Harmonic amplitude frequency modulator based on artificial surface plasmons

Abstract

The application discloses a kind of harmonic amplitude frequency modulators based on artificial surface plasmon, belong to novel microwave device field, by metal backplate, upper layer metal structure and separate dielectric layer constitute, upper layer metal structure is by the periodic arrangement of artificial surface plasmon unit structure loaded with PIN tube into time domain coding artificial surface plasmon waveguide, transition structure being arranged at the two ends of the time domain coding artificial surface plasmon waveguide, and high-frequency isolation structure of connection control signal composition, by controlling the period and duty cycle of the square wave signal, the frequency and amplitude adjustment of output harmonic signal are carried out, and 0 order harmonic is filtered out, the application has the amplitude frequency of output harmonic signal adjustable, can filter out 0 order harmonic, with the advantages of easy processing, small size and low cost.

Description

Technical Field

[0001] This invention relates to the field of novel microwave device technology, and in particular to a harmonic amplitude-frequency modulator based on artificial surface plasmons. Background Technology

[0002] As an important branch of metamaterials, surface plasmon polaritons (SSPPs) have been proposed to manipulate the response of surface electromagnetic waves at low frequencies. Due to their unique strong field confinement and field enhancement properties, SSPPs have found widespread application in novel waveguides. Artificial structures supporting SSPPs can adjust their dispersion relation by changing the geometric parameters of the structural units, thus providing an effective means for customized design. In traditional information systems, the signal spectrum is fixed, making it difficult to meet the growing demands for intelligence and diversity. Programmable spectrum is a technology that allows the signal spectrum to be switched to different modes as needed. Through spectrum programming, signal frequency components can be flexibly allocated according to the user's wishes, providing an effective solution for fully utilizing spectrum resources. Advances in metamaterials have provided unprecedented degrees of freedom for manipulating electromagnetic waves at subwavelength scales, resulting in significantly enhanced nonlinearity and thus offering the possibility of controlling intensity, phase, and polarization. In particular, the concept of time-domain coding has been proposed, opening a new avenue for generating and controlling nonlinear responses in free space. With the increasing demands of intelligent information systems, high-density array systems are an important potential application scenario for programmable spectrum technology. However, in high-density array scenarios, current time-domain coding materials are not suitable for widespread use due to their size limitations. Therefore, seeking the integration of time-domain coding technology and high-density array schemes will become the focus of research. Summary of the Invention

[0003] This invention provides a harmonic amplitude-frequency modulator based on artificial surface plasmons. The modulator uses time-domain coding and generates customized harmonic signals by adjusting the period and duty cycle of the control signal when the control signal is a square wave. This makes the amplitude and frequency of the output harmonic signal adjustable, and can filter out the 0th order harmonic. It also has the advantages of being easy to manufacture, small in size and low in cost.

[0004] This invention provides a harmonic amplitude-frequency modulator based on artificial surface plasmons.

[0005] From bottom to top, it includes: a metal backplate, a separating dielectric layer, and an upper metal structure;

[0006] The upper metal structure comprises a time-domain encoded artificial surface plasmon waveguide formed by periodically arranging artificial surface plasmon units loaded with PIN diodes, a transition structure disposed at both ends of the time-domain encoded artificial surface plasmon waveguide, and a high-frequency isolation structure for connecting control signals.

[0007] In an artificial surface plasmon unit structure loaded with PIN tubes, one end of the PIN tube is connected to a central metal guide strip, and the other end is connected to a metal rack. The metal rack is provided with metal through holes, and the metal rack is connected to the metal back plate through the metal through holes.

[0008] The transition structure is used to transition the input signal to the time-domain coded artificial surface plasmon waveguide. The transition structure is designed with a gradually changing metal slot length. The closer to the time-domain coded artificial surface plasmon waveguide, the longer the metal slot; the farther away from the time-domain coded artificial surface plasmon waveguide, the shorter the metal slot depth.

[0009] The high-frequency isolation structure is connected to the center of the central metal conductor of the time-domain encoded artificial surface plasmon waveguide to provide a control signal. The control signal is a square wave signal. By controlling the period and duty cycle of the square wave signal, the frequency and amplitude of the output harmonic signal are adjusted, and the 0th order harmonic is filtered out.

[0010] In one embodiment of the present invention, frequency adjustment of the output harmonic signal by controlling the period of the square wave signal includes:

[0011] A square wave signal is applied to both ends of the PIN diode. The frequency of the output harmonic signal is different depending on the period of the square wave signal. The first harmonic frequency of the output harmonic signal is the sum of the fundamental frequency and the frequency of the applied square wave signal. By adjusting the period of the square wave signal at both ends of the PIN diode, the first harmonic frequency of the output harmonic signal can be dynamically controlled.

[0012] In one embodiment of the present invention, adjusting the amplitude of the output harmonic signal by controlling the duty cycle of the square wave signal includes:

[0013] A square wave signal is applied to both ends of the PIN diode. The amplitude of the output harmonic signal varies depending on the duty cycle of the square wave signal. When the duty cycle is 0, the amplitude of the output harmonic signal is the largest. The smaller the duty cycle, the smaller the amplitude of the output harmonic signal. By adjusting the duty cycle of the square wave signal at both ends of the PIN diode, the amplitude of the output harmonic signal can be dynamically controlled.

[0014] In one embodiment of the present invention, the high-frequency isolation structure is composed of a metal sheet and a metal wire.

[0015] In one embodiment of the present invention, the metal sheet is square with a side length of one-quarter wavelength.

[0016] In one embodiment of the present invention, the width of the metal wire is 0.2 mm.

[0017] The harmonic amplitude-frequency modulator based on artificial surface plasmons in this invention has the following beneficial effects:

[0018] 1. This invention is characterized by its simplicity in manufacturing and ease of processing. By adjusting the geometric dimensions of the basic structural units of the artificial surface plasmon material, the dispersion characteristics of the material can be adjusted, simplifying the design of the modulator. Furthermore, the modulator is composed of a series of basic units of the artificial surface plasmon material, making it easy to process.

[0019] 2. This invention features adjustable amplitude and frequency of the output harmonic signal. In this invention, the frequency and amplitude of the output harmonic signal can be modulated by changing the period and duty cycle of the control signal;

[0020] 3. This invention has the function of simultaneously filtering out the 0th harmonic. In this invention, by designing the parameters of the time-domain encoded SSPP waveguide unit, a 180° phase difference of the 0th harmonic can be achieved in both on and off states, thereby filtering out the 0th harmonic.

[0021] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of a harmonic amplitude-frequency modulator based on artificial surface plasmons according to an embodiment of the present invention;

[0024] Figure 2 This is a side cross-sectional view of a harmonic amplitude-frequency modulator based on artificial surface plasmons provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram illustrating the harmonic variations resulting from changing the frequency of a control signal according to an embodiment of the present invention. Figure 3 (a) is the input signal, (b)(c)(d) are the control signals, and (e)(f)(g) are the output signals.

[0026] Figure 4 To illustrate the harmonic variations resulting from changing the duty cycle of the control signal according to an embodiment of the present invention, Figure 4 (a)(c)(e)(g)(i) are control signals, (b)(d)(f)(h)(j) are output signals, (k) is input signal, and (l) is a comparison diagram of amplification effect and duty cycle change;

[0027] Figure 5 This is a schematic diagram of the function of filtering out the 0th harmonic according to an embodiment of the present invention, wherein (a) of 5 is the input signal, (b)(c)(d) are control signals, and (e)(f)(g) are output signals. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] like Figure 1 and Figure 2 As shown, the harmonic amplitude-frequency modulator based on artificial surface plasmons comprises, from bottom to top: a metal backplate, a separating dielectric layer, and an upper metal structure.

[0030] The upper metal structure consists of a time-domain encoded artificial surface plasmon waveguide formed by periodically arranging artificial surface plasmon units loaded with PIN diodes, a transition structure disposed at both ends of the time-domain encoded artificial surface plasmon waveguide, and a high-frequency isolation structure for connecting control signals.

[0031] In an artificial surface plasmon unit structure loaded with PIN tubes, one end of the PIN tube is connected to a central metal guide strip, and the other end is connected to a metal rack. The metal rack is provided with metal through holes, and the metal rack is connected to the metal back plate through the metal through holes.

[0032] The transition structure is used to transition the input signal to the time-domain coded artificial surface plasmon waveguide. The transition structure is designed with a gradually changing metal slot length. The closer to the time-domain coded artificial surface plasmon waveguide, the longer the metal slot; the farther away from the time-domain coded artificial surface plasmon waveguide, the shorter the metal slot depth.

[0033] The high-frequency isolation structure is connected to the center of the central metal conductor of the time-domain encoded artificial surface plasmon waveguide to provide a control signal. The control signal is a square wave signal. By controlling the period and duty cycle of the square wave signal, the frequency and amplitude of the output harmonic signal are adjusted, and the 0th harmonic is filtered out.

[0034] In one embodiment of the present invention, the high-frequency isolation structure serves to prevent high-frequency signals from leaking from the port. The high-frequency isolation structure is composed of a metal sheet and a metal wire, with the metal sheet acting as a distributed capacitor.

[0035] In one embodiment of the present invention, the metal sheet is square with a side length of one-quarter wavelength (corresponding to the operating frequency).

[0036] In one embodiment of the present invention, the metal wire serves as a DC power supply path, and the wire width is generally designed to be about 0.2 mm.

[0037] It is understandable that the transition result is connected to the input signal, and the input signal is controlled by the control signal.

[0038] In an embodiment of the present invention, frequency adjustment of the output harmonic signal by controlling the period of the square wave signal includes: applying a square wave signal to both ends of the PIN diode; different periods of the square wave signal result in different frequencies of the output harmonic signal; the first harmonic frequency of the output harmonic signal is the sum of the fundamental frequency and the frequency of the applied square wave signal; and by adjusting the period of the square wave signal at both ends of the PIN diode, dynamic control of the first harmonic frequency of the output harmonic signal is achieved.

[0039] It is understandable that when a square wave signal is applied across the two ends of a PIN diode, different periods of the square wave signal will result in different frequencies of the output harmonic signals; for example... Figure 3 As shown, when a square wave signal of 0.05 GHz is applied, the first harmonic of the output signal is 5.05 GHz (fundamental frequency is 5 GHz); when a square wave signal of 0.08 GHz is applied, the first harmonic of the output signal is 5.08 GHz; and when a square wave signal of 0.1 GHz is applied, the first harmonic of the output signal is 5.1 GHz. It can be seen that the first harmonic frequency of the output signal is the sum of the fundamental frequency and the applied square wave frequency. Therefore, the first harmonic frequency of the output signal can be dynamically controlled by adjusting the period of the square wave signal across the diode.

[0040] In an embodiment of the present invention, the amplitude adjustment of the output harmonic signal by controlling the duty cycle of the square wave signal includes: applying a square wave signal to both ends of the PIN diode; different duty cycles of the square wave signal result in different amplitudes of the output harmonic signal; when the duty cycle is 0, the amplitude of the output harmonic signal is the largest; the smaller the duty cycle, the smaller the amplitude of the output harmonic signal; by adjusting the duty cycle of the square wave signal at both ends of the PIN diode, dynamic control of the output harmonic amplitude is achieved.

[0041] It is understandable that when a square wave signal is applied to both ends of a PIN diode, different duty cycles of the square wave signal will result in different amplitudes of the output harmonic signals. For example... Figure 4 As shown, the output signal amplitude is at its maximum when the duty cycle is 0, and the smaller the duty cycle, the smaller the output signal amplitude. Therefore, the output harmonic amplitude can be dynamically controlled by adjusting the duty cycle of the square wave signal at both ends of the PIN diode.

[0042] The modulator in this embodiment of the invention can also filter out the 0th harmonic. Specifically, when the PIN diode of the artificial surface plasmon structure is in both the "on" and "off" states, the phase state of its transmitted signal is exactly opposite. Based on this characteristic, when a square wave signal is applied across the PIN diode, the fundamental frequency of the output signal will be eliminated. Figure 5 As shown. This is because the two artificial surface plasmon units are exactly out of phase and are constantly switching between the two states under the control of a square wave signal, thus canceling out the fundamental frequency signal.

[0043] Based on the above introduction, Figure 2 It describes the variation of the output harmonic signal as the control signal frequency changes. From Figure 2 It can be seen that when the control signal frequency changes from 50MHz to 100MHz, the output signal spectrum will also generate a first harmonic with a difference of 50MHz to 100MHz symmetrically around the 0th harmonic. Figure 3 It can be seen that changing the duty cycle of the control signal from 20% to 88% monotonically reduces the amplitude of the 0th harmonic of the output signal from -15.7dBm to -35dBm. This demonstrates that the present invention can achieve amplitude and frequency modulation of the output signal. By designing the dimensions of the time-domain encoded SSPP waveguide unit, each unit generates a phase difference of Δk in both on and off states. Furthermore, by designing the number of periods n, the entire time-domain encoded SSPP waveguide segment generates a phase difference of Δk*n = 180° in both on and off states. Therefore, based on the Fourier transform equation of the input signal, control signal, and output signal, the 0th harmonic can be filtered out. Figure 4 As can be seen, control signals of different frequencies can all achieve the filtering of the 0th harmonic.

[0044] The harmonic amplitude-frequency modulator based on artificial surface plasmons proposed in this embodiment of the invention applies time-domain coding. When the control signal is a square wave, a customized harmonic signal is generated by adjusting the period and duty cycle of the control signal, so that the amplitude and frequency of the output harmonic signal can be adjusted. It can filter out the 0th order harmonic and has the advantages of easy processing, small size and low cost.

[0045] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A harmonic amplitude-frequency modulator based on artificial surface plasmons, characterized in that, From bottom to top, it includes: a metal backplate, a separating dielectric layer, and an upper metal structure; The upper metal structure comprises a time-domain encoded artificial surface plasmon waveguide formed by periodically arranging artificial surface plasmon units loaded with PIN diodes, a transition structure disposed at both ends of the time-domain encoded artificial surface plasmon waveguide, and a high-frequency isolation structure for connecting control signals. In an artificial surface plasmon unit structure loaded with PIN tubes, one end of the PIN tube is connected to a central metal guide strip, and the other end is connected to a metal rack. The metal rack is provided with metal through holes, and the metal rack is connected to the metal back plate through the metal through holes. The transition structure is used to transition the input signal to the time-domain coded artificial surface plasmon waveguide. The transition structure is designed with a gradually changing metal slot length. The closer to the time-domain coded artificial surface plasmon waveguide, the longer the metal slot; the farther away from the time-domain coded artificial surface plasmon waveguide, the shorter the metal slot depth. The high-frequency isolation structure is connected to the center of the central metal conductor of the time-domain encoded artificial surface plasmon waveguide to provide a control signal. The control signal is a square wave signal. By controlling the period and duty cycle of the square wave signal, the frequency and amplitude of the output harmonic signal are adjusted, and the 0th order harmonic is filtered out.

2. The harmonic amplitude-frequency modulator based on artificial surface plasmons according to claim 1, characterized in that, Frequency adjustment of the output harmonic signal by controlling the period of the square wave signal includes: A square wave signal is applied to both ends of the PIN diode. The frequency of the output harmonic signal is different depending on the period of the square wave signal. The first harmonic frequency of the output harmonic signal is the sum of the fundamental frequency and the frequency of the applied square wave signal. By adjusting the period of the square wave signal at both ends of the PIN diode, the first harmonic frequency of the output harmonic signal can be dynamically controlled.

3. The harmonic amplitude-frequency modulator based on artificial surface plasmons according to claim 1, characterized in that, The amplitude adjustment of the output harmonic signal by controlling the duty cycle of the square wave signal includes: A square wave signal is applied to both ends of the PIN diode. The amplitude of the output harmonic signal varies depending on the duty cycle of the square wave signal. When the duty cycle is 0, the amplitude of the output harmonic signal is the largest. The smaller the duty cycle, the smaller the amplitude of the output harmonic signal. By adjusting the duty cycle of the square wave signal at both ends of the PIN diode, the amplitude of the output harmonic signal can be dynamically controlled.

4. The harmonic amplitude-frequency modulator based on artificial surface plasmons according to claim 1, characterized in that, The high-frequency isolation structure consists of metal sheets and metal wires.

5. The harmonic amplitude-frequency modulator based on artificial surface plasmons according to claim 4, characterized in that, The metal sheet is square, with a side length of one-quarter wavelength.

6. The harmonic amplitude-frequency modulator based on artificial surface plasmons according to claim 4, characterized in that, The width of the metal wire is 0.2 mm.

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