A 2-bit high-power amplification non-reciprocal reflective metasurface

Abstract

The embodiments of the present application relate to the field of communication technology, and in particular to a 2-bit high-power amplification non-reciprocal reflective metasurface, comprising a plurality of metasurface units distributed in an array; each metasurface unit comprises a first metal layer, an intermediate layer, and a second metal layer stacked in sequence; the second metal layer comprises a receiving metal patch and a transmitting metal patch; the receiving metal patch is provided with two diodes, and both diodes are located on the longitudinal center axis of the receiving metal patch; the slot direction of the transmitting metal patch is orthogonal to the slot direction of the receiving metal patch; the first metal layer comprises a phase shifter, the phase shifter comprising a first series diode and a second series diode constituting a reconfigurable 90-degree phase shift circuit, and by adjusting the diode state, the phase of the electromagnetic wave has 2 bits, i.e., four independent control capabilities. The embodiments of the present application can achieve stable phase modulation while ensuring stable gain amplification characteristics.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of communication technology, and in particular to a 2-bit high-power amplification non-reciprocal reflective metasurface. Background Art

[0002] Digitally coded metasurfaces are a new type of artificial electromagnetic structure that has been developed in recent years and has attracted the attention of researchers around the world. Compared with analog metasurfaces (two-dimensional metamaterials), digitally coded metasurfaces can digitally quantize and manipulate electromagnetic waves, thereby obtaining significant physical properties such as beamforming and control, orbital angular momentum beamforming, Doppler stealth, and radar cross-section reduction. Digitally coded metasurfaces usually integrate electrically controlled lumped elements such as switching diodes (PINs), varactors, or micro-electromechanical systems (MEMS) switches to manipulate the amplitude, phase, polarization, and other parameters of electromagnetic waves. Due to the integration of the above-mentioned lossy electronic components, traditional digitally coded metasurface units can often only attenuate and control electromagnetic energy. This greatly reduces the efficiency of the system, and the power tolerance problem caused by the lossy components limits the application of metasurfaces in wireless communication scenarios.

[0003] Research on power-amplifying metasurface units with energy-enhancing properties has important application value. Existing power-amplifying metasurface unit structures, on the one hand, achieve transmissive non-reciprocal electromagnetic wave transmission through receiving and transmitting patch cascade amplifiers, and adjust the bias voltage to achieve controllable gain. On the other hand, by designing a patch unit with two orthogonal hourglass-shaped coupling slots, a reflective non-reciprocal amplification function for orthogonal polarized waves over a wide frequency range is achieved. However, existing power-amplifying metasurface units, whether transmissive or reflective, are unable to achieve stable control of the electromagnetic wave phase while amplifying electromagnetic energy. Summary of the Invention

[0004] The embodiment of the present application provides a 2-bit high-power amplification non-reciprocal reflective metasurface, which achieves stable phase modulation while ensuring stable gain amplification characteristics.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a 2-bit high-power amplification non-reciprocal reflective metasurface, including a plurality of metasurface units distributed in an array; each metasurface unit includes a first metal layer, an intermediate layer and a second metal layer stacked in sequence; the second metal layer includes a receiving metal patch and a transmitting metal patch; two diodes are provided on the receiving metal patch, and both diodes are located on the longitudinal center axis of the receiving metal patch; both the transmitting metal patch and the receiving metal patch are provided with slots, and the slot direction of the transmitting metal patch is orthogonal to the slot direction of the receiving metal patch; the first metal layer includes a phase shifter, the phase shifter includes a first series diode and a second series diode, the first series diode and the second series diode each include two series-connected diodes, and the first series diode is connected in parallel at both ends of the second series diode; the first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit; by adjusting the diode shape of the receiving metal patch

[0006] The state and the state of the first series diode and the second series diode of the phase shifter make the electromagnetic wave phase have 2 bits, that is, four 5 independent control capabilities; the metasurface unit also includes a power amplifier arranged on the first metal layer, one end of the power amplifier is connected to the

[0007] The other end is connected to the transmitting metal patch through a metallized via.

[0008] In some exemplary embodiments, the intermediate layer includes a first dielectric layer, a third metal layer, a prepreg, and a second dielectric layer stacked in sequence; for DC signals, the third metal layer serves as a ground to provide a reference level for the DC voltage; for radio frequency signals, the third metal layer serves as a metal reflective surface to enhance the reflection capability of electromagnetic wave signals.

[0009] In some exemplary embodiments, the metasurface unit further includes a first bias signal line and a second bias signal line disposed on the first metal layer.

[0010] Two bias signal lines; the first bias signal line is connected to the receiving metal patch through a metallized via, and is cascaded with a fan-shaped branch through a quarter-wavelength high-impedance line to strangle the RF signal from the receiving metal patch and provide a DC path for the bias signal; the second bias signal line is connected to one end of the phase shifter, and is cascaded with a fan-shaped branch through a quarter-wavelength high-impedance line to strangle the RF signal from the receiving metal patch; the other end of the phase shifter is grounded through an inductor L1.

[0011] In some exemplary embodiments, a capacitor C0 is provided between the receiving metal patch and the phase shifter. The capacitor C0 is used to isolate the phase shifter.

[0012] The first bias signal and the second bias signal are separated.

[0013] In some exemplary embodiments, the receiving metal patch and the transmitting metal patch are laid in parallel on the surface of the middle layer; the power amplifier is a unilateral power amplifier; the first metal layer integrates the unilateral power amplifier so that the x-polarized wave is incident on the metasurface in the forward direction.

[0014] When the surface unit is connected, the electromagnetic wave signal is amplified, and because the slot direction of the receiving metal patch is orthogonal to the slot direction of the transmitting metal patch, the reflected wave is converted into a y-polarized wave; if the y-polarized wave is incident back to the metasurface unit, the electromagnetic wave signal is attenuated.

[0015] And the reflected wave is converted into an x-polarized wave.

[0016] In some exemplary embodiments, the slots on the receiving metal patch include a first slot and a second slot, and the first slot and the second slot are symmetrical along the longitudinal center axis.

[0017] In some exemplary embodiments, the two diodes on the receiving metal patch are located between the first slot and the second slot; the spacing between the two diodes is greater than half the length of the first slot along the longitudinal center axis and less than the first slot.

[0018] The length along the longitudinal center axis.

[0019] In some exemplary embodiments, the first slot and the second slot are both rectangular slots; the length direction of the rectangular slot is parallel to the longitudinal center axis.

[0020] In some exemplary embodiments, the slot on the emitting metal patch includes a U-shaped slot; the length direction of the U-shaped slot is perpendicular to the length direction of the first slot; or the length direction of the U-shaped slot is perpendicular to the length direction of the second slot.

[0021] In some exemplary embodiments, the first metal layer and the second metal layer are both copper metal layers; and the first metal layer and the second metal layer have the same thickness.

[0022] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0023] The embodiment of the present application provides a 2-bit high-power amplification non-reciprocal reflective metasurface, comprising a plurality of metasurface units distributed in an array; each metasurface unit comprises a first metal layer, an intermediate layer, and a second metal layer stacked in sequence; the second metal layer comprises a receiving metal patch and a transmitting metal patch; two diodes are provided on the receiving metal patch, and both diodes are located on the longitudinal center axis of the receiving metal patch; both the transmitting metal patch and the receiving metal patch are provided with slots, and the slot direction of the transmitting metal patch is orthogonal to the slot direction of the receiving metal patch; the first metal layer comprises a phase shifter, and the phase shifter comprises a first series diode and The second series diode, the first series diode and the second series diode each include two diodes connected in series, and the first series diode is connected in parallel at both ends of the second series diode; the first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit; by adjusting the diode state of the receiving metal patch and the state of the first series diode and the second series diode of the phase shifter, the phase of the electromagnetic wave has 2 bits, that is, four independent control capabilities; the metasurface unit also includes a power amplifier arranged on the first metal layer, one end of the power amplifier is connected to the phase shifter, and the other end is connected to the transmitting metal patch through a metallized via.

[0024] The 2-bit high-power amplification non-reciprocal reflective metasurface provided by the present application, on the one hand, ensures stable gain amplification characteristics while achieving stable phase modulation by designing a metasurface unit structure with an integrated power amplifier and phase shifter, that is, a power amplification metasurface unit with adjustable gain and phase. On the other hand, by designing the structure of the power amplifier and phase shifter cascaded metasurface unit, non-reciprocal reflective transmission in the form of orthogonal polarization conversion of electromagnetic waves is achieved. In addition, by designing the structure of the power amplifier and phase shifter cascaded metasurface unit, the present application enables the phase modulation type metasurface to work normally in high-power scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0026] Figure 1 A schematic diagram of the three-dimensional structure of a metasurface unit in a 2-bit high-power amplification non-reciprocal reflective metasurface structure provided in one embodiment of the present application;

[0027] Figure 2 A side view of a metasurface unit in a 2-bit high-power amplification non-reciprocal reflective metasurface structure provided in one embodiment of the present application;

[0028] Figure 3 A schematic diagram of the planar structure of the second metal layer provided in one embodiment of the present application;

[0029] Figure 4 A schematic diagram of the planar structure of the first metal layer provided in one embodiment of the present application;

[0030] Figure 5 A schematic circuit diagram of a metasurface unit provided in one embodiment of the present application;

[0031] Figure 6 An S-parameter amplitude curve diagram of a power amplifier circuit under a small signal model provided in one embodiment of the present application;

[0032] Figure 7 A stability curve diagram of a power amplifier circuit under a small signal model provided in one embodiment of the present application;

[0033] Figure 8 A schematic diagram of the physical structure of the second metal layer provided in one embodiment of the present application;

[0034] Figure 9 A schematic diagram of the physical structure of the first metal layer provided in one embodiment of the present application;

[0035] Figure 10 A schematic diagram of testing a 2-bit high-power amplification non-reciprocal reflective metasurface structure according to an embodiment of the present application;

[0036] Figure 11 The S-parameter phase curve of the metasurface structure of the present application, simulated and measured at an incident power of -30 dBm, provided in one embodiment of the present application, and the three phase differences corresponding to the four states;

[0037] Figure 12 The forward S-parameter amplitude curve of the metasurface structure of the present application, simulated and measured at an incident power of -30 dBm, corresponding to four states of 2 bits, provided in one embodiment of the present application;

[0038] Figure 13 The reverse amplitude attenuation curve of the metasurface unit structure of the present application, simulated and measured at an incident power of -30 dBm, corresponding to four states of 2 bits, provided in one embodiment of the present application;

[0039] Figure 14 Simulated and measured reflection coefficient amplitude curves of the metasurface structure of the present application and the metasurface structure without integrated power amplifier, provided for an embodiment of the present application at an incident power of -30 dBm, corresponding to four states of 2 bits;

[0040] Figure 15 Curves showing the amplitude response of the metasurface structure of the present application and the metasurface structure without an integrated power amplifier as a function of input power, provided in one embodiment of the present application, corresponding to four states of 2 bits;

[0041] Figure 16 The curve of the phase response of the metasurface structure of the present application as a function of input power provided in one embodiment of the present application corresponds to 4 states of 2 bits. DETAILED DESCRIPTION

[0042] As can be seen from the background technology, the currently available power amplification metasurfaces cannot achieve quantitative control of the electromagnetic wave phase stability while amplifying the electromagnetic energy.

[0043] Metasurfaces (artificial electromagnetic surfaces) are a new type of two-dimensional electromagnetic material composed of periodic or aperiodic arrangements of subwavelength artificial units. By designing their unit structure, size, and array topology, metasurfaces can exhibit unique electromagnetic properties not found in natural materials. Furthermore, they are characterized by thinness, light weight, simple fabrication processes, and ease of integration. Consequently, metasurfaces have been widely studied and applied in the electromagnetic and communications fields. Depending on whether they are tunable, metasurfaces can be categorized as either static or dynamic. The former is typically a purely passive design, whose electromagnetic properties are entirely dependent on the passive structure and cannot be dynamically adjusted. The latter, on the other hand, typically incorporates active devices or specialized materials, such as pin-type switching diodes (PINs), varactors, micromechanical switches (MEMS), liquid crystals, graphene, and vanadium dioxide. By applying specific conditions to alter the operating state of the active devices or the properties of the specialized materials, metasurfaces achieve dynamic control of electromagnetic waves, making them more suitable for use in complex communications environments. In particular, for the phase control of electromagnetic waves, different numbers of bits are used to describe it according to the different quantized numbers of phase states. For example, 1 bit represents two phase states, and the phase difference between adjacent states is 180 degrees; 2 bits represent four phase states, and the phase difference between adjacent states is 90 degrees, and so on.

[0044] Nonreciprocity refers to the phenomenon in which electromagnetic waves propagating in opposite directions through an object exhibit different electromagnetic losses, phase shifts, and other properties. Nonreciprocal materials have found widespread application in numerous branches of physics, including thermodynamics, mechanics, electromagnetism, and optics. Irreversible devices such as circulators and isolators are widely used in radar and communication systems. Generally, the three types of metasurfaces integrated with lossy devices mentioned above exhibit reciprocity in electromagnetic wave manipulation. Specifically, the three metasurfaces integrated with lossy devices, namely, the switching diode (PIN), the varactor diode, and the micromechanical switch (MEMS), exhibit reciprocity in electromagnetic wave manipulation. Traditional nonreciprocal devices in electromagnetics are primarily based on magnetic materials, such as ferrites. However, these materials are typically large, costly, and difficult to integrate with metasurfaces. Some researchers have proposed nonmagnetic nonreciprocal metasurfaces. By integrating transistor-like amplifiers or isolators into the metasurface structure, they can achieve smaller size and improved integrability. Other researchers have proposed asymmetric metamaterials based on time modulation, but these control systems significantly increase the complexity.

[0045] Power amplifiers are typical physical boundary devices and are the basic building blocks of various microwave circuit functional devices. Power amplifiers exhibit strong nonlinear, nonreciprocal, and energy-enhancing operating characteristics. Compared to the three lossy devices mentioned above, power amplifiers are binary boundary devices. Their nonlinear, nonreciprocal, and energy-enhancing properties are also affected by two variables: DC bias and electromagnetic matching. In recent years, power-amplifying metasurfaces, which integrate active unilateral power amplifiers with metasurfaces, have achieved a variety of physical properties, such as nonmagnetic nonreciprocity, enhanced reflection, high-power absorption, and full-duplex reflected beams, sparking research interest among researchers both domestically and internationally.

[0046] The polarization of an electromagnetic wave is typically represented by the trajectory of the electric field intensity vector endpoints in space over time. Polarization conversion involves changing the polarization of an electromagnetic wave, such as converting a linearly polarized wave to a circularly polarized wave or a co-polarized wave to a cross-polarized wave. Traditionally, polarization conversion has been achieved using transition waveguides and other methods. Polarization-converting metasurfaces offer a new approach to achieving this. Through a uniquely designed unit structure, they achieve polarization conversion between incident and scattered waves, offering significant application potential in electromagnetic fields and wireless communications.

[0047] A related art proposes a transmissive metasurface unit structure combined with a power amplifier. By cascading two amplifiers, receiving and transmitting patches, non-reciprocal electromagnetic wave transmission is achieved, and the bias voltage is adjusted to achieve controllable gain. However, since this is a transmissive metasurface, beam steering is easier to achieve than a reflective metasurface, and it cannot inherently control the phase of the electromagnetic wave. Another related art proposes a reconfigurable reflective metasurface unit structure combined with a power amplifier. By designing a patch unit with two orthogonal hourglass-shaped coupling slots, it achieves amplification of orthogonally polarized waves over a wide frequency range. However, it does not achieve electromagnetic wave phase control, but only controls the electromagnetic wave amplitude gain through an integrated amplifier, and cannot control the beam angle. Another related art proposes a reflective metasurface unit structure in the form of a cascaded radiating patch, an amplifier, and a phase shifter. Through a periodic gradient phase arrangement, it achieves beam radiation and amplification in a specific direction without magnetic non-reciprocity. However, the phase corresponding to each unit is pre-set by the phase shifter, i.e., fixed and unchangeable, and dynamic phase control is impossible.

[0048] From the above description, it can be seen that one of the advantages of existing power-amplifying metasurfaces is that their metasurface units are cascaded with power amplifiers, thereby achieving energy amplification of electromagnetic waves. However, the current power-amplifying metasurface structure design can basically only amplify the signal energy, that is, enhance the amplitude of the electromagnetic wave; without achieving stable phase quantization control while achieving electromagnetic wave amplification. Based on this, in order to address the technical problems existing in power-amplifying metasurfaces, this application proposes a 2-bit high-power-amplifying non-reciprocal reflective metasurface.

[0049] In order to solve the above technical problems, the embodiment of the present application provides a 2-bit high-power amplification non-reciprocal reflective metasurface, including a plurality of metasurface units distributed in an array; each metasurface unit includes a first metal layer, an intermediate layer, and a second metal layer stacked in sequence; the second metal layer includes a receiving metal patch and a transmitting metal patch; two diodes are provided on the receiving metal patch, and the two diodes are both located on the longitudinal center axis of the receiving metal patch; the transmitting metal patch and the receiving metal patch are both provided with slots, and the slot direction of the transmitting metal patch is orthogonal to the slot direction of the receiving metal patch; the first metal layer includes a phase shifter, and the phase shifter includes a first series The first series diode and the second series diode each include two series-connected diodes, and the first series diode is connected in parallel at both ends of the second series diode; the first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit; by adjusting the diode state of the receiving metal patch and the state of the first series diode and the second series diode of the phase shifter, the phase of the electromagnetic wave has 2 bits, that is, four independent control capabilities; the metasurface unit also includes a power amplifier arranged on the first metal layer, one end of the power amplifier is connected to the phase shifter, and the other end is connected to the transmitting metal patch through a metallized via. The present application aims to provide a power amplification reflective metasurface design with adjustable gain and phase. By designing a 2-bit high-power amplification non-reciprocal reflective metasurface, stable phase modulation is achieved while ensuring stable gain amplification characteristics.

[0050] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0051] The present invention provides a 2-bit high-power amplification non-reciprocal reflective metasurface. Figure 1 , which is a schematic diagram of the three-dimensional structure of a metasurface unit in the 2-bit high-power amplification non-reciprocal reflective metasurface structure provided in an embodiment of the present application. The 2-bit high-power amplification non-reciprocal reflective metasurface provided in an embodiment of the present application includes multiple metasurface units distributed in an array. Figure 2 FIG. 1 shows a side view of a metasurface unit provided in an embodiment of the present application. Figure 2 As shown, each metasurface unit includes a first metal layer 101, an intermediate layer 102, and a second metal layer 103 stacked in sequence. The second metal layer 103 is located above the first metal layer 101, and the intermediate layer 102 is located between the first metal layer 101 and the second metal layer 103. Figure 2As shown, components 111 are laid on the first metal layer 101 and the second metal layer 103, and a plurality of metallized vias 110 penetrating the middle layer 102 are provided on the middle layer 102. Different metallized vias 110 are used to achieve connectivity between different components 111 and each layer.

[0052] Please continue to see Figure 2 The middle layer 102 includes a first dielectric layer 1021, a third metal layer 1022, a prepreg 1023, and a second dielectric layer 1024 stacked in sequence. For DC signals, the third metal layer 1022 acts as a ground to provide a reference level for the DC voltage; for RF signals, the third metal layer 1022 acts as a metal reflective surface to enhance the reflection capability of electromagnetic wave signals. The materials of the first dielectric layer 1021 and the second dielectric layer 1024 are both Rogers 4350 (εr = 3.66, tanδ = 0.004), and the material of the prepreg 1023 is Rogers 4450F (εr = 3.52, tanδ = 0.004). In addition, in some embodiments, in order to route the bias lines of the metasurface, multiple dielectric layers need to be added. For example, three dielectric layers are added between the second metal layer 103 and the second dielectric layer 1024, and a prepreg is provided between each adjacent dielectric layer.

[0053] See Figure 3 The second metal layer 103 includes a receiving metal patch 1031 and a transmitting metal patch 1032; the receiving metal patch 1031 is provided with two diodes, and both diodes are located on the longitudinal center axis A of the receiving metal patch 1031; the transmitting metal patch 1032 and the receiving metal patch 1031 are both provided with slots, and the slot direction of the transmitting metal patch 1032 is orthogonal to the slot direction of the receiving metal patch 1031. Figure 3 As shown, the receiving metal patch 1031 is located at the lower left of the second metal layer 103, and the transmitting metal patch 1032 is located at the upper right of the second metal layer 103. Both diodes are located on the longitudinal center axis A of the receiving metal patch 1031. In other words, the line connecting the two diodes coincides with the longitudinal center axis A of the receiving metal patch 1031. For example, both diodes are PIN diodes.

[0054] Specifically, the receiving metal patch 1031 is a reconfigurable receiving metal patch, having an O-shaped slot-shaped metal structure with a PIN diode loaded at each end of its longitudinal centerline A. The receiving metal patch 1031 converts linearly polarized waves in space into quasi-TEM waves in the microstrip line through the metallized through-hole 110. The two PIN diodes are placed along the longitudinal centerline A in the same direction. Two metallized through-holes are provided on the left and right sides of the receiving metal patch 1031, serving as control voltage references for the PIN diodes. For a positive bias voltage, the lower PIN diode switches to the on state, while the upper PIN diode is in the off state. For a negative bias voltage, the state of the PIN diode is opposite to that for a positive bias voltage. By switching the control voltage from a positive voltage to a negative voltage, a current in the opposite direction is generated, and the receiving metal patch 1031 can generate a 180-degree phase difference in the cascade phase shift circuit.

[0055] As mentioned above, the middle layer 102 is provided with a plurality of metallized vias 110 penetrating the middle layer 102. Different metallized vias 110 are used to achieve connectivity between different components 111 and each layer. Figure 3 , the multiple through holes at the upper left corner B are used for grounding of the components in the power amplifier circuit, that is, they are connected to the third metal layer 1022 in the middle layer 102; the three through holes at the lower left corner are located at the receiving metal patch 1031, and the two through holes on the left and right ( Figure 3 C, D in the middle) is used to connect the third metal layer 1022 in the middle layer 102, and is used to provide a reference ground level for the DC signal, and receives the through hole ( Figure 3 E in the middle) is used to connect the circuit of the first metal layer 101; a through hole ( Figure 3 F in the middle) is used to connect the circuit of the first metal layer 101; a through hole in the lower right corner ( Figure 3 G in the middle) is the bias line after entering for capacitors C8, C9, C10, and C11 ( Figure 5 The grounding is shown in the lower left corner of the figure, that is, it is connected to the third metal layer 1022 of the middle layer 102.

[0056] In some embodiments, the slots on the receiving metal patch 1031 include a first slot 1031 a and a second slot 1031 b , and the first slot 1031 a and the second slot 1031 b are symmetrical along the longitudinal center axis A.

[0057] In some embodiments, the two diodes on the receiving metal patch 1031 are located between the first slot 1031a and the second slot 1031b; the spacing between the two diodes is greater than half of the length of the first slot 1031a along the longitudinal central axis A, and less than the length of the first slot 1031a along the longitudinal central axis A; or, the spacing between the two diodes is greater than half of the length of the second slot 1031b along the longitudinal central axis A, and less than the length of the second slot 1031b along the longitudinal central axis A.

[0058] like Figure 2 As shown, in some embodiments, the first slot 1031a and the second slot 1031b are both rectangular slots; the length direction of the rectangular slot is parallel to the longitudinal center axis A.

[0059] It should be noted that the receiving metal patch 1031 is also provided with multiple through-holes 1033. These through-holes 1033 communicate with corresponding metallized vias 110 on the middle layer 102. A through-hole 1033 is provided on both the left and right sides of the receiving metal patch 1031. These two through-holes 1033 communicate with two metallized vias 110 on the middle layer 102, respectively, serving as control voltage references for the PIN diodes.

[0060] In some embodiments, the slot on the emitting metal patch 1032 is a U-shaped slot 1032a; the length direction of the U-shaped slot 1032a is perpendicular to the length direction of the first slot 1031a; or, the length direction of the U-shaped slot 1032a is perpendicular to the length direction of the second slot 1031b.

[0061] In some embodiments, the receiving metal patch 1031 and the transmitting metal patch 1032 are laid parallel to each other on the middle layer 102, and both the receiving metal patch 1031 and the transmitting metal patch 1032 are provided with slots. Specifically, the slots on the receiving metal patch 1031 are rectangular slots, and the slots on the transmitting metal patch 1032 are U-shaped slots. The rectangular slots and the U-shaped slots are arranged orthogonally, that is, the extending direction of the rectangular slots is perpendicular to the extending direction of the U-shaped slots. The slot directions of the receiving metal patch 1031 and the transmitting metal patch 1032 are orthogonal because the gain of the power amplifier 1012 must be less than the isolation between the transmitting and receiving ports to ensure the stability of the power amplifier 1012.

[0062] In some embodiments, the first metal layer 101 and the second metal layer 103 are both copper metal layers; and the first metal layer 101 and the second metal layer 103 have the same thickness.

[0063] In some embodiments, the third metal layer 1022 may also be a copper metal layer; the thickness of the third metal layer 1022 may be the same as or different from that of the first metal layer 101 and the second metal layer 103 .

[0064] It should be noted that the receiving metal patch 1031 and the transmitting metal patch 1032 are both arranged on the surface of the second metal layer 103 away from the intermediate layer 102 (the second dielectric layer 1024), that is, the receiving metal patch 1031 and the transmitting metal patch 1032 are both arranged on the upper surface of the second metal layer 103. The second metal layer 103 is arranged above the first metal layer 101, that is, the receiving metal patch 1031 and the transmitting metal patch 1032 are both arranged on the top surface of the metasurface unit.

[0065] See Figure 4 The first metal layer 101 includes a phase shifter 1011, which includes a first series diode and a second series diode. The first series diode and the second series diode each include two series-connected diodes, and the first series diode is connected in parallel at both ends of the second series diode. The first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit. By adjusting the diode state of the receiving metal patch 1031 and the state of the first series diode and the second series diode of the phase shifter 1011, the phase of the electromagnetic wave has 2 bits, that is, four independent control capabilities. Figure 4 As shown, signal line 0 corresponds to the second bias signal line, and signal line 1 corresponds to the first bias signal line.

[0066] It should be noted that in Figure 4 The bias voltage of the power amplifier 1012 is loaded at the V of the power amplifier 1012, corresponding to Figure 5 VDD.

[0067] Specifically, the phase shifter 1011 is a 90-degree reconfigurable phase shifter. In order to improve the phase resolution of the surface element to electromagnetic waves, the present application combines four PIN diodes to realize a reconfigurable 90-degree phase shift circuit. Figure 5 As shown, for a positive bias voltage, the first series diode (diode D2 and diode D3 in series) is switched to the on state and the second series diode (diode D4 and diode D5 in series) is switched to the off state; for a negative bias voltage, the first series diode (diode D2 and diode D3 in series) is switched to the off state and the second series diode (diode D4 and diode D5 in series) is switched to the on state. Phase shifter 1011 allows signals to pass through different path lengths, achieving a 90-degree phase difference. The DC path of phase shifter 1011 is grounded at one end through inductor L1 to provide a reference voltage for the PIN diode. The other end uses a quarter-wavelength high-impedance line cascaded with fan-shaped branches to suppress the RF signal from the receiving metal patch 1031, and the DC bias voltage of the PIN diode is applied to the back end, i.e., bias signal line 0.

[0068] In some embodiments, the metasurface unit further includes a first bias signal line (bias signal line 1) and a second bias signal line (bias signal line 0) provided on the first metal layer 101; the bias signal line 1 is connected to the back of the receiving metal patch 1031, and the first bias signal line ( Figure 5 The middle signal line 1) is connected to the receiving metal patch 1031 through a metalized via, and is connected to the fan-shaped branch through a quarter-wavelength high-impedance line to suppress the RF signal from the receiving metal patch 1031 and provide a DC path for the bias signal; the second bias signal line ( Figure 5 The middle signal line 0) is connected to one end of the phase shifter 1011 and is connected to a fan-shaped branch through a quarter-wavelength high-impedance line to suppress the RF signal from the receiving metal patch 1031; the other end of the phase shifter 1011 is grounded through an inductor L1.

[0069] In some embodiments, a capacitor C0 is provided between the receiving metal patch 1031 and the phase shifter 1011, and the capacitor C0 is used to isolate the first bias signal ( Figure 5 signal line 1) and the second bias signal ( Figure 5 With this configuration, the four discrete phase states of the metasurface unit can be achieved by adjusting the two control voltages of the PIN diodes loaded on the reconfigurable receiving metal patch and the reconfigurable phase shifter. Figure 5 The lower right corner is the equivalent circuit model of the PIN diode in different states.

[0070] In some embodiments, the metasurface unit further includes a power amplifier 1012 disposed on the first metal layer 101. One end of the power amplifier 1012 is connected to the phase shifter 1011, and the other end is connected to the transmitting metal patch 1032 via a metalized via. The power amplifier 1012 is a unilateral power amplifier. The first metal layer 101 integrates the unilateral power amplifier, so that when an x-polarized wave is incident on the metasurface unit in the forward direction, the electromagnetic wave signal is amplified. Because the slot directions of the receiving metal patch 1031 and the transmitting metal patch 1032 are orthogonal, the reflected wave is converted to a y-polarized wave. If the y-polarized wave is incident back on the metasurface unit in the reverse direction, the electromagnetic wave signal is attenuated, and the reflected wave is converted to an x-polarized wave, giving the metasurface unit a non-reciprocal characteristic. The slot directions of the receiving metal patch 1031 and the transmitting metal patch 1032 are orthogonal because the gain of the power amplifier 1012 must be less than the isolation between the transmitting and receiving ports to ensure the stability of the power amplifier 1012.

[0071] Taking into account that the input impedance of the power amplifier is irrelevant to the performance of the amplifier, for convenience, the output impedance of the receiving metal patch 1031 is set to the standard 50 ohms in the simulation, and the proposed method is not limited to this standard impedance. A unilateral power amplifier is inserted between the reconfigurable phase shifter and the transmitting metal patch 1032 to achieve amplification of the incident wave and non-reciprocal transmission. In addition, compared with the metasurface unit that only integrates PIN diodes, the power amplifier has a high output power capability, thereby improving the power carrying capacity of the metasurface unit. This application selects a power amplifier model TQP7M9102 manufactured by QORVO. This type of amplifier requires an external matching network to achieve its good performance, which provides greater flexibility in the common analog design of the cascade structure.

[0072] It should be noted that the phase shifter 1011 is disposed on the surface of the first metal layer 101 that is away from the intermediate layer 102 (the first dielectric layer 1021). Similarly, the power amplifier 1012 is also disposed on the surface of the first metal layer 101 that is away from the intermediate layer 102 (the first dielectric layer 1021). That is, both the phase shifter 1011 and the power amplifier 1012 are disposed on the lower surface of the first metal layer 101. In other words, both the phase shifter 1011 and the power amplifier 1012 are disposed on the bottom surface of the metasurface unit.

[0073] Figure 5 The dotted box in the upper right corner shows the matching network diagram of the power amplifier circuit. A suitable matching network is designed to achieve good performance of the amplifier. Figure 6 The figure shows the S-parameter amplitude curve of the amplifier circuit obtained by simulation. The simulation shows that the designed power amplifier circuit has a gain of more than 10dB and an isolation of more than 20dB, indicating that the amplifier circuit has good energy enhancement and non-reciprocity. In addition, stability is the key to any amplifier integrated system. Figure 7 The figure shows the stability curve of the amplifier circuit obtained by simulation, which indicates that the amplifier circuit is in an unconditionally stable state.

[0074] In order to verify the correctness of the simulation design, the following Figure 10 The experimental test device and test method shown. Figure 10 The left side shows a simulation diagram. Figure 10 The diagram on the right shows a real-world measurement scenario. The metasurface structure described in this application is connected to an orthogonal mode conversion waveguide. Two WR229 waveguide converters transmit and receive a pair of orthogonally polarized waves in the 3.95 GHz to 4.05 GHz frequency range. The waveguide converters are connected to a vector network analyzer via a coaxial cable to measure the required data. Figure 8 and Figure 9 They are the physical pictures of the second metal layer 103 and the first metal layer 101 respectively. Figure 8 and Figure 9 As shown, in order to align with the actual orthogonal mode conversion waveguide port, the structure size of the processed metasurface unit of the present application is expanded. Figure 11 As shown in FIG, four discrete phase responses corresponding to three differential phase states can be achieved at a low input power level of -30 dBm, which verifies the 2-bit phase control capability of the metasurface structure of the present application. Figure 12 It can be seen from the figure that the electromagnetic wave transmitted in the forward direction has a gain of more than 4dB in all four states through the reflection of the structure of the present application. Figure 13 An attenuation of more than 10dB was observed in the experiment, which shows the non-reciprocal polarization conversion and enhancement characteristics of the structure of the present application. At the same time, we compared the performance difference between the structure of the present application and the structure of the present application without integrated amplifier. It can be seen that the transmission performance of the structure of the present application without integrated amplifier in four discrete states is as follows: Figure 14 This indicates that the metasurface unit without integrated amplifier, i.e., only integrated with PIN diodes, can only attenuate the wave intensity but cannot increase it.

[0075] In addition, the amplitude responses of the structure of the present application and the structure of the present application without integrated amplifier as the input power changes were measured, such as Figure 15 As shown. It can be observed that the gain of the structure of the present application is improved by 8.1dB compared with the structure of the present application without integrated amplifier, which shows that the structure of the present application has good power handling capability. The saturated output power of the structure of the present application exceeds 27dBm, indicating that there is more than 147.7W / m 2 The output power intensity is suitable for high-power space microwave transmission. In addition, the phase response of the structure of the present application is measured as a function of input power, such as Figure 16 Before the 1dB output power compression point, the phase variation of the structure of the present application is less than 7°, indicating good phase stability in high-power scenarios.

[0076] The present application designs a power-amplifying reflective metasurface with adjustable gain and phase. Specifically, first, the present application provides a 2-bit high-power-amplifying non-reciprocal reflective metasurface, which not only enhances the electromagnetic wave by the metasurface, but also has the ability to regulate the phase of the electromagnetic wave by 2 bits, that is, four states. The gain of the electromagnetic wave can also be achieved by adjusting the bias voltage of the amplifier. In wireless communications, more flexible beamforming, information transmission with a higher signal-to-noise ratio, and expanded communication area coverage can be achieved. Second, the present application provides a 2-bit high-power-amplifying non-reciprocal reflective metasurface, which is a design method for non-magnetic non-reciprocal devices that realize polarization conversion, that is, the forward-transmitted electromagnetic wave is enhanced and orthogonal polarization conversion is achieved, while the reverse-transmitted electromagnetic wave is orthogonally polarized but attenuated. Third, the present application provides a 2-bit high-power-amplifying non-reciprocal reflective metasurface, which improves the power carrying capacity of traditional digital coding metasurface units, making digital coding metasurfaces suitable for high-power communication and energy scenarios. Fourth, this application provides a 2-bit high-power amplification non-reciprocal reflective metasurface that integrates a unilateral power amplifier with a metasurface unit. This ensures the stability of the integrated amplification system while reducing the aperture of the non-reciprocal metasurface. This enables a higher degree of integration of the metasurface, facilitating the deployment of wireless communication devices.

[0077] Compared with the prior art, the advantages of the 2-bit high-power amplification non-reciprocal reflective metasurface provided by the present application are as follows: (1) The present application realizes the amplification of electromagnetic waves by cascading power amplifiers, and can realize gain control by adjusting the bias voltage. By regulating the PIN diode state of the reconfigurable receiving metal patch and the PIN diode state of the phase shifter cascaded therewith, the 2-bit control capability of the electromagnetic wave phase is realized. This metasurface with adjustable amplitude and phase and amplification characteristics can realize more flexible beamforming, high signal-to-noise ratio information transmission and expanded communication area coverage in wireless communications. It can also be connected to a digital control platform, such as FPGA, to realize programmable high-speed beam steering. (2) The present application realizes the non-reciprocal transmission of electromagnetic waves in the form of polarization conversion by cascading unilateral power amplifiers and setting the slot direction of the reconfigurable receiving metal patch orthogonal to the slot direction of the transmitting metal patch, that is, the electromagnetic wave transmitted in the forward direction is enhanced and the orthogonal polarization conversion is realized, and the electromagnetic wave transmitted in the reverse direction is orthogonally polarized but attenuated. A design method for a non-magnetic non-reciprocal device is provided, which has certain application value in waveform processing and full-duplex transmission in modern wireless communication systems. (3) This application integrates a phase-controlled metasurface unit with a power amplifier. Due to the high power tolerance characteristics of the power amplifier, the power carrying capacity of the traditional metasurface unit is improved, making the metasurface suitable for high-power communication and energy scenarios. (4) This application integrates a unilateral power amplifier with a metasurface unit, ensuring the stability of the integrated amplification system while reducing the aperture of the digital metasurface with non-reciprocal characteristics. This makes the metasurface have a higher degree of integration, which is conducive to the deployment of equipment in wireless communication scenarios.

[0078] It should be noted that the selection of the power amplifier and the selection of the PIN diode used in the metasurface structure of the present application can be replaced by other types of devices. Phase control can be achieved by using other phase-modulating materials or devices such as varactors or MEMS switches in addition to PIN diodes, and other phase quantization forms different from 2 bits can be achieved. In addition, the metasurface structure of the present application can achieve the same function in other frequency bands by changing the size of the metal patch and the material of the dielectric substrate. In addition, it is also possible not to adopt this integrated design structure, but to make the reconfigurable receiving metal patch and the transmitting metal patch in this structure independent units, and to achieve the same function by reserving ports at the receiving and transmitting points, and cascading 90-degree phase shifters and power amplifiers through the ports. Finally, the present application can adopt a structural form in which the power amplifier is not integrated in this metasurface unit, and realize the non-reciprocal transmission of electromagnetic waves by time modulation coding.

[0079] In summary, the present application designs a metasurface unit structure that integrates a power amplifier and a phase shifter to ensure stable gain amplification characteristics while achieving stable phase modulation, that is, a power amplification metasurface unit with adjustable gain and phase. The present application also realizes the non-reciprocal transmission of reflective electromagnetic waves in the form of orthogonal polarization conversion by designing a structure of a metasurface unit that integrates a power amplifier and a phase shifter. In addition, the present application also realizes the normal operation of the phase modulation type metasurface in high-power scenarios by designing a structure of a metasurface unit that integrates a power amplifier and a phase shifter.

[0080] The 2-bit high-power amplification non-reciprocal reflective metasurface provided in this application has good application prospects. In recent years, metasurfaces with integrated power amplifiers have been a hot research topic. They can achieve electromagnetic wave amplification and dynamic gain control. Compared with passive metasurfaces or metasurfaces with integrated lossy devices, their advantages include: (1) achieving forward gain and dynamic gain control by adjusting the amplifier bias voltage; (2) unilateral power amplification realizes electromagnetic wave transmission with non-reciprocal characteristics.

[0081] The metasurface unit in this application is a phase-adjustable power-amplifying metasurface unit. Compared to other known power-amplifying metasurface units, its advantages include independent control of the phase of the electromagnetic wave, thereby achieving amplitude- and phase-adjustable electromagnetic wave beam steering. This provides a design solution for beamforming, signal coverage, and high-power wireless energy transmission in wireless communications.

[0082] The 2-bit high-power amplification non-reciprocal reflective metasurface provided by this application is a phase-adjustable power amplification non-reciprocal reflective metasurface formed by orderly arranging metasurface units. Specifically, it has the following application prospects: (1) Solving the heat and power tolerance problems caused by lossy components, which makes it impossible for coding metasurfaces to cover high-power and wide-range electromagnetic signals. This application is conducive to realizing a new wireless communication system architecture with high efficiency, high signal transmission quality and wide coverage; (2) Based on the field-enhanced reconfigurable and beam-reconfigurable characteristics of the active power amplifier coding metasurface, the enhanced blind spot elimination technology of 6G smart metasurfaces for wireless communication signals and the expansion of wireless channel reshaping range are studied; (3) Combined with the power amplification metasurface of space-time coding, by loading information, the downlink RF link module can be reduced, thereby improving the efficiency of the wireless communication system and reducing its manufacturing cost, especially for wireless communication systems in the millimeter wave THz frequency band, it has important application potential and research value. (4) The power amplification metasurface combined with space-time coding has high power and nonlinear harmonic enhanced beam scanning characteristics, which is conducive to the research of new radar systems. (5) The research and design of new energy-carrying communication systems are carried out by integrating electromagnetic energy-converging beams with digital information and utilizing the separation and control mode of fundamental and harmonic waves generated by power-amplifying metasurfaces combined with space-time coding. (6) The exploration of new metamaterials, energy-carrying communication technologies, and the development of next-generation wireless communication technologies have important scientific significance and application value.

[0083] Based on the above technical solution, the embodiment of the present application provides a 2-bit high-power amplification non-reciprocal reflective metasurface, including a plurality of metasurface units distributed in an array; each metasurface unit includes a first metal layer 101, an intermediate layer 102, and a second metal layer 103 stacked in sequence; the second metal layer 103 includes a receiving metal patch 1031 and a transmitting metal patch 1032; two diodes are provided on the receiving metal patch 1031, and both diodes are located on the longitudinal center axis A of the receiving metal patch 1031; both the transmitting metal patch 1032 and the receiving metal patch 1031 are provided with slots, and the slots of the transmitting metal patch 1032 The direction is orthogonal to the slot direction of the receiving metal patch 1031. The first metal layer 101 includes a phase shifter 1011, which includes a first series diode and a second series diode. The first series diode and the second series diode each include two diodes connected in series, with the first series diode connected in parallel across the second series diode. The first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit. By adjusting the diode state of the receiving metal patch 1031 and the state of the first series diode and the second series diode of the phase shifter 1011, the phase of the electromagnetic wave has two bits, i.e., four independent control capabilities. The metasurface unit also includes a power amplifier 1012 disposed on the first metal layer 101. One end of the power amplifier 1012 is connected to the phase shifter 1011, and the other end is connected to the transmitting metal patch 1032 through a metallized via.

[0084] The 2-bit high-power amplification non-reciprocal reflective metasurface provided by the present application, on the one hand, ensures stable gain amplification characteristics while achieving stable phase modulation by designing a metasurface unit structure with an integrated power amplifier and phase shifter, that is, a power amplification metasurface unit with adjustable gain and phase. On the other hand, by designing the structure of the power amplifier and phase shifter cascaded metasurface unit, non-reciprocal reflective transmission in the form of orthogonal polarization conversion of electromagnetic waves is achieved. In addition, by designing the structure of the power amplifier and phase shifter cascaded metasurface unit, the present application enables the phase modulation type metasurface to work normally in high-power scenarios.

[0085] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A 2-bit high-power amplification non-reciprocal reflective metasurface, characterized in that: The invention comprises a plurality of metasurface units distributed in an array; each of the metasurface units comprises a first metal layer, an intermediate layer and a second metal layer stacked in sequence; The second metal layer includes a receiving metal patch and a transmitting metal patch; the receiving metal patch is provided with two diodes, and both diodes are located on the longitudinal center axis of the receiving metal patch; the transmitting metal patch and the receiving metal patch are both provided with slots, and the slot direction of the transmitting metal patch is orthogonal to the slot direction of the receiving metal patch; The first metal layer includes a phase shifter, which includes a first series diode and a second series diode. The first series diode and the second series diode each include two diodes connected in series, and the first series diode is connected in parallel across the second series diode. The first series diode and the second series diode constitute a reconfigurable 90-degree phase shift circuit. By adjusting the diode state of the receiving metal patch and the states of the first series diode and the second series diode of the phase shifter, the phase of the electromagnetic wave has two bits, i.e., four independent control capabilities. The metasurface unit further includes a power amplifier disposed on the first metal layer, one end of the power amplifier being connected to the phase shifter, and the other end being connected to the emitting metal patch through a metallized via.

2. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 1, characterized in that: The intermediate layer includes a first dielectric layer, a third metal layer, a prepreg and a second dielectric layer stacked in sequence; For a DC signal, the third metal layer acts as a ground to provide a reference level for the DC voltage; For radio frequency signals, the third metal layer acts as a metal reflection surface to enhance the reflection capability of electromagnetic wave signals.

3. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 1, wherein: The metasurface unit further includes a first bias signal line and a second bias signal line provided on the first metal layer; The first bias signal line is connected to the receiving metal patch through a metallized via and is cascaded with fan-shaped branches through a quarter-wavelength high-impedance line to throttle the radio frequency signal from the receiving metal patch and provide a DC path for the bias signal; The second bias signal line is connected to one end of the phase shifter and is cascaded with a fan-shaped branch through a quarter-wavelength high-impedance line to suppress the radio frequency signal from the receiving metal patch; The other end of the phase shifter is grounded via an inductor L1.

4. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 3, wherein: A capacitor C0 is provided between the receiving metal patch and the phase shifter, and the capacitor C0 is used to isolate the first bias signal from the second bias signal.

5. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 1, wherein: The receiving metal patch and the transmitting metal patch are laid in parallel on the surface of the middle layer; The power amplifier is a unilateral power amplifier; the first metal layer integrates a unilateral power amplifier, so that when the x-polarized wave is incident on the metasurface unit in the forward direction, the electromagnetic wave signal is amplified, and because the slot direction of the receiving metal patch is orthogonal to the slot direction of the transmitting metal patch, the reflected wave is converted into a y-polarized wave; if the y-polarized wave is incident back into the metasurface unit in the reverse direction, the electromagnetic wave signal is attenuated, and the reflected wave is converted into an x-polarized wave.

6. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 1, wherein: The slots on the receiving metal patch include a first slot and a second slot, and the first slot and the second slot are symmetrical along the longitudinal center axis.

7. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 6, characterized in that: The two diodes on the receiving metal patch are located between the first slot and the second slot; The distance between the two diodes is greater than half of the length of the first slot along the longitudinal center axis and less than the length of the first slot along the longitudinal center axis.

8. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 6, wherein: The first slot and the second slot are both rectangular slots; The length direction of the rectangular groove is parallel to the longitudinal center axis.

9. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 6, wherein: The slot on the transmitting metal patch is a U-shaped slot; The length direction of the U-shaped groove is perpendicular to the length direction of the first slot; or the length direction of the U-shaped groove is perpendicular to the length direction of the second slot.

10. The 2-bit high-power amplification non-reciprocal reflective metasurface according to claim 1, characterized in that: The first metal layer and the second metal layer are both copper material metal layers; The first metal layer and the second metal layer have the same thickness.

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