Planar end-fire beam pointing reconfigurable antenna

Abstract

The invention provides a plane end-fire wave beam pointing reconfigurable antenna, which comprises a dielectric substrate, driving dipoles, guiders and reflectors are symmetrically arranged on the upper surface and the lower surface of the dielectric substrate respectively, the driving dipoles, the guiders and the reflectors are connected and form a ternary array, a coaxial cable is arranged on the dielectric substrate, and the coaxial cable is connected with the driving dipoles, the guiders and the reflectors. A coaxial cable is arranged on the dielectric substrate, the coaxial cable is connected with the driving dipole, the coaxial cable excites the ternary array to generate an end-fire radiation beam, the dielectric substrate is also provided with a switch and bias circuit, the switch and bias circuit comprises a switch, and the reconfigurable end-fire radiation beam is generated by controlling the on-off state combination of the switch. The planar end-fire beam pointing reconfigurable antenna has the beneficial effects that the planar end-fire beam pointing reconfigurable antenna has excellent circuit characteristics and radiation characteristics, and also has the advantages of compact size, simple structure and capability of reducing the complexity and the cost of a radio frequency antenna module.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a planar end-fire beam-pointing reconfigurable antenna. Background Art

[0002] An end-fire antenna is an antenna whose maximum radiation direction is parallel to the plane where the radiator is located. Common end-fire antenna forms include Yagi antennas and helical antennas. End-fire antennas have a wide range of application needs in both military and civilian fields, especially in some scenarios with limited space dimensions, such as handheld devices, cordless phones, vehicle-mounted and aircraft systems, which often require the application of low-profile end-fire antennas. On the other hand, beam-pointing reconfigurable antennas have the characteristics of dynamically controlling beam scanning, which can effectively reduce multipath fading and electromagnetic interference and improve channel capacity. Therefore, low-profile, end-fire, beam-pointing reconfigurable antennas have received widespread attention in recent years.

[0003] There are currently two mainstream implementation methods for beam-pointing reconfigurable antennas:

[0004] 1. Change the radiation structure of the antenna: introduce diodes or other switching elements to affect the radiation path and current distribution of the antenna, adjust the switching director and reflector, and regulate the radiation pattern of the antenna.

[0005] 2. Change the antenna feed network: By changing the feed phase of the elements in the antenna array, a beam with a specified direction and width is obtained.

[0006] The main problems of current beam-pointing reconfigurable antennas are as follows:

[0007] 1. Due to the presence of reflectors and directors, antennas often have a considerable footprint. When the antenna size decreases, the antenna Q value increases, affecting the antenna impedance bandwidth and front-to-back ratio.

[0008] 2. Changing the feed network usually requires a large number of antenna elements, and the phase and amplitude of each element need to be independently controlled, which makes the system more complex. Summary of the invention

[0009] In order to solve the problems in the prior art, the present invention provides a planar end-fire beam-pointing reconfigurable antenna. Based on the traditional planar printed Yagi antenna, a folding structure is introduced, and the director and reflector of the antenna are directly excited, and then the director and reflector are switched by controlling the switch, and finally the beam pointing is reconfigurable, while achieving broadband and high front-to-back ratio, the size of the antenna is significantly reduced.

[0010] The present invention provides a planar end-fire beam pointing reconfigurable antenna, comprising a dielectric substrate, wherein the upper surface and the lower surface of the dielectric substrate are symmetrically provided with a driven dipole, a guide, and a reflector, respectively, the driven dipole is connected to the guide and the reflector, the guide is connected to the reflector, the driven dipole, the guide, and the reflector form a three-element array, a coaxial cable is arranged on the dielectric substrate, the coaxial cable is connected to the driven dipole, the coaxial cable excites the three-element array to generate an end-fire radiation beam, and a switch and a bias circuit are also arranged on the dielectric substrate, the switch and the bias circuit include a switch, and a reconfigurable end-fire radiation beam is generated by controlling the on-off state combination of the switch.

[0011] As a further improvement of the present invention, the coaxial cable includes an outer conductor and an inner conductor, the driven dipole is provided with a first arm and a second arm, the outer conductor is connected to the second arm located on the lower surface of the dielectric substrate, and the inner conductor passes through the dielectric substrate and is connected to the first arm on the upper surface of the dielectric substrate.

[0012] As a further improvement of the present invention, the guide is provided with a third arm, a fourth arm, a fifth arm and a sixth arm, the third arm and the fifth arm are arranged on the upper surface of the dielectric substrate, and the fourth arm and the sixth arm are arranged on the lower surface of the dielectric substrate.

[0013] As a further improvement of the present invention, the inverter is provided with a seventh arm, an eighth arm, a ninth arm and a tenth arm, the seventh arm and the ninth arm are arranged on the upper surface of the dielectric substrate, and the eighth arm and the tenth arm are arranged on the lower surface of the dielectric substrate.

[0014] As a further improvement of the present invention, the driven dipole, the director, and the reflector are connected via a microstrip line.

[0015] As a further improvement of the present invention, the widths of the driven dipole, the guide and the reflector are respectively 4-6 mm, the length of the driven dipole is 0.3-0.4λ0, and the spacing between the guide and the driven dipole, and between the reflector and the driven dipole is equal, which is 0.1-0.15λ0.

[0016] As a further improvement of the present invention, the switch and the bias circuit are respectively arranged on the edges of the guide and the reflector, and the switch and the bias circuit also include an inductor and a DC connecting line.

[0017] As a further improvement of the present invention, the number of the switches and bias circuits is equal to the sum of the number of the arms of the guide and the number of the arms of the reflector.

[0018] As a further improvement of the present invention, the driven dipole, the guide, and the reflector are rectangular, stepped, or butterfly-shaped; the reflector and the guide are connected to the driven dipole via a connecting line to form a ternary array, and the length of the connecting line is 0.03-0.05λ0.

[0019] As a further improvement of the present invention, the dielectric substrate has a thickness of 0.8 mm, a relative dielectric constant of 3.38, and a loss tangent of 2.7×10 -3 .

[0020] The beneficial effects of the present invention are: 1. Low profile: The antenna of the present invention adopts a single-layer plate structure with a low profile, and the profile height is controlled below 0.01λ0, which is easy to process and integrate; 2. Small footprint: The antenna of the present invention adopts a folding structure, which effectively reduces the distance between the driving dipole and the reflector, and the overall footprint does not exceed 0.08λ0 2 ; 3. Broadband characteristics: The -10dB impedance bandwidth of the antenna of the present invention is 23.1%; 4. Good end-fire radiation characteristics: the peak front-to-back ratio exceeds 15dB, and the peak gain is 6.1dBi; 5. The use of VO2 realizes the reconfiguration of beam pointing, and the beam switching directions are 90° and 270°. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional schematic diagram of a planar end-fire beam-pointing reconfigurable antenna of the present invention;

[0022] Figure 2 is a schematic diagram of the upper surface of the planar end-fire beam pointing reconfigurable antenna of the present invention;

[0023] Figure 3 is a schematic diagram of the lower surface of the planar end-fire beam pointing reconfigurable antenna of the present invention;

[0024] Figure 4 is a simulation curve diagram of the reflection coefficient of the planar end-fire beam pointing reconfigurable antenna of the present invention;

[0025] Figure 5 is a simulation curve diagram of the front-to-back ratio of the planar end-fire beam pointing reconfigurable antenna of the present invention;

[0026] Figure 6 is a gain simulation curve diagram of the planar end-fire beam pointing reconfigurable antenna of the present invention;

[0027] FIG7 shows the normalized radiation patterns of the planar end-fire beam pointing reconfigurable antenna in states I and II when operating at 2.75 GHz; FIG7(a)(b) is the state I diagram; FIG7(c)(d) is the state II diagram. DETAILED DESCRIPTION

[0028] The invention discloses a planar end-fire beam pointing reconfigurable antenna, comprising a dielectric substrate 1, a driven dipole, a guide, a reflector, a switch and a bias circuit and a coaxial cable 13, wherein the upper surface and the lower surface of the dielectric substrate 1 are symmetrically provided with the driven dipole, the guide and the reflector respectively, the switch and the bias circuit are arranged at the edges of the guide and the reflector, the coaxial cable 13 comprises an outer conductor and an inner conductor, the outer conductor is connected to an arm (a second arm 202) of the driven dipole located on the lower surface of the dielectric substrate 1, the inner conductor penetrates the dielectric substrate 1 and is connected to a first arm 201 of the driven dipole located on the upper surface of the dielectric substrate 1; the coaxial cable 13 is arranged at the geometric center of the planar end-fire beam pointing reconfigurable antenna, and is used to excite two arms (a first arm 201 and a second arm 202) of the driven dipole, the guide and the reflector are used to realize end-fire radiation, and the switch and the bias circuit are combined by controlling the on-off state of a switch (a phase change material radio frequency switch VO2) to generate a reconfigurable end-fire radiation beam.

[0029] The driven dipole, director and reflector form a three-element array. The radiation beam has a superposition effect in the direction of the director and produces a cancellation effect in the direction of the reflector opposite to the direction of the director, thereby forming an end-fire radiation beam.

[0030] The driving dipole, the guide and the reflector are connected through microstrip lines, the driving dipole is respectively connected to the guide and the reflector through microstrip lines, and the guide is connected to the reflector through microstrip lines. The driving dipole, the guide and the reflector are rectangular, stepped or butterfly-shaped.

[0031] The widths of the driven dipole, director and reflector are the same or different and are used to adjust the resonant frequency of the antenna. The widths of the driven dipole, director and reflector are 4-6 mm respectively. The lengths of the driven dipole, director and reflector are used to control the impedance matching of the antenna. The length of the director is slightly smaller than that of the driven dipole, and the length of the reflector is slightly larger than that of the driven dipole. The length of the driven dipole is 0.3-0.4λ0. The spacing between the director and the driven dipole, and between the reflector and the driven dipole is equal, which is used to control the front-to-back ratio of the antenna, and the spacing is 0.1-0.15λ0.

[0032] The switch and bias circuit are arranged at the edge of the guide and the reflector, including VO2, inductor 14 and DC connection line 15. The switch and bias circuit is equal to the sum of the number of the arms of the guide and the arms of the reflector.

[0033] The beam switching directions of a planar end-fire beam pointing reconfigurable antenna disclosed by the present invention are 90 degrees and 270 degrees.

[0034] like Figures 1 to 3 As shown, this embodiment uses a thickness of 0.8 mm, a relative dielectric constant of 3.38, and a loss tangent of 2.7×10-3 Rogers 4003C is used as the dielectric substrate 1, and the driving dipole, reflector, and guide are symmetrically printed on the upper and lower surfaces of the dielectric substrate 1, wherein the arm 201 of the driving dipole, the arm (seventh arm 301, eighth arm 303) of the reflector, and the arm (third arm 401, fifth arm 403) of the guide are printed on the upper surface of the dielectric substrate 1, the arm (second arm 202) of the driving dipole, the arm (eighth arm 302, tenth arm 304) of the reflector, and the arm (fourth arm 402, sixth arm 404) of the guide are printed on the lower surface of the dielectric substrate 1, and the switch (switch 5~ A switch 12) and a bias circuit are arranged at the edges of the reflector and the director, a coaxial cable 13 is arranged at the geometric center of the antenna, an outer conductor is connected to a second arm 202 of the driven dipole located on the lower surface of the dielectric substrate 1, and an inner conductor penetrates the dielectric substrate 1 and is connected to a first arm 201 of the driven dipole located on the upper surface of the dielectric substrate 1. When the driven dipole, the reflector, and the director are excited by an electrical signal passing through the coaxial cable 13, the combined array of the driven dipole, the reflector, and the director generates electromagnetic radiation in an end-fire direction, and a reconfigurable end-fire radiation beam is generated by controlling the on-off state combination of multiple switches.

[0035] like Figure 2 and Figure 3 As shown, the planar end-fire beam pointing reconfigurable antenna of the present invention adopts the Yagi-Uda structure, and the reflector and the director are used as excitation elements at the same time, which are connected to the driving dipole through a connecting line to form a three-element array. The shape selection of the driving dipole, reflector and director has a large degree of freedom, and can be rectangular, butterfly-shaped, stepped or equivalently deformed, etc. This embodiment adopts a butterfly shape, and the widths of the driving dipole, reflector and director are the same or different, which can be used to adjust the resonant frequency of the antenna. The width of the driving dipole, reflector and director is 4-6mm. In this embodiment, the widths of the driving dipole, reflector and director are the same, and the longer bottom sides are 5mm, and the shorter bottom sides are 4mm. The lengths of the driven dipole, reflector and director are used to control the impedance matching of the antenna. The length of the director is slightly smaller than the driven dipole, and the length of the reflector is slightly larger than the driven dipole. The length of the driven dipole is 0.3-0.4λ0. In this embodiment, the length of the driven dipole is 0.36λ0. The reflector and the guide are spaced equally from the driven dipole and are connected by a connecting wire to control the front-to-back ratio of the antenna. The length of the connecting wire is 0.03-0.05λ0. In this embodiment, the length of the connecting wire is 0.038λ0.

[0036] like Figure 2 and Figure 3As shown, switches and bias circuits are provided at the edges of the reflector and the guide, and the switches and bias circuits are composed of VO2, inductor 14 and DC connection line 15. The number of switches is equal to the sum of the number of arms of all reflectors (the seventh arm 301, the eighth arm 302, the ninth arm 303, and the tenth arm 304) and the arms of the guides (the third arm 401, the fourth arm 402, the fifth arm 403, and the sixth arm 404). In this embodiment, a total of eight switches are used to achieve two states of reconfigurable beam pointing. The first state is defined as switches 5, 8, 10, and 11 are turned on, and the remaining four switches are turned off. The antenna is equivalent to a Yagi antenna array composed of a driven dipole, the ninth arm 303 and the tenth arm 304 of the reflector, and the third arm 401 and the fourth arm 402 of the guide, and the beam is pointed in the -Y (270°) direction. The second state is defined as switches 6, 7, 9, and 12 being turned on, and the remaining four switches being turned off. The antenna is equivalent to a Yagi antenna array consisting of a driven dipole, reflectors 301, 302, and directors 403, 404, and the beam is pointed in the +Y (90°) direction.

[0037] Table 1 shows the on-off combination of the switches in the two beam pointing states of the antenna in this embodiment.

[0038] Table 1

[0039]

[0040] According to the above parameters, the high-frequency electromagnetic simulation software HFSS was used to simulate and analyze the reflection coefficient, front-to-back ratio, gain, efficiency and radiation pattern of the designed planar, end-fire, beam-pointing reconfigurable antenna. The analysis results are as follows:

[0041] Since the present embodiment has structural symmetry, theoretically the reflection coefficient, front-to-back ratio and gain curve in the two states should be consistent, and the simulation results also verify this point. Therefore, Figures 4 to 6 Only one simulation result curve is given in the figure.

[0042] like Figure 4-6 As shown, the simulated impedance bandwidth of the embodiment of the present invention is 23% (2.57-3.24 GHz), the simulated maximum front-to-back ratio exceeds 17 dB, and the simulated in-band peak gain reaches 6.1 dB.

[0043] As shown in FIG. 7 , the simulation results of the beam pointing diagrams in two working states of this embodiment are given, wherein the beam pointing switches as the working state changes, and the beam pointing in the two states are respectively and

[0044] In summary, the planar end-fire beam-pointing reconfigurable antenna of the present invention has the advantages of compact size, simple structure, and reduced complexity and cost of the radio frequency antenna module while having excellent circuit characteristics and radiation characteristics.

[0045] The present invention provides a planar end-fire beam-pointing reconfigurable antenna, which solves the problems of large footprint and high profile of the existing beam-pointing reconfigurable antenna, while taking into account a wider impedance bandwidth and a high front-to-back ratio.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. Low profile: The antenna of the present invention adopts a single-layer plate structure with a low profile, and the profile height is controlled below 0.01λ0, which is easy to process and integrate;

[0048] 2. Small footprint. The antenna of the present invention adopts a folding structure, which effectively reduces the distance between the driving dipole and the reflector. The overall footprint does not exceed 0.08λ0 2 ;

[0049] 3. Broadband characteristics: the -10dB impedance bandwidth of the antenna of the present invention is 23.1%;

[0050] 4. Good end-fire radiation characteristics, peak front-to-back ratio exceeds 15dB, peak gain 6.1dBi;

[0051] 5. The beam pointing can be reconfigured using VO2, and the beam switching directions are 90° and 270°.

[0052] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A planar end-fire beam pointing reconfigurable antenna, characterized in that: The invention comprises a dielectric substrate (1), wherein a driven dipole, a guide, and a reflector are symmetrically arranged on the upper surface and the lower surface of the dielectric substrate (1), respectively; the driven dipole is connected to the guide and the reflector respectively; the guide is connected to the reflector; the driven dipole, the guide, and the reflector form a three-element array; a coaxial cable (13) is arranged on the dielectric substrate (1), the coaxial cable (13) is connected to the driven dipole, and the coaxial cable (13) excites the three-element array to generate an end-fire radiation beam; a switch and a bias circuit are also arranged on the dielectric substrate (1); the switch and the bias circuit include a switch, and a reconfigurable end-fire radiation beam is generated by controlling the on-off state combination of the switch.

2. The planar end-fire beam pointing reconfigurable antenna according to claim 1, characterized in that: The coaxial cable (13) comprises an outer conductor and an inner conductor, the driven dipole is provided with a first arm (201) and a second arm (202), the outer conductor is connected to the second arm (202) located on the lower surface of the dielectric substrate (1), and the inner conductor passes through the dielectric substrate (1) and is connected to the first arm (201) on the upper surface of the dielectric substrate (1).

3. The planar end-fire beam pointing reconfigurable antenna according to claim 2, characterized in that: The guide is provided with a third arm (401), a fourth arm (402), a fifth arm (403), and a sixth arm (404); the third arm (401) and the fifth arm (403) are arranged on the upper surface of the dielectric substrate (1); and the fourth arm (402) and the sixth arm (404) are arranged on the lower surface of the dielectric substrate (1).

4. The planar end-fire beam pointing reconfigurable antenna according to claim 3, characterized in that: The deflector is provided with a seventh arm (301), an eighth arm (302), a ninth arm (303), and a tenth arm (304); the seventh arm (301) and the ninth arm (303) are arranged on the upper surface of the dielectric substrate (1), and the eighth arm (302) and the tenth arm (304) are arranged on the lower surface of the dielectric substrate (1).

5. The planar end-fire beam pointing reconfigurable antenna according to claim 1, characterized in that: The driven dipole, the director and the reflector are connected via a microstrip line.

6. The planar end-fire beam pointing reconfigurable antenna according to claim 1, characterized in that: The widths of the driven dipole, the guide and the reflector are 4-6 mm respectively, the length of the driven dipole is 0.3-0.4λ0, and the spacings between the guide and the driven dipole, and between the reflector and the driven dipole are equal, which are 0.1-0.15λ0.

7. The planar end-fire beam pointing reconfigurable antenna according to claim 1, characterized in that: The switch and the bias circuit are respectively arranged at the edges of the guide and the reflector, and the switch and the bias circuit also include an inductor (14) and a DC connection line (15).

8. The planar end-fire beam-steering reconfigurable antenna according to claim 4, characterized in that: The number of the switches and bias circuits is equal to the sum of the number of the arms of the guide and the number of the arms of the reflector.

9. The planar end-fire beam pointing reconfigurable antenna according to claim 1, characterized in that: The driving dipole, the guide and the reflector are rectangular, stepped or butterfly-shaped; the reflector and the guide are connected with the driving dipole via a connecting line to form a three-element array, and the length of the connecting line is 0.03-0.05λ0.

10. The planar end-fire beam-steering reconfigurable antenna according to claim 1, characterized in that: The dielectric substrate (1) has a thickness of 0.8 mm, a relative dielectric constant of 3.38, and a loss tangent of 2.7×10 -3 , the switch is a phase change material radio frequency switch.

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