An electronic beam steering reflectarray antenna based on continuous phase control

Abstract

The present invention provides an electronic beam steering reflective array antenna based on continuous phase control, comprising a beam steering reflective unit; the beam steering reflective unit is a square dielectric layer carrying a square metal ring, a metal sheet is provided at the center of the square metal ring, the metal sheets are slotted in the middle and connected by a varactor diode; a bias network is passed through the square dielectric layer, a phase control plate is closely attached to the bottom of the square dielectric layer, and the bias network connects the varactor diode and the phase control plate. The antenna unit of the present invention has a simple structure, can perform continuous phase control and wide-range spatial beam steering, and has broadband characteristics.

Description

Technical Field

[0001] The invention relates to an electronic beam steering reflective array antenna based on continuous phase control, belonging to the technical field of microwave antennas. Background Art

[0002] In recent years, the successful networking of Beidou satellites has increased the demand for big data communication services. Modern communication satellites use vertical high-gain beams with alternating frequency and polarization to illuminate the communication area. A set of feed sources need to be placed in front of the offset reflector, where each feed source produces a separate beam. This requires multiple reflectors to achieve angular separation between the beam and the electrical performance, which occupies valuable satellite space and adds additional mass and volume. As an emerging antenna form, reconfigurable reflectarray antennas can cope with the above situation well. Reconfigurable reflectarray antennas are composed of feed sources, periodically arranged reconfigurable units, and phase control circuits. By loading adjustable devices such as PIN diodes and varactor diodes on the reconfigurable units, the auxiliary phase control circuit can dynamically change the reflection phase of each unit, achieving high gain, low cost, wide-angle two-dimensional beam scanning and arbitrary shape shaped beams. Electronic beam steering reflectarray antennas are widely used in national economy and defense fields such as satellite communications, target detection, missile guidance, and vehicle-mounted radar. However, the existing electronic beam steering reflectarray antennas have a relatively complex structure, making it difficult to achieve continuous phase control, difficult to take into account large-scale spatial beam steering, and do not have broadband characteristics. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an electronic beam steering reflectarray antenna based on continuous phase control. The antenna unit structure of the electronic beam steering reflectarray antenna based on continuous phase control is simple, and can perform continuous phase control and large-range spatial beam steering, and has broadband characteristics.

[0004] The present invention is achieved through the following technical solutions.

[0005] The present invention provides an electronic beam steering reflective array antenna based on continuous phase control, comprising a beam steering reflective unit; the beam steering reflective unit is a square dielectric layer carrying a square metal ring, a metal sheet is arranged at the center of the square metal ring, the metal sheets are grooved in the middle and connected through varactor diodes; a bias network runs through the square dielectric layer, a phase control plate is tightly attached to the bottom of the square dielectric layer, and the bias network connects the varactor diode and the phase control plate.

[0006] A notch is provided in the middle of each side of the square metal ring.

[0007] The metal sheet is a square metal sheet.

[0008] The middle slot of the metal sheet is a through slot.

[0009] The beam steering reflection unit constitutes an antenna array, and a phase control board is embedded on the back of the array. A DAC chip on the phase control board is connected to the beam steering reflection unit through a voltage output matrix circuit. The phase control board is also provided with a circuit for connecting the DAC chip to a host computer for communication.

[0010] The phase control plate is located at the center of the array distribution of the beam steering reflection unit, and a feed horn is connected and installed on the front side of the surface where the beam steering reflection unit is located.

[0011] The array is distributed as a 12*12 unit array, and the focal diameter ratio is 0.88.

[0012] The DAC chip on the phase control board adopts AD5504.

[0013] The varactor diode is SMV1430 and is mounted in the form of a metal patch.

[0014] The square dielectric layer is a two-layer structure, the upper layer is embedded with square metal rings and metal sheets, the upper layer is made of F4BM265 material, and the lower layer is made of FR4 material as the feed backplane layer.

[0015] The beneficial effects of the present invention are: the antenna unit has a simple structure, can perform continuous phase control and wide-range spatial beam steering, and has broadband characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a monomer structure of at least one embodiment of the present invention;

[0017] Figure 2 yes Figure 1 A top view of

[0018] Figure 3 yes Figure 1 A bottom view of the square dielectric layer where the medium beam steering reflector unit is located;

[0019] Figure 4 yes Figure 1 Schematic diagram of the installation method of the center feed speaker;

[0020] Figure 5 is a schematic diagram of HFSS simulation results of a beam steering reflection unit in one embodiment of the present invention;

[0021] Figure 6 is the far-field pattern of the E-plane and the H-plane of the beam steering reflection unit in one embodiment of the present invention;

[0022] Figure 7is a beam steering far-field pattern of a beam steering reflection unit array at 0°, -10°, -30°, and -60° in one embodiment of the present invention;

[0023] Figure 8 is a bandwidth gain diagram of an embodiment of the present invention.

[0024] In the figure: 1- beam steering reflection unit, 2- varactor diode, 3- bias network, 4- phase control board, 5- host computer, 6- feed horn. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0026] Example 1

[0027] like Figures 1 to 3 An electronic beam steering reflective array antenna based on continuous phase control is shown, comprising a beam steering reflective unit 1; the beam steering reflective unit 1 is a square dielectric layer with a square metal ring, a metal sheet is provided at the center of the square metal ring, a groove is provided in the middle of the metal sheet and the metal sheets are connected via a varactor 2; a bias network 3 is passed through the square dielectric layer, a phase control plate 4 is closely attached to the bottom of the square dielectric layer, and the bias network 3 connects the varactor 2 and the phase control plate 4.

[0028] Thus, the separated patch is connected to the varactor diode to generate the phase difference. The bias network connects the varactor diode and the phase control board to provide the required voltage to the varactor diode.

[0029] Example 2

[0030] Consistent with Example 1, and further optimized in details, there is a notch in the middle of each side of the square metal ring.

[0031] Furthermore, the metal sheet is a square metal sheet.

[0032] Furthermore, the middle groove of the metal sheet is a through groove.

[0033] Example 3

[0034] Consistent with Example 1, and further optimized in details, the beam steering reflection unit constitutes an antenna array, the phase control board is embedded on the back of the array, a DAC chip on the phase control board 4 is connected to the beam steering reflection unit 1 through a voltage output matrix circuit, and a circuit is also arranged on the phase control board 4 for communicating with the DAC chip and connecting it to the host computer 5. The host computer controls the phase control board to output a suitable voltage value.

[0035] Further, such as Figure 1 , Figure 4As shown, the phase control plate 4 is located at the center of the array distribution of the beam steering reflection unit 1, and the feed horn 6 is placed in front of the surface where the beam steering reflection unit 1 is located.

[0036] Preferably, the array is distributed as a 12*12 unit array with a focal diameter ratio of 0.88.

[0037] Example 4

[0038] Consistent with the first embodiment, and more preferably in detail, the DAC chip on the phase control board 4 adopts AD5504.

[0039] Preferably, the varactor diode 2 is SMV1430 and is mounted in the form of a metal patch.

[0040] Preferably, the square dielectric layer is a two-layer structure, the upper layer is embedded with square metal rings and metal sheets, the upper layer is made of F4BM265 material, and the lower layer is made of FR4 material as the feed backplane layer.

[0041] Example 5

[0042] Basically consistent with the above embodiments, different capacitance values ​​of the varactor diode can change the metal current distribution and leakage magnetic flux on both sides of the welding gap, thereby generating a phase difference. Based on this principle, the present application designs an electronic beam steering reflection unit with a center frequency of 8.5GHz, which is composed of two metal layers and two dielectric layers. The middle notched square metal ring and the slotted square metal sheet constitute the upper reflection unit. The square ring of the notch has a side length of 14mm, a width of 1mm, and a size of 2.5mm; the side length of the slotted square metal sheet is 8.5mm, and the middle gap is 0.42mm; the lower metal layer uses copper with a side length of 15mm, and the upper dielectric layer uses F4BM265 material with a thickness of 3mm. The lower layer is the feed backplane layer, and the material used is FR4 with a thickness of 1.2mm. The varactor diode is connected to the separated metal patch. When the DC reverse bias voltage is turned on and increased, the varactor diode can produce different phase differences by changing the resonance characteristics. In addition, the bias point is located at the non-radiating zero electric field point of the electron beam steering reflection unit, and the bias point is connected to the bias network of the underlying dielectric through a metal through-hole. The bias network welding inductor ensures the isolation of DC signals and RF signals and reduces the additional losses caused by the bias network. According to the SMV1430 varactor diode data sheet, its capacitance range can be from 0.31pF-9pF (0V-30V). In the simulation, the varactor diode (SMV1430) is modeled as lumped boundary conditions: R = 0.78ohm, L = 450pH and C = 0.31pF-2.63pF (0V-30V). The HFSS simulation results of the electron beam steering reflection unit are shown in the figure. Figure 5As shown. The phase and fixed capacitance mapping relationship of the electronic beam steering reflection unit is in the range of 0.25pF-2.65pF, and has a phase modulation range of 305°, while maintaining a reasonable phase slope, producing a wider unit bandwidth in the frequency range. At 8.5GHz, because of the series resistance in the varactor diode, significant power loss occurs, so it can be observed that the amplitude fluctuation is about -1.4dB near the center of the junction capacitance variation range.

[0043] In order to meet the needs of continuous electronic phase control, a DAC chip AD5504 is selected to design the phase control board. The chip has four output voltage channels, 12-bit resolution, and a voltage output range of 0V-30V or 0V-60V. Because AD5504 requires a reference voltage of 30V or 60V, a voltage boost module needs to be introduced. When a voltage output matrix is ​​calculated, the voltage data is converted into 12-bit binary data, and then communicated with AD5504 through the SPI protocol. The four output channels of AD5504 can simultaneously output 4 different analog voltage values ​​to control the different variable capacitance values ​​of the varactor diodes on the four electronic beam steering units.

[0044] The antenna array has a total of 12×12 units, with a focal diameter ratio of 0.88. It uses forward feeding, and the phase center of the feed horn is 160 mm from the array. Figure 4 As shown in Figure 1, the compensation phase distribution of the reflective array is calculated according to Formula 1, and then simulation calculations are performed to test the effectiveness of the unit design.

[0045] Θ=k0(d i -(x i cosα+y i sinα)sinβ) (1)

[0046] Far-field radiation direction obtained from the simulation of an electronic beam steering reflectarray with continuous phase control in HFSS Figure 6 As shown. Figure 6 In the figure, the main beam gain at 0° is 20.66dBi, and the trends of the E-plane and H-plane are roughly the same, with precise pointing.

[0047] Next, the array beam scanning characteristics at 8.5 GHz are studied, such as Figure 7As shown. The gain at 0° is 20.66dBi; the gain at -10° is 21.26dBi; the gain at -30° is 19.35dBi; and the gain at -60° is 16.24dBi. The maximum gain is obtained at -10°. The beam scanning loss is caused by the response of the microstrip unit and the reduction of the projected aperture area when scanning the beam. The feed horn adopts a positive feed mode, which results in the maximum gain at -10°. The beam steering far-field radiation pattern is consistent with the expectation, and the beam steering angle is relatively accurate in a small range, but the beam pointing angle is 3° to 6° away from the expected after 50° deflection.

[0048] Broadband is an important indicator for measuring reflectarray antennas. Figure 8 The bandwidth gain plot is shown, and the -1 dB bandwidth of the electronic beam steering reflectarray based on continuous phase control is 6.47%.

Claims

1. An electronic beam steering reflector array antenna based on continuous phase control, comprising a beam steering reflector unit (1), characterized in that: The beam steering reflection unit (1) is a square dielectric layer with a square metal ring, a metal sheet is provided at the center of the square metal ring, the metal sheets are slotted in the middle and connected via a varactor diode (2); a bias network (3) runs through the square dielectric layer, a phase control plate (4) is closely attached to the bottom of the square dielectric layer, and the bias network (3) connects the varactor diode (2) and the phase control plate (4).

2. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: A notch is provided in the middle of each side of the square metal ring.

3. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The metal sheet is a square metal sheet.

4. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The middle slot of the metal sheet is a through slot.

5. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The beam steering reflection unit (1) forms an antenna array, and a phase control board (4) is embedded on the back of the array. A DAC chip is provided on the phase control board (4) and is connected to the beam steering reflection unit (1) via a voltage output matrix circuit. The phase control board (4) is also provided with a circuit for communicating the DAC chip to a host computer (5).

6. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 5, characterized in that: The phase control plate (4) is located at the center of the array distribution of the beam steering reflection unit (1), and a feed horn (6) is placed in front of the surface where the beam steering reflection unit (1) is located.

7. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 5, characterized in that: The array is distributed as a 12*12 unit array, and the focal diameter ratio is 0.

88.

8. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The DAC chip on the phase control board (4) adopts AD5504.

9. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The variable capacitance diode (2) adopts SMV1430 and is mounted in the form of a metal patch.

10. The electronic beam steering reflectarray antenna based on continuous phase control as claimed in claim 1, characterized in that: The square dielectric layer is a two-layer structure, the upper layer is embedded with square metal rings and metal sheets, the upper layer is made of F4BM265 material, and the lower layer is made of FR4 material as the feed backplane layer.

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