A dipole antenna with adjustable beam shape

Abstract

The present invention discloses a dipole antenna with adjustable beam shape. The antenna pairs a metal strip loaded by a PIN tube with a metal strip fed by an inverting output network. The channel of the PIN tube is used to control the amplitude ratio of the currents of the two, as well as the current amplitude ratio and phase difference between the inner and outer strips of the PIN tube. Combined with a slotted rectangular metal ground, the antenna realizes switching between pointed single-beam radiation and flat-top beam radiation in the end-fire direction, while taking into account matching bandwidth stability, small size, low structural complexity and low loss.

Description

Technical Field

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

[0002] Dipole antennas are widely used in wireless communications due to their simple structure, low cost, high efficiency, and ease of integration with RF circuits. A dipole antenna with adjustable beam shape is one that can quickly and electrically adjust the beam shape according to demand while maintaining the antenna's matching state, thereby improving the antenna's adaptability and coverage diversity. In terms of implementation, a dipole antenna with adjustable beam shape implemented as a single antenna avoids the need to install an array consisting of multiple antenna units on a single device. This helps avoid complex amplitude and phase control systems and a large antenna aperture, reducing system complexity and cost, and has significant 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 operation of the metasurface guiding structure located at different positions of the dipole or to construct superimposed 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 the problem of large differences in matching bandwidth under different states.

[0004] However, switching between a pointed single-beam radiation pattern and a flat-top beam radiation pattern—that is, switching between focused radiation and wide-area uniform and stable radiation—is not currently possible. Therefore, it is necessary to propose a beam-adjustable dipole antenna that can switch between pointed single-beam radiation and flat-top beam radiation, providing a new radiation pattern adaptability to enhance wireless system performance while also balancing matching bandwidth stability, small size, low structural complexity, and low loss in different states. Summary of the Invention

[0005] Purpose of the invention: In response to the above-mentioned existing technologies, a beam-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, the upper surface of which comprises a metal strip, 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 parallel and spaced apart; one end of the vertical coupling strip is connected to the adjacent ends of the horizontal metal strip pair, 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 rearward, 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 includes a bias branch connected to the metal strips, the connection point being between the two PIN diodes, and the input end of the bias branch one is connected in series with a DC blocking resistor;

[0007] 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 points are located outside the vertical grooves; 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;

[0008] The short L-shaped metal strip pair, the long L-shaped metal strip, the intermediate dielectric substrate, and the rectangular metal ground constitute an inverting output network. A signal is input through the inverting output network, stimulates the horizontal metal strip pair via the vertical coupling strip, and is further coupled to the metal strip loaded by the PIN tube, thereby realizing a dipole antenna with switchable pointed single-beam radiation and flat-top beam radiation.

[0009] 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.

[0010] Furthermore, on the metal strip, the interval between two PIN diodes is between 1.02 and 0.98λ0.

[0011] 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.

[0012] Furthermore, the short L-shaped metal strips are aligned, 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.

[0013] Furthermore, on the rectangular metal floor, the spacing between two vertical grooves is 1.10~1.18λ0.

[0014] Beneficial Effects: Existing dipole antennas with adjustable beam shape fail to achieve switching between pointed single-beam radiation and flat-top beam radiation, and suffer from large differences in matching bandwidth under different states, large size, complex structure, or high loss. The present invention pairs a metal strip loaded by a PIN tube with a metal strip fed by an inverting output network, utilizes the channel of the PIN tube to control the amplitude ratio of the currents between the two, as well as the current amplitude ratio and phase difference between the inner and outer strips of the PIN tube, and combines it with a slotted rectangular metal ground to achieve switching between pointed single-beam radiation and flat-top beam radiation in the end-fire direction, while also achieving matching bandwidth stability, small size, low structural complexity, and low loss.

[0015] 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 state currents are used to form pointed single beam radiation and flat-top beam radiation, respectively.

[0016] The slotted rectangular metal ground plane is located on the lower surface of the dielectric substrate. The vertical slots on both sides can suppress the horizontal current on both sides of the rectangular metal ground plane, preventing the horizontal current 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 plane, it can achieve radiation in the end-fire direction.

[0017] The metal strip pair, vertical coupling strip, short L-shaped metal strip pair and 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, and the differential excitation of the entire antenna is achieved through the vertical coupling metal strip pair. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the top view of the beam-adjustable dipole antenna of the present invention;

[0019] Figure 2 Schematic diagram of the structure of the dipole antenna with adjustable beam shape according to the present invention when viewed from above;

[0020] Figure 3 For the embodiment of the present invention in the PIN on and off state | S 11|Simulation response;

[0021] Figure 4 The embodiment of the present invention is at the center frequency (2.8 GHz) when the PIN is on and off. E Surface simulation pattern. DETAILED DESCRIPTION

[0022] The present invention will be further explained below with reference to the accompanying drawings.

[0023] 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 bottom layer slotted rectangular metal ground 301, bias branches 302 and 303, as well as metallized through-holes 401 and 402, and a DC blocking resistor 701.

[0024] On the top surface of the intermediate dielectric substrate 201, the metal strips 101 supporting the PIN diodes 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 order from front to back. The metal strips 101 supporting the PIN diodes 501 and 502 are located directly in front of the horizontal metal strip pair 102. The two are arranged parallel to each other 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 spacing between the PIN diodes 501 and 502 is between 1.02 and 0.98λ0, and they are symmetrically loaded. One end of the vertical coupling strip 103 is connected to the adjacent ends of the horizontal metal strip pair 102, and the other end is connected to one end of the short L-shaped metal strip pair 104, which is arranged symmetrically back to back. The vertical portion of the long L-shaped metal strip 105 faces rearward, and the distance between its horizontal portion and the horizontal metal strip pair 102 is between 0.28 and 0.32 λ. The horizontal length of the short L-shaped metal strip is between 0.10 and 0.14 λ, and the horizontal length of the long L-shaped metal strip 105 is between 0.29 and 0.33 λ. One end of the bias branch 106 is connected to the metal strip 101, with the connection point located between the PIN diodes 501 and 502. A DC blocking resistor 701 is connected in series with the input end of the bias branch 106.

[0025] The slotted rectangular metal ground plane 301 and the bias branches 302 and 303 are located on the bottom surface of the intermediate dielectric substrate 201. The spacing between the vertical slots symmetrically placed along the edges of the slotted rectangular metal ground plane 301 is 1.10 to 1.18 λ. One end of the bias branches 302 and 303 is symmetrically connected to the edges of the rectangular metal ground plane, with the connection points located outside the vertical slots. Two metal vias 401 extend through the intermediate dielectric substrate 201, connecting the two ends of the metal strip 101 loaded by the PIN tubes 501 and 502 to the other ends of the bias branches 302 and 303. Two metal vias 402 extend through the dielectric substrate 201, connecting the horizontal endpoints of the short L-shaped metal strip pair 104 to the slotted rectangular metal ground plane 301.

[0026] Bias branch 106 and bias branches 302 and 303 provide a DC bias loop for PIN diodes 501 and 502. Short L-shaped metal strip pair 104, long L-shaped metal strip 105, intermediate dielectric substrate 201 and grooved rectangular metal ground 301 form an inverting output network.

[0027] 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.

[0028] During this process, bias branches 106, 302, and 303, consisting of multiple metal shorts, choke inductors 601-611, and DC blocking resistors 701, provide a DC bias circuit for PIN diodes 501 and 502. The microwave signal is primarily concentrated on the inverting output network, vertical coupling strip 103, horizontal metal strip pair 102, and the metal strip 101 supporting the PIN diode. When PIN diodes 501 and 502 are disconnected, the current amplitudes on both sides of the metal strip 101 supporting the PIN diode are significantly reduced, and the phase difference relative to the intermediate current increases. Simultaneously, the ratio of the intermediate current in the PIN diode-supported metal strip 101 to the current amplitude in the metal strip pair 102 increases significantly. As a result, the overall radiation is converged toward the end-fire direction by the slotted rectangular metal ground 301, forming a pointed single-beam radiation pattern. When PIN diodes 501 and 502 are conducting, the amplitude of the current on either side of the metal strip 101 loaded by the PIN diodes increases, and the phase difference relative to the intermediate current decreases. Simultaneously, the ratio of the intermediate current in the PIN diodes loading metal strip 101 to the current amplitude in the metal strip pair 102 decreases significantly. Consequently, the slotted rectangular metal ground plane 301 creates a relatively uniform far-field region in the end-fire direction, achieving flat-top beam radiation. The vertical slots in the slotted rectangular metal ground plane 301 suppress horizontal currents on either side of the rectangular metal ground plane, preventing them from affecting the flat-top beam radiation effect when PIN diodes 501 and 502 are conducting.

[0029] 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 achieve differential excitation of the entire antenna and enable the radiator to work normally. In summary, the overall antenna can achieve switching between pointed single-beam radiation and flat-top beam radiation, and can take into account the stability of the matching bandwidth, size and loss.

[0030] 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 embodiment is RogersRO4003C, which is a single antenna implementation solution with a horizontal antenna size of 1.47λ0. Its main function is to electrically control the switching between the pointed single beam radiation and the flat top beam radiation while maintaining the antenna matching. The simulated matching response is as follows Figure 3As shown in the figure, 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 in the PIN on-off state, the matching is stable with slight changes, 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 (2.8GHz) 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 single-beam radiation is achieved, and the gain is 4.23dBi.

[0031] 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 principles of the present invention. These improvements and modifications should also be regarded as within 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 spaced apart 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 (106) is connected in series with a DC blocking resistor (701); The lower surface of the intermediate layer dielectric substrate (201) includes a rectangular metal ground (301), a bias branch 2 (302), and a bias branch 3 (303); the upper edge of the rectangular metal ground (301) is symmetrically loaded with two vertical grooves; one end of the bias branch 2 (302) and the bias branch 3 (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 end of the bias branch 2 (302) and the bias branch 3 (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 layer 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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