Impedance matching for repetitive high voltage all-solid-state Marx generator and excimer DBD UV sources

The purpose of impedance matching for a Marx generator and DBD lamp is to limit the output current of the Marx generator,provide a large discharge current at ignition,and obtain fast voltage rising/falling edges and large overshoot.In this paper,different impedance matching circuits（series inductor,parallel capacitor,and series inductor combined with parallel capacitor） are analyzed.It demonstrates that a series inductor could limit the Marx current.However,the discharge current is also limited.A parallel capacitor could provide a large discharge current,but the Marx current is also enlarged.A series inductor combined with a parallel capacitor takes full advantage of the inductor and capacitor,and avoids their shortcomings.Therefore,it is a good solution.Experimental results match the theoretical analysis well and show that both the series inductor and parallel capacitor improve the performance of the system.However,the series inductor combined with the parallel capacitor has the best performance.Compared with driving the DBD lamp with a Marx generator direcdy,an increase of 97.3%in radiant power and an increase of 59.3%in system efficiency are achieved using this matching circuit.

Synthesis of carbon-coated cobalt ferrite core-shell structure composite:A method for enhancing electromagnetic wave absorption properties by adjusting impedance matching

Cobalt ferrite has problems such as poor impedance matching and high density,which results in unsatisfactory electromagnetic wave(EMW)absorption performance.In this study,the CoFe_(2)O_(4)@C core-shell structure composite was synthesized by a two-step hydrothermal method.X-ray diffraction,transmission electron microscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis,and vector network analysis et al.were used to test the structure and EMW absorption properties of CoFe_(2)O_(4)@C composite.The results show that the reflection loss(RL)of the CoFe_(2)O_(4)@C composite reaches the maximum value of25.66 dB at 13.92 GHz,and the effective absorbing band(EAB)is 4.59 GHz(11.20-15.79 GHz)when the carbon mass content is 6.01%.The RL and EAB of CoFe_(2)O_(4)@C composite are increased by 219.55%and 4.59 GHz respectively,and the density is decreased by 20.78%compared with the cobalt ferrite.Such enhanced EMW absorption properties of CoFe_(2)O_(4)@C composite are attributed to the attenuation caused by the strong natural resonance of the cobalt ferrite,moreover,the carbon coating layer adjusts the impedance matching of the composite,and the introduced dipole polarization and interface polarization can cause multiple Debye relaxation processes.

Simulation of High-Transmission Chiral Metamaterial with Impedance Matching to a Vacuum

For a previously simulated eight-broadband negative-refraction-index chiral metamaterial, we use S-parameter retrieval methods to determine the complex effective permittivity, permeability, and the impedance. We also calculate the figure of merit, which is defined as the ratio of the real and the imaginary refraction components, and compare it with those of fishnet metamaterials. The simulation results show that our chiral metamaterial exhibits high transmission and impedance matching to a vacuum. Also, we determine that the electric and magnetic dipoles of the surface plasmons play an important role in determining the nine resonance frequencies. Therefore, this investigation provides an experimental basis for developing metamaterial devices with multiple and broad resonance frequency bands.

Low-loss Cd-substituted Mg ferrites with matching impedance for high-frequency-range antennas

The effects of Cd^(2+) ions on the microstructure,magnetic properties,and dielectric properties of Bi_(2)O_(3)-added MgFe_(2)O_(4) ferrites(Cd_(x)Mg_(1-x)Fe_(2)O_(4),x=0.00,0.15,0.30 and 0.45)are obtained by adopting the solid-state reaction method at a low temperature(910℃).The objective is to achieve matching impedances,low magnetic and dielectric losses(tanδμand tanδε,respectively),and a relatively large miniaturization factor to reduce antenna size.Experimental results indicate that the cations occupying the tetrahedral(A)and octahedral(B)ion sites are redistributed,resulting in an enhanced super-exchange interaction between the two sublattices.As a result,improved magnetization,including the increase in saturation magnetization(41.74 emu/g)and decrease in coercivity(63.75 Oe),is realized.The real part of permeability(μ')also increases with increasing concentration of Cd^(2+) ions.When x is 0.15,matching impedances with equivalent μ'and ε'values are obtained over a long frequency range(1–150MHz).Moreover,the formation of a dense microstructure guarantees that losses occur at low orders of magnitude(tanδμ≈10−2 and tanδε≈10−3).Accordingly,these properties afford wide application perspectives for the proposed compounds in the high-frequency region,i.e.,from high-frequency to very-high-frequency bands.

A Novel Impedance Matching Approach for Passive UHF RFID Transponder ICs

This paper presents a novel impedance matching approach for passive UHF RFID transponder ICs,which are compatible with the ISO/IEC 18000-6B standard and operate in the 915MHz ISM band. The passive UHF RFID transponder with complex impedances is powered by received RF energy. The approach uses the parasitic inductance of the antenna to implement ASK modulation by adjusting the capacitive reactance of the matching network, which changes with the backscatter circuit. The impedance matching achieves maximum power transfer between the reader, antenna, and transponder. The transponder IC,whose operating distance is more than 4m with the impedance matching approach,is fabricated using a Chartered 0.35μm two-poly four-metal CMOS process that supports Schottky diodes and EEPROM.

Impedance Matching Algorithm for Selection of Suitable Explosives for Any Rock Mass-A Case Study

Proper selection of the explosive is an important part of blast design.The judicious selection of explosives is governed by economic considerations and site/field conditions.The mine management desires to select an explosive that will give the lowest cost per unit of rock broken,while assuring that fragmentation,fragment size distribution,muck pile profile,muck pile diggability,displacement of the rock,onset of movement,face movement,burden relief rate,ground vibration and noise remains within control limits.Factors which influence the selection of an explosive include explosive cost,charge diameter,cost of drilling,fragmentation difficulties and fragment size requirement with loose muck pile condition,water conditions,atmospheric temperature,propagating ground,storage considerations,sensitivity considerations,explosive atmospheres and nearness of communities from mine.All these concerns can be handled effectively by using the impedance matching technology where explosive impedance is matched with rock impedance for optimal blast performance with due concern to productivity,economics and environment.This paper discusses a case study in limestone mines where rock impedance was determined by carrying out surface refraction test and a patented algorithm was used to estimate the explosives’properties i.e.VOD(velocity of detonation)and density of explosives required.

Inversion of Seabed Geotechnical Properties in the Arctic Chukchi Deep Sea Basin Based on Time Domain Adaptive Search Matching Algorithm

The chirp sub-bottom profiler,for its high resolution,easy accessibility and cost-effectiveness,has been widely used in acoustic detection.In this paper,the acoustic impedance and grain size compositions were obtained based on the chirp sub-bottom profiler data collected in the Chukchi Plateau area during the 11th Arctic Expedition of China.The time-domain adaptive search matching algorithm was used and validated on our established theoretical model.The misfit between the inversion result and the theoretical model is less than 0.067%.The grain size was calculated according to the empirical relationship between the acoustic impedance and the grain size of the sediment.The average acoustic impedance of sub-seafloor strata is 2.5026×10^(6) kg(s m^(2))^(-1)and the average grain size(θvalue)of the seafloor surface sediment is 7.1498,indicating the predominant occurrence of very fine silt sediment in the study area.Comparison of the inversion results and the laboratory measurements of nearby borehole samples shows that they are in general agreement.

Adaptive impedance matching using quantum genetic algorithm

An adaptive technique adopting quantum genetic algorithm （QGA） for antenna impedance tuning is presented. Three examples are given with different types of antenna impedance. The frequency range of the dual standards is from 1.7 to 2.2 GHz. Simulation results show that the proposed tuning technique can achieve good accuracy of impedance matching and load power. The reflection coefficient and VSWR obtained are also very close to their ideal values. Comparison of the proposed QGA tuning method with conventional genetic algorithm based tuning method is Moreover, the proposed method can be useful for software wireless bands. also given, which shows that the QGA tuning algorithm is much faster. defined radio systems using a single antenna for multiple mobile and

Enhanced electromagnetic wave absorption via optical fiber-like PMMA@Ti_(3)C_(2)T_(x)@SiO_(2) composites with improved impedance matching

Ti_(3)C_(2)T_(x) nanosheets have attracted significant attention for their potential in electromagnetic wave absorption(EWA).However,their inherent self-stacking and exorbitant electrical conductivity inevitably lead to serious impedance mismatch,restricting their EWA application.Therefore,the optimization of impedance matching becomes crucial.In this work,we developed polymethyl methacrylate(PMMA)@Ti_(3)C_(2)T_(x)@SiO_(2) composites with a sandwich-like core–shell structure by coating SiO_(2) on PMMA@Ti_(3)C_(2)T_(x).The results demonstrate that the superiority of the SiO_(2) layer in combination with PMMA@Ti_(3)C_(2)T_(x),outperforming other relative graded distribution structures and meeting the requirements of EWA equipment.The resulting PMMA@Ti_(3)C_(2)T_(x)@SiO_(2) composites achieved a minimum reflection loss of-58.08 dB with a thickness of 1.9 mm,and an effective absorption bandwidth of 2.88 GHz.Mechanism analysis revealed that the structural design of SiO_(2) layer not only optimized impedance matching,but also synergistically enhanced multiple loss mechanisms such as interfacial polarization and dipolar polarization.Therefore,this work provides valuable insights for the future preparation of high-performance electromagnetic wave absorbing Ti_(3)C_(2)T_(x)-based composites.

An easily-prepared impedance matched Josephson parametric amplifier

An impedance matched parametric amplifier(IMPA)with Josephson junctions is fabricated and characterized.A hybrid structure containing coplanar and strip structures is implemented to realize an impedance taper line and a plate capacitor in an LC nonlinear resonator based on Josephson junctions.The upper plate of the capacitor is isolated with SiNx without grounding as well as the strips.Such easily-prepared designs greatly reduce the requirements for lithography alignment and precision,which makes the fabrication process more reliable.The experimental results show that in such IMPA a gain higher than 25 dB with a bandwidth of about 100 MHz can be obtained.This broadband amplifier operates close to the quantum limit.By adjusting the working point,a higher bandwidth of about 400 MHz can be obtained with a gain of about 17 dB.

Theoretical Analysis of Triple Liquid Stub Tuner Impedance Matching for ICRH on Tokamaks

The impedance matching is crucial for continuous wave operation of ion cyclotron resonance heating（ICRH） antennae with high power injection into plasmas.A sudden increase in the reflected radio frequency power due to an impedance mismatch of the ICRH system is an issue which must be solved for present-day and future fusion reactors.This paper presents a method for theoretical analysis of ICRH system impedance matching for a triple liquid stub tuner under plasma operational conditions.The relationship of the antenna input impedance with the plasma parameters and operating frequency is first obtained using a global solution.Then,the relations of the plasma parameters and operating frequency with the matching liquid heights are indirectly obtained through numerical simulation according to transmission line theory and matching conditions.The method provides an alternative theoretical method,rather than measurements,to study triple liquid stub tuner impedance matching for ICRH,which may be beneficial for the design of ICRH systems on tokamaks.

Research on the Mechanism of Impedance Matching for Underwater Acoustic Transmitter based on Mathematical Modelling and Corresponding Balance Transformer

With the progress of power transmission technology, it is necessary for researchers to conduct related research on impedance matching. In this paper, we conduct research on the mechanism of impedance matching for underwater acoustic transmitter based on mathematical modelling and corresponding balance transformer. To realize underwater acoustic signal of wide band and high power emission, in addition to need the bandwidth performance good transducer array yuan, to a large extent also depends on a good matching between the transducer and amplifier. The result shows the feasibility and robustness of our designed system.

Modelling of Impedance Matching Circuit with Digital Capacitor in Narrowband Power Line Communication

Power line communication technology is used in various applications, from high voltage network to the low voltage network, as it is the only wired communication technology that is comparable with wireless communication network. It works by injecting a modulated carrier wave into the electric cables from one transceiver to another. But still, the noise level and impedance mismatch are still the main concern of this technology, particularly in the low voltage network in residential area. Power line has additive non-white noise and extremely harsh environment for communication. At the same time, there is signal attenuation along the power line caused by the impedance mismatch in the power line network. Even though these problems can be controlled using a band-pass filter and an impedance matching circuit respectively, but the impedances in the power line are time and location variant and it is rather difficult to design a circuit that allows maximum power transfer in the system all the time. Thus in this paper, a new adaptive impedance matching circuits is proposed for narrowband power line communication. This methodology is derived based on the RLC band-pass filter circuit. This concept is designed to achieve simpler configuration and higher matching resolution.

Design of a distributed power amplifier based on T-type matching networks

The impedance characteristics of distributed amplifiers are analyzed based on T-type matching networks, and a distributed power amplifier consisting of three gain cells is proposed. Non-uniform T-type matching networks are adopted to make the impedance of artificial transmission lines connected to the gate and drain change stage by stage gradually, which provides good impedance matching and improves the output power and efficiency. The measurement results show that the amplifier gives an average forward gain of 6 dB from 3 to 16. 5 GHz. In the desired band, the input return loss is typically less than - 9. 5 dB, and the output return loss is better than -8.5 dB. The output power at 1-dB gain compression point is from 3.6 to 10. 6 dBm in the band of 2 to 16 GHz while the power added efficiency （PAE） is from 2% to 12. 5% . The power consumption of the amplifier is 81 mW with a supply of 1.8 V, and the chip area is 0.91 mm × 0.45 mm.

Self-Adaptive Matching Method of Signal and Energy Transmission

Aimed at the rapid message setting of the passive systems, the efficiency of energy transmission and the characteristics of signal transmission in the message setting are analyzed, which is based on the methods of the circuit analysis and the electromagnetic induction technology. A self-adaptive impedance matching method of signal and energy transmission, which can set the message rapidly and effectively, is put forward. The electromagnetic induct setting system will reach the highest energy transmission efficiency when the equivalent resistance of the second loop is equal to the resistance of the first loop. The greater the ratio of the equivalent resistances is, the higher efficient the signal transmission has. Moreover, the validity of the method is verified by circuit design and tests.

羰基铁基复合材料的高效吸波-防腐双功能特性研究

随着5G先进通信技术和雷达探测技术的快速发展,电磁污染问题和特种装备的隐身突防问题日益突出。铁磁性吸波材料凭借高饱和磁化强度和优异的电磁波衰减能力已发展为应用较为广泛的隐身材料,然而,由于应用环境的多元化,铁磁性吸波材料的腐蚀问题严重制约其实际应用。本文采用多步液相反应,成功制备出具备优异吸波-防腐双功能的多级结构羰基铁基复合材料。该材料最低反射损耗高达-48.3 dB,有效吸收带宽达7.0 GHz。同时,其抗腐蚀性能也得到大幅改善,自腐蚀电压Ecorr显著右移至-0.22 V,自腐蚀电流密度Icorr下降至1.21×10^(-7)A/cm^(2)。为新型高性能铁磁性吸波材料的设计和工程应用提供了有力支撑,对于解决电磁污染和装备隐身问题具有重要意义。

Sub-6 GHz GaAs pHEMT高功率吸收型单刀双掷开关

基于0.5μm GaAs赝配高电子迁移率晶体管(pHEMT)工艺,设计了一款高功率吸收型单刀双掷开关芯片。芯片采用堆叠技术和前馈电容技术来提高功率容量和线性度。通过在传统串并联结构的输出端口引入串并联阻容匹配网络,实现了芯片在导通和关断状态下的良好端口匹配。该开关芯片的尺寸为0.82 mm×0.37 mm。实测结果显示,在0.7~6.0 GHz的工作频段内,该开关实现了低于1.1 dB的插入损耗、高于36 dB的隔离度、优于15 dB的通路回波损耗和优于10 dB的断路回波损耗。此外,0.1 dB功率压缩点在1、2、4和6 GHz时,均约40 dBm。

TiN/Fe_(2)N/C composite with stable and broadband high-temperature microwave absorption

Facing the complex variable high-temperature environment,electromagnetic wave(EMW)absorbing materials maintaining high stability and satisfying absorbing properties is essential.This study focused on the synthesis and EMW absorbing performance evaluation of TiN/Fe_(2)N/C composite materials,which were prepared using electrostatic spinning followed by a high-temperature nitridation process.The TiN/Fe_(2)N/C fibers constructed a well-developed conductive network that generates considerable conduction loss.The heterogeneous interfaces between different components generated a significant level of interfacial polarization.Thanks to the synergistic effect of stable dielectric loss and optimized impedance matching,the TiN/Fe_(2)N/C composite materials demonstrated excellent and stable absorption performance across a wide temperature range(293-453 K).Moreover,TiN/Fe_(2)N/C-15 achieved a minimum reflection loss(RL)of−48.01 dB and an effective absorption bandwidth(EAB)of 3.64 GHz at 2.1 mm and 373 K.This work provides new insights into the development of high-efficiency and stabile EMW absorbing materials under complex variable high-temperature conditions.

A new theory of rock-explosive matching based on the reasonable control of crushed zone

Rational rock-explosive matching is of great importance to enhancing explosive energy effective utilization and improving rock fragmentation effect.The traditionally emphasized method of acoustic impedance matching is not rational.Based on blasting breakage mechanism,a new theory of rock-explosive matching in drilling and blasting is proposed.The new approach chooses explosive parameters by reasonable control of the size of crushed zone under the condition of fully fragmentation between adjacent blast holes.This method can directly reflect the blasting fragmentation effect and energy effective utilization,which is easy to implement.Also,a modified model is developed,taken adjacent blast hole blasting loading into account.As a result,explosive parameters of different grades of rock are given in full coupling on-site mixed explosive charge for different project objectives.

Rational design of hollow rice-grainedα-Fe_(2)O_(3)/carbon nanofibers with optimized impedance matching for electromagnetic wave absorption enhanced

Electromagnetic wave absorption materials are widely used in electronic equipment and military fields.However,high cost and complex preparation processes become a major obstacle in promoting popularization in the civil field.To solve the problems above,researchers have made great efforts to develop Fe-based carbon composites.However,most of the typical composites require a high filling ratio while achieving excellent properties.Therefore,in this study,carbon nanofibers(CNFs)combined with the hollow rice-grainedα-Fe_(2)O_(3)nanoparticles were prepared by the in-situ transformation method.The rational microstructure design provided a solution for reducing the filling ratio,optimizing impedance matching,and improving electromagnetic wave absorption performance.The strong reflection loss value(−38.1 dB)and broad effective absorption bandwidth(4.6 GHz)for Fe_(2)O_(3)/CNFs composites were achieved with a low filling ratio(20 wt.%),and the analysis of electromagnetic parameters validated that the microstructure of Fe_(2)O_(3)/CNFs plays a crucial role in the performance improvement.With the optimized impedance matching and simple preparation method,Fe_(2)O_(3)/CNFs have broad application prospects in electromagnetic wave absorption.