Dipole antenna with adjustable beam form

Abstract

A metal strip loaded by a PIN tube is matched with a metal strip pair fed by an inverted output network, the amplitude ratio of currents of the metal strip and the metal strip pair and the amplitude ratio and the phase difference of currents on the strips on the inner side and the outer side of the PIN tube are controlled by using a channel of the PIN tube, and a rectangular metal ground with a groove is combined, so that the beam form is adjustable. Switching between pinnacle single-beam radiation and flat-top beam radiation in the end-fire direction is achieved, and the matching bandwidth stability, the small size, the low structural complexity and the low loss can be taken into account.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a dipole antenna. Background Art

[0002] Dipole antennas are widely used in the field of wireless communications due to their simple structure, low cost, high efficiency, and easy integration with RF circuits. A dipole antenna with adjustable beam shape refers to an antenna that can quickly adjust the beam shape electrically according to demand and maintain the matching state of the antenna, thereby improving the adaptability of the antenna and the diversity of its coverage. Comparing the implementation forms, a dipole antenna with adjustable beam shape in the form of a single antenna can avoid installing an array composed of multiple antenna units on a single device, which is conducive to avoiding complex amplitude and phase control systems and larger antenna apertures, reducing system complexity and cost, and has good engineering and research value.

[0003] There are two main types of existing dipole antennas with adjustable beam shapes: beam pointing control and beam number control. The main design method for beam pointing control is to control the on-off of the metasurface steering structure located at different positions of the dipole or to construct superposition or offset currents in a specific direction to achieve beam pointing control. However, there are problems such as large differences in matching bandwidth under different states, large size or complex structure. The method for controlling the number of beams is to construct a phase difference reconfigurable circuit in the dipole feeding network to output different phase differences so that the dipole can switch between single-beam and dual-beam radiation forms. The problem is that a complex feeding network is required, resulting in large size and high loss, and there is also a problem of large differences in matching bandwidth under different states.

[0004] However, the switching between the pointed single beam radiation form and the flat-top beam radiation form, that is, the switching between the focused radiation and the large-scale uniform and stable radiation form, has not been realized. Therefore, it is necessary to propose a beam-adjustable dipole antenna that can switch between the pointed single beam radiation and the flat-top beam radiation, provide a new radiation form adaptability to improve the performance of the wireless system, and take into account the matching bandwidth stability, small size, low structural complexity and low loss in different states. Summary of the invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a beam-shaped adjustable dipole antenna that can switch between pointed single-beam radiation and flat-top beam radiation is proposed, and can take into account matching bandwidth stability, small size, low structural complexity and low loss.

[0006] Technical solution: A dipole antenna with adjustable beam shape, comprising an intermediate dielectric substrate, wherein the upper surface of the intermediate dielectric substrate comprises metal strips, a horizontal metal strip pair, a vertical coupling strip, a short L-shaped metal strip pair, and a long L-shaped metal strip arranged in sequence from front to back; wherein two PIN diodes are symmetrically loaded on the metal strips; the metal strips are located directly in front of the horizontal metal strip pair, and the two are arranged in parallel and spaced apart; one end of the vertical coupling strip is connected to one end of the horizontal metal strip pair close to each other, and the other end of the vertical coupling strip is connected to one end of the short L-shaped metal strip pair arranged symmetrically back to back; the vertical portion of the long L-shaped metal strip is arranged backward, and the horizontal portion is spaced apart from the horizontal portion of the horizontal metal strip pair; the upper surface of the intermediate dielectric substrate also comprises a bias branch connected to the metal strips, the connection point is located between the two PIN diodes, and the input end of the bias branch one is connected in series with a DC blocking resistor; The lower surface of the intermediate layer dielectric substrate includes a rectangular metal ground, a second bias branch, and a third bias branch; the upper edge of the rectangular metal ground is symmetrically loaded with two vertical grooves; one end of the second bias branch and the third bias branch are symmetrically connected to the upper edge of the rectangular metal ground, and the connection point is located outside the vertical groove; the other ends of the second bias branch and the third bias branch are respectively connected to the two ends of the metal strip through metal through holes; the horizontal end points of the short L-shaped metal strip pair are respectively connected to the rectangular metal ground through metal through holes; The short L-shaped metal strip pair, the long L-shaped metal strip, the middle layer dielectric substrate and the rectangular metal ground form an inverting output network; the signal is input through the inverting output network, excites the horizontal metal strip pair through the vertical coupling strip, and is further coupled to the metal strip loaded by the PIN tube, so as to realize a dipole antenna with switchable pointed single beam radiation and flat top beam radiation.

[0007] Furthermore, the distance between the metal strip loaded by the PIN tube and the horizontal metal strip pair is between 0.12 and 0.16λ0.

[0008] Furthermore, on the metal strip, the interval between two PIN diodes is between 1.02 and 0.98λ0.

[0009] Furthermore, the distance between the horizontal portion of the long L-shaped metal strip and the pair of horizontal metal strips is between 0.28 and 0.32λ0.

[0010] Furthermore, the short L-shaped metal strips are centered, and the horizontal length of each short L-shaped metal strip is between 0.10 and 0.14λ0, and the horizontal length of the long L-shaped metal strips is between 0.29 and 0.33λ0.

[0011] Furthermore, on the rectangular metal floor, the spacing between two vertical grooves is 1.10~1.18λ0.

[0012] Beneficial effect: The existing dipole antenna with adjustable beam shape fails to realize the switching between pointed single beam radiation and flat top beam radiation, and has the problems of large difference in matching bandwidth, large size, complex structure or large loss in different states. The present invention pairs the metal strip loaded by the PIN tube with the metal strip fed by the inverted output network, uses the channel of the PIN tube to control the amplitude ratio of the currents of the two, as well as the current amplitude ratio and phase difference on the inner and outer strips of the PIN tube, and combines with the grooved rectangular metal ground to realize the switching between the pointed single beam radiation and the flat top beam radiation in the end-fire direction, and can take into account the matching bandwidth stability, small size, low structural complexity and low loss.

[0013] Specifically, when the PIN diode is disconnected, the current in the middle of the metal strip is significantly enhanced, the currents on both sides are significantly weakened relative to the middle current, and the phase difference between the currents on both sides and the middle current increases. When the PIN diode is turned on, the current in the middle of the metal strip is relatively weakened, the currents on both sides are enhanced, and the phase difference between the currents on both sides and the middle current decreases. The two states of current are used to form pointed single-beam radiation and flat-top beam radiation, respectively.

[0014] The grooved rectangular metal ground is located on the lower surface of the dielectric substrate. The vertical grooves on both sides can control the horizontal currents on both sides of the rectangular metal ground to prevent the horizontal currents on both sides from affecting the flat-top beam radiation effect when the PIN tube is in the on state. At the same time, as a reflection ground, it can realize radiation in the end-fire direction.

[0015] The metal strip pair, the vertical coupling strip, the short L-shaped metal strip pair and the long L-shaped metal strip are placed in sequence. The signal forms an anti-phase output coupling with the two short L-shaped metal strips through the long L-shaped metal strip. The differential excitation of the overall antenna is achieved through the vertical coupling metal strip pair. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the top view of the structure of the dipole antenna with adjustable beam shape of the present invention; Figure 2 It is a schematic diagram of the structure of the dipole antenna with adjustable beam shape in an upward view according to the present invention; Figure 3 For the embodiment of the present invention when the PIN is turned on and off | S 11|Simulation response; Figure 4 The embodiment of the present invention is at the center frequency (2.8 GHz) when the PIN is turned on and off. E Surface simulation pattern. DETAILED DESCRIPTION

[0017] The present invention will be further explained below in conjunction with the accompanying drawings.

[0018] like Figure 1 , Figure 2 As shown, a dipole antenna with adjustable beam shape is composed of a metal strip 101 loaded by PIN tubes 501 and 502 on the top layer, a horizontal metal strip pair 102, a vertical coupling strip 103, a short L-shaped metal strip pair 104, a long L-shaped metal strip 105, a bias branch 106, a middle layer dielectric substrate 201, a grooved rectangular metal ground 301 on the bottom layer, bias branches 302 and 303, and metallized through holes 401 and 402, and a DC isolation resistor 701.

[0019] On the upper surface of the intermediate dielectric substrate 201, the metal strips 101 loaded by the PIN tubes 501 and 502, the horizontal metal strip pair 102, the vertical coupling strip 103, the short L-shaped metal strip pair 104, and the long L-shaped metal strip 105 are arranged in sequence from front to back. Among them, the metal strips 101 loaded by the PIN tubes 501 and 502 are located directly in front of the horizontal metal strip pair 102, and the two are arranged in parallel with a distance between 0.12 and 0.16λ0, where λ0 is the free space wavelength corresponding to the center frequency. On the metal strip 101, the interval between the PIN diodes 501 and 502 is between 1.02 and 0.98λ0, and they are loaded symmetrically. One end of the vertical coupling strip 103 is connected to the end of the horizontal metal strip pair 102 that is close to each other, and the other end of the vertical coupling strip 103 is connected to one end of the short L-shaped metal strip pair 104 that is symmetrically arranged back to back. The vertical portion of the long L-shaped metal strip 105 is arranged backward, and the distance between the horizontal portion and the horizontal metal strip pair 102 is between 0.28 and 0.32λ0. The horizontal length of the short L-shaped metal strip is between 0.10 and 0.14λ0, and the horizontal length of the long L-shaped metal strip 105 is between 0.29 and 0.33λ0. One end of the bias branch 106 is connected to the metal strip 101, and the connection point is located between the PIN diodes 501 and 502. The DC blocking resistor 701 is connected in series to the input end of the bias branch 106.

[0020] The grooved rectangular metal ground 301 and the bias branches 302 and 303 are located on the lower surface of the middle layer dielectric substrate 201. On the grooved rectangular metal ground 301, the spacing between the vertical grooves symmetrically loaded on the upper edge of the rectangular metal ground is 1.10~1.18λ0. One end of the bias branches 302 and 303 are symmetrically connected to the upper edge of the rectangular metal ground, and the connection point is located outside the vertical groove. Two metal through holes 401 penetrate the middle layer dielectric substrate 201, connecting the two ends of the metal strip 101 loaded by the PIN tubes 501 and 502 with the other end of the bias branches 302 and 303. Two metal through holes 402 penetrate the dielectric substrate 201, connecting the horizontal end points of the short L-shaped metal strip pair 104 with the grooved rectangular metal ground 301.

[0021] The bias branch 106 and the bias branches 302 and 303 provide a DC bias loop for the PIN diodes 501 and 502. The short L-shaped metal strip pair 104, the long L-shaped metal strip 105, the intermediate dielectric substrate 201 and the grooved rectangular metal ground 301 form an inverting output network.

[0022] In the present invention, the signal is input through the inverting output network, stimulates the horizontal metal strip pair 102 through the vertical coupling strip 103, and is further coupled to the metal strip 101 loaded by the PIN tubes 501 and 502. Under the action of the overall structure, a dipole antenna with switchable pointed single beam radiation and flat top beam radiation is realized.

[0023] In this process, the bias branches 106, 302, 303 composed of multiple metal short lines, choke inductors 601-611, and DC isolation resistors 701 provide a DC bias loop for the PIN diodes 501 and 502. The microwave signal is mainly concentrated on the inverting output network, the vertical coupling strip 103, the horizontal metal strip pair 102, and the metal strip 101 loaded by the PIN tube. When the PIN diodes 501 and 502 are disconnected, the current amplitude on both sides of the metal strip 101 loaded by the PIN tube is significantly weakened, and the phase difference relative to the middle current increases. At the same time, the ratio of the middle current of the metal strip 101 loaded by the PIN tube to the current amplitude on the metal strip pair 102 increases significantly. Therefore, the overall radiation is converged in the end-fire direction under the action of the grooved rectangular metal ground 301, forming a pointed single beam radiation. When the PIN diodes 501 and 502 are turned on, the current amplitude on both sides of the metal strip 101 loaded by the PIN tube increases, and the phase difference relative to the middle current decreases. At the same time, the ratio of the middle current of the metal strip 101 loaded by the PIN tube to the current amplitude on the metal strip pair 102 decreases significantly. Therefore, under the action of the grooved rectangular metal ground 301, a relatively uniform far field area is formed in the end-fire direction, realizing flat-top beam radiation. The vertical grooves on the grooved rectangular metal ground 301 can suppress the horizontal current on both sides of the rectangular metal ground, avoiding the horizontal current on both sides from affecting the flat-top beam radiation effect when the PIN tubes 501 and 502 are turned on.

[0024] Since the current intensity of the metal strip 101 loaded by the PIN tube is always weaker than the current of the horizontal metal strip pair 102, the on-off effect of the PIN tubes 501 and 502 on the antenna matching is very weak, which is conducive to obtaining a stable matching bandwidth under different radiation states. The antenna radiator only uses a pair of PIN tubes 501 and 502, which is conducive to reducing losses. The long L-shaped metal strip 105 and the short L-shaped metal strip pair 104 form an anti-phase output coupling, which can realize differential excitation of the entire antenna and enable the radiator to work normally. In summary, the overall antenna can realize the switching between pointed single-beam radiation and flat-top beam radiation, and can take into account the matching bandwidth stability, size and loss.

[0025] The present invention can realize the switching between the pointed single beam radiation form and the flat top beam radiation form, and can take into account the matching bandwidth stability, small size, low structural complexity and low loss. The substrate used in this implementation is RogersRO4003C, which is a single antenna implementation solution, and the antenna size in the horizontal direction is 1.47λ0. Its main function is to realize the switching between the pointed single beam radiation and the flat top beam radiation by electronic control under the premise of maintaining antenna matching. The simulated matching response is as follows Figure 3 As shown, when the PIN tube is turned on: the 10-dB impedance matching bandwidth covers 2.772-2.832 GHz, that is, the relative bandwidth is 2.141%; when the PIN tube is turned off: the 10-dB impedance matching bandwidth covers 2.775-2.835 GHz, and the relative bandwidth is 2.139%. It can be seen that when the PIN is on and off, the matching is stable and the change is small, which is conducive to maintaining stable operation of the system. Figure 4 These are two examples of the PIN on and off states at the center frequency (2.8 GHz) of this embodiment. E The surface simulation radiation pattern shows that when the PIN tube is turned on, flat-top radiation within the range of ±30° is achieved, and the gain within this range is between 2.23 dBi±0.04 dBi. When the PIN tube is disconnected, pointed-top single-beam radiation is achieved, and the gain is 4.23dBi.

[0026] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dipole antenna with adjustable beam shape, characterized in that: The invention comprises an intermediate layer dielectric substrate (201), wherein the upper surface of the intermediate layer dielectric substrate (201) comprises a metal strip (101), a horizontal metal strip pair (102), a vertical coupling strip (103), a short L-shaped metal strip pair (104), and a long L-shaped metal strip (105) arranged in sequence from front to back; wherein two PIN diodes are symmetrically loaded on the metal strip (101); the metal strip (101) is located directly in front of the horizontal metal strip pair (102), and the two are arranged in parallel and spaced apart; one end of the vertical coupling strip (103) is connected to the horizontal metal strip pair (102); One end of the strip pair (102) is close to each other, and the other end of the vertical coupling strip (103) is connected to one end of a short L-shaped metal strip pair (104) symmetrically arranged back to back; the vertical portion of the long L-shaped metal strip (105) is arranged backward, and the horizontal portion is arranged at intervals from the horizontal portion of the horizontal metal strip pair (102); the upper surface of the intermediate layer dielectric substrate (201) also includes a bias branch (106) connected to the metal strip (101), the connection point is located between the two PIN diodes, and the input end of the bias branch one (106) is connected in series with a DC blocking resistor (701); The lower surface of the intermediate layer dielectric substrate (201) comprises a rectangular metal ground (301), a second bias branch (302), and a third bias branch (303); the upper edge of the rectangular metal ground (301) is symmetrically loaded with two vertical grooves; one end of the second bias branch (302) and the third bias branch (303) are symmetrically connected to the upper edge of the rectangular metal ground (301), and the connection point is located outside the vertical groove; the other ends of the second bias branch (302) and the third bias branch (303) are respectively connected to the two ends of the metal strip (101) through metal through holes; the horizontal end points of the short L-shaped metal strip pair (104) are respectively connected to the rectangular metal ground (301) through metal through holes; The short L-shaped metal strip pair (104), the long L-shaped metal strip (105), the intermediate dielectric substrate (201) and the rectangular metal ground (301) form an inverting output network; a signal is input through the inverting output network, stimulates the horizontal metal strip pair (102) via the vertical coupling strip (103), and is further coupled to the metal strip (101) loaded by the PIN tube, thereby realizing a dipole antenna with switchable pointed single beam radiation and flat top beam radiation.

2. The dipole antenna with adjustable beam shape according to claim 1, characterized in that: The distance between the metal strip (101) loaded by the PIN tube and the horizontal metal strip pair (102) is between 0.12 and 0.16λ0.

3. The dipole antenna with adjustable beam shape according to claim 1, characterized in that: On the metal strip (101), the interval between the two PIN diodes is between 1.02 and 0.98λ0.

4. The dipole antenna with adjustable beam shape according to claim 2 or 3, characterized in that: The distance between the horizontal portion of the long L-shaped metal strip (105) and the horizontal metal strip pair (102) is between 0.28 and 0.32λ0.

5. The dipole antenna with adjustable beam shape according to claim 2 or 3, characterized in that: In the pair of short L-shaped metal strips (104), the horizontal length of each short L-shaped metal strip is between 0.10 and 0.14λ0, and the horizontal length of the long L-shaped metal strip (105) is between 0.29 and 0.33λ0.

6. The dipole antenna with adjustable beam shape according to claim 2 or 3, characterized in that: On the rectangular metal ground (301), the spacing between two vertical grooves is 1.10-1.18λ0.

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