth of the single-fed long-stub antenna is 60MHz, corresponding to the frequency band of 0.875-0.935GHz. Compared with the single-fed long-stub antenna, the impedance bandwidth of the proposed solution is increased by 54MHz while reducing the total length of the antenna stub by half. Figure 10 and Figure 11 Together, these findings demonstrate that the present invention achieves a wider impedance bandwidth in the low-frequency band through the synergistic design of small-sized double stubs, frequency-modulated inductors, and distributed doubly fed feeders.

[0053] like Figure 12 As shown, to further verify the performance advantages of the present invention, the efficiency of antenna systems under the same matching conditions was compared. Figure 12It can be seen that the average system efficiency of the distributed dual-fed small-size antenna in the LTE B8 band is -1.5dB, while that of the single-fed long-stub antenna in the LTE B8 band is -1.9dB. In other words, while reducing the antenna size by half, the in-band average system efficiency of the proposed solution is improved by 0.4dB. This further demonstrates that this embodiment not only achieves low-frequency miniaturization and broadband coverage, but also maintains good performance in terms of system efficiency.

[0054] This embodiment addresses the technical challenges of limited physical length of low-frequency antennas in mobile phone environments with limited clearance, high capacitive reactance of input impedance, and the difficulty of achieving impedance matching and broadband coverage in traditional single-feed structures while miniaturizing the antenna. It proposes a small-size low-frequency mobile phone antenna solution combining a frequency-modulated inductor and a distributed dual-feed with phase difference. Specifically, on one hand, a frequency-modulated inductor is connected in series in the feed branch. The inductive reactance generated by the frequency-modulated inductor cancels the capacitive reactance of the radiating stub due to the reduced physical length, shifting the antenna input impedance from the low-impedance, high-capacitive-reactance region back to the matching region, thus providing an impedance basis for effective low-frequency operation of the small-size stub. On the other hand, a power divider distributes the single-path feed signal to two branches, and a phase shifter is set in one of the branches to introduce a phase difference. This allows the two small-size radiating stubs to simultaneously excite two resonant modes that are close to each other in the low-frequency band. By coordinating the adjustment of the phase shift angle and inductor parameters, the two resonant modes are brought closer together and superimposed, thus transforming the single-resonance operation mode of the traditional single-feed antenna into a dual-mode broadband operation mode. Therefore, this embodiment does not simply rely on extending the length of the radiating stub to obtain low-frequency resonance. Instead, it achieves low-frequency band coverage under relatively small physical size conditions through a cooperative mechanism of impedance compensation and dual-mode excitation. The embodiments and comparative results further demonstrate that, with a total stub length of 30mm, the proposed solution achieves dual-mode characteristics around 0.9GHz, with a -6dB impedance bandwidth of 114MHz for the small-sized antenna, compared to 60MHz for the controllable single-feed long-stub antenna. Simultaneously, within the LTE B8 band, the average system efficiency of the proposed solution is -1.5dB, compared to -1.9dB for the controllable solution. This demonstrates that the present invention can achieve continuous broadband coverage while significantly shortening the physical size of the low-frequency antenna and maintaining good system efficiency, thus possessing the beneficial effect of adapting to the miniaturization and broadband design requirements of low-frequency antennas under limited clearance conditions in mobile terminals.

[0055] In summary, this embodiment achieves this through the following... Figure 1 The overall technical concept of frequency modulation inductor compensation and distributed doubly fed with phase difference shown is combined with, for example, Figure 2 and Figure 3 The small-sized double-stubby specific structure is shown, and through Figures 4 to 12The comparison and test results shown verify that the present invention can still achieve LTE B8 band coverage with a total stub length of only 30mm, and shows significant advantages over long stub single-fed antennas in terms of bandwidth and system efficiency.

Claims

1. An antenna based on distributed doubly-fed technology, characterized in that, include: It includes a radiating stub (1), a radiating stub (2), a frequency modulation inductor (9), a frequency modulation inductor (10), and a feed network; the feed network includes a low-frequency feed port (5), a power divider (3), and a microstrip line phase shifter (4); the low-frequency feed port (5) is connected to the input terminal of the power divider (3), and the output terminal of the power divider (3) forms two feed branches, of which at least one feed branch is equipped with the microstrip line phase shifter (4), and the two feed branches are respectively connected to the radiating stub (1) and the radiating stub (2) through the frequency modulation inductor (9) and the frequency modulation inductor (10); The power divider (3) and the microstrip line phase shifter (4) form a distributed doubly fed circuit with a phase difference, so that the radiating stub (1) and the radiating stub (2) excite two resonant modes that are close to each other in the low frequency band, and form a continuous broadband coverage under the impedance compensation of the frequency modulation inductor (9) and the frequency modulation inductor (10).

2. An antenna based on distributed doubly-fed technology according to claim 1, characterized in that, The power supply network also includes a matching network, which is located between the low-frequency power supply port (5) and the power divider (3).

3. An antenna based on distributed doubly-fed technology according to claim 2, characterized in that, By adjusting the phase angle of the microstrip line phase shifter (4), the radiating stub (1) and the radiating stub (2) are simultaneously excited in the low-frequency band by the first resonant mode and the second resonant mode. The center frequencies of the first resonant mode and the second resonant mode are close to each other to form a continuous broadband covering the target low-frequency band.

4. An antenna based on distributed doubly-fed technology according to claim 3, characterized in that, The frequency modulation inductor (9) and the frequency modulation inductor (10) are used to compensate for the capacitive reactance effect caused by the reduction in the physical length of the radiating stub (1) and the radiating stub (2), so that the radiating stub (1) and the radiating stub (2) can achieve impedance matching under the condition that the physical size is much smaller than a quarter wavelength corresponding to the target frequency.

5. An antenna based on distributed doubly-fed technology according to claim 4, characterized in that, The radiating stub (1) and the radiating stub (2) are metal inverted L-antenna stubs; The antenna also includes a plastic frame (6), a main dielectric substrate (7) and a metal ground plane (8). The radiating stubs (1) and (2) are disposed outside the plastic frame (6), and the metal ground plane (8) is disposed outside the main dielectric substrate (7). The plastic frame (6) is perpendicularly connected to the main dielectric substrate (7).

6. An antenna based on distributed doubly-fed technology according to claim 5, characterized in that, The plastic frame (6) is an FR4 dielectric substrate, and the main dielectric substrate (7) is a Rogers RO4003C dielectric substrate; The thickness of the radiating branch (1) and the radiating branch (2) is 0.02 mm, the thickness of the plastic frame (6) is 0.5 mm, the thickness of the main dielectric substrate (7) is 0.8 mm, and the thickness of the metal floor (8) is 0.02 mm.

7. An antenna based on distributed doubly-fed technology according to claim 6, characterized in that, The power divider (3) includes a 25-ohm microstrip line (3a) and a 50-ohm microstrip line (3b).

8. An antenna based on distributed doubly-fed technology according to claim 7, characterized in that, The 25-ohm microstrip line (3a) has a width of 5.5 mm, and the 50-ohm microstrip line (3b) has a width of 2.2 mm; The length of the radial branch (1) and the radial branch (2) is 15 mm, and the total length of the branches is 30 mm. The main dielectric substrate (7) has a size of 75mm × 140mm, and the metal floor (8) has a size of 74mm × 139mm.

9. An antenna based on distributed doubly-fed technology according to claim 8, characterized in that, When the phase shift angle of the microstrip phase shifter (4) is 50 degrees, the corresponding length of the 50-ohm microstrip line is 28 mm; or, when the phase shift angle of the microstrip phase shifter (4) is 45 degrees, the corresponding length of the 50-ohm microstrip line is 25 mm.

10. A terminal, characterized in that, The antenna includes the distributed doubly fed antenna as described in any one of claims 1 to 9.

Images