A broadband continuous phase reconstruction high-gain metasurface antenna

Abstract

The application discloses a broadband continuous phase reconstruction high-gain metasurface antenna, which comprises the following steps: taking a U-shaped slot patch antenna as a design principle, designing a high-gain broadband antenna, and having an air layer in the middle to realize efficient electromagnetic wave radiation in a wide frequency range; combining a reflective phase shifter, adjusting the capacitance value of a loaded varactor diode, realizing continuous modulation of the phase of the radiated electromagnetic wave, and realizing unit decoupling in the antenna array through a direct current isolation structure; combining a high-gain broadband phase reconfigurable antenna model, optimizing the geometric parameters of the model by using an electromagnetic simulation software, and outputting the radiation electromagnetic response of the design model; and designing the whole antenna based on the designed unit model.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to the prototype design of a novel high-gain metasurface antenna with broadband continuous phase reconstruction for navigation, positioning and remote sensing. Background Technology

[0002] In modern wireless communication, navigation and positioning, and remote sensing, antennas, as key front-end devices, directly determine the communication quality and operational reliability of the system. The 1.575GHz band, in particular, has an extremely wide range of applications. The 1.575GHz band corresponds to the L1 frequency of the US GPS in the Global Navigation Satellite System (GNSS), and is also an important component of the B1 frequency of my country's BeiDou Navigation Satellite System. Furthermore, this band overlaps with some low-altitude communication, UAV remote sensing, vehicle-to-everything (V2X) positioning, and emergency communication applications, thus placing extremely high demands on antenna performance.

[0003] In satellite navigation and positioning applications, 1.575 GHz signals typically originate from medium-Earth orbit satellites tens of thousands of kilometers above the Earth, resulting in extremely low received power, usually below -130 dBm. To ensure the receiver can correctly acquire and demodulate navigation signals from a noisy background, the receiving antenna needs high gain, wide bandwidth coverage, and good directivity. Meanwhile, with the rise of new applications such as drones, power line inspection, autonomous driving, and emergency monitoring, terminal devices in the 1.575 GHz band are no longer limited to simple navigation reception but require higher communication link reliability and multi-functional signal processing in dynamic environments. This further drives antenna design to evolve from fixed radiation directions and fixed frequency band operating modes towards reconfigurability, intelligence, and broadband capabilities.

[0004] However, traditional antenna designs often have several limitations in the 1.575GHz band. First, while common single microstrip patch antennas are simple in structure, their narrow bandwidth and limited gain cannot meet the requirements for wide-band multi-system compatibility. For example, signals from multiple constellations such as GPS, BeiDou, GLONASS, and Galileo have frequency differences within the 1.5–1.6GHz range; if the antenna bandwidth is insufficient, full-band coverage cannot be achieved simultaneously. Second, traditional fixed-structure antennas lack flexible control over beam direction and cannot perform spatially selective enhancement for complex scenarios, resulting in a significant decrease in received signal quality under conditions such as obstruction by tall buildings, mountain valleys, or drone maneuvering. Furthermore, some traditional active array antennas that use phase-shifting networks for beamforming require a large number of phase shifters and RF links, leading to excessive cost and power consumption, making them unsuitable for lightweight terminal devices.

[0005] To address the aforementioned issues, various antenna reconfiguration technologies have emerged in recent years, among which schemes based on electromagnetic metasurfaces and reflective phase shifters have attracted widespread attention. Among these schemes, reflective phase shifters based on varactor diodes have become the core technology for achieving antenna phase control. Under reverse bias, the junction capacitance of a varactor diode is continuously adjustable with the bias voltage, and when combined with a transmission line or resonant cavity, it can form a variable reactance load. Integrating the varactor diode into the reflective phase shifter structure allows for continuous adjustment of the reflected signal phase by changing the bias voltage. Compared to traditional phase shifters, this scheme eliminates the need for complex active amplification or digital control circuits, resulting in a simpler structure, lower power consumption, and the ability to achieve a wide range of phase control. This enables the antenna to flexibly adjust the beam direction according to changes in the operating environment, thereby enhancing gain and anti-interference capabilities in specific directions. Summary of the Invention

[0006] The purpose of this invention is to provide a high-gain metasurface antenna with broadband continuous phase reconstruction, which can achieve high-gain broadband phase modulation in the x-axis polarization direction by controlling the voltage values ​​on both sides of the varactor diode loaded in the reflective phase shifter.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] A broadband continuous phase reconfiguration high-gain metasurface antenna includes multiple broadband continuous phase reconfiguration high-gain metasurface antenna elements.

[0009] The broadband continuous phase reconstructed high-gain metasurface antenna element has a six-layer structure;

[0010] The first layer of the antenna unit in this invention is a metal layer, which includes a metal patch with a U-shaped slot as a radiation surface for electromagnetic waves. The metal patch has openings, and a circular copper pillar is used to guide the electromagnetic waves fed from the sixth metal layer to the first layer. With the center of the first layer as the origin, the bottom direction of the U-shaped slot is set as the x-axis of the rectangular coordinate system, and the connection direction perpendicular to the x-axis is set as the y-axis. The following description follows this principle.

[0011] The fourth layer of the antenna unit in this invention is a metal layer, which serves as a metal ground layer to improve the unit's directivity and increase its gain.

[0012] The sixth layer of the antenna unit in this invention is a metal layer, which includes a reflective phase shifter structure based on a varactor diode, a DC control port of the varactor diode, and a DC circuit isolation structure. The varactor diode is located in the reflective phase shifter structure in this layer.

[0013] In this invention, the second and fifth layers of the antenna unit are dielectric substrate layers with the same material but different thicknesses. A circular copper pillar in the middle is used to connect the patch of the first metal layer and the output of the reflective phase shifter in the sixth metal layer.

[0014] In this invention, the third layer of the antenna unit is an air layer, which is supported by a circular copper pillar welded between the sixth layer and the first layer. This achieves the expansion of the antenna unit bandwidth while reducing the thickness of the dielectric substrate and lowering the cost.

[0015] In this invention, the antenna unit based on the reflective phase shifter structure of the varactor diode is located on the sixth layer. This structure consists of an input port, an output port, and two load ports with varactor diodes loaded. The varactor diodes are located between the metal patches of the phase shifter structure. The capacitance of the varactor diodes is controlled by an external DC power supply, which controls the reactance of the load ports of the reflective phase shifter structure, modulates the phase of the reflected signal output by the reflective phase shifter structure, thereby modulating the phase of the electromagnetic wave radiation of the unit.

[0016] In this invention, the DC control port of the varactor diode of the antenna unit is located on the sixth layer. This port is connected to the metal patch of the reflective phase shifter and is connected in parallel with the negative terminals of the six varactor diodes in the reflective phase shifter structure. The positive terminals of the varactor diodes are connected to the designed ground patch to form a loop. The capacitance value can be controlled by feeding a negative voltage into the DC control port. Each unit has an independent DC control port, so the phase of the unit can be modulated independently.

[0017] In this invention, the DC circuit isolation structure of the antenna unit is located on the sixth layer. This structure uses two capacitors, which are respectively loaded at the input and output ports of the reflective phase shifter structure. By utilizing the DC isolation characteristics of the capacitors, the DC feed voltage of the unit is isolated, thereby eliminating the interference between different DC feed voltages of different units in the antenna.

[0018] The antenna in this invention comprises multiple antenna elements arranged at fixed intervals;

[0019] The antenna consists of 4×4 antenna elements arranged at a fixed interval, with 4 rows of antenna elements arranged along the x-axis and 4 columns of antenna elements arranged along the y-axis.

[0020] Each unit has an independent DC control port for connecting to an external power supply and for independently modulating the phase of the antenna unit.

[0021] The DC power supply port in this invention is made of a metal patch, and the design dimensions of the metal patch are based on the model of the external control terminal connection cable.

[0022] Beneficial effects

[0023] According to specific embodiments provided by the present invention, the present invention achieves the following technical effects:

[0024] This invention provides a broadband continuous phase reconfiguration high-gain metasurface antenna, comprising multiple broadband continuous phase reconfiguration high-gain metasurface antenna elements. Each broadband continuous phase reconfiguration high-gain metasurface antenna element integrates a reflective phase shifter. The structure has six parallel varactor diodes. By controlling the voltage values ​​on both sides of the varactor diodes through a feed input, the phase modulation of the radiated electromagnetic wave can be achieved.

[0025] The broadband continuous phase reconfiguration high-gain metasurface antenna element of the present invention can achieve continuous modulation of the phase of the radiated electromagnetic wave in the x-axis polarization direction, with a modulation range greater than 315°.

[0026] The broadband continuous phase reconfiguration high-gain metasurface antenna element of the present invention has a gain of 7.95 dB in the x-axis polarization direction.

[0027] The broadband continuous phase reconfiguration high-gain metasurface antenna element of the present invention can achieve continuous phase modulation in the x-axis polarization direction with a return loss of less than -10dB, a bandwidth of 1.400GHz-1.649GHz, covering 1.575GHz, and a total bandwidth of 249MHz. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram illustrating the principle of a continuous phase reconstruction phase shifter designed in this invention;

[0030] Figure 2 This is a schematic diagram of the principle simulation of a continuous phase reconstruction phase shifter designed in this invention;

[0031] Figure 3 This is a schematic diagram of the topology of a high-gain metasurface antenna element with broadband continuous phase reconfiguration designed in this invention;

[0032] Figure 4 This is a schematic diagram of the first metal layer of a broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention;

[0033] Figure 5 This is a schematic diagram of the sixth metal layer of a broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention;

[0034] Figure 6This is a schematic diagram of a side view of a high-gain metasurface antenna element with broadband continuous phase reconfiguration designed according to the present invention;

[0035] Figure 7 This is a simulation S11 return loss curve of a broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention;

[0036] Figure 8 This is a simulated radiation phase curve of a high-gain metasurface antenna element with broadband continuous phase reconfiguration designed according to the present invention;

[0037] Figure 9 This is a simulation three-dimensional gain diagram of a broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention;

[0038] Figure 10 This is a schematic diagram of the topology of a broadband continuous phase reconfiguration high-gain metasurface antenna designed according to the present invention;

[0039] Figure 11 This is a schematic diagram of the bottom layer of a broadband continuous phase reconfiguration high-gain metasurface antenna designed according to the present invention;

[0040] Figure 12 Simulated S11 return loss curves of a broadband continuous phase reconfiguration high-gain metasurface antenna designed for this invention under the same voltage of all elements.

[0041] Figure 13 Simulated two-dimensional gain curves of a broadband continuous phase reconfiguration high-gain metasurface antenna designed for this invention under the same voltage in all elements;

[0042] Figure 14 Simulated two-dimensional gain curves of beam deflection achieved by a broadband continuous phase reconfiguration high-gain metasurface antenna control unit designed for this invention under different voltages; Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and comprehensively described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The system architecture or scenario in which this invention is applied

[0045] High-gain metasurface antenna elements with broadband continuous phase reconfiguration are one of the essential components of next-generation wireless communication and satellite navigation systems. These antenna elements achieve stable operation across a wide frequency band while possessing continuously adjustable phase and high directional gain. They can flexibly perform beamforming and coverage optimization according to communication environments and application requirements, demonstrating broad application prospects in scenarios such as multi-system compatible reception, low-altitude UAV communication, vehicle-to-everything (V2X) communication, and satellite navigation in complex environments. They are expected to effectively solve the problems of insufficient bandwidth, limited gain, and poor spatial coverage flexibility of traditional fixed antennas.

[0046] Detailed description of the principle of the broadband continuous phase reconstruction high-gain metasurface antenna of the present invention

[0047] This invention belongs to the field of electromagnetic materials. Its main components are an antenna with a U-shaped slot and an air sandwich layer, a reflective phase shifter based on a varactor diode, and a DC isolation structure.

[0048] U-slot antennas are a typical type of broadband microstrip antenna. Their design concept involves introducing a U-slot structure into a traditional rectangular patch antenna, thereby exciting additional resonant modes within the radiating patch. This allows two or more adjacent resonant points to couple and merge, ultimately forming a wide operating bandwidth. To further improve bandwidth and radiation characteristics, the antenna typically uses a low-dielectric-constant air layer as the substrate dielectric, which effectively reduces the quality factor. This enables the broadening and merging of adjacent resonances.

[0049] The working principle of traditional rectangular patch antennas is based on or The resonance of a single mode, with its high quality factor, limits the antenna bandwidth. Introducing a U-shaped slot is equivalent to adding a parasitic resonant element to the patch surface, which can excite a new resonant point near the dominant mode resonance. For a rectangular patch, its fundamental resonant frequency is approximately:

[0050]

[0051] in, At the speed of light, For patch length, It is the equivalent dielectric constant.

[0052] The length of the U-shaped groove approximately determines its parasitic resonant frequency.

[0053]

[0054] in, This is the equivalent electrical length of the U-shaped groove. By adjusting... This can bring the parasitic resonance closer to the dominant mode resonance, thereby forming a dual-mode or even multi-mode adjacent resonance structure.

[0055] Based on the equivalent admittance matrix analysis, the feed copper pillar, U-slot, and patch edge can be considered as three sub-antenna elements. Their equivalent input admittance is:

[0056]

[0057] When two adjacent resonant frequencies are sufficiently close, and the quality factor is... At lower impedance levels, these resonances manifest as the superposition of two loops on the Smith chart in the impedance plane. If the smaller loop can approximately enclose the Smith circle center, the input impedance is well matched over a wider frequency range, thus achieving a broadband characteristic with an S11 return loss of less than -10dB.

[0058] Compared to traditional foam or high-dielectric-constant substrates, air layers have extremely low dielectric constants. This can significantly reduce the storage effect of electromagnetic energy, making the resonant circuit... The value decreased. This low The air layer effect makes it easier to broaden and combine U-slot resonances and patch master mode resonances, resulting in a wider impedance bandwidth. Simultaneously, the air layer reduces dielectric loss, improves radiation efficiency, and increases antenna gain. Experiments show that the gain of a U-slot antenna with an air layer design can be stably maintained in the 7–8 dB range.

[0059] The main parameters for optimizing the design, achieved through simulation software, include:

[0060] Patch length and width: determine the master mode resonant frequency and input impedance; U-slot length and spacing: determine the location of parasitic mode resonant frequencies; air layer thickness: directly affects the effective dielectric constant and resonant quality factor; copper pillar position and radius: affect coupling strength and impedance matching characteristics.

[0061] Reflective phase shifters achieve phase control of radio frequency signals through a combination of directional couplers and variable loads. Common topologies include L-type and... Type, among which The type structure, by introducing three varactor diodes at the reflection port, can achieve complete 360° phase adjustment while ensuring low insertion loss, making it particularly valuable in applications such as navigation and positioning, and remote sensing.

[0062] According to the appendix Figure 1 The reflective phase shifter consists of a 3dB branch coupler (with a characteristic impedance of...) , and Composed of microstrip lines, It consists of a transmission line and two symmetrical reflective loads. Each reflective load consists of a section of transmission line (characteristic impedance is...). Electrical length It consists of a varactor diode (equivalent to a resistor R and a capacitor C in series). The varactor diode is connected in parallel at the far end of the transmission line. The equivalent input impedance of the reflective load is... Under ideal transmission line conditions, it can be written as

[0063]

[0064] At the coupler port, the reflection coefficient corresponding to the reflective load is:

[0065]

[0066] in, Let be the impedance of the coupler port. It can be seen that as the capacitance of the varactor diode changes, the reflection coefficient and phase of the reflective load also change, ultimately affecting the output phase of the reflective phase shifter. That is, by controlling the voltage across the varactor diode, the output phase of the reflective phase shifter can be modulated.

[0067] Since the antenna elements need to be connected through a microstrip power divider when forming an antenna array, capacitors are added at the input and output ports of the designed reflective phase shifter to prevent mutual interference between the DC feed voltages of the elements. The DC isolation effect of the capacitors eliminates voltage interference between the elements.

[0068] The key parameters for optimizing the design, achieved through simulation software, include characteristic impedance. , Electrical length Within the capacitance variation range, this maximizes the phase modulation range and unit gain of the phase shifter, while simultaneously matching the bandwidth of the loaded U-slot antenna. This allows the antenna element to achieve continuous phase modulation across all S11 return losses below -10dB. Figure 3 The paper presents the principle simulation design diagram of the optimized reflective phase shifter with a center frequency of 1.575GHz.

[0069] Detailed description of the broadband continuous phase reconstructed high-gain metasurface antenna element of the present invention

[0070] The topology of the broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention is shown in the attached figure. Figure 3 As shown, the design drawings for the first and sixth metal layers, as well as the side view, are attached. Figure 4 , 5As shown in Figure 6, the U-shaped slot is achieved by etching a metal patch into the first metal layer. The opening direction of the U-shaped slot is distributed along the x-axis. By introducing a U-shaped slot structure into a traditional rectangular patch antenna, additional resonant modes are excited in the radiating patch, allowing two or more adjacent resonant points to couple and merge, ultimately forming a working bandwidth covering a wider frequency range. By using circular copper pillars, the electromagnetic waves from the feed network in the sixth metal layer are guided to the U-shaped slotted patch in the first layer, thereby radiating into space. The copper pillars not only guide the electromagnetic waves but also create an air layer between the second and fifth dielectric substrate layers, effectively reducing the quality factor, expanding the unit bandwidth, and improving the overall gain.

[0071] To achieve phase modulation of radiated electromagnetic waves, this invention adjusts the voltage across the varactor diode loaded in the reflective phase shifter in the sixth layer, thereby adjusting its capacitance value and controlling the reactance of the load port of the reflective phase shifter structure, thus modulating the phase of the reflected signal. A DC feed port is designed in the sixth layer to allow access to an external DC power supply, and a DC isolation structure is designed to isolate the DC feed voltage of each unit through capacitors, preventing inter-unit interference.

[0072] This invention determines a set of optimal parameter values ​​by adjusting the geometric parameters of the antenna element period, the geometric parameters of the U-shaped slot copper metal patch in the first layer, the geometric parameters of the reflective phase shifter, DC isolation structure, DC feed structure in the sixth metal layer, the material and thickness parameters of the two dielectric substrates, and the thickness parameter of the air layer. This results in the antenna element controlled by the varactor diode having the largest phase variation range, the largest bandwidth, and the highest gain.

[0073] The antenna element designed in this invention has a size of p=95mm, and the thicknesses of the two F4B dielectric substrates are h1=0.5mm and h2=1mm, respectively, with dielectric constants of... =3.5, loss coefficient =0.004.

[0074] The specific dimensions of the broadband continuous phase reconfiguration high-gain metasurface antenna element designed in this invention are shown in the table below: In the reflective phase shifter structure in the sixth layer, the dimensions of all microstrip lines can be calculated by the characteristic impedance value, so the specific microstrip lines and their corresponding characteristic impedance parameters are given.

[0075]

[0076] The varactor diode selected in this invention is of type SMV1232-079LF. As the voltage changes from 0V to 15V, the equivalent capacitance of this diode continuously changes from 4.15pF to 0.72pF, while its equivalent inductance and equivalent resistance are 0.7nH and 1.5Ω, respectively. This characteristic of continuously varying capacitance is the basis for achieving continuous phase modulation in the antenna element.

[0077] This invention utilizes the commercial software Ansys HFSS to perform full-wave simulation of the electromagnetic response of the antenna element. The simulation results for S11 return loss, radiation phase modulation, and element gain are shown in the attached figure. Figure 7 Appendix Figure 8 and attached Figure 9 As shown. Since the capacitance of a varactor diode can continuously change with the external voltage, the simulation results of the unit performance can be obtained by scanning the range of capacitance change. (See attached diagram.) Figure 7 As shown, the bandwidth range of unit S11 with a return loss below -10dB is 1.400GHz-1.649GHz, with a total bandwidth of 249MHz and a relative bandwidth greater than 10%, meeting the broadband characteristics. (See attached image.) Figure 8 As shown, by scanning the varactor diode capacitance range in 0.1pF increments, the unit radiation phase can be continuously varied, and the range covers a greater than 315°. (See attached image.) Figure 9 As shown, the unit gain is 7.95dB, which meets the high gain characteristic.

[0078] Detailed description of the broadband continuous phase reconfiguration high-gain metasurface antenna of the present invention

[0079] After designing the structure of a broadband continuous phase reconfiguration high-gain metasurface antenna element and confirming its radiation characteristics through full-wave simulation, this invention generates a broadband continuous phase reconfiguration high-gain metasurface antenna by arranging multiple elements at equal intervals in the x and y directions.

[0080] In this invention, the antenna consists of 4×4 antenna elements arranged at a fixed spacing. Four rows of antenna elements are arranged along the x-axis with a spacing of 95mm, and four columns of antenna elements are arranged along the y-axis with a spacing of 95mm. Simultaneously, the second dielectric substrate is extended by 10mm on both sides along the y-axis and perforations are added for antenna mounting. The perforation size is adapted to external mounting components. Antenna topology diagram and schematic diagram of the sixth metal layer are attached. Figure 10 Appendix Figure 11 As shown. Each unit has an independent DC control port for connecting to an external power supply and independently modulating the phase of the antenna unit. The DC control port is a metal patch, the size of which is compatible with common solder-type female connectors.

[0081] This invention simulates the basic performance and beam manipulation performance of a broadband, continuous phase reconfiguration, high-gain metasurface antenna by setting a microstrip line side-feed configuration in a real-world scenario to power the designed antenna. The main beam is generated by ensuring the phase of all elements in the antenna is consistent. A far-field beamforming algorithm is used to calculate the required phase for each element, and phase compensation is achieved by changing the capacitance of the varactor diodes in each element. The simulated main beam S11 return loss curve, main beam gain curve, and simulated gain curve with 42° y-direction deflection are attached. Figure 12 Appendix Figure 13 Appendix Figure 14 As shown, the broadband continuous phase reconfiguration high-gain metasurface antenna of the present invention can achieve significant beam deflection.

[0082] Future Prospects of the Invention

[0083] This invention uses specific examples to illustrate its principles and implementation methods. It provides pioneering ideas for future researchers in the prototype design of phase-reconfigurable antennas. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this invention; obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations of this invention fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-gain metasurface antenna with broadband continuous phase reconfiguration, characterized in that, The antenna includes multiple high-gain broadband elements based on reflective phase shifter modulation, connected to an external power supply and antenna elements via a DC control port, and continuously modulating the phase of the electromagnetic wave radiated by the antenna by controlling the capacitance value of the varactor diode in the phase shifter.

2. The antenna unit according to claim 1 has a six-layer structure, consisting of two dielectric substrates, one air layer, and three metal layers; The first layer is a metal layer containing a metal patch with a U-shaped slot, which serves as a radiation surface for electromagnetic waves. The metal patch has openings, and a circular copper pillar is used to guide the electromagnetic waves fed from the sixth metal layer to the first layer. With the center of the first layer as the origin, the bottom direction of the U-shaped slot is set as the x-axis of the rectangular coordinate system, and the connection direction perpendicular to the x-axis is set as the y-axis. The fourth layer in the middle is a metal layer, which serves as a metal ground layer to improve the directivity of the unit and increase the gain; The sixth bottom layer is a metal layer, which includes a reflective phase shifter structure based on varactor diodes, a DC control port of varactor diodes, and a DC circuit isolation structure. The second and fifth layers are dielectric substrate layers; The third layer is an air layer, which is supported by a circular copper pillar welded between the sixth layer and the first layer; By connecting a DC voltage to the DC control port of the sixth layer, the voltage difference across the varactor diode in the sixth metal layer is controlled, thereby continuously modulating the phase of the electromagnetic wave radiated by the antenna element.

3. The antenna element according to claim 2, characterized in that, A reflective phase shifter structure based on varactor diodes is used. This structure consists of an input port, an output port, and two load ports with varactor diodes. The varactor diodes are located between the metal patches of the phase shifter structure. The capacitance of the varactor diodes is controlled by an external DC power supply, which controls the reactance of the load ports of the reflective phase shifter structure. This continuously modulates the phase of the reflected signal output by the reflective phase shifter structure, thereby continuously modulating the phase of the electromagnetic wave radiation of the unit.

4. The antenna element according to claim 2, characterized in that, The output port of the phase shifter structure based on varactor diode in the sixth metal layer is designed to connect to the radiating patch with U-shaped groove loaded in the first metal layer. The connection is achieved by welding with circular copper pillars, and a third air layer is set up. This expands the bandwidth of the antenna unit while reducing the thickness of the dielectric substrate, thereby reducing costs.

5. The antenna element according to claim 2, characterized in that, By adjusting the geometric parameters of the antenna element period, the geometric parameters of the U-shaped slotted metal patch in the first metal layer, the geometric parameters of the DC isolation structure, phase shifter structure, DC control port, air layer thickness, the geometric parameters of the thickness of the two dielectric substrates, as well as the material dielectric constant and loss tangent parameters, a set of optimal geometric and material parameter values ​​are determined so that the antenna element phase variation range is maximized, the bandwidth is maximized, and the gain is highest under varactor diode modulation.

6. The antenna element according to claim 2, characterized in that, A DC circuit isolation structure is used, which employs two capacitors, respectively applied to the input and output ports of a varactor diode-based reflective phase shifter structure. By utilizing the DC isolation characteristics of the capacitors, the DC feed voltage of the isolation unit is isolated, thereby eliminating interference between different DC feed voltages of different units in the antenna.

7. The antenna according to claim 1, characterized in that, The antenna consists of 4×4 antenna elements arranged at a fixed interval, with 4 rows of antenna elements along the x-axis and 4 columns of antenna elements along the y-axis. All elements have independent DC control ports for connecting to an external power supply and for independently modulating the phase of the antenna elements.

Images