Characteristics Of Radio Frequency Research Articles

Precisely tuning ε′-negative and ε′-near-zero responses by synergistic effect of graphene and carbon black in ternary metacomposites

Understanding how to precisely regulate the magnitude and dispersion characteristics of radio-frequency (RF) ε’-negative and ε’-near-zero (ENZ) responses presents a challenge. This challenge significantly impacts the design of versatile electronic devices. In this study, we introduce a synergistic strategy utilizing graphene (GR) and carbon black (CB) in ternary metacomposites for tunable ε’-negative and ENZ responses. Due to the randomly constructed 3-dimensional (3D) conductive GR-CB networks in a CaCu3Ti4O12 matrix, we observed two types of ε’-negative response mechanisms: electric dipole resonance and low-frequency plasma oscillation, which dominate at different frequency bands. Consequently, the weakly ε’-negative values (0 < |ε’| 〈1000) and frequency dispersion were successfully adjusted due to the interplay between these two mechanisms. The ENZ frequencies were also tuned over ∼580 MHz, 225 MHz, ∼189 MHz and ∼ 188 MHz with variable GR-to-CB ratios. Furthermore, we studied the conduction behavior, loss mechanism, and electrical characteristics of the ε’-negative metacomposites to shed light on the relationship between microstructural changes and dielectric performance.

Studies on Dual Sputtered CuGaO2 Thin Films

There has been extensive research conducted on n-type transparent conducting oxide (TCO) films like Sn-doped In2O3 (ITO) [1], Al-doped ZnO (AZO) [2], etc. P-type transparent conducting oxides are yet to be researched extensively. Active devices such as p-n junction devices and transistors are required to make progress in the development of transparent electronics. In this effort, research in p-Type TCOs is important. Most of the p-Type TCOs are copper-based ternary oxides [3].In this work, CuGaO2 thin films were prepared using the dual-target RF magnetron sputtering technique. Cu2O and Ga2O3 targets were simultaneously sputtered on quartz substrates. The sputtering power of Cu2O was kept constant at 50 W and the sputtering power of Ga2O3 was varied. The films were deposited at room temperature and were subsequently annealed in nitrogen ambiance at 900 °C. The X-ray diffraction and optical studies were performed to analyze the films to optimize their properties.[1] Fallah, H.; Ghasemi, M.; Hassanzadeh, A.; Steki, H. The effect of annealing on structural, electrical and optical properties of nanostructured ITO films prepared by e-beam evaporation. Mater. Res. Bull. 2007, 42, 487–496[2] Shantheyanda, B.P.; Todi, V.O.; Sundaram, K.B.; Vijayakumar, A.; Oladeji, I. Compositional study of vacuum annealed Al doped ZnO thin films obtained by RF magnetron sputtering. J. Vac. Sci. Technol. A 2011, 29, 051514.[3] Sundaresh, S.; Bharath, A.H.; Sundaram, K.B. Effect of Cu2O Sputtering Power Variation on the Characteristics of Radio Frequency Sputtered p-Type Delafossite CuCrO2 Thin Films. Coatings 2023, 13, 395.

Characteristics of a hybrid radio frequency capacitively and inductively coupled plasma using hydrogen gas

A hybrid combination of a radio frequency (RF) capacitively coupled plasma (CCP) equipped with a ring-shaped hollow powered electrode and an inductively coupled plasma (ICP) with a helical antenna is investigated in hydrogen gas. Characteristics of the RF hybrid plasma are measured by a Langmuir probe at a fixed position in the center between the RF powered and grounded electrode for various CCP powers of 50–150 W. The voltage drop across the CCP is found to be almost independent of the ICP power. The RF hybrid plasma attains a high ion density of the order of 1010 cm−3 between the electrodes even at a low CCP input power of 50 W. The plasma density is strongly affected by the CCP generator power, while the floating potential is controlled by the ICP power, whereas the electron temperature is independent of the ICP power for various CCP powers. The negative ion production is enhanced by increasing the ICP power, resulting in a decrease in the ratio of the negative to the positive charge saturation current detected by the Langmuir probe. The maximum ratio of the negative ion density to the electron density is approximately 8 at a CCP power of 50 W and an ICP power of 250 W.

Simple Modeling and Analysis of Total Ionizing Dose Effects on Radio-Frequency Low-Noise Amplifiers

In this study, the degradation characteristics of radio frequency (RF)-low-noise amplifiers (LNA) due to a total ionizing dose (TID) is investigated. As a device-under-test (DUT), sample LNAs were prepared using silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs) as core elements. The LNA was based on a cascode stage with emitter degeneration for narrowband applications. By using a simplified small-signal model of a SiGe HBT, design equations such as gain, impedance matching, and noise figure (NF) were derived for analyzing TID-induced degradations in the circuit-level performance. To study radiation effects in circuits, the SiGe-RF-LNAs fabricated in a commercial 350 nm SiGe technology were exposed to 10-keV X-rays to a total ionizing dose of up to 3 Mrad(SiO2). The TID-induced performance changes of the LNA were modeled by applying degradation to device parameters. In the modeling process, new parameter values after irradiation were estimated based on information in the literature, without direct measurements of SiGe HBTs used in the LNA chip. As a result, the relative contributions of parameters on the circuit metrics were compared, identifying dominant parameters for degradation modeling. For the TID effects on input matching (S11) and NF, the base resistance (RB) and the base-to-emitter capacitance (Cπ) of the input transistor were mostly responsible, whereas the transconductances (gm) played a key role in the output matching (S22) and gain (S21). To validate the proposed approach, it has been applied to a different LNA in the literature and the modeling results predicted the TID-induced degradations within reasonable ranges.

Study of Mid-Pressure Ar Radiofrequency Plasma Used in Plasma-Enhanced Atomic Layer Deposition of α-Al2O3

This study investigated the characteristics of radiofrequency, middle-pressure argon plasma used in the atomic layer deposition (ALD) of Al2O3 films. Based on the electrical characteristics—the current, voltage, and phase shift between them—and the stability of the plasma plume, the optimum plasma power, allowing reliable switching on of the plasma for any step of an ALD cycle, was determined. Spectral measurements were performed to determine the gas temperature and reactive species that could be important in the ALD process. The density of metastable argon atoms was estimated using tunable laser absorption spectroscopy. It was concluded that plasma heating of substrates did not affect film growth. The crystallization-enhancing effect of plasma observed in these experiments was due to the action of OH radicals produced in the plasma.

A broadband low‐loss SPDT RF switch using a new off‐chip compensation technology

SummaryAn off‐chip compensation technology for low‐loss and broadband characteristics of radio frequency (RF) switches is proposed based on mathematical analysis of series shunt single pole double throws switches in this letter. This compensation technology can absorb the parasitic parameters of the switch Field Effect Transistor, improving the insertion loss and return loss of the switch as well as supporting higher bandwidth. To verify the design principle, a RF switch, using the SANAN GaAs 0.15 um pseudomorphic High Electron Mobility Transistors (pHEMT) process, and an off‐chip compensation network were designed and implemented. Specifically, after using an off‐chip compensation network, the measured bandwidth of switch has been expanded from 1.1–8.8 to 0.8–11 GHz, while the input and output return loss have also improved significantly.

Investigation of Antibacterial Efficacy of CuCrO2 Delafossite Thin Films Against E. coli

Terminals used in hospitals, information systems displaying patient information, and smartphones use touch panels that incorporate n and p transparent conducting oxide (TCO) layers [1]. There are a lot of pre-existing research present on n-type TCO while at the same time similar research interest related to p-type TCOs has been lacking. This is due to the inherently high electrical resistivity or low optical transparency of p-type TCOs. Recently, there has been a spike in research related to p-type delafossite thin films, owing to their excellent electrical and optical properties as compared to the other p-type counterparts. Cu-based p-type delafossite materials exhibit low resistivity and at the same time good optical transparency in the visible region. Among the Cu-based delafossites, copper chromium oxide (CuCrO2) exhibits the lowest electrical resistivity reported yet. Use of CuCrO2 as the p-type TCO along with a suitable n-type TCO might demonstrates significant potential to be used for optoelectronic applications.In this work, CuCrO2 thin films have been deposited on quartz substrates using dual target RF magnetron sputtering technique. This involved dual sputtering of 3- inch Cu2O and Cr2O3 targets. The substrate temperature was maintained at 400 °C during the deposition with Ar used as the sputtering gas. This was followed by post deposition annealing. Previous research carried out by our group has indicated that single-phase CuCrO2 was obtained at an annealing temperature of 650 °C in N2 ambiance for 4 hours [2, 3]. Successful synthesis of single-phase CuCrO2 has been confirmed using XPS and XRD study. The resistivity of CuCrO2 was obtained as 0.652 Ω-cm, which is the lowest reported so far. The optical study denoted an average optical transmission of > 60% in the visible wavelength spectrum and a high optical bandgap of 3.2 eV. The antibacterial efficacy of different thickness of CuCrO2 thin films was tested against E. coli bacterial strain and compared against the efficacy of plain quartz in this research work. Results showed that with an increase in the thickness of CuCrO2 thin films, the efficacy against E. coli increases. The highest antibacterial efficacy of 78.07 % was shown by 2000 A° CuCrO2 thin film.[1] Chiu T-W, Yang Y-C, Yeh A-C, Wang Y-P, Feng Y-W. Antibacterial property of CuCrO2 thin films prepared by RF magnetron sputtering deposition. Vacuum. 2013;87:174-177.[2] Sundaresh S, Bharath AH, Sundaram KB. Effect of Annealing Temperature on Radio Frequency Sputtered p-Type Delafossite Copper Chromium Oxide (CuCrO2) Thin Films and Investigation of Diode Characteristics Forming Transparent pn-Heterojunction. Coatings2023.[3] Sundaresh S, Bharath AH, Sundaram KB. Effect of Cu2O Sputtering Power Variation on the Characteristics of Radio Frequency Sputtered p-Type Delafossite CuCrO2 Thin Films. Coatings2023.

Low-damage interface enhancement-mode AlN/GaN high electron mobility transistors with 41.6% PAE at 30 GHz

This paper reports a low-damage interface treatment process for AlN/GaN high electron mobility transistor (HEMT) and demonstrates the excellent power characteristics of radio-frequency (RF) enhancementmode (E-mode) AlN/GaN HEMT. An RF E-mode device with 2.9-nm-thick AlN barrier layer fabricated by remote plasma oxidation (RPO) treatment at 300 °C. The device with a gate length of 0.12-μm has a threshold voltage (V th) of 0.5 V, a maximum saturation current of 1.16 A/mm, a high I on/I off ratio of 1 × 108, and a 440-mS/mm peak transconductance. During continuous wave (CW) power testing, the device demonstrates that at 3.6 GHz, a power added efficiency is 61.9% and a power density is 1.38 W/mm, and at 30 GHz, a power added efficiency is 41.6% and a power density is 0.85 W/mm. Furthermore, the RPO treatment improves the mobility of RF E-mode AlN/GaN HEMT. All results show that the RPO processing method has good applicability to scaling ultrathin barrier E-mode AlN/GaN HEMT for 5G compliable frequency ranging from sub-6 GHz to Ka-band.

Comparison of pulse-modulated and continuous operation modes of a radio-frequency inductive ion source

The paper describes an experimental study of the characteristics of a pulse-modulated radio-frequency (RF) discharge sustained at low pressures, typical of the operating modes of RF gridded ion sources. The motivation for the study is the question of whether the RF pulse-modulated mode can increase the efficiency of the ion source. The ion current values extracted from an RF inductive ion source operating in continuous and pulse-modulated modes were compared. The experimental data were also compared with the parameter calculations based on a 0D numerical model of the discharge. The measurements showed that the pulse-modulated operation mode of the RF ion source had a noticeable advantage when the power of the RF generator was 140 W or lower. However, as the generator power increased, the advantage was lost because the pulse-modulated operation mode, having a higher RF power instant value, entered the region of existence sooner than the continuous mode, where the ion production cost begins to grow with RF power.

Bi-Substituted Ferrite Garnet Type Magneto-Optic Materials Studied at ESRI Nano-Fabrication Laboratories, ECU, Australia

Since 2007, at the Electron Science Research Institute (ESRI) nano-fabrication laboratories, Edith Cowan University, Australia, we have devoted research efforts to the synthesis and characterization of bismuth-containing ferrite-garnet-type thin-film magneto-optic (MO) materials of different compositions. We report on the growth and characteristics of radio frequency (RF) magnetron sputtered bismuth-substituted iron-garnet thin films. We study the process parameters associated with the RF magnetron sputter deposition technique and investigate the results of optimizing process parameters. To achieve the best MO properties, we employ a few unique techniques, such as co-sputtered nanocomposite films and all-garnet multilayer structures, as well as the application of oxygen plasma treatment to amorphous garnet layers immediately following the deposition process. We demonstrated a remarkable enhancement in the MO properties of Bi-containing ferrite-type garnet thin-film materials, including record-high MO figures of merit and improved conventional and unconventional hysteresis loops of Faraday rotation. Previously unpublished research results on the forward-looking applications of magnetic garnet coatings applied to microparticles of advanced luminescent materials are reported. In the context of developing the next-generation ultra-fast optoelectronic devices, such as light intensity switches and modulators, high-speed flat panel displays, and high-sensitivity sensors, it is important to consider the desirable optical, magnetic, and magneto-optic properties that are found in highly bismuth-substituted iron garnet thin-film materials of various composition types.

Polarization angle dependence of vertically propagating radio-frequency signals in South Polar ice

To better understand the effect of ice properties on the capabilities of radio experiments designed to measure ultra-high energy neutrinos (UHEN), we recently considered the timing and amplitude characteristics of radio-frequency (RF) signals propagating along multi-kilometer, primarily horizontal trajectories through cold Polar ice at the South Pole. That analysis indicated satisfactory agreement with a model of ice birefringence based on ice crystal (cˆ-axis) data culled from the South Pole Ice Core Experiment (SPICE). Here we explore the geometrically complementary case of signals propagating along primarily vertical trajectories, using extant data from the Askaryan Radio Array (ARA) experiment, supplemented by a refined analysis of older RICE experimental data. The timing characteristics of the South Polar data are in general agreement with the same birefringence model, although a several nanosecond discrepancy is found in comparison to Taylor Dome data. Re-analysis of older RICE data also confirm the correlation of signal amplitudes reflected from internal-layers with the direction of ice flow, similar to previous observations made along a traverse from Dome Fuji to the Antarctic coast. These results have two important implications for radio-based UHEN experiments: (i) if birefringence can be locally calibrated, the timing characteristics of signals propagating from neutrino-ice interactions to a distant receiver might be used to infer the distance-to-vertex, which is necessary to estimate the energy of the progenitor neutrino, (ii) the measured reflectivity of internal layers may result in previously-unanticipated backgrounds to UHEN searches, requiring significantly more modeling and analysis.

Impedance Characteristic Analysis and Preliminary Experimental Results of a High-Power RF Plasma Source

To study the characteristics of radio frequency (RF) power coupling, RF plasma diagnostics, actively cooled tube, and negative ion production, a plasma source was designed as a small-scale test facility. The matching network was carefully designed and successfully applied to the 2-MHz RF plasma source. In this article, the design method of the matching unit will be presented; with the assistance of this matching unit, the RF plasma source was successfully lit and the reflected power was reduced to a very low level. A <inline-formula> <tex-math notation="LaTeX">$V\!\!-\!\!I$ </tex-math></inline-formula> probe was installed in front of or in the rear of the matching network, respectively, to <i>in situ</i> measure the RF voltage, current, and phase angle. The equivalent resistance of the RF plasma source was analyzed in detail. The RF power coupling efficiency was derived in two different methods, and the relationship between the coupling efficiency and the equivalent resistance of the plasma source is verified. At the same time, the equivalent resistance of the plasma source was also collected to optimize the matching unit.

Effects of Substrates on Structural and Morphological Characteristics of Radio Frequency Sputtered ZnO Layers

High quality Zinc Oxide nanostructures (ZONSs) with customized traits became demanding for diverse applications. Based on this fact, some ZONSs with varied layer thicknesses (100 to 400 nm) were deposited on three types of Si (plain, polished and etched) and borosilicate glass substrates using the radio frequency (RF) sputtering method. Asdeposited samples were characterized systematically using various techniques to determine the effects of the substrates on their structures and morphologies. The XRD analyses of the sample showed the formation of high quality nanocrystallites with varying sizes where the crystallinity was improved with the increase of layer thickness and change of substrates. The FESEM and AFM images exhibited the nucleation of dense nanocrystallites with some pores/voids with enhanced surface roughness. In addition, the EDX spectra displayed the presence of appropriate chemical elements in the ZONSs layers. Sample grown on the etched Si substrate at layer thickness of 300 nm was found to be optimum. The results for the etched Si were presented. It was demonstrated that by optimizing the RF sputtering parameters (power of 100 W, Argon flow of 10 sccm and pressure of 10-5 mb) the structural and morphological traits of the layered ZONSs can be tailored. The proposed ZONSs may be useful for various optoelectronic applications including the metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors fabrication.

Effect of Oxygen Flow Rate on the Characteristics of RF Sputtered ZnO Thin Films

Zinc Oxide (ZnO) thin films were deposited on glass substrate by radio frequency (RF)reactive magnetron sputtering technique at variable Oxygen flow rates while Argon flow rates waskept constant. The effect of oxygen flow rate on structural, electrical, optical properties of nanostructured ZnO thin films were investigated by X-ray diffractometer, scanning eletron microscopy(SEM), Hall effect measurements and UV-Visible spectrophotometer. X-ray diffraction (XRD) datareveals films are polycrystalline hexagonal structure with (002) peak as a preferred orientation andcrystallite size was found to be in range12 nm-16 nm.The electrical resistivity of films decreasesfrom 10-1 Ω-cm to 10-2 Ω-cm. All deposited ZnO thin films shows high transmittance above 95% inthe visible range 360 nm-800 nm. The optical band gap and refractive indices have been calculatedusing UV-Vis transmission spectra. Oxygen gas flow rates found to have large impact onoptoelectronic properties of ZnO films.

RF and Thermo-Mechanical Examinations of Output Windows forW-Band Gyrotron

The reflection and transmission characteristics of edge-cooled single-disk output radio frequency (RF) windows of 95-GHz 100-kW gyrotron were studied. RF characteristics of output windows made off sapphire (rhombohedral, single crystalline), silicon nitride composite, and pyrolytic boron nitride (poly crystalline) (PBN) were compared. At the operating frequency, the return losses of 64.0, 60.0, and 50.0 dB were obtained, respectively, for sapphire, silicon nitride composite, and PBN while the related transmission losses turned to be, respectively, better than -0.01, -0.02, and -0.04 dB. The heat load due to RF power absorption in the disk was least for sapphire and maximum for PBN window. The structural analyses of these RF windows predicted the least deflection and least tensile stress for silicon nitride and PBN windows, respectively. Comparable bandwidths were offered by silicon nitride window (790 MHz) of thickness 1.13 mm and PBN (773 MHz) of thickness 2.19 mm. However, a major safety margin and thus structural integrity was offered by the silicon nitride (factor of safety 30.6) window in comparison to PBN (factor of safety 10.6).

Batteryless and Self-Reconfigurable Multimode RF Network using All-Passive Energy Smart-Sensing

In recent years, replacing the external control stimuli with internal control using characteristics of radio frequency (RF) signals (such as waveform or power level) has attracted considerable attention to the design of reconfigurable multifunctional RF devices. However, even with the most exciting techniques, the control process always needs a chip-based system to sense the power level or waveform of the incident RF signal, which is realised by additional supporting electronic components of the sensing and microcontroller circuits. Therefore, to achieve a batteryless structure, a majority of conventional works focus on using energy harvesters to convert energy from external environmental sources to DC energy for the electronic circuits. Herein, we propose a novel alternative approach to replace the traditional energy harvesters in batteryless RF devices with all-passive energy smart-sensing circuits. By exploiting the features of a nonlinear semiconductor device under different incident RF power values, the proposed network can passively self-sense the RF power level and dynamically self-control RF signal flow and power ratio. The operation of the proposed network can be considered as purely self-adaptation with control from the RF power level. Moreover, normal RF devices can be transformed to all-passive and batteryless purely self-reconfigurable devices via integration with the proposed structure. As proof of concept, the proposed network is integrated with a two-port antenna to experimentally demonstrate its purely self-reconfigurable polarisation. The proposed strategy is hereby expected to extend the field of batteryless self-reconfigurable multifunctional RF devices and pave promising new paths for the development of future intelligent, smart RF devices.

Development of effective drying strategy with a combination of radio frequency (RF) and convective hot-air drying for inshell hazelnuts and enhancement of nut quality

Drying characteristics of combined radio frequency (RF) and hot-air (HA) were investigated for inshell hazelnuts (Corylus avellana L.), which have air-gap between kernel and shell (shell, kernel, and air-gap between them). Inshell hazelnuts were subjected to HA, HA followed by RF (HAFRF), RF followed by HA (RFHA), and HA assisted RF (HARF) drying (simultaneous process). Fiber optic sensors were used to monitor temperature profiles for both hazelnut kernels and shells at three representative locations (center, edge, and corner) in a tray in 6-kW 27.12-MHz RF system with or without HA (~75 °C). RF heating resulted in higher kernel temperature than shell and was effective to remove kernel moisture. When RF heating was applied during or before HA drying, energy efficiency, drying efficacy, and nut quality were enhanced. This study provided a better understanding of drying characteristics of combined RF and HA process and suggested efficient RF-implemented drying strategies for inshell hazelnuts.

Sex-specific efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation: An individual patient data meta-analysis

Atrial fibrillation (AF) is a growing health burden, and pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) represents an attractive therapeutic option. Sex-specific differences in the epidemiology, pathophysiology, and clinical presentation of AF and PVI are recognized. We aimed at comparing the efficacy, safety, and procedural characteristics of CB and RF in women and men undergoing a first PVI procedure. We searched for randomized controlled trials and prospective observational studies comparing CB and RF ablation with at least 1 year of follow-up. After merging individual patient data from 18 data sets, we investigated the sex-specific (procedure failure defined as recurrence of atrial arrhythmia, reablation, and reinitiation of antiarrhythmic medication), safety (periprocedural complications), and procedural characteristics of CB vs RF using Kaplan-Meier and multilevel models. From the 18 studies, 4840 men and 1979 women were analyzed. An analysis stratified by sex correcting for several covariates showed a better efficacy of CB in men (hazard ratio for recurrence 0.88; 95% confidence interval 0.78-0.98, P = .02) but not in women (hazard ratio 0.98; 95% confidence interval 0.83-1.16; P = .82). For women and men, the energy source had no influence on the occurrence of at least 1 complication. For both sexes, the procedure time was significantly shorter with CB (-22.5 minutes for women and -27.1 minutes for men). CB is associated with less long-term failures in men. A better understanding of AF-causal sex-specific mechanisms and refinements in CB technologies could lead to higher success rates in women.

Development of a pulsed radio frequency ignited multicusp-free negative hydrogen ion source.

A multicusp-free external antenna based radio frequency (RF) negative hydrogen (H-) ion source was developed to produce 16 mA of H- ion current at -50 kVDC accelerating voltage operated with a pulse width of 2 ms at 2 Hz repetition rate. A pulsed RF igniter system is devised for generating the initial electron and ion pairs required to generate the main plasma in the pulsed mode. This pulsed RF igniter reliably starts ignition with a hydrogen gas flow rate in the range of 18-50 standard cubic centimeter per minute (SCCM). This system eliminates the need of igniter in continuous operation although it is operated in low power mode. This source operating at a low average power and without any moving parts can be expected to have a superior lifetime. This paper describes the development and operational characteristics of the pulsed RF ignited H- ion source.

Phase-Resolved Measurement of Atmospheric-Pressure Radio-Frequency Pulsed Discharges in Ar/CH4/CO2 Mixture

In order to comprehensively investigate the discharge characteristics of an atmospheric-pressure radio-frequency (RF) pulsed discharge in Ar/CH4/CO2, a phase-resolved measurement is given in this paper. Firstly, the discharge characteristics of RF plasma in a gas mixture of Ar, CO2 and CH4 are investigated under different parameters. It is found peak power is more efficient than duty cycle in increasing the discharge area. Besides, a phase-resolved morphology of RF plasma is given. The discharge in the positive cycle is longer in length and stronger in emission intensity than in the negative cycle. Secondly, different activation paths of species have been obtained by using phase-resolved optical emission spectroscopy. Ar species is mainly activated by electron collision effect, while CH and C2 are mainly activated by Ar metastable species. Finally, detailed electron kinetics is analyzed. The results show that most energy is transferred to the vibrational excitation compared to elastic activation, electronic excitation, and ionization under different ratios of CO2 and CH4 to Ar. Besides, under a higher ratio of CH4 and CO2 to Ar, the generating rate of species and power loss rate are higher. It proves that higher fraction of CO2 and CH4 is better for the conversion rate and energy efficiency under RF discharge in theory, which guides the reforming of CH4 and CO2 in RF discharge.