C-band broadband mobile communication antenna with unidirectional and bidirectional directional diagram reconfigurable function

Abstract

The invention discloses a C-band broadband mobile communication antenna with a unidirectional and bidirectional directional diagram reconfigurable function, which can control the radiation direction of the antenna by controlling the working state of a PIN diode pair by controlling a direct current bias circuit, and realizes unidirectional radiation and bidirectional radiation in two directions respectively. And the bandwidth and gain performance of the antenna are improved compared with those of the existing design scheme. Free switching of three working states of two unidirectional radiation and one bidirectional radiation can be realized, and communication with a plurality of devices in different directions in a mobile communication scene is facilitated.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a C-band broadband mobile communication antenna with a unidirectional and bidirectional directional pattern reconfigurable function. Background Art

[0002] Driven by the Internet of Everything (IoE), wireless communication scenarios and functions are becoming increasingly complex. Wireless communication systems are placing higher demands and expectations on the RF front-end (RFF). As an integral component of the RF front-end, the antenna has become a bottleneck limiting the performance of wireless technologies. Designing high-performance antennas within limited space and cost is a research priority now and for a long time to come. Reconfigurable antenna technology, which integrates the functions of multiple antennas into a single antenna, is an effective means of achieving antenna miniaturization.

[0003] Compared to other bands, the C-band has both certain diffraction and anti-interference capabilities and a relatively fast transmission rate, enabling image, video, and data transmission. However, C-band antennas have limited energy and frequency bands in mobile communication scenarios, and the antenna's radiation direction must be aligned with the target direction, and the receiving direction must be aligned with the incoming wave direction when operating. Therefore, in mobile communications, whether it is terminal-to-base station communication or terminal-to-terminal communication, pattern alignment is required to ensure communication quality. Pattern-reconfigurable antennas can not only dynamically adjust the antenna's operating state according to the actual scenario to achieve pattern alignment, but also improve the antenna's radiation directional gain, enhance energy utilization, and achieve antenna miniaturization. Currently, most research on pattern-reconfigurable antennas has the problem of difficulty in simultaneous unidirectional and bidirectional reconfiguration, a narrow operating bandwidth, and low radiation gain. Therefore, it is very necessary to design a C-band broadband mobile communication antenna with unidirectional and bidirectional pattern reconfiguration capabilities. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention provides a C-band broadband mobile communication antenna with reconfigurable unidirectional and bidirectional radiation patterns. This antenna controls the radiation direction of the antenna by controlling the operating state of a PIN diode pair through a DC bias circuit, achieving unidirectional radiation and bidirectional radiation in two directions, respectively. The antenna also boasts improved bandwidth and gain performance compared to existing designs. The antenna can freely switch between two unidirectional radiation modes and one bidirectional radiation mode, facilitating communication with multiple devices in different locations in mobile communication scenarios.

[0005] The technical solutions adopted by the present invention to solve the technical problems are as follows:

[0006] A C-band broadband mobile communication antenna with a unidirectional and bidirectional reconfigurable radiation pattern, comprising two 180° rotationally symmetrical radiation structures;

[0007] The radiation structure is fed by a coaxial line and a parallel double-wire structure, and the PIN diode pair loaded on the parallel double-wire structure is controlled by a DC bias feeding structure to achieve control of the radiation direction;

[0008] The radiation structure comprises an upper and lower dielectric substrate; a dipole radiation structure is formed by printing two 180° rotationally symmetrical rectangular patch structures on both sides of the upper and lower dielectric substrates and combining them with a feeding structure;

[0009] The antenna of the dipole radiation structure is provided with a U-shaped slot structure to change the current distribution on the dipole surface, thereby increasing the radiation frequency band at the edge of the original dipole working band to achieve a bandwidth widening effect;

[0010] A reflective structure is provided near the center of the substrate at the contact surface of the upper and lower dielectric substrates of the dipole antenna structure, so that the antenna radiation has directionality and improves the antenna radiation gain;

[0011] Two short strip guide structures are added to one side of the dipole antenna structure to further improve the antenna radiation gain;

[0012] The length of the reflective structure is longer than that of the dipole antenna, and the length of the directing structure is shorter than that of the dipole antenna;

[0013] The DC bias control circuit of the PIN diode extends from a position close to the PIN diode from the printed circuit to one side of the dielectric substrate, so as to facilitate the control of the working state of the PIN diode pair.

[0014] Preferably, the radiation structure adopts TXF microwave polytetrafluoroethylene copper-clad laminate material with a thickness of H1=H2=0.5 mm, a dielectric constant of 2.65, and a loss tangent of 0.0022.

[0015] Preferably, the radiation structure is printed on a square dielectric substrate with a side length of W0 = L0 = 58 mm.

[0016] Preferably, the C-band broadband mobile communication antenna is printed on a two-layer dielectric substrate in a butterfly-shaped structure.

[0017] Preferably, the reflective structure is printed on the junction surface of the upper and lower dielectric substrates and consists of a rectangular strip parallel to the X-axis and two parallelogram strips at an angle of ±60° to the X-axis, wherein the two parallelogram strips are bent in a direction away from the center of the dielectric substrate; the widths of the three strips are equal, dR = 3 mm, the length of the rectangular strip is LR = 30.5 mm, the two parallelogram strips have the same size, the short side length is dR = 3 mm, the long side length is Lb = 10 mm, and the center of the rectangular strip parallel to the X-axis is SF = 3.5 mm away from the center of the substrate.

[0018] Preferably, the radiation structure is printed on the upper surface of the first layer of dielectric substrate and the lower surface of the second layer of dielectric substrate; the two parts have the same structure, both of which are rectangular strips minus the U-shaped groove structure, and the two parts are symmetrical about the intersection of the center line of the rectangular strip and the center line of the dielectric substrate; the width of the rectangular strip is d = 2.9 mm, the length is Ls = 15.8 mm, the overlapping length of the two rectangular strips is d = 2.9 mm, and the center of the strip is SR = 10 mm away from the center of the dielectric substrate; the U-shaped groove subtracted from the rectangular strip is composed of three small rectangular strips with a width of gwg = 0.5 mm and a length of gl = 2 mm, the center line of the U-shaped groove coincides with the center line of the rectangular strip, the openings of the U-shaped grooves all point to the side away from the center line of the dielectric substrate, and the center of the U-shaped groove is Lsg = 7 mm away from the edge of the rectangular strip.

[0019] Preferably, the guide structure is printed on the upper surface of the first dielectric substrate and the lower surface of the second dielectric substrate; the two parts have the same structure, both are rectangular strips with a length of LD = 20.3 mm and a width of dR = 3 mm, the two rectangles overlap with each other in the xoy plane projection, and the center of the rectangular strip is SD = 12.5 mm away from the center of the dielectric substrate.

[0020] Preferably, the feeding structure consists of a coaxial line and a parallel double line; the parallel double line structure is composed of two rectangular metal strips with a length of s = 22.9 mm and a width of d = 2.9 mm, which are printed on the upper surface of the first layer of dielectric substrate and the lower surface of the second layer of dielectric substrate and have exactly the same dimensions; the two ends of the parallel double line are respectively connected to the rectangular strips of the radiation structure; the coaxial line is located at the center of the dielectric substrate, the inner core of the coaxial line passes through the two layers of dielectric substrate and is welded to the rectangular metal strip on the upper surface of the first layer of dielectric substrate, and the outer core of the coaxial line is welded to the rectangular metal strip printed on the lower surface of the second layer of dielectric substrate.

[0021] Preferably, the C-band broadband mobile communication antenna has a control structure; the control structure is configured by loading PIN diodes on parallel double wires and configuring corresponding control circuits; four, i.e., two pairs of PIN diodes and six, i.e., three pairs of DC control lines are loaded; the two pairs of PIN diodes are symmetrically loaded on the parallel double wires, with the cathodes of the PIN diodes close to the center of the dielectric substrate, the anodes of the PIN diodes away from the center of the dielectric substrate, and the distance between the centers of the PIN diodes and the center of the dielectric substrate is dD = 1 mm; the DC control lines are slender strips with a width of Wc = 0.2 mm and a length of WL = 27.55 mm, both parallel to the x-axis, connecting the parallel double wires and the edges of the dielectric substrate to facilitate control of the operating state of the PIN diodes; the centerline of one pair of DC control lines coincides with the centerline of the dielectric substrate, and the centerlines of the other two pairs of DC control lines are dC = 3.4 mm away from the center of the dielectric substrate.

[0022] Preferably, the C-band broadband mobile communication antenna controls the antenna radiation direction by controlling the on / off state of the PIN diode pair; when one pair of PIN diode pairs is turned on and the other pair of PIN diode pairs is turned off, the radiation structure controlled by the branch where the turned-on PIN diode pair is located works and performs directional radiation; the radiation structure controlled by the branch where the turned-off PIN diode pair is located cannot work and cannot radiate electromagnetic waves; when the two pairs of PIN diode pairs are turned on at the same time, the radiation structures controlled by the two branches can both work, realizing bidirectional radiation.

[0023] The beneficial effects of the present invention are as follows:

[0024] This invention implements a single- and bidirectional reconfigurable antenna design based on a reflective structure and PIN diodes. It can freely switch between three operating states: two unidirectional radiation modes and one bidirectional radiation mode, facilitating communication with multiple devices in different orientations in mobile communication scenarios. Furthermore, the introduction of a U-shaped slot structure broadens the antenna's operating bandwidth. The introduction of reflective and directive structures not only improves the antenna's directional radiation capability but also increases antenna gain and communication range. The design of a DC feed structure allows for more flexible control of the antenna's radiation direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to the present invention, (a) a top view, and (b) an oblique view.

[0026] Figure 2 It is a printed structure on the upper surface of the first dielectric substrate of the present invention.

[0027] Figure 3 The reflective structure is printed at the junction of the first and second dielectric substrates of the present invention.

[0028] Figure 4 4 is an S-parameter diagram of the antenna according to an embodiment of the present invention.

[0029] Figure 5 1 and 2 are the directional patterns of the antenna according to the embodiment of the present invention, (a) 4.9 GHz, (b) 4.5 GHz.

[0030] Figure 6 : These are gain curves of the antenna of an embodiment of the present invention, (a) is a curve diagram showing how the gain in the main radiation direction varies with frequency when the antenna radiates to the left, (b) is a curve diagram showing how the gain in the main radiation direction varies with frequency when the antenna radiates to the right, (c) is a curve diagram showing how the gain in the left direction of the antenna varies with frequency when the antenna radiates bidirectionally, and (d) is a curve diagram showing how the gain in the right direction of the antenna varies with frequency when the antenna radiates bidirectionally. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and examples.

[0032] In response to the current demands placed on antenna design in wireless communication systems, and the challenges of achieving simultaneous unidirectional and bidirectional reconfiguration, as well as insufficient bandwidth and gain, this paper proposes a C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable radiation patterns. This antenna controls the radiation direction by controlling the operating state of a PIN diode pair through a DC bias circuit, achieving unidirectional and bidirectional radiation, respectively. Furthermore, the antenna's bandwidth and gain performance are improved compared to existing designs.

[0033] The technical solution adopted in the present invention is:

[0034] A C-band broadband mobile communication antenna with reconfigurable unidirectional and bidirectional radiation patterns comprises a two-way radiating structure with 180° rotational symmetry. These two symmetrical structures are fed by a coaxial line and a parallel double-wire structure. A DC bias feed structure controls the PIN diode pairs loaded on the parallel double-wires to achieve control of the radiation direction. Each radiating structure comprises two upper and lower dielectric substrates and a radiating structure. A dipole radiating structure is formed by printing two 180° rotationally symmetric rectangular patch structures on either side of the upper and lower dielectric substrates and combining them with the feed structure. A U-shaped slot structure is added to the dipole antenna to alter the current distribution on the dipole surface, thereby expanding the radiating frequency band at the edge of the original dipole operating band and achieving bandwidth broadening. Based on this bandwidth-broadening dipole antenna structure, a reflective structure is added near the center of the contact surface between the upper and lower dielectric substrates to make the antenna radiation directional and improve the antenna radiation gain. Two short strip guide structures are added to the other side of the dipole antenna to further improve the antenna radiation gain. The length of the reflecting structure is longer than that of the dipole antenna, and the length of the directing structure is shorter than that of the dipole antenna. The DC bias control circuit of the PIN diode extends from the printed circuit to one side of the dielectric substrate near the position of the PIN diode, which is convenient for controlling the working state of the PIN diode pair. The present invention can control the radiation direction of the antenna by controlling the on and off states of the PIN diode pair. When one pair of PIN diode pairs is turned on and the other pair of PIN diode pairs is turned off, the radiation structure controlled by the branch where the turned-on PIN diode pair is located works, and directional radiation can be performed. The radiation structure controlled by the branch where the turned-off PIN diode pair is located cannot work and cannot radiate electromagnetic waves. When the two pairs of PIN diode pairs are turned on at the same time, the radiation structures controlled by the two branches can both work, and bidirectional radiation can be achieved. Compared with the unidirectional radiation state, the working bandwidth of the antenna is wider in bidirectional radiation, and the working frequency band is shifted to low frequency.

[0035] This C-band broadband mobile communication antenna, with reconfigurable unidirectional and bidirectional patterns, features a radiating structure on both the upper and lower layers. Both layers are made of TXF microwave polytetrafluoroethylene copper-clad laminate material with a thickness of H1 = H2 = 0.5 mm, a dielectric constant of 2.65, and a loss tangent of 0.0022. The antenna's radiating structure is printed on a square dielectric substrate with a side length of W0 = L0 = 58 mm.

[0036] The entire antenna is a butterfly-shaped structure printed on a two-layer dielectric substrate. Due to the symmetry of the antenna structure, the following description only shows the radiation structure on one side of the antenna. The radiation structure on the other side can be obtained by rotating the antenna 180° around the center of the dielectric substrate.

[0037] The antenna's reflective structure, printed on the junction of the upper and lower dielectric substrates, consists of a rectangular strip parallel to the X-axis and two parallelogram strips angled at ±60° to the X-axis. The two parallelogram strips are curved away from the center of the dielectric substrate. All three strips have an equal width of dR = 3 mm, and the rectangular strip length is LR = 30.5 mm. The two parallelogram strips have identical dimensions, with a shorter side length of dR = 3 mm and a longer side length of Lb = 10 mm. The center of the rectangular strip parallel to the X-axis is 3.5 mm from the center of the substrate, SF.

[0038] The antenna's radiating structure is printed on the top surface of the first dielectric substrate and the bottom surface of the second dielectric substrate. Both components are identical, consisting of a rectangular strip minus a U-shaped slot. The two components are symmetrical about the intersection of the strip's centerline and the substrate's centerline. The rectangular strip has a width of d = 2.9 mm and a length of Ls = 15.8 mm. The two strips overlap by a length of d = 2.9 mm, and the strip center is SR = 10 mm from the substrate's centerline. The U-shaped slot, which is removed from the rectangular strip, consists of three smaller rectangular strips with a width of gwg = 0.5 mm and a length of gl = 2 mm. The centerline of the U-shaped slot coincides with the centerline of the rectangular strip, and the opening of each U-shaped slot points away from the substrate's centerline. The center of the U-shaped slot is Lsg = 7 mm from the edge of the rectangular strip.

[0039] The antenna's director structure is printed on the top surface of the first dielectric substrate and the bottom surface of the second dielectric substrate. Both components are identical, consisting of rectangular strips with a length of LD = 20.3 mm and a width of dR = 3 mm. The two rectangles overlap in their projections on the xoy plane, and the center of the rectangular strip is SD = 12.5 mm from the center of the dielectric substrate.

[0040] The antenna's feed structure consists of a coaxial cable and two parallel wires. The parallel wire structure consists of two identical rectangular metal strips (s = 22.9 mm in length and d = 2.9 mm in width) printed on the top surface of the first and bottom surfaces of the second dielectric substrate. The ends of the parallel wires are connected to the rectangular strips of the radiating structure. The coaxial cable is located at the center of the dielectric substrate. The inner core of the coaxial cable passes through the two dielectric substrates and is welded to the rectangular metal strip on the top surface of the first dielectric substrate. The outer core of the coaxial cable is welded to the rectangular metal strip printed on the bottom surface of the second dielectric substrate.

[0041] The antenna's control structure involves loading PIN diodes onto parallel double wires and configuring the corresponding control circuitry. This antenna design incorporates four (two pairs) of PIN diodes and six (three pairs) of DC control lines. The two pairs of PIN diodes are symmetrically loaded onto the parallel double wires, with the cathodes of the PIN diodes near the center of the dielectric substrate, and the anodes of the PIN diodes away from the center. The distance between the centers of the PIN diodes and the substrate is dD = 1 mm. The DC control lines are slender strips with a width of Wc = 0.2 mm and a length of WL = 27.55 mm, parallel to the x-axis. These lines connect the parallel double wires to the edges of the dielectric substrate to facilitate control of the PIN diodes' operating state. The centerline of one pair of DC control lines coincides with the centerline of the dielectric substrate, while the centerlines of the other two pairs are dC = 3.4 mm from the center of the substrate.

[0042] The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable radiation patterns has three operating states. Switching between these three operating states can be achieved by controlling the PIN diode pairs loaded on the parallel double wires via a DC control circuit. When the left PIN diode pair is conductive, the antenna radiates electromagnetic waves to the left. When the right PIN diode pair is conductive, the antenna radiates electromagnetic waves to the right. When both PIN diode pairs are conductive, the antenna radiates electromagnetic waves in both the left and right directions.

[0043] Example:

[0044] Figure 1The figure below is a schematic diagram of the antenna. The antenna consists of two layers of 0.5mm thick TXF microwave polytetrafluoroethylene copper-clad laminate material with a dielectric constant of 2.65 and a loss tangent of 0.0022, a metal printed structure on the dielectric substrate, and two pairs of symmetrically distributed PIN diodes. When the PIN diode is on, it is equivalent to a 2.1Ω resistor in series with a 0.6nH inductor. When off, it is equivalent to an 8000Ω resistor in parallel with a 0.17pF capacitor in series with a 0.6nH inductor. The antenna has a symmetrical structure. The printed structure on the top surface of the first dielectric substrate, excluding the DC control structure, and the printed structure on the bottom surface of the second dielectric substrate, excluding the DC control structure, are rotationally symmetrical. Furthermore, the printed structure on the top surface of the first dielectric substrate, excluding the DC control structure, and the printed structure on the bottom surface of the second dielectric substrate, excluding the DC control structure, are flip-symmetrical structures. The DC control structure on the top surface of the first dielectric substrate is identical to that on the bottom surface of the second dielectric substrate: small rectangular strips 0.2 mm wide and symmetrically arranged about the centerline of the dielectric substrate. The printed structures on the bottom surface of the first dielectric substrate and the top surface of the second dielectric substrate are both rotationally and flip-symmetrical. The antenna primarily consists of five components: a radiating structure, a reflector structure, a guide structure, a feed structure, and a DC control structure.

[0045] Figure 2 This is the printed structure on the top surface of the first dielectric substrate layer of the antenna. Similar to the printed structure on the bottom surface of the second dielectric substrate layer, this layer includes four structures from both ends to the center: a guide structure, a radiating structure, a feed structure, and a control structure. The guide structure has a length of LD = 20.3 mm, a width of dR = 3 mm, and a distance of SD = 12.5 mm from the center of the substrate. The radiating structure has a length of Ls = 15.8 mm, a width of d = 2.9 mm, and a distance of s = 22.9 mm from the edges of the two rectangular strips. The U-shaped slot in the radiating structure consists of small rectangular strips with a length of gl = 2 mm and a width of gwg = 0.5 mm. The distance between the center of the U-shaped slot and the edge of the radiating structure is Lsg = 7 mm. The feed mechanism is the long rectangular strip in the middle, with a length of s = 22.9 mm and a width of d = 2.9 mm. The control structure consists of two PIN diodes and three DC control lines. The center of the two PIN diodes is dD = 1 mm from the center of the dielectric substrate, and the width is 1 mm. The three DC control lines have a width of Wc=0.2 mm, a spacing of dC=3.4 mm, and are arranged symmetrically about the center of the substrate.

[0046] Figure 3The printed structures are located on the lower surface of the first dielectric substrate and the upper surface of the second dielectric substrate. These structures form the antenna's two reflector structures, each consisting of a rectangular strip and two parallelogram strips. The rectangular strips are LR = 30.5 mm long, dR = 3 mm wide, and SF = 3.5 mm from the center of the dielectric substrate. The parallelogram strips are connected to the rectangular strips, each with a short side length of dR = 3.5 mm and a long side length of Lb = 10 mm. The angle between the long and short sides is 60°.

[0047] Figure 4 The following are the S-parameter curves for the antenna. When the antenna radiates bilaterally, the impedance bandwidth (S11 < -10dB) is 4.05 GHz to 5.12 GHz, with a relative bandwidth of 23.3%. When the antenna radiates to the left, the impedance bandwidth is 4.32 GHz to 5.44 GHz, with a relative bandwidth of 23%. When the antenna radiates to the right, the impedance bandwidth is 4.34 GHz to 5.47 GHz, with a relative bandwidth of 23%. The figure shows that the antenna's S11 curve has two continuous radiation frequency bands within the bandwidth, achieving a broadened impedance bandwidth.

[0048] Figure 5 The antenna's radiation pattern is shown in Figure (a). Because the antenna's center frequency is around 4.9 GHz for unidirectional radiation and around 4.5 GHz for bidirectional radiation, the antenna's unidirectional radiation pattern is shown at 4.9 GHz, while the antenna's bidirectional radiation pattern is shown at 4.5 GHz. Figure (a) shows that the antenna's radiation patterns on the left and right sides are roughly symmetrical, with nearly equal gains in the main radiation directions. Figure (b) shows that the antenna's radiation patterns are roughly symmetrical on both sides, with nearly equal gains in both radiation directions.

[0049] Figure 6Figure 1 shows how the antenna's radiation gain varies with frequency. Figure (a) plots the gain in the main radiation direction as it varies with frequency when the antenna radiates to the left. The figure shows that the antenna's gain remains relatively stable at around 5.7 dBi in the 4.32 GHz to 5.21 GHz frequency range, and decreases rapidly in the 5.21 GHz to 5.44 GHz frequency range. Figure (b) plots the gain in the main radiation direction as it varies with frequency when the antenna radiates to the right. The figure shows that the antenna's gain remains relatively stable at around 5.7 dBi in the 4.34 GHz to 5.25 GHz frequency range, and decreases rapidly in the 5.25 GHz to 5.47 GHz frequency range. Figure (c) plots the gain in the left direction as it varies with frequency when the antenna radiates bidirectionally. The figure shows that the antenna's gain remains relatively stable at around 4 dBi in the 4.05 GHz to 5.00 GHz frequency range, and decreases rapidly in the 5.00 GHz to 5.12 GHz frequency range. Figure (d) is a curve chart showing the change in the gain in the right direction of the antenna with frequency when the antenna radiates bidirectionally. From the figure, it can be seen that the antenna gain remains relatively stable at around 4dBi in the frequency range of 4.05GHz-5.00GHz, and the antenna gain decreases rapidly in the range of 5.00GHz-5.12GHz.

[0050] Table 1 shows the reconfigurable working state control of the directional pattern of a C-band broadband mobile communication antenna with unidirectional and bidirectional directional pattern reconfiguration function.

[0051] Table 1 Directional pattern reconfigurable state control table

[0052] Antenna working status PIN1-1, PIN1-2 PIN2-1, PIN2-2 One-way left radiation conduction Deadline One-way right radiation Deadline conduction Bidirectional radiation conduction conduction

Claims

1. A C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns, characterized in that: It includes two 180° rotationally symmetrical radiating structures; The radiation structure is fed by a coaxial line and a parallel double-wire structure, and the PIN diode pair loaded on the parallel double-wire structure is controlled by a DC bias feeding structure to achieve control of the radiation direction; The radiation structure includes two layers of dielectric substrates, upper and lower; A dipole radiation structure is formed by printing two 180° rotationally symmetrical rectangular patch structures on both sides of the upper and lower dielectric substrates and combining them with a feeding structure. The antenna of the dipole radiation structure is provided with a U-shaped slot structure to change the current distribution on the dipole surface, thereby increasing the radiation frequency band at the edge of the original dipole working band to achieve a bandwidth widening effect; A reflective structure is provided near the center of the substrate at the contact surface of the upper and lower dielectric substrates of the dipole antenna structure, so that the antenna radiation has directionality and improves the antenna radiation gain; Two short strip guide structures are added to one side of the dipole antenna structure to further improve the antenna radiation gain; The length of the reflective structure is longer than that of the dipole antenna, and the length of the directing structure is shorter than that of the dipole antenna; The DC bias control circuit of the PIN diode extends from a position close to the PIN diode from the printed circuit to one side of the dielectric substrate, so as to facilitate the control of the working state of the PIN diode pair.

2. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The radiation structure adopts TXF microwave polytetrafluoroethylene copper-clad laminate material with a thickness of H1=H2=0.5mm, a dielectric constant of 2.65, and a loss tangent of 0.0022.

3. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The radiation structure is printed on a square dielectric substrate with a side length of W0 = L0 = 58 mm.

4. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The C-band broadband mobile communication antenna is printed on a two-layer dielectric substrate in a butterfly-shaped structure.

5. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The reflective structure is printed on the junction of the upper and lower dielectric substrates and consists of a rectangular strip parallel to the X-axis and two parallelogram strips at an angle of ±60° to the X-axis, wherein the two parallelogram strips are bent away from the center of the dielectric substrate; the width of the three strips is equal to dR = 3 mm, the length of the rectangular strip is LR = 30.5 mm, the two parallelogram strips have the same size, with a short side length of dR = 3 mm and a long side length of Lb = 10 mm, and the center of the rectangular strip parallel to the X-axis is 3.5 mm away from the center of the substrate SF.

6. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The radiant structure is printed on the upper surface of the first dielectric substrate and the lower surface of the second dielectric substrate; the two parts have the same structure, both of which are rectangular strips minus the U-shaped groove structure, and the two parts are symmetrical about the intersection of the center line of the rectangular strip and the center line of the dielectric substrate; the width of the rectangular strip is d = 2.9 mm, the length is Ls = 15.8 mm, the overlapping length of the two rectangular strips is d = 2.9 mm, and the distance between the center of the strip and the center of the dielectric substrate is SR = 10 mm; the U-shaped groove subtracted from the rectangular strip is composed of three small rectangular strips with a width of gwg = 0.5 mm and a length of gl = 2 mm, the center line of the U-shaped groove coincides with the center line of the rectangular strip, the opening of the U-shaped groove points to the side away from the center line of the dielectric substrate, and the center of the U-shaped groove is Lsg = 7 mm away from the edge of the rectangular strip.

7. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The guide structure is printed on the upper surface of the first dielectric substrate and the lower surface of the second dielectric substrate; the two parts have the same structure, both are rectangular strips with a length LD = 20.3 mm and a width dR = 3 mm. The two rectangles overlap with each other in the xoy plane, and the center of the rectangular strip is SD = 12.5 mm from the center of the dielectric substrate.

8. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The feeding structure consists of a coaxial line and a parallel double line. The parallel double line structure is composed of two rectangular metal strips with a length of s = 22.9 mm and a width of d = 2.9 mm, printed on the upper surface of a first dielectric substrate and the lower surface of a second dielectric substrate, and having exactly the same dimensions. The two ends of the parallel double line are respectively connected to the rectangular strips of the radiation structure. The coaxial line is located at the center of the dielectric substrate. The inner core of the coaxial line passes through the two dielectric substrates and is welded to the rectangular metal strip on the upper surface of the first dielectric substrate. The outer core of the coaxial line is welded to the rectangular metal strip printed on the lower surface of the second dielectric substrate.

9. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The C-band broadband mobile communication antenna has a control structure; the control structure is composed of two pairs of PIN diodes loaded on parallel double wires and configured with corresponding control circuits; four pairs of PIN diodes and three pairs of DC control lines are loaded; the two pairs of PIN diodes are symmetrically loaded on the parallel double wires, with the cathodes of the PIN diodes close to the center of the dielectric substrate, the anodes of the PIN diodes away from the center of the dielectric substrate, and the distance between the centers of the PIN diodes and the center of the dielectric substrate is dD = 1 mm; the DC control lines are slender strips with a width of Wc = 0.2 mm and a length of WL = 27.55 mm, all parallel to the x-axis, connecting the parallel double wires and the edges of the dielectric substrate to facilitate control of the operating state of the PIN diodes; the centerline of one pair of DC control lines coincides with the centerline of the dielectric substrate, and the centerlines of the other two pairs of DC control lines are dC = 3.4 mm away from the center of the dielectric substrate.

10. The C-band broadband mobile communication antenna with unidirectional and bidirectional reconfigurable directional patterns according to claim 1, characterized in that: The C-band broadband mobile communication antenna controls the antenna radiation direction by controlling the on / off state of a PIN diode pair. When one PIN diode pair is turned on and the other is turned off, the radiation structure controlled by the branch where the turned-on PIN diode pair is located works and performs directional radiation. The radiation structure controlled by the branch where the turned-off PIN diode pair is located cannot work and cannot radiate electromagnetic waves. When both PIN diode pairs are turned on at the same time, the radiation structures controlled by both branches can work, achieving bidirectional radiation.

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