阅读说明：本技术 一种基于超材料结构的太赫兹双面二倍频器件 (Terahertz double-sided frequency doubler based on metamaterial structure ) 是由 董亚洲 张雅鑫 杨自强 梁华杰 寇伟 梁士雄 于 2020-08-17 设计创作，主要内容包括：本发明属于太赫兹器件技术领域,涉及一种太赫兹偶次倍频器,具体为一种基于超材料结构的太赫兹双面二倍频器件。本发明通过在悬置微带的基板底部设置了开口金属环结构,由于开口环在肖特基二极管处位置有一个电场汇聚的作用,使得能量能更好的馈入肖特基二极管,提高了太赫兹波的利用效率,增加了整体的电路性能,增加了整体倍频器的倍频效率及输出功率。(The invention belongs to the technical field of terahertz devices, relates to a terahertz even-order frequency multiplier, and particularly relates to a terahertz double-sided frequency doubler based on a metamaterial structure. According to the invention, the open metal ring structure is arranged at the bottom of the substrate of the suspension microstrip, and the split ring has an electric field convergence effect at the Schottky diode, so that energy can be better fed into the Schottky diode, the utilization efficiency of terahertz waves is improved, the overall circuit performance is increased, and the frequency doubling efficiency and the output power of the overall frequency multiplier are increased.)

1. The utility model provides a terahertz is two-sided two frequency doublers now based on metamaterial structure which characterized in that: the terahertz frequency doubling circuit comprises an input end waveguide, an output end microstrip waveguide transition, a split ring structure and a terahertz frequency doubling circuit;

the input end waveguide is of a two-section structure, one section is a standard WR-10 waveguide input, the other section is an input height reducing waveguide, the last stage of the input height reducing waveguide is a first short circuit surface, and the standard WR-10 waveguide is sequentially connected with the input height reducing waveguide and the suspension micro-strip; the electromagnetic wave mode input by the standard waveguide is a TE10 mode, and the input matching is carried out by changing the length of the input height-reducing waveguide and the distance from the first short-circuit surface to the diode, so that energy is converged into the diode.

The output end microstrip waveguide is in a two-section structure in a transition mode, and comprises a section of standard WR-5 waveguide, the other section of the standard WR-5 waveguide is an output height reducing waveguide, and the last stage of the output height reducing waveguide is a second short circuit surface; and the output end microstrip waveguide is used for transiting quasi-TEM second harmonic generated by the Schottky diode and transmitted by the terahertz frequency doubling circuit to be converted into a TE10 mode for output.

The terahertz frequency doubling circuit comprises a suspension microstrip, a Schottky diode, an output matching circuit, a quarter matching transition and a high-low impedance filter which are connected in sequence;

the Schottky diode passes through a subsequent output matching circuit, and unnecessary higher harmonics generated by the Schottky diode are reflected, so that required second harmonics are obtained;

the quarter matching transition is a connecting part for connecting the output matching circuit and the output end microstrip waveguide transition, is of a multi-branch structure, and has the length of one quarter of the wavelength;

the high-low impedance filter is connected with the output height-reducing waveguide and is used for direct current feed, and meanwhile, generated second harmonic energy is prevented from leaking through a direct current end, so that the energy is transitionally output through the output end microstrip waveguide.

The split ring structure is a metal split resonant ring and is arranged on the back of the substrate of the suspension microstrip, an opening of the split ring structure is positioned under the Schottky diode, and the opening part is fully covered by the projection of the Schottky diode on the substrate; the open ring structure resonates with an input electromagnetic wave, and the input electromagnetic wave converges at the opening of the ring.

2. The terahertz double-sided frequency doubler based on the metamaterial structure as claimed in claim 1, wherein: the terahertz frequency doubling circuit uses a quartz substrate.

3. The terahertz double-sided frequency doubler based on the metamaterial structure as claimed in claim 1, wherein: the Schottky diode is a planar Schottky diode.

4. The terahertz double-sided frequency doubler based on the metamaterial structure as claimed in claim 1, wherein: the structure of the high-low impedance filter is a sixth-order high-low impedance low-pass filter.

5. The terahertz double-sided frequency doubler based on the metamaterial structure as claimed in claim 1, wherein: the open ring structure is an open circular ring.

6. The terahertz double-sided frequency doubler based on the metamaterial structure as claimed in claim 1, wherein: a balanced structure is adopted.

Technical Field

The invention belongs to the technical field of terahertz devices, relates to a terahertz even-order frequency multiplier, and particularly relates to a terahertz double-sided frequency doubler based on a metamaterial structure.

Background

An electromagnetic wave having a frequency in the range of 0.1 to 10THz is generally defined as a terahertz wave (THz wave) which is intermediate between a millimeter wave and infrared light, in a transition region from electronics to optics. The THz wave occupies a special position in an electromagnetic wave spectrum, has the characteristics of high frequency, wide bandwidth, good safety and the like, and is widely applied to security inspection, communication, radar and radio astronomy. Because the frequency of the terahertz wave is high, in order to obtain a stable and reliable signal source, the terahertz wave is often obtained by using a frequency doubling method, and the process is usually realized by a frequency multiplier.

The traditional frequency multiplier realizes the introduction of terahertz waves into a terahertz circuit through the transition of a microstrip probe after fundamental waves are transmitted through a standard rectangular waveguide, the traditional terahertz circuit is matched with a radio frequency circuit from a circuit angle, energy analysis is not carried out from a field angle, the working characteristics of a diode cannot be completely achieved, and the working efficiency and the output power of the frequency multiplier are lower.

Disclosure of Invention

Aiming at the problems or the defects, the invention provides a terahertz double-sided frequency doubler based on a metamaterial structure, which aims to solve the problems of low working efficiency and low output power of the existing terahertz frequency doubler.

A split ring is additionally arranged at a Schottky diode at the bottom of a dielectric substrate of the terahertz double-sided frequency doubling device based on the metamaterial structure, and the ring can concentrate an electric field of a working frequency band at the center of the diode, so that more energy can be fed into the diode, and the diode can work in a better state.

For frequency multipliers, the input signal is a sinusoidal signal v_in＝V₀cosw₀t, output current of

According to the formula, the output signal contains a large amount of harmonic components and direct current components, and after the output circuit is matched, the required signal can be filtered out by adding a circuit structure such as a filter and the like, and the unnecessary signal is reflected, so that the efficiency is increased.

A terahertz double-sided frequency doubling device based on a metamaterial structure comprises an input end waveguide, an output end microstrip waveguide transition, a split ring structure and a terahertz frequency doubling circuit;

the input end waveguide is of a two-section structure, one section is a standard WR-10 waveguide input, the other section is an input height reducing waveguide, the last stage of the input height reducing waveguide is a first short circuit surface, and the standard WR-10 waveguide is sequentially connected with the input height reducing waveguide and the suspension micro-strip. The electromagnetic wave mode input by the standard waveguide is a TE10 mode, and the input matching is carried out by changing the length of the input height-reducing waveguide and the distance from the first short-circuit surface to the diode, so that energy can be better converged into the diode.

The output end microstrip waveguide is in a two-section structure in transition mode and comprises a section of standard WR-5 waveguide, the other section of standard WR-5 waveguide is an output height reducing waveguide, and the last stage of the output height reducing waveguide is a second short circuit surface. And the output end microstrip waveguide is used for transiting quasi-TEM second harmonic generated by the Schottky diode and transmitted by the terahertz frequency doubling circuit to be converted into a TE10 mode for output.

The terahertz frequency doubling circuit comprises a suspension microstrip, a Schottky diode, an output matching circuit, a quarter matching transition and a high-low impedance filter which are connected in sequence.

The suspension microstrip has the advantages of small transmission loss, weak dispersion characteristic, wide frequency band range and large impedance range, good heat dissipation performance and low requirement on manufacturing tolerance, and is a good choice for hybrid and monolithic integrated circuits.

The Schottky diode is a Schottky diode, the most obvious characteristic of the Schottky diode is that reverse recovery time is extremely short, the Schottky diode is particularly suitable for high-frequency application, meanwhile, by utilizing the nonlinear effect of the diode, when fundamental waves enter the Schottky diode through an input end waveguide, the Schottky diode can generate multiple harmonics, unnecessary higher harmonics generated by the Schottky diode are reflected through a subsequent output matching circuit, and therefore the required second harmonics are obtained.

The quarter matching transition is a connecting part for connecting the output matching circuit and the output end microstrip waveguide transition. The part is a multi-branch structure, the length of the part is one fourth of the wavelength, the terahertz wave reflection can be caused because the suspended micro-strip is directly connected by branches with different impedances, the bandwidth can be expanded and the reflection can be reduced by utilizing the one fourth micro-strip transition structure, and the circuit matching effect is good.

The high-low impedance filter is connected with an output height-reducing waveguide, and the high-low impedance filter is mainly used for direct current feed, and simultaneously prevents generated second harmonic energy from leaking through a direct current end, so that the energy is transitionally output through the output end microstrip waveguide.

The split ring structure is a metal split type split resonant ring, the split type split resonant ring is arranged on the back of a substrate of the suspension microstrip, the split position of the split type split resonant ring is located under the Schottky diode, the split part is fully covered by the projection of the Schottky diode on the substrate, the electric field in the input height-reducing waveguide is in a TE10 mode, the direction of the electric field is perpendicular to the split position of the split type resonant ring, the size of the split type. The expression of power is P ═ U²It is clear that the power can be increased significantly when the electric field U is increased.

Furthermore, the terahertz frequency doubling circuit uses a quartz substrate.

Further, the schottky diode is a planar schottky diode.

Furthermore, the frequency multiplier uses a balanced structure, the structure can not generate third harmonic, so that a filter circuit of the third harmonic is not needed to be designed, the circuit size of the terahertz frequency multiplier is reduced due to the characteristic, and the internal loss of the circuit is favorably reduced.

In summary, the open metal ring structure is arranged at the bottom of the substrate of the suspended microstrip, and the split ring has an electric field convergence effect at the schottky diode, so that energy can be better fed into the schottky diode, the utilization efficiency of terahertz waves is improved, the overall circuit performance is improved, and the frequency doubling efficiency and the output power of the overall frequency multiplier are increased.

Drawings

FIG. 1 is a schematic diagram of an electric field distribution of an embodiment in a split-ring structure;

FIG. 2 is a schematic circuit diagram of a Schottky diode structure in an embodiment;

FIG. 3 is an overall circuit schematic of an embodiment;

figure 4 is a graph comparing the efficiency of the open ring and the acyclic structure of the examples.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

According to the invention, the standard rectangular waveguide inputs the terahertz fundamental wave by using HFSS simulation software, and the input matching is carried out by changing the length of the input height-reducing waveguide and the distance from the first short-circuit surface to the diode, so that energy can be better converged into the diode, and the input energy is transmitted to the frequency doubling circuit.

The structure of the high-low impedance filter is a sixth-order high-low impedance low-pass filter.

As shown in fig. 3, the distance of the first short-circuited surface indicates the distance from the schottky diode to the input probe port, and is a quarter wavelength of the output harmonic. The S (1, 1) reflection coefficient of the input signal can be stabilized below-20 dB by adjusting the size of the input height-reducing waveguide.

Fig. 4 is a graph comparing the efficiency of the ring structure with the open ring structure and the ring structure without the open ring structure in this embodiment. Through the open metal ring structure arranged at the bottom of the substrate of the suspension microstrip, because the split ring has an electric field convergence effect at the Schottky diode, energy can be better fed into the Schottky diode for increasing the frequency doubling efficiency and the output power of the whole frequency multiplier.

And the output second harmonic can be completely output through the design of the output matching circuit. Meanwhile, quarter-wavelength matching output is adopted, and energy is transited to output end microstrip waveguide from an output matching circuit.

In this embodiment, the frequency multiplier uses a balanced structure, which does not generate third harmonic, so that a filter circuit of the third harmonic is not required to be designed.

In summary, the open metal ring structure is arranged at the bottom of the substrate of the suspended microstrip, and the split ring has an electric field convergence effect at the schottky diode, so that energy can be better fed into the schottky diode, the utilization efficiency of terahertz waves is improved, the overall circuit performance is improved, and the frequency doubling efficiency and the output power of the overall frequency multiplier are increased.