CN108768303A - Application of the molybdenum disulfide in making odd harmonic microwave multiplier - Google Patents

Abstract

The invention discloses the application of molybdenum disulfide in the preparation of an odd harmonic microwave frequency multiplier. The odd harmonic microwave frequency multiplier includes a cavity, input coaxial joints and output coaxial A joint and a cover plate matched with the cavity. The high-frequency substrate of the molybdenum disulfide frequency multiplier is arranged in the cavity. A microstrip line connected to the shaft joint and the output coaxial joint, the microstrip line is provided with gaps, and molybdenum disulfide is provided between the gaps. The invention utilizes the good nonlinear microwave characteristics of molybdenum disulfide, and applies it to nonlinear devices such as frequency multipliers. The frequency multiplier made of molybdenum disulfide has good nonlinear performance and does not generate echo signals. , the circuit design is very simple, and the frequency multiplication effect is good, and the third frequency multiplication loss is equivalent to the fundamental wave.

Description

Application of Molybdenum Disulfide in Making Odd Harmonic Microwave Frequency Doubler

technical field

The invention relates to the field of microwaves, in particular to the application of molybdenum disulfide in the preparation of odd harmonic microwave frequency doublers.

Background technique

Microwave and millimeter wave frequency sources are widely used in systems such as radar, communication, guidance, and test instruments. The frequency multiplier is one of the important components of the frequency source. In the microwave and millimeter wave frequency bands, two-port passive frequency multipliers are widely used in the design of frequency multiplication sources. In terms of stability and noise, the performance of high-frequency two-port passive frequency multipliers is better than that of active oscillators. . However, in the prior art, non-linear resistance, non-linear reactance frequency multiplication, and graphene frequency multiplication are mainly used.

The frequency doubling efficiency of the non-linear resistor is low, and the highest efficiency that can be achieved is 1/N ^2, resulting in the fundamental wave loss being far greater than the third frequency doubling loss.

Nonlinear reactance is often used for low-order frequency multiplication. In actual circuits, due to poor matching and high-level losses of diodes, frequency multiplication losses always exist, resulting in complex design structures.

In recent years, due to its high electron traction rate and good thermal conductivity, graphene is considered to be the next generation of electronic materials, and has become a hot research direction. The disadvantage of graphene is that it will generate echo signals, so we need to The fundamental wave and the harmonic component to be recovered are in a state of total reflection, and the total reflection is to reflect the fundamental wave and the harmonic component to be recovered back to the input reflection network through graphene, resulting in a complex design of the frequency doubler structure. Therefore, the frequency multiplication loss of the graphene frequency multiplier is relatively high, and the working efficiency is not high, which greatly limits the usage scenarios of the graphene frequency multiplier.

Contents of the invention

The object of the present invention is to provide a method to solve the above problems, fully utilize the nonlinear microwave characteristics of molybdenum disulfide, suitable for molybdenum disulfide of nonlinear devices such as frequency multipliers in the production of odd harmonic microwave frequency multipliers application.

In order to achieve the above object, the technical solution adopted by the present invention is as follows: the application of molybdenum disulfide in the manufacture of odd harmonic microwave frequency multipliers.

Molybdenum disulfide has good optical nonlinearity and is mainly used in diodes, field effect transistors and other fields. For example, the document Observation of Intense Second Harmonic Generation from MoS2Atomic Crystals describes the optical nonlinearity of molybdenum disulfide, which provides new applications for optoelectronic devices. The literature Ultra-strongnonlinear optical processes and trigonal warping in MoS2layers reported that 1L-MoS2 has very strong optical nonlinearity. At the same time, there is no public report on the nonlinear microwave characteristics of MoS2 _two -dimensional materials. Whether it is suitable for frequency doublers and other non-linear For linear devices, the jury is still out. Therefore, this invention uses a single-layer MoS2 to load the microstrip gap to study the odd harmonic microwave frequency doubler. Under the excitation of electromagnetic field, molybdenum disulfide will output the fundamental wave and its multiplied frequency components. The molybdenum disulfide two-port frequency multiplier circuit has a natural even harmonic suppression function, and the output frequency components only contain fundamental waves and odd harmonics, which are suitable for nonlinear frequency devices, such as frequency multipliers.

As a preference: the odd-order harmonic microwave frequency doubler includes a cavity, input coaxial connectors and output coaxial connectors respectively located at both ends of the cavity, and a cover plate matching the cavity, and molybdenum disulfide is arranged in the cavity Frequency doubler high-frequency substrate, the molybdenum disulfide frequency doubler high-frequency substrate includes a high-frequency substrate, a microstrip line that is arranged on the high-frequency substrate and is respectively connected to the microstrip line input coaxial joint and the output coaxial joint, and the microstrip line Gaps are provided, and molybdenum disulfide is provided between the gaps.

As preferably: the preparation method of the high-frequency substrate of the molybdenum disulfide frequency doubler is:

(1) According to the input signal and frequency multiplication times, the output frequency is obtained;

(2) Design the microstrip line and microstrip gap according to the input frequency and output frequency;

(3) Molybdenum disulfide is transferred to the microstrip gap.

Compared with the prior art, the present invention has the advantages of: compared with graphene, graphene produces an echo signal, resulting in complex design, and the third harmonic frequency multiplication loss is less than the odd harmonic frequency multiplication loss, and in the present invention, Using molybdenum disulfide, the nonlinear performance is good, no echo signal will be generated, the circuit design is very simple, and the frequency doubling effect is good, and the third frequency doubling loss is equivalent to the fundamental wave.

Description of drawings

Fig. 1 is the structural representation of embodiment 1;

Fig. 2 is embodiment 1 circuit schematic diagram;

Fig. 3 is the design flowchart of embodiment 1;

Fig. 4 is a schematic circuit diagram of comparative example 1;

Fig. 5 is the design flowchart of ratio embodiment 1;

6 is a schematic diagram of the ratio of the triple frequency of molybdenum disulfide to the fundamental wave loss in Example 1.

Fig. 7 is the ratio schematic diagram of graphene triple frequency and fundamental wave loss in comparative example 1;

Fig. 8 is the non-linear resistance frequency doubling derivation circuit of comparative embodiment 2;

Fig. 9 is a circuit for deriving nonlinear reactance frequency multiplication in Comparative Example 2.

In the figure: 1. Cover plate; 2. High-frequency substrate; 3. Cavity; 4. Input coaxial connector; 5. Output coaxial connector; 6. Microstrip line; 7. Input reflection network; 8. Output reflection network; 9. Graphene; 10. Molybdenum disulfide.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

Embodiment 1: Referring to Fig. 1, Fig. 2 and Fig. 3, this embodiment illustrates the application of molybdenum disulfide 10 in making odd harmonic microwave frequency doublers. This embodiment makes full use of the nonlinear microwave characteristics of molybdenum disulfide 10 .

Wherein: the odd harmonic microwave frequency multiplier includes a cavity 3, an input coaxial connector 4 and an output coaxial connector 5 respectively located at both ends of the cavity 3, a cover plate 1 matching the cavity 3, the cavity 3 is provided with molybdenum disulfide 10 frequency multiplier high-frequency substrate 2, said molybdenum disulfide 10 frequency multiplier high-frequency substrate 2 includes high-frequency substrate 2, is arranged on the high-frequency substrate 2 and microstrip line 6 input coaxial joint 4 and The microstrip line 6 connected to the output coaxial connector 5 is provided with gaps between the microstrip lines 6 and molybdenum disulfide 10 is provided between the gaps.

The manufacture method of described molybdenum disulfide 10 frequency multiplier high-frequency substrate 2 is:

(1) According to the input signal and frequency multiplication times, the output frequency is obtained;

(2) Design microstrip line 6 and microstrip gap according to input frequency and output frequency;

(3) Molybdenum disulfide 10 is transferred to the microstrip gap.

Comparative Example 1:

Referring to Fig. 4 and Fig. 5, a kind of graphene 9 odd-order harmonic frequency multipliers, comprise cavity 3 components and cover plate 1, described cavity 3 components comprise cavity 3 and are respectively positioned at cavity 3 input same Shaft joint 4 and output coaxial joint 5 also comprise graphene 9 frequency multiplier high-frequency substrate 2; Described graphene 9 frequency multiplier high-frequency substrate 2 comprises high-frequency substrate 2, the input reflection network 7 that is arranged on high-frequency substrate 2, Graphene 9 and output reflection network 8, described input reflection network 7 and output reflection network 8 are respectively positioned at the front end and the rear end of graphene 9;

Let the output signal be the fundamental wave f ₀ , the number of times of frequency multiplication is N, wherein the output signal after frequency multiplication is Nf ₀ , and the frequency component of the signal to be recovered is (2n+1)f ₀ , where n=1, 2, 3, 4...and (2n+1)≠N;

The input reflection network 7 is in a matching state for _f0 , and is in a grounding state for the signal frequency component to be recovered;

The output reflection network 8 is in a matching state to Nf ₀ , and is in a state of total reflection to the fundamental wave and the harmonic component to be recovered, and the total reflection is to reflect the fundamental wave and the harmonic component to be recovered back to the input through graphene 9 Reflection Network7.

The input reflective network 7 and the output reflective network 8 adopt a 50-ohm microstrip line 6 connected in parallel with high and low impedance resonant circuits to realize reflection and recovery of harmonic components.

The design method of graphene 9 odd harmonic frequency multiplier is:

(1) According to the input signal and frequency multiplication times, the output frequency is obtained;

(2) determine the signal frequency component of recovery;

(3) design input reflection network 7 and output reflection network 8, obtain graphene 9 frequency multiplier high-frequency substrate 2;

(4) obtain the graphene 9 frequency multiplier with graphene 9 frequency multiplier high-frequency substrate 2;

(5) Design the external structures such as the cavity 3 and the cover plate 1 to obtain a graphene 9 odd harmonic frequency multiplier.

In combination with Example 1 and Comparative Example 1, it can be seen that graphene 9 will generate echo signals, so we need to be in a state of total reflection for the fundamental wave and the harmonic components to be recovered, resulting in the need to set the input reflection network 7 and the output reflection network 8 , resulting in complex structure design of the frequency multiplier, high frequency multiplication loss, and low work efficiency.

However, in the present invention, due to the good nonlinear microwave characteristics of molybdenum disulfide 10, echo signals will not be generated, the circuit design is very simple, and the frequency multiplication effect is good, and it has a natural even-order harmonic suppression function, and the output frequency component only contains fundamental Odd harmonics are involved, so the circuit design is simple.

Referring to Fig. 2 and Fig. 4, it can be seen from the comparison of Fig. 2 and Fig. 4 that molybdenum disulfide 10 is used in embodiment 1, and the triple frequency multiplication is equivalent to the fundamental wave output, which reduces the recovery of stubs. When the excitation frequency is 1GHz and the excitation power is 18dBm, the frequency multiplication loss of the third harmonic is equivalent to that of the first harmonic. Comparative Example 1 uses graphene 9, and the third frequency multiplication loss of the graphene 9 frequency multiplier is half of the spare loss of the first harmonic.

Referring to Figure 6 and Figure 7, it can be seen from the comparison of Figure 6 and Figure 7 that at the same frequency, the ratio of the triple frequency of graphene 9 to the fundamental wave loss is 0.001-0.006, with a difference of about 25dBm; The ratio of frequency to fundamental wave loss is 0.1-0.4, which is equivalent to the fundamental wave.

Comparative Example 2: Referring to FIG. 8 , the frequency multiplication efficiency of all non-linear resistance frequency multipliers decreases according to the square of the frequency multiplication times. That is to say, no matter what structure and software the designer uses to design the nonlinear resistor frequency multiplier, the highest efficiency of the double frequency is less than 25%; the triple frequency is less than 11.1%; the quadruple frequency is less than 5.25%; and so on .

The resistor R is driven by the power supply Vs. The back part of the circuit is a plurality of band-pass filters, which are used to isolate harmonics and output power. If the input frequency is W, the nth frequency multiplier is the nth harmonic of the fundamental wave, and the output frequency is nW.

In the case of higher power requirements or broadband requirements, we often use non-linear resistors for frequency multiplication.

Its advantages lie in its stability and wide bandwidth. But its disadvantage is that its frequency multiplication efficiency is low, so the application is not as popular as reactance frequency multiplication. but in mm In the microwave stage, the nonlinear reactance doubler does not satisfy the Manly-Rowe formula, so its high efficiency advantage is not as obvious as in the microwave stage. As shown in Figure 1, when the input frequency is ω, the nth frequency multiplier is the nth harmonic of the fundamental wave, and the output frequency is nω. The inequality that reflects the relationship between the input power P1 and the output power Pn of the frequency multiplier of the nonlinear resistance is called the Page-Pantell inequality.

The voltage and current on the resistor R can be expressed as:

Where Vn and In are:

Voltage v(t) and current i(t) are real functions, so Vn=V-n*

and In=I-n*. Therefore, the nth harmonic power can be obtained by the following formula:

Multiply both sides of the formula (1-1) by n2In* and sum to get:

Taking partial derivatives on both sides of formula (1-2) can get:

So into the formula (1-6), we get:

Also v(0)=v(T) and i(0)=i(T). Then the partial derivative of i(t) with respect to t is also periodic, so the first item on the right side of formula (1-8) is always equal to 0.

Then formula (1-8) can be simplified, and combined with formula (1-5), we can get:

For a positive non-linear resistance, the integral of formula (1-9) is always greater than zero. So you can get:

Connect a resistive load to the fundamental frequency and the frequency of the required harmonic order n, and connect a reactive load to the remaining harmonics, then the formula (1-10) can be simplified as P1+n2Pn>0, and the input power P1 is greater than zero, and the harmonic power Pn<0, the maximum efficiency of the non-linear resistance frequency doubler is:

Formula (1-11) expresses the frequency multiplication efficiency of all non-linear resistance frequency multipliers, which decreases according to the square of the frequency multiplication times. That is to say, no matter what structure and software the designer uses to design the nonlinear resistance frequency multiplier, the highest efficiency of the frequency doubler is less than 25%; the frequency tripler is less than 11.1%; the frequency quadruple is less than 6.25% ; and so on.

Comparative Example 3: Referring to FIG. 9 , nonlinear reactance frequency multiplication is adopted, and in the nonlinear reactance frequency multiplier, the frequency multiplication efficiency can reach 100% under ideal conditions. However, in the actual circuit, due to the poor matching and the senior loss of the diode, the frequency multiplication loss always exists.

Capacitor C is driven by power supplies Vs1 and Vs2. The back part of the circuit is a plurality of band-pass filters, which are used to isolate harmonics and output power.

Nonlinear reactive frequency doublers can be divided into two categories: diode frequency multipliers and transistor frequency multipliers. Commonly used diode frequency multipliers are varactor diodes and step diodes. The former is often used for low-order frequency multiplication, and its efficiency is high. According to the Manly-Rowe formula of the nonlinear reactance frequency multiplication principle, it can reach 100% under ideal conditions. Step diodes are often used for high-order frequency multiplication. Since the high-order frequency multiplier of the varactor needs an idle circuit to realize, the step diode is simpler in circuit.

If the steady-state sinusoidal voltage wave is loaded on the varactor diode, its current and voltage waveform will be distorted, thereby generating harmonic components. The size of the harmonic component has a great relationship with the nonlinearity of the diode.

As shown in Figure 9, the Manly-Rowe formula of nonlinear reactance frequency multiplication expresses the relationship between input power and output power. Among them, the capacitor C is driven by the sources Vs1 and Vs2. The back part of the circuit is a plurality of band-pass filters, which are used to isolate harmonics, and the output requires power.

The Manly-Rowe formula says: For any lossless nonlinear reactive element, power is conserved. This relationship can be used in oscillators, parametric amplifiers, microwaves, and even frequency multipliers in the light wave band. Generally, this formula is used for power gain and frequency multiplication frequency conversion efficiency budget.

In the nonlinear reactance frequency multiplier, the frequency multiplication efficiency can reach 100% under ideal conditions. However, in the actual circuit, due to the poor matching and the loss of the diode itself, the frequency multiplication loss always exists.

Claims (1)

1. application of the molybdenum disulfide in making odd harmonic microwave multiplier.