Anti-damage phased array antenna based on artificial surface plasmon

Abstract

The invention particularly relates to an anti-damage phased-array antenna based on artificial surface plasmon. The anti-damage phased-array antenna comprises a power divider, multiple paths of artificial surface plasmon phase shift channels connected with the power divider, and artificial surface plasmon miniaturized Vivaldi antennas connected with respective ends of the artificial surface plasmon phase shift channels; the power divider divides an input radio frequency signal into multiple paths of signals with the same amplitude and phase, and the multiple paths of signals are fed into the multiple paths of artificial surface plasmon phase shift channels respectively; the multiple paths of artificial surface plasmon phase shift channels respectively regulate and control fed-in signals, and output multiple paths of signals which are equal in amplitude and have gradient phase differences at equal intervals; multiple paths of signals are respectively fed into the artificial surface plasmon miniaturized Vivaldi antenna to form a synthetic wave beam with a certain scanning angle. According to the invention, under the condition of not adding any additional part, only the nonlinear dispersion and group velocity regulation and control characteristics of the artificial surface plasmon are utilized, and a solution is provided for realizing front door coupling suppression of high-degree-of-freedom systems such as a frequency hopping system and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial electromagnetic materials and antennas, and in particular to a damage-resistant phased array antenna based on artificial surface plasmons. Background Art

[0002] The frequency hopping system is widely used in various scenarios such as electronic countermeasures and mobile communications due to its advantages such as strong security and high spectrum utilization. However, the broadband characteristics make it easier for short damaging pulses to enter the frequency hopping system from terminal components such as phased array antennas, aggravating front-door coupling and posing safety hazards to circuits and systems. The linear dispersion characteristics of traditional phased array systems cause high-power microwave pulses to enter the system, and the different frequency components will shift to the same phase after a certain period of time. That is, the peak value of the superimposed time domain pulse after entering the system remains unchanged, making it difficult to achieve antenna damage protection.

[0003] In order to achieve front-door coupling protection, structures such as antenna covers, absorbers, frequency selective surfaces, and energy selective surfaces can be introduced outside the system. Antenna covers and absorbers prevent high-power microwave pulses from entering the system by filtering out or absorbing electromagnetic waves outside the working frequency band. Frequency selective surfaces and energy selective surfaces design electromagnetic surfaces with special electromagnetic effects so that signals within the working frequency band can pass selectively, while interference signals and high-power microwave pulses outside the band are blocked, thereby suppressing front-door coupling. In addition to introducing protection structures outside the system, designing additional protection circuits and components inside the system is also a common method. For example, cascading limiters and filters can be used to prevent high-power microwave pulses from entering the back-end circuit, thereby protecting the circuit and system. However, existing solutions all have two disadvantages: First, the introduction of any additional structure will increase the cost, size, and complexity of the system. Second, for short and broadband high-power microwave pulses, these methods are more difficult to achieve front-door coupling protection.

[0004] The nonlinear dispersion characteristics of artificial surface plasmons can be used to achieve high-power microwave pulse suppression without introducing additional designs and components, thus solving the above problems. Artificial surface plasmons are an electromagnetic mode that simulates the excellent characteristics of surface plasmons in the optical band in the microwave band. They have the advantages of field confinement, field enhancement, and flexible and controllable dispersion. They are widely used in microwave devices and systems such as filters, couplers, amplifiers, frequency multipliers, and communication systems. By introducing adjustable elements such as PIN diodes and varactor diodes into artificial surface plasmon structures, subwavelength electromagnetic fields can be manipulated, that is, the amplitude and phase of electromagnetic waves can be manipulated, thereby realizing reconfigurable devices, circuits, and systems, greatly expanding the application of artificial surface plasmons in various devices and systems. However, the research on front-gate coupling suppression using the excellent physical properties of artificial surface plasmons is not sufficient at present, and has only been proven in principle, and cannot be directly applied to system applications and flexible and multifunctional scenarios such as phased array antennas and frequency hopping systems.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] The present invention provides a damage-resistant phased array antenna based on artificial surface plasmons, which can realize front-door coupling suppression of high-degree-of-freedom systems such as frequency hopping systems and enhance the damage protection capability of the phased array antenna.

[0007] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0008] According to a first aspect of the present invention, there is provided an artificial surface plasmon-based damage-resistant phased array antenna, comprising: a power divider, a plurality of artificial surface plasmon phase shifting channels connected to the power divider, and an artificial surface plasmon miniaturized Vivaldi antenna to which each artificial surface plasmon phase shifting channel is terminated;

[0009] The power divider divides the input radio frequency signal into first multiple-path signals with the same amplitude and phase, and the first multiple-path signals are respectively fed into multiple artificial surface plasmon shifting channels;

[0010] The multiple artificial surface plasmon phase shifting channels respectively regulate the fed signals and output second multiple signals with equal amplitudes and equally spaced gradient phase differences;

[0011] The second multi-path signals are respectively fed into the artificial surface plasmon miniaturized Vivaldi antennas respectively terminated by the multi-path artificial surface plasmon shifting channels to form a synthetic beam with a certain scanning angle.

[0012] In some exemplary embodiments, the power splitter is formed by cascading a plurality of one-to-two power splitters.

[0013] In some exemplary embodiments, the artificial surface plasmon shift channel is composed of a plurality of artificial surface plasmon adjustable units arranged in a transverse periodic manner.

[0014] In some exemplary embodiments, the top metal layer of the artificial surface plasmon adjustable unit is composed of a T-shaped metal patch and a concave metal patch nested together, and the top of the T-shaped patch is connected to the metal ground through a metal through-hole; two varactor diodes are introduced between the gap between the T-shaped metal patch and the concave metal patch to achieve real-time regulation of the electromagnetic properties.

[0015] In some exemplary embodiments, the artificial surface plasmon shift channel further includes a choke structure.

[0016] In some exemplary embodiments, the power divider, the multi-path artificial surface plasmon shifting channel and the choke structure are packaged in a metal packaging box.

[0017] In some exemplary embodiments, the artificial surface plasmon miniaturized Vivaldi antenna adopts a single-layer plate configuration, wherein the bottom metal layer is composed of a 50-ohm microstrip feed line and a fan-shaped patch, and the top metal layer is based on a gradient slot line expanded in an exponential curve, and an artificial surface plasmon comb structure is introduced at the edge of the gradient slot line and the metal parts on both sides of the structure.

[0018] According to a second aspect of the present invention, a real-time control method for electromagnetic characteristics of an anti-damage phased array antenna based on artificial surface plasmons is provided, characterized in that it includes:

[0019] By adjusting the capacitance value of the varactor diode, the amplitude and phase of the electromagnetic wave can be controlled, thereby achieving the reconfiguration and real-time control of the damage-resistant phased array antenna.

[0020] The damage-resistant phased array antenna based on artificial surface plasmon provided by the present invention utilizes the nonlinear dispersion and group velocity control characteristics of artificial surface plasmon to provide a solution for realizing the front-door coupling suppression of high-degree-of-freedom systems such as frequency hopping systems, and enhances the damage-resistant capability of the phased array antenna and the system without affecting the system's own functions and increasing the system's complexity and cost, thus reflecting the system-level application advantages of artificial surface plasmon. The advantages include the following:

[0021] 1. The nested artificial surface plasmon unit design proposed in the present invention improves the compactness of the structure, and introduces parallel varactor diodes to achieve unit loss reduction and real-time control of electromagnetic waves. The artificial surface plasmon phase shift channel realized after period extension achieves 360° continuous phase shift within the wide bandwidth range of the X-band.

[0022] 2. Compared with the traditional microstrip Vivaldi antenna under the same conditions, the artificial surface plasmon miniaturized Vivaldi antenna proposed in the present invention can achieve a 30.5% reduction in lateral size and a 41.9% increase in gain, thereby realizing efficient energy conversion between guided waves and space waves.

[0023] 3. The artificial surface plasmon-based phased array antenna implemented by the present invention can support a broadband frequency hopping system, and can realize beam scanning within a spatial range of -45° to 45° in the 8GHz to 11GHz frequency band, and simultaneously support high-power microwave interference pulse suppression.

[0024] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification are used to explain the principles of the present invention. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0026] Figure 1 A schematic diagram schematically illustrates an exemplary embodiment of an artificial surface plasmon-based anti-damage phased array antenna according to the present invention;

[0027] Figure 2 Schematic diagrams schematically showing a low-loss artificial surface plasmon tunable unit and simulation results of an exemplary embodiment of the present invention: (a) structural diagram; (b) equivalent circuit model; (c) dispersion curve; (d) group velocity curve.

[0028] Figure 3 Schematic diagrams schematically showing the phase shift channel and simulation results of the artificial surface plasmon of an exemplary embodiment of the present invention: (a) structural schematic diagram; (b) amplitude simulation results of scattering parameters; (c) phase simulation results of transmission coefficients; (d) measured phase shift results at different frequencies.

[0029] Figure 4Schematic diagrams schematically showing the artificial surface plasmon miniaturized Vivaldi antenna and simulation results of an exemplary embodiment of the present invention: (a) structural schematic diagram; (b) antenna H-plane radiation pattern at the center frequency of 9 GHz; (c) antenna E-plane radiation pattern at the center frequency of 9 GHz; (d) reflection coefficient; (e) gain curve.

[0030] Figure 5 Schematic diagrams showing a phased array antenna based on artificial surface plasmons and simulation results of an exemplary embodiment of the present invention: (a) structural schematic diagram; (b) feeding network structure diagram; (c) antenna beam scanning pattern at a center frequency of 9 GHz; (d) reflection coefficient at different scanning angles; (e) 8 GHz antenna beam scanning pattern; (f) 10 GHz antenna beam scanning pattern; (g) 11 GHz antenna beam scanning pattern.

[0031] Figure 6 The diagram schematically shows the measured results of time domain pulses of the phased array antenna based on artificial surface plasmon of an exemplary embodiment of the present invention: (a) the scanning angle is 0°, and a broadband modulated Gaussian pulse of 5-30 GHz is input; (b) the scanning angle is 30°, and a broadband modulated Gaussian pulse of 5-30 GHz is input; (c) the scanning angle is 0°, and a narrowband modulated Gaussian pulse of 8-9 GHz is input; (d) the scanning angle is 30°, and a broadband modulated Gaussian pulse of 5-30 GHz is input; (e) when the scanning angle is 0°, after inputting modulated Gaussian pulses of different frequencies and different bandwidths, the measured results of the peak pulse compression rate; (f) when the scanning angle is 30°, after inputting modulated Gaussian pulses of different frequencies and different bandwidths, the measured results of the peak pulse compression rate. DETAILED DESCRIPTION

[0032] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present invention will be more comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0033] In addition, the accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0034] In this example implementation, a damage-resistant phased array antenna based on artificial surface plasmons is provided. The nonlinear dispersion characteristics and group velocity control capability of artificial surface plasmons are utilized to achieve antenna damage protection without introducing additional designs and components, thereby solving the problem of weak front-door coupling protection capability. The damage protection capability of the phased array antenna and the effectiveness of the proposed method are verified.

[0035] The damage-resistant phased array antenna based on artificial surface plasmon includes: a power divider, a plurality of artificial surface plasmon phase-shifting channels connected to the power divider, and an artificial surface plasmon miniaturized Vivaldi antenna to which each artificial surface plasmon phase-shifting channel is terminated; the power divider divides the input radio frequency signal into a first plurality of signals with the same amplitude and phase, and the first plurality of signals are respectively fed into the plurality of artificial surface plasmon phase-shifting channels; the plurality of artificial surface plasmon phase-shifting channels respectively regulate the fed signals and output second plurality of signals with equal amplitudes and equally spaced gradient phase differences; the second plurality of signals are respectively fed into the artificial surface plasmon miniaturized Vivaldi antenna to which each artificial surface plasmon phase-shifting channel is terminated to form a synthetic beam with a certain scanning angle.

[0036] The damage-resistant phased array antenna based on artificial surface plasmons and applied to a frequency hopping system in this exemplary implementation will be described in more detail below with reference to the accompanying drawings and embodiments.

[0037] refer to Figure 1 The damage-resistant phased array antenna based on artificial surface plasmon shown in the figure includes a power divider, four artificial surface plasmon phase-shifting channels and artificial surface plasmon miniaturized Vivaldi antennas terminated by the four artificial surface plasmon phase-shifting channels, which supports the frequency hopping system. After the RF signal is input into the system, it is divided into four signals with the same amplitude and phase through the power divider, and respectively fed into four completely identical artificial surface plasmon phase-shifting channels. The four signals are respectively regulated by the phase shifting function of the artificial surface plasmon channel, so that the four signals with equal amplitude and equally spaced gradient phase difference are output. The phase difference is recorded as The phase difference of the feed can be changed in real time by adjusting the applied voltage of each artificial surface plasmon channel. In addition, the artificial surface plasmon phase shift channel is equivalent to the integration of the phase shifter and the feeding network in the traditional architecture. The terminated artificial surface plasmon Vivaldi antenna has the advantage of miniaturization, which improves the miniaturization and integration level of the phased array antenna.

[0038] Exemplarily, the power divider divides the radio frequency signal into four signals with the same amplitude and phase, and the power divider is formed by cascading three one-to-two power dividers.

[0039] In order to achieve low-loss and high-efficiency transmission of artificial surface plasmon modes, an artificial surface plasmon phase shifting channel was proposed as a key component for constructing a phased array antenna based on artificial surface plasmons.

[0040] For example, the specific structure of the artificial surface plasmon transfer channel is as follows: Figure 3 As shown in (a), it consists of n low-loss artificial surface plasmon adjustable units with a period of p arranged horizontally and periodically. Among them, n is related to the phase shifting ability of the designed artificial surface plasmon unit and the phased array scanning angle. According to the phased array scanning angle, the phase shifting channel needs to have the ability to shift the phase by how many degrees, and then divide this degree by the degree that each unit can shift the phase, which is the required number of units n.

[0041] Specifically, if the phased array requires the phase shift channel to have a 360-degree phase shift capability, and the unit we designed can shift the phase by 14.4 degrees at the center operating frequency, then 25 units are needed to cover the 360-degree phase shift, and n is at least 25.

[0042] In order to achieve low-loss and high-efficiency transmission of artificial surface plasmon modes, and to design and regulate the nonlinear dispersion and group velocity characteristics of artificial surface plasmons from the unit level, a low-loss artificial surface plasmon tunable unit is proposed.

[0043] An exemplary structural diagram of a low-loss artificial surface plasmon tunable unit is shown in FIG. Figure 2 As shown in (a). Compared with the traditional artificial surface plasmon unit, the nested structure design reduces the unit size in the vertical direction, and its compactness improves the miniaturization and integration of the artificial surface plasmon unit. Its top metal is composed of a T-shaped metal patch and a concave metal patch nested together, and the top of the T-shaped patch is connected to the metal ground through a metal through-hole with a diameter of 0.3 mm. The unit introduces two varactor diodes between the gaps of the two patches to achieve real-time regulation of electromagnetic properties. By adjusting the capacitance value C of the varactor diode, the artificial surface plasmon transmission structure can manipulate the electromagnetic field on a subwavelength scale, that is, control the amplitude and phase of the electromagnetic wave, thereby achieving reconfiguration and real-time regulation of devices, circuits and systems. The effectiveness of this control strategy was verified by the simulation software CST eigenmode solver, as shown in Figure 2As shown in (b), the dispersion curve of the artificial surface plasmon is a nonlinear curve that deviates from the light and gradually approaches a fixed cutoff frequency as the wave number increases. Keeping the structural parameters unchanged and only increasing the capacitance value C from 0.05pF to 0.2pF, the cutoff frequency of the low-loss artificial surface plasmon unit decreases from 18.9GHz to 12.3GHz. When the capacitance value C changes, the phase shift generated by the unit is

[0044]

[0045] Depend on Figure 2 (c) It can be obtained that, at a fixed operating frequency, when the capacitance value increases from C1 to C2, the low-loss artificial surface plasmon adjustable unit will produce a phase difference This phase shift capability can be used to construct an artificial surface plasmon phase shift channel to provide a phase difference between adjacent elements in a phased array to achieve beam scanning. Taking an artificial surface plasmon channel composed of 25 units as an example, when the phase difference That is, a phase shift function covering 360° can be achieved in the range of 5.5GHz to 12.3GHz.

[0046] According to the relationship between the dispersion curve and the guided wave group velocity, the change of group velocity with frequency when the capacitance value C changes is as follows: Figure 2 As shown in (d). It can be seen that when the capacitance value C of the varactor diode is fixed, as the frequency increases, the group velocity of electromagnetic wave transmission becomes slower and slower; and at the same frequency, by adjusting the external voltage of the varactor diode, the capacitance value C can be changed, and then the transmission speed of electromagnetic waves of different frequencies can be controlled in real time. This feature is not available in traditional transmission lines such as microstrip lines. At the same time, the inherent nonlinear dispersion and group velocity control characteristics of artificial surface plasmons make it inherently resistant to damage. In order to study its ability to suppress external high-power microwave pulses, we can take Gaussian pulses as an example for discussion. The Gaussian pulse can be regarded as a periodic signal with a pulse width much smaller than the period T. The frequency domain expression of the Gaussian pulse is:

[0047]

[0048] And the peak value P of the Gaussian pulse is equal to the sum of the amplitudes of all discrete frequency components, that is,

[0049]

[0050] Among them, σ is the variance of the Gaussian pulse, a i represents the amplitude of the ith frequency component. It can be seen that P is equal to the peak value of the superposition of different frequency components under any phase shift. When a Gaussian pulse is input into a transmission system with linear dispersion characteristics such as a traditional microstrip, after a period of time t0, different frequency components have the same phase shift e at the output end. -jkw0t0, where the wave number k is a constant in the linear dispersion system, ω0 = 2π / T. Therefore, after passing through the linear dispersion system, the peak value of the output time domain pulse remains unchanged in an ideal state.

[0051] However, unlike traditional systems with linear dispersion characteristics, artificial surface plasmons have nonlinear dispersion characteristics and low-pass characteristics. Ignoring the loss in its passband, its frequency response can be expressed as

[0052]

[0053] Therefore, after the Gaussian pulse passes through the artificial surface plasmon unit, the output signal spectrum can be expressed as

[0054]

[0055] At this time, the wave number k is a variable, and it can be obtained that different frequency components of the Gaussian pulse have different group velocities when passing through the artificial surface plasmon transmission structure. The higher the frequency, the slower the transmission speed, and it is cut off at a certain frequency, such as Figure 2 (d). Therefore, after a period of time t0, the peak values ​​of all different frequency components cannot be superimposed at the same time, that is, the same high peak effect as the input pulse cannot be formed. At this time, the output time domain pulse presents a tailing shape, and the peak value is reduced, which effectively realizes the high-power microwave pulse suppression with wide spectrum characteristics. In addition, when the capacitance value C increases, the group velocity of all frequency components decreases, and the cutoff frequency becomes lower, and the high-power microwave pulse suppression effect is further enhanced. Similar to the above analysis, if the input signal is a modulated Gaussian pulse, its spectrum shape is similar to the Gaussian pulse spectrum after the center frequency is shifted. After passing through the artificial surface plasmon transmission structure, the peak values ​​of different frequency components will still not be superimposed at the same time due to different group velocities, thereby achieving high-power microwave pulse suppression.

[0056] In summary, the nonlinear dispersion characteristics and group velocity control capabilities of the proposed low-loss artificial surface plasmon unit can achieve phase shifting and high-power microwave pulse suppression without introducing additional designs and components, and also lay the foundation for the subsequent design of damage-resistant phased array antennas based on artificial surface plasmons.

[0057] Based on the artificial surface plasmon phase shift channel composed of the above-mentioned low-loss artificial surface plasmon units, the capacitance value C can be adjusted by setting the external voltage of the varactor diode, thereby changing the wave number of the artificial surface plasmon wave at a fixed frequency, and the phase of the artificial surface plasmon phase shift channel can be controlled in real time. At the same time, since the capacitance value C of the varactor diode can be continuously changed, the phase of the artificial surface plasmon phase shift channel can be continuously changed from 0° to 360° in the entire X-band, which has higher accuracy than digital phase shifters and is suitable for broadband frequency hopping systems.

[0058] Selecting the central operating frequency as 9 GHz, and using the full-wave simulation software CST, we can obtain the simulation results of the scattering parameter amplitude of the artificial surface plasmon shift channel under different capacitance values ​​C, such as Figure 3 (b) It can be seen that within the working frequency band, the artificial surface plasmon shift channel has good transmission and reflection performance in different states, the reflection coefficient S11 is lower than -15dB at 9GHz, and the transmission coefficient S21 is higher than -3dB at 9GHz, which can ensure the normal transmission of electromagnetic energy. Figure 3 (c) shows the change of the phase of the transmission coefficient S21 with the capacitance value C. It can be seen that when the capacitance value changes continuously from 0.05pF to 0.117pF, the phase of the artificial surface plasmon phase shift channel changes continuously from 0° to 360°, achieving precise and flexible control of the electromagnetic wave phase. For further experimental verification, the artificial surface plasmon phase shift channel sample was prepared using PCB technology, and the scattering parameters of the sample were tested using a vector network analyzer. Figure 3 (d) shows the measured results of the phase shift of the artificial surface plasmon phase shift channel transmission coefficient S21 at different frequencies. It can be seen that as the control voltage continues to decrease, the artificial surface plasmon phase shift channel can achieve 360° phase shift in the entire X-band, proving that it can effectively support the operation of broadband frequency hopping systems.

[0059] In order to construct a phased array antenna based on artificial surface plasmons that supports a broadband frequency hopping system, in addition to proposing an artificial surface plasmon phase shifting channel for phase shifting and feeding, it is also necessary to design a broadband miniaturized antenna unit suitable for the phased array system to achieve efficient energy conversion between guided waves and space waves. The traditional microstrip Vivaldi antenna achieves effective radiation by gradually expanding the slot line according to a linear or exponential law. However, according to the traveling wave mechanism, the length of the antenna slot line usually needs to be greater than a full wavelength corresponding to the lowest operating frequency, and the opening width of the antenna slot line usually needs to be greater than half of the full wavelength corresponding to the lowest operating frequency. This size limits its structural design and makes it difficult to apply to scenarios such as highly integrated miniaturized systems.

[0060] In order to effectively reduce the size of the antenna while ensuring the unchanged electromagnetic properties such as gain and bandwidth, an artificial surface plasmon structure was introduced based on the traditional Vivaldi antenna to obtain an artificial surface plasmon miniaturized Vivaldi antenna.

[0061] For example, the structure of the artificial surface plasmon miniaturized Vivaldi antenna is as follows: Figure 4As shown in (a). A single-layer board configuration is adopted, and its bottom metal is composed of a 50-ohm microstrip feed line and a fan-shaped patch. The top metal is based on a gradient slot line that is expanded with an exponential curve. Artificial surface plasmon comb structures are introduced at the edge of the gradient slot line and the metal parts on both sides of the structure. Among them, since the artificial surface plasmon has slow-wave characteristics, its dispersion curve deviates from the light according to the law of nonlinear change. Therefore, when the electromagnetic wave travels in the propagation area of ​​the Vivaldi antenna, it has a larger phase shift and electrical length than traditional structures such as microstrip lines at the same frequency and the same physical scale. Therefore, the introduction of an artificial surface plasmon comb structure at the edge of the gradient slot line can compress the physical scale required by the traditional Vivaldi antenna and effectively realize the miniaturization of the Vivaldi antenna. At the same time, the gradient artificial surface plasmon comb structure design adopted in the metal parts on both sides of the structure can improve the directional radiation characteristics of the Vivaldi antenna within a certain frequency band, thereby improving the gain of the antenna.

[0062] The present invention utilizes the nonlinear dispersion characteristics of artificial surface plasmons without adding any additional components and integrates them into the phased array design. For example, artificial surface plasmon channels are used to replace traditional microstrip lines or waveguides, so that front-gate coupling suppression (anti-damage) can be achieved.

[0063] In order to verify the electromagnetic performance of the artificial surface plasmon miniaturized Vivaldi antenna and compare it with the traditional microstrip configuration Vivaldi antenna, full-wave simulation was performed using the commercial software Ansoft HFSS, and samples were prepared using PCB technology for experimental verification. The reflection coefficients of the two samples were measured using a vector network analyzer, and the results were as follows: Figure 4 (d) As shown. It can be seen that the artificial surface plasmon miniaturized Vivaldi antenna operates in the frequency band of 7.8GHz-10.9GHz, with a relative bandwidth of 34.4%, and has good reflection performance within the band. The radiation pattern and gain of the antenna sample were measured in a microwave darkroom, where the simulated and measured patterns of the H and E surfaces are shown in Figure 4 (bc) shows that the simulation and measured results of the gain are shown in Figure 4 (e) As shown. It can be seen that at the center frequency of 9GHz, the measured gain of the artificial surface plasmon miniaturized Vivaldi antenna is 6.1dB. According to the above simulation and measured results, under the same other conditions, the bandwidth and reflection coefficient of the artificial surface plasmon miniaturized Vivaldi antenna are basically the same as those of the traditional microstrip Vivaldi antenna, and the lateral size is reduced by 30.5%, and the gain is increased by 41.9%, which proves the excellent electromagnetic properties of the artificial surface plasmon miniaturized Vivaldi antenna.

[0064] The following is a beam scanning verification of the damage-resistant phased array antenna based on artificial surface plasmons:

[0065] Taking the one-dimensional four-element phased array antenna proposed in this embodiment as a prototype example, various parts are integrated to realize the phased array antenna based on artificial surface plasmon, and the beam scanning function is verified. The structural schematic diagram is shown in FIG. Figure 5 As shown in (a), in order to enhance the system stability and reduce the direct interference of external signals to the internal circuit, a corresponding metal packaging box is designed to improve the electromagnetic compatibility of the system. The terminal antenna is connected to the feeding network placed inside the metal packaging box through an SMA connector. The specific structure of the feeding network is as follows Figure 5 As shown in (b), it mainly consists of three parts: power divider, artificial surface plasmon shift channel and choke structure.

[0066] To avoid the formation of grating lobes, the spacing between the four antenna elements is set to 14 mm, that is, 0.42 center frequency working wavelength. When the beam scanning angles of the phased array antenna are 0°, ±15°, ±30°, and ±45°, respectively, the feeding phase difference of adjacent antenna units is They should be ±39.1°, ±75.6°, ±106.9°, and ±130.9°, respectively. In order to verify the electromagnetic performance of the phased array antenna based on artificial surface plasmons and compare it with the traditional microstrip phased array antenna, full-wave simulation was performed and samples were prepared using PCB process and cavity process for experimental verification. An antenna test system was built in a microwave darkroom environment to measure the electromagnetic performance of the two antenna samples, such as scattering parameters, radiation patterns, and gain. The sample to be tested was placed on a turntable that can rotate 180° and connected to port one of the vector network analyzer through a coaxial cable. The receiving horn antenna was placed in a position that meets the far-field test conditions and connected to port two of the vector network analyzer. At the same time, a voltage control module was used to set the applied voltage values ​​for different channels of the phased array antenna sample based on artificial surface plasmons. According to the phase difference calculated above, the external voltages of the four artificial surface plasmon shifting channels are all set to 4.92V, and the beam scanning angle of the phased array antenna based on artificial surface plasmon is 0°; the four external voltages are set to 3.25V, 3.69V, 4.22V, and 4.92V, respectively, and the beam scanning angle of the phased array antenna based on artificial surface plasmon is 15°; the four external voltages are set to 10.5V, 2.93V, 3.72V, and 4.92V, respectively, and the beam scanning angle of the phased array antenna based on artificial surface plasmon is 30°; the four external voltages are set to 4.33V, 8.15V, 3.12V, and 4.92V, respectively, and the beam scanning angle of the phased array antenna based on artificial surface plasmon is 45°. By applying the above voltages to the four artificial surface plasmon shift channels in reverse order, the beam scanning angles of the phased array antenna based on artificial surface plasmon can be controlled to be 0°, -15°, -30°, and -45° respectively.

[0067] The measured results of the normalized radiation pattern of the antenna are as follows: Figure 5 As shown in (c), it can be seen that at the center frequency of 9 GHz, the phased array antenna based on artificial surface plasmon can achieve beam scanning in the spatial range of -45° to 45°. The measured results of the reflection coefficient are shown in Figure 5 As shown in (d), it can be seen that the phased array antenna based on artificial surface plasmon has good reflection characteristics in the X-band broadband range and at different beam scanning angles, and the reflection coefficient can reach below -18dB at the center operating frequency of 9GHz. In order to verify the beam scanning capability of the phased array antenna based on artificial surface plasmon in a broadband range, Figure 5 (eg) The measured results of the phased array antenna radiation pattern at different frequencies are shown. It can be found that the phased array antenna based on artificial surface plasmon can achieve beam scanning in the range of -45° to 45° in the range of 8GHz-11GHz, proving that it can effectively support the operation of broadband frequency hopping system.

[0068] The following is the front-door coupling suppression verification of the damage-resistant phased array antenna based on artificial surface plasmon:

[0069] The nonlinear dispersion characteristics and group velocity control capabilities enable the artificial surface plasmon phase shifting channel to have the ability to suppress time-domain pulse peaks on the basis of phase shifting capabilities. Based on the analysis of the dispersion design and group velocity control of the low-loss artificial surface plasmon unit, the nonlinear dispersion of the artificial surface plasmon makes it impossible for the peaks of all different frequency components of the high-power microwave pulse to be superimposed at the same time after passing through the system, that is, it is impossible to form the same high peak effect as the input pulse. At this time, the output time domain pulse presents a tailing shape and the peak value is reduced, which effectively realizes the suppression of high-power microwave pulses with wide spectrum characteristics and greatly improves the channel's anti-damage capability.

[0070] On this basis, the present invention verifies the damage resistance of the phased array antenna based on artificial surface plasmons. Figure 6 (ab) shows the measured results of the output time domain pulses of the traditional microstrip phased array antenna and the phased array antenna based on artificial surface plasmon when the antenna scanning angle is 0° and 30° respectively, after the input frequency is 5-30GHz and the pulse peak is 1V. It can be found that when the antenna scanning angle is 0°, the output time domain signal peaks are 1.99×10 -4 V and 0.55×10 -4 V; when the antenna scanning angle is 30°, the output time domain signal peaks are 1.74×10 -4 V and 0.46×10 -4V. The above results fully demonstrate the ability of the artificial surface plasmon-based phased array antenna to suppress and control typical high-power microwave pulses. In addition, Figure 6 (cd) shows the measured results of the output time domain pulses of the traditional microstrip phased array antenna and the phased array antenna based on artificial surface plasmon when the antenna scanning angle is 0° and 30° respectively, after the input frequency is 8-9GHz and the pulse peak is 1V. The waveforms of the output pulses are similar, and no obvious distortion occurs. When the antenna scanning angle is 0°, the output time domain signal peaks are 9.59×10 -4 V and 8.81×10 -4 V; when the antenna scanning angle is 30°, the output time domain signal peaks are 10.71×10 -4 V and 8.65×10 -4 The above results show that the phased array antenna based on artificial surface plasmon has a good suppression effect on broadband damage pulses, and the envelope of the received narrowband working signal remains basically unchanged with only a slight decrease in the peak value.

[0071] In order to quantitatively reflect the suppression effect of different channels on high-power microwave pulses, the time domain pulse peak value P of the output channel after the same signal is input through the artificial surface plasmon shift is calculated. SPP The peak value of the time domain pulse P output through the microstrip channel with the same conditions MS The ratio of is defined as the peak compression ratio η, that is,

[0072]

[0073] According to the definition in the above formula, the peak compression rate η can be used to quantitatively describe the suppression effect of the phased array antenna based on artificial surface plasmon on high-power microwave pulses. Figure 6(ef) shows the peak compression rate of the phased array antenna based on artificial surface plasmon after inputting modulated Gaussian pulses of different frequencies and bandwidths when the antenna scanning angles are 0° and 30°, respectively. The horizontal and vertical axes represent the upper and lower edges of the modulated Gaussian pulse frequency band, and the colors represent the values ​​of the peak compression rate. It can be seen that when any modulated Gaussian pulse is input, the peak compression rate η of the phased array antenna based on artificial surface plasmon is less than 1, and the wider the bandwidth and the higher the center frequency, the lower the peak compression rate. At the same time, after inputting a modulated Gaussian pulse with a low frequency greater than 15 GHz, the peak compression rate of the phased array antenna based on artificial surface plasmon is less than 0.1, which can be regarded as completely suppressing the external damage pulse. This result proves from the system level the effectiveness of using the nonlinear dispersion characteristics and group velocity control capability of artificial surface plasmons to simultaneously achieve beam scanning and high-power microwave pulse peak suppression. It provides an effective solution for reducing the front-door coupling of high-flexibility and high-complexity systems such as phased array antennas and frequency-hopping systems without affecting the functions of the active link itself and without increasing the system complexity and cost.

[0074] It should be noted that the above figures are only schematic illustrations of the processes included in the exemplary embodiments of the present invention, and are not intended to be limiting. In addition, it is also easy to understand that these processes can be executed synchronously or asynchronously in multiple modules, for example.

[0075] Other embodiments of the invention will readily occur to those skilled in the art after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0076] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A damage-resistant phased array antenna based on artificial surface plasmons, characterized in that: include: A power divider, a plurality of artificial surface plasmon phase shifting channels connected to the power divider, and an artificial surface plasmon miniaturized Vivaldi antenna terminated by each artificial surface plasmon phase shifting channel; The power divider divides the input radio frequency signal into first multiple-path signals with the same amplitude and phase, and the first multiple-path signals are respectively fed into multiple artificial surface plasmon shifting channels; The multiple artificial surface plasmon phase shifting channels respectively regulate the fed signals and output second multiple signals with equal amplitudes and equally spaced gradient phase differences; The second multi-path signals are respectively fed into the artificial surface plasmon miniaturized Vivaldi antennas respectively terminated by the multi-path artificial surface plasmon shifting channels to form a synthetic beam with a certain scanning angle.

2. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 1, characterized in that: The power divider is formed by cascading a plurality of one-to-two power dividers.

3. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 1, characterized in that: The artificial surface plasmon shift channel is composed of a plurality of artificial surface plasmon adjustable units arranged laterally and periodically.

4. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 3, characterized in that: The top metal layer of the artificial surface plasmon adjustable unit is composed of a T-shaped metal patch and a concave metal patch nested together, and the top of the T-shaped patch is connected to the metal ground through a metal through-hole; Two varactor diodes are introduced between the gap between the T-shaped metal patch and the concave metal patch to achieve real-time regulation of electromagnetic properties.

5. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 3 or 4, characterized in that: The artificial surface plasmon transfer channel also includes a choke structure.

6. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 5, characterized in that: The power divider, the multi-path artificial surface plasmon shifting channels and the choke structure are packaged in a metal packaging box.

7. The damage-resistant phased array antenna based on artificial surface plasmon according to claim 1, characterized in that: The artificial surface plasmon miniaturized Vivaldi antenna adopts a single-layer plate configuration, wherein the bottom metal layer is composed of a 50-ohm microstrip feed line and a fan-shaped patch, and the top metal layer is based on a gradient slot line expanded in an exponential curve, and an artificial surface plasmon comb structure is introduced at the edge of the gradient slot line and the metal parts on both sides of the structure.

8. A real-time control method for electromagnetic characteristics of an anti-damage phased array antenna based on artificial surface plasmons, characterized in that: include: By adjusting the capacitance value of the varactor diode, the amplitude and phase of the electromagnetic wave can be controlled, thereby achieving the reconfiguration and real-time control of the damage-resistant phased array antenna.

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