Radio Frequency Waves Research Articles

Radiofrequency waves increase the brain levels of inflammatory biomarkers, neurotrophin and serotonin

The increase in mobile technology has raised concerns about the potential health effects of mobile phone radiation. The biological impact of exposure to radiofrequency (RF) waves emitted by electronic devices has been extensively studied and is a concern for the public, policymakers, and health researchers. The study aimed to examine the impact of 900 MHz radiofrequency waves on biomarkers such as interleukin (IL)-1α, IL-1β, tumour necrosis factor (TNF)-α, homocysteine, nerve growth factor, and serotonin in rats' serum and brain tissue. Thirty adult male Sprague Dawley rats (200 ± 20g) were randomly assigned to three groups (n=10): control (not exposed to RF), exposed I (2 hours per day), and exposed II (4 hours per day). The exposed groups were exposed to 900 MHz RFW for 30 consecutive days. The results showed that only the exposed group II significantly increased serum serotonin levels compared to the control group (P=0.0496). IL-1α, TNF-α, and nerve growth factor levels in brain tissue increased significantly in both exposed groups compared to the control group (P<0.0001). The control group had significantly lower levels of IL-1β compared to exposed groups I (P=0.0289) and II (P=0.0004). Additionally, serotonin and homocysteine levels in the brains of exposed II were significantly higher compared to the other groups (P<0.0001). The results showed disruptions in all biomarkers, indicating the potential impacts of daily exposure to 900 MHz radiofrequency waves from mobile phones on brain function. This suggests that mobile phone radiation may affect brain function.

Analysis of fusion alphas interaction with RF waves in D-T plasma at JET

This work studies the influence of radio frequency (RF) waves in the ion cyclotron resonance heating (ICRH) range of frequencies on fusion alphas during the recent JET D-T campaign. Fusion alphas from D-T reactions are created with energies of about 3.5 MeV and therefore have significant Doppler shifts enabling synergistic interactions between them and RF waves at a broad range of frequencies, including the ones foreseen for future fusion machines in ITER (Schneider et al 2021 Nucl. Fusion 61 126058) and SPARC (Creely et al 2020 J. Plasma Phys. 86 865860502). Resonant interactions between RF waves and alphas, also called synergistic effects, will modify the alpha distribution and ultimately will have an impact on alpha orbit losses and heating. Data from JET 3.43 T/2.3 MA pulses based on the hybrid scenario (Hobirk et al 2023 Nucl. Fusion; Hobirk et al 29th IAEA FEC23 Conf. (16–21 October 2023); Challis et al 48th EPS Conf. on Plasma Physics (27 June–1 July 2022) during the DTE2 campaign (Maggi et al 2023 Nucl. Fusion)) were used for the analysis in this study. The impact of synergistic effects on alpha orbit losses and alpha heating are assessed. The conclusions are based on the analysis of experimental data for fast alpha losses, i.e. measurements from neutral particle analyser (NPA), fast ion losses scintillator detector, Faraday cups (FCs), and TRANSP (Hawryluk et al 1980 Physics of Plasmas Close to Thermonuclear Conditions vol 1 (CEC) pp 19–46) simulations. Experimental data and TRANSP analysis indicates that there are indeed changes in the alpha distribution function (DF) due to interaction with RF waves. Data from the NPA show increased 4He flux in the range from a few hundred keV up to 800 keV for pulses with RF power, while TRANSP clearly shows modifications in the fast alpha DF for these energies. Data from the scintillator detector and the FCs were compared for pulses with and without ICRH power and versus cases with enhanced alpha losses due to MHD activity. The trends from these diagnostics consistently show no additional alpha losses due to interaction with RF waves. TRANSP predictions for the impact of ynergistic effects on alpha heating show up to a 42% increase in alpha electron heating and up to a 25% increase in alpha ion heating. These effects, however, become negligibly small, less than 1%, when alpha heating is compared to the total auxiliary heating power in the investigated JET pulses.

Influence of radio frequency wave driving frequency on capacitively coupled plasma discharge

A two-dimensional symmetric fluid model is established to study the influence of radio frequency (RF) wave driving frequency on the capacitively coupled plasma discharge. The relationship between the driving frequency and electron density is obtained by solving the electron energy balance equation. The calculation results show that the average electron density first increases rapidly with the increase in driving frequency and then gradually tends to saturation at a threshold frequency. A fluid simulation is also carried out, which provides similar results. Physical studies on this phenomenon are conducted, revealing that the essence of this phenomenon is due to the inability of electrons to quickly respond to potential changes within the boundary sheath when the driving frequency of RF exceeds the plasma frequency. In addition, it is also found that increasing gas pressure can enhance the electron density and the type of gas can also affect the electron density.

A distance adaptive dual-hop routing algorithm for underwater optical wireless networks

Three main kinds of underwater wireless communication, which employ acoustic waves, radio frequency and optical waves, have attracted intensive research interests in recently years. Among them, the underwater optical wireless communication (UOWC) is characterized by high propagation speed and large transmission bandwidth. But, the optical waves in underwater environment are significantly affected by absorption and scattering effects, which limit their transmission range. In order to enhance the performance of UOWC, designing a transmission and energy efficiency routing algorithm has become a non-ignorable issue in UOWC. In this paper, a transmission distance adaptive dual-hop (TDAD) routing algorithm is proposed for underwater optical wireless networks (UOWNs) to improve their efficiency in packet-delivery and energy-consumption. Unlike the existing routing algorithms designed for UOWNs, which pre-set the transmission range of network nodes, the proposed TDAD algorithm adaptively selects the transmission range for each node according to the diversity of heterogeneous service requests and employs location and energy information in its dual-hop based routing procedure. Simulation results indicate that the proposed TDAD algorithm remarkably improves packet delivery rate with more balanced energy consumption when compared to the deviation angle-based single-hop (DAS) algorithm and the distributed sector-based (DS) routing algorithm.

Is Renal Denervation Effective in Treating Resistant Hypertension?

Resistant hypertension is diagnosed in patients whose blood pressure target is unmet despite the use of three or more antihypertensive medications. Systemic sympathetic hyperactivation is associated with the development of resistant hypertension. As the kidney is largely pervasive of the sympathetic nervous system renal denervation procedure was developed to control blood pressure by attenuating the renal and systemic sympathetic hyperactivity. Renal denervation is a minimally invasive procedure that uses radiofrequency or ultrasound energy waves to reduce the activity of the renal artery nerves. Previous clinical trials have shown conflicting results regarding the efficacy of the procedure. Symplicity HTN-1 and -2 trials showed effective blood pressure lowering results in the renal denervation group with a good safety profile. However, the Symplicity HTN-3 trial showed no difference in blood pressure lowering effect between the renal denervation and control Sham procedure groups. Notwithstanding, some recent clinical trials with Sham control and meta-analysis showed clinical benefits of renal denervation. Other clinical benefits of renal denervation include glucose control, cardiovascular protective effect, reduction of obstructive sleep apnea, and neuralgia control. A subset of patients with satisfactory blood pressure control response to the procedure may experience improved glucose control due to the overall reduced sympathetic activity and insulin resistance. Sympathetic activity control after renal denervation has cardioprotective effects, especially for those with arrhythmia and left ventricular hypertrophy. Also, renal denervation could be helpful in renalorigin pain control. Renal denervation is an effective, safe, non-invasive procedure with many clinical benefits beyond blood pressure control. Further development in the procedure technique and selection of target patients are needed for wider clinical use of renal denervation in resistant hypertension.

Simulation of a Radio-Frequency Wave Based Bacterial Biofilm Detection Method in Dairy Processing Facilities

This paper describes the principles behind the radio-frequency (RF) sensing of bacterial biofilms in pipes and heat exchangers in a dairy processing plant using an electromagnetic simulation. Biofilm formation in dairy processing plants is a common issue where the absence of timely detection and subsequent cleaning can cause serious illness. Biofilms are known for causing health issues and cleaning requires a large volume of water and harsh chemicals. In this work, milk transportation pipes are considered circular waveguides, and pasteurizers/heat exchangers are considered resonant cavities. Simulations were carried out using the CST studio suite high-frequency solver to determine the effectiveness of the real-time RF sensing. The respective dielectric constants and loss tangents were applied to milk and biofilm. In our simulation, it was observed that a 1 µm thick layer of biofilm in a milk-filled pipe shifted the reflection coefficient of a 10.16 cm diameter stainless steel circular waveguide from 0.229 GHz to 0.19 GHz. Further sensitivity analysis revealed a shift in frequency from 0.8 GHz to 1.2 GHz for a film thickness of 5 µm to 10 µm with the highest wave reflection (S11) peak of ≈−120 dB for a 6 µm thick biofilm. A dielectric patch antenna to launch the waves into the waveguide through a dielectric window was also designed and simulated. Simulation using the antenna demonstrated a similar S11 response, where a shift in reflection coefficient from 0.229 GHz to 0.19 GHz was observed for a 1 µm thick biofilm. For the case of the resonant cavity, the same antenna approach was used to excite the modes in a 0.751 m × 0.321 m × 170 m rectangular cavity with heat exchange fins and filled with milk and biofilm. The simulated resonance frequency shifted from 1.52 GHz to 1.54 GHz, for a film thickness varying from 1 µm to 10 µm. This result demonstrated the sensitivity of the microwave detection method. Overall, these results suggest that microwave sensing has promise in the rapid, non-invasive, and real-time detection of biofilm formation in dairy processing plants.

Atmospheric Noise Measurements in the Garden: Detecting Universalities in Inter-Spheric Waiting Time Statistics

Lightning flashes result in an instantaneous emission of electromagnetic (EM) waves that encompass a broad spectrum of frequencies in the domain of radio waves. The signature of these impulses in the region of the very low frequency (VLF) of radio waves and bellow are called spherics. These impulsive signals traverse great distances in the waveguide between the Earth’s ionosphere and its surface. Due to the abundance of lightnings the lower end of the EM spectrum is dominated by the waveforms of these emission. It is called atmospheric radio noise because of its origin. This article outlines a straightforward approach for capturing spherics activity within the VLF radio wave range. Employing data processing techniques, we pinpoint the timestamps of spherics within time series data. The distribution of inter-spheric times is analyzed across various detection threshold levels. Utilizing recordings spanning two distinct years and seasons, we replicate the established form of the inter-spheric time distribution described in the literature. Notably, we demonstrate that by rescaling the time intervals between spherics with the mean time for a specific recording and given detection threshold, the distributions collapse to a master curve. This universal pattern is accurately characterized by a single-parameter mean-scaled Gamma distribution. Additionally, we note the similarities in the distribution of inter-spheric times with patterns found in earthquake recurrence times.

High‐Latitude Off‐Great Circle Propagation Associated With the Solar Terminator

AbstractLarge‐scale ionospheric gradients associated with the solar terminator can deflect high frequency (HF) radio waves to off‐great circle paths during the morning and evening, negatively impacting technologies reliant on HF radio wave propagation. For example, geolocation algorithms used by scientific and military over‐the‐horizon radars (OTHRs) generally assume on‐great circle propagation, and thus lateral deviations from the great‐circle path can lead to positioning errors. In this study, radio wave propagation is simulated via 3D numerical ray traces though an empirical, high‐latitude model ionosphere initialized for a variety of times of the day and year to explore and quantify high‐latitude off‐great circle propagation associated with the solar terminator. Analysis of these simulations show large scale east‐west ionospheric gradients due to the solar terminator can cause lateral deviations in north‐directed propagation paths exceeding 20° at sunrise and sunset depending on radio wave frequency, though the largest portion of received signal power tends to experience maximum deflections of 5°. An exploration of the dependence of propagation direction on deflection shows that propagation paths parallel to the solar terminator tend to experience the largest deflections. Since the solar terminator at high latitudes is at an angle with respect to north in the winter and summer, propagation paths oriented west or east of north can experience larger deflections than north oriented paths at sunrise and sunset during these times of year. Impacts of these diurnal deflections on the operation of OTHR and scientific radar are discussed, as well as possible strategies for mitigating them.

Combined ns pulsed-RF excitation and impedance matching considerations for the production of moderate E/n atmospheric pressure discharges for gas conversion

Sub-breakdown radiofrequency (RF) discharges enabled by a nanosecond (ns) pulse ignition source are studied at atmospheric pressure in a range of gas mixtures from completely inert (in Ar) to completely reactive (in CO2). An electrical characterisation of the continuous wave (CW) RF discharge (13.56 MHz) is performed to determine plasma impedance and plasma power dissipation. Two different measurement methods to electrically characterize the system are described and compared. One method uses in-situ measurements of discharge parameters (voltage, current and the phase angle), and the other method performs ex-situ measurements of the load circuit using a vector network analyser. It was found that RF plasma power deposition depended on the applied RF power as well as the gas mixture composition. Using the in-situ voltage, current and phase angle measurements, plasma power deposition was calculated to be as much as 85% and 76% of the applied RF power for the pure Ar and pure CO2 cases, respectively. A preliminary qualitative assessment of the plasma composition was performed by optical emission spectroscopy, and CO2 conversion by mass spectrometry. CO2 to CO conversions of 11.2% and 5.5% in a 20:80 (CO2:Ar) mixture and in 100% CO2, respectively, were observed. This study demonstrates a RF plasma source for gas conversion applications at atmospheric pressure in a completely reactive gas.

Boosting radio frequency radiation with collisional processes in picosecond laser filamentation

When focused in air, ultrashort pulse lasers generate a plasma that produces ultrabroadband radio frequency (RF) radiation via both ponderomotive and plasma wake field current mechanisms. We have performed experiments with high energy pulses and pulse durations up to 5 ps, while holding the power constant. These longer pulses drive much higher electron densities and temperatures, especially as collisional processes become important, and we in turn have measured substantially increased RF generation. We have also developed a Drude numerical model of the ionization within the laser pulse, the heating due to collisions, and the ensuing current density evolution. We find that the low frequency scaling of the simulated current matches the experimental data, which indicates that the ponderomotive currents dominate the RF generation for these atmospheric pressure plasmas. However, the experimentally measured spectra also show an additional low frequency (1–10 GHz) component that grows with laser pulse length, which is consistent with the plasma wake surface wave RF also becoming important as the plasma temperature approaches 100 eV.

Iterative addition of parallel non-local effects to full wave ICRF finite element models in axisymmetric tokamak plasmas

The current response of a hot magnetized plasma to a radio-frequency wave is non-local, turning the electromagnetic wave equation into an integro-differential equation. Non-local physics gives rise to wave physics and absorption processes not observed in local media. Furthermore, non-local physics alters wave propagation and absorption properties of the plasma. In this work, an iterative method that accounts for parallel non-local effects in 2D axisymmetric tokamak plasmas is developed, implemented, and verified. The iterative method is based on the finite element method and Fourier decomposition, with the advantage that this numerical scheme can describe non-local effects while using a high-fidelity antenna and wall representation, as well as limiting memory usage. The proposed method is implemented in the existing full wave solver FEMIC and applied to a minority heating scenario in ITER to quantify how parallel non-local physics affect wave propagation and dissipation in the ion cyclotron range of frequencies (ICRF). The effects are then compared to a reduced local plane wave model, both verifying the physics implemented in the model, as well as estimating how well a local plane wave approximation performs in scenarios with high single pass damping. Finally, the new version of FEMIC is benchmarked against the ICRF code TORIC.

Actively tunable laser action in GeSn nanomechanical oscillators.

Mechanical forces induced by high-speed oscillations provide an elegant way to dynamically alter the fundamental properties of materials such as refractive index, absorption coefficient and gain dynamics. Although the precise control of mechanical oscillation has been well developed in the past decades, the notion of dynamic mechanical forces has not been harnessed for developing tunable lasers. Here we demonstrate actively tunable mid-infrared laser action in group-IV nanomechanical oscillators with a compact form factor. A suspended GeSn cantilever nanobeam on a Si substrate is resonantly driven by radio-frequency waves. Electrically controlled mechanical oscillation induces elastic strain that periodically varies with time in the GeSn nanobeam, enabling actively tunable lasing emission at >2 μm wavelengths. By utilizing mechanical resonances in the radio frequency as a driving mechanism, this work presents wide-range mid-infrared tunable lasers with ultralow tuning power consumption.

Equilibrium reconstruction constrained by the consistency of current simulation on EAST

The attainment of a reliable equilibrium is a critical aspect of tokamak experiments and physics analysis. A common method for establishing a reliable equilibrium current involves reconstructing it from indirect measurements, such as those obtained from polarimeter-interferometers (POINT) and motional Stark effect (MSE) systems. However, uncertainties still exist in the reconstruction results. For the equilibrium reconstruction on the EAST tokamak, which is based on the POINT system, the primary sources of uncertainty are the limited scope of measurements and the sensitivity of the reconstruction process. This paper proposes an enhanced approach that utilizes current simulation as a constraint to maintain consistency between the initial equilibrium and the simulated results. The radio frequency waves driven current is identified as a particularly influential component due to its interaction with the q profiles of the equilibrium and the deposition region of the waves. Two specific discharges are presented to illustrate how a new equilibrium can be achieved, which enhances consistency between the equilibrium and the simulated current, taking into account the dependencies of various components.

Statistical Analysis of Off‐Great Circle Radio Wave Propagation in the Polar Cap

AbstractHigh latitude ionospheric density structures such as polar cap patches and arcs are capable of deflecting high frequency (HF) radio waves to off‐great circle paths, and are likely detrimental to technologies dependent on HF radio propagation. In this study, nearly 2.5 years of 4.6–14.4 MHz data from a multi‐frequency HF radio link between Qaanaaq, Greenland and Alert, Canada are used to investigate high‐latitude off‐great circle propagation in the polar cap. After an example of HF radio propagation affected by polar cap patches is shown in detail, a statistical analysis of the occurrence and impacts of off‐great circle deflections in the polar cap is presented. Off‐great circle propagation is shown to be increasingly common with increasing frequency up to 11.1 MHz, such that averaged over 1 year, received 11.1 MHz signals experienced deflections >30° from the great circle direction 65.6% of the time. The occurrence of these deflections across the year is shown to be at a maximum in the winter, while occurrence across the day varies with season. Trends across both time of day and time of year for 11.1 and 14.4 MHz deflections are consistent with polar cap patch occurrence trends. Off‐great circle deflections are shown to be associated with increased time‐of‐flights, a larger range of positive and negative Doppler shifts, increased Doppler spreads, and lower signal‐to‐noise ratios. These results are discussed in the context of ionospheric phenomena in the polar cap, and implications for over‐the‐horizon radars operating at high latitudes.

The Ellipticity of High Frequency Transionospheric Radio Waves

AbstractThe polarization state of transionospheric high frequency (HF) radio waves can be determined using the crossed‐dipole antennas of the Radio Receiver Instrument (RRI) onboard Enhanced Polar Outflow Probe (e‐POP) on the CAScade, Smallsat, and IOnospheric Polar Explorer/Swarm‐E satellite. Coordinated experiments between ground radars and RRI showed that the radio waves have high ellipticity angles (elliptical or circular polarization) for propagation direction 6°–25° from the perpendicular direction to the local geomagnetic field. However, from magnetoionic theory and a typical assumption of roughly equal power in the O‐ and X‐modes, radio waves can have high ellipticity angles only when the propagation direction is within 10° of perpendicularity. This investigation uses coordinated experiments between the Saskatoon SuperDARN radar and RRI. Magnetoionic modeling reveals that the relative strengths of the O‐ and X‐modes for the HF radio waves transmitted from the Saskatoon SuperDARN change significantly poleward of the radar. Differences in the relative power between the two wave modes were found to significantly modify the polarization state of radio waves, and govern the sense of rotation of the wave. Even a relatively modest 2–5 dB power difference in the X‐mode over the O‐mode was found to result in unexpected observations of circularly polarized radio waves at aspect angles 6°–10° from perpendicular, and unexpected elliptically polarized waves observed at aspect angles more than 10° from perpendicular. Therefore, a combination of RRI observations and modeling, which accounts for relative differences in the O‐ and X‐mode powers, was used here to better understand the unexpected observations of polarization states of transionospheric radio waves.

Real-time tracking of radial artery vessel wall using a Kalman filter-based ultrasound single-plane wave RF signal time-frequency information fusion algorithm

ObjectiveThe goal of our study was to achieve real-time dynamic tracking of the radial artery vessel wall in everyday life, which is crucial for blood pressure estimation and cardiovascular disease prediction. MethodsThe algorithm integrates time–frequency information from ultrasound single-plane wave RF (radiofrequency) signals and consists of three main components: feature frame ROI (region of interest) selection, inter-frame cross-correlation and intra-frame autocorrelation, and feature frame Kalman filtering. ResultsExperimental validation on a silicone gel ultrasound phantom with simulated blood vessels demonstrates an average diameter estimation error of less than 0.5% compared to ground truth values. Comparative experiments show similar relative errors (2.83%, 2.43%) to the optical flow method, with a computational speed 7.32 times faster. The algorithm accurately aligns extracted pulse waves with pressure pulse waves at six local feature points per cycle. ConclusionThe proposed method achieves a favorable balance between speed and accuracy in tracking the radial artery vessel wall. It holds significant potential for real-time monitoring of physiological health parameters, offering precise and dynamic tracking capabilities. SignificanceThis algorithm addresses the challenges of non-invasive real-time tracking, benefiting blood pressure estimation and cardiovascular disease prediction. Its integration of time–frequency information and efficient computational speed make it valuable for the scientific community and public in monitoring physiological health parameters.

Non‐Hermitian Broadside Coupled Split Ring Resonators with Directional Sensitivity

AbstractDirectional radiofrequency (RF) sensing, also known as radio direction finding, is essential in various applications that involve localizing RF sources. However, existing RF sensing technologies face challenges due to their large antenna sizes and complex RF signal processing circuits, which hinder the realization of miniaturized subwavelength direction sensors. In this article, a non‐Hermitian broadside coupled split ring resonators (BC‐SRRs) are presented, which can identify the direction of an incident RF signal with angles ranging from 0° to 180°. The non‐Hermitian Hamiltonian of the system, which can be interpreted by the temporal coupled mode theory, gives rise to asymmetric resonant modes of the BC‐SRRs. The asymmetry allows the direct measurement of RF wave incident angle by probing the resonant strength of the two BC‐SRRs. For the proof of concept, a one‐stage Dickson voltage multiplier is employed to rectify the RF signals and demonstrate angle sensing ability by relating the rectified voltage to the incident angle. The results showcase the potential of the proposed technique using non‐Hermitian BC‐SRRs as a pathway toward subwavelength antenna‐based radio direction finding.

Low-frequency whistler waves driven by energetic electrons in plasmas of solely electron cyclotron wave heating

Whistler waves are a type of low-frequency electromagnetic wave common in nature, which is usually associated with energetic electron phenomena. This study presents experimental observations of low-frequency whistler wave instabilities driven by energetic electrons through wave–particle interactions on EXL-50. The energetic electrons are generated by electron cyclotron waves (ECWs) through stochastic heating [Wang et al., J. Plasma Phys. 89, 905890603 (2023)] and do not match the characteristics of the runaway electrons [Shi et al., Nucl. Fusion 62, 086047 (2022)]. In the steady-state plasma of the Energy iNNovation XuanLong-50 (EXL-50), whistler waves within the 30–120 MHz frequency range were observed during electron cyclotron resonance heating. These waves displayed multiple frequency bands, and the frequencies of waves were directly proportional to the Alfvén velocity. Furthermore, it was interesting to find that superposition of lower hybrid wave into ECW resulted in the suppression of these whistler waves. The experimental results may indicate that the whistler waves are driven by energetic electrons (excluding runaway electrons). These discoveries carry significant implications for several areas of research, including the investigation of wave–particle interactions, the development of radio frequency wave current drivers, their potential impact on the electron dynamics in future fusion devices, and even the presence of unusually low-frequency whistler waves in Earth's radiation belts.

Vector-based feedback of continuous wave radiofrequency compression cavity for ultrafast electron diffraction.

The temporal resolution of ultrafast electron diffraction at weakly relativistic beam energies (100 keV) suffers from space-charge induced electron pulse broadening. We describe the implementation of a radio frequency (RF) cavity operating in the continuous wave regime to compress high repetition rate electron bunches from a 40.4 kV DC photoinjector for ultrafast electron diffraction applications. Active stabilization of the RF amplitude and phase through a feedback loop based on the demodulated in-phase and quadrature components of the RF signal is demonstrated. This scheme yields 144 ± 19 fs RMS temporal resolution in pump-probe studies.

Efficacy of capacitive-resistive therapy on the treatment of myofascial pain – A randomized control trial

BackgroundMyofascial pain syndrome is a painful musculoskeletal condition with muscle spasm, referred pain, stiffness, restricted range of motion. Capacitive-resistive diathermy heats deep tissues by transferring energy through radiofrequency waves. Although this modality is used to treat various musculoskeletal disorders, there is no specific data on myofascial trigger points. Thus, we aimed to evaluate the effectiveness of capacitive-resistive diathermy on the myofascial trigger points. MethodsThirty-six volunteers with active myofascial trigger points were included. Patients were randomly and equally allocated into two groups. Group-1 is the capacitive-resistive diathermy treatment group; Group-2 is the placebo capacitive-resistive diathermy (PG). Visual analog scale (VAS), pain pressure threshold (PPT), neck disability index (NDI), neck range of motion (nROM), Short form-36 (SF-36) were used as outcomes before and after the intervention. ResultsIn both groups, VAS, PPT, NDI score significantly improved within the groups (p < 0.05). The CRG showed a statistically significant improvement in nROM for flexion, extension, and rotation (p < 0.05). However, ROM increase in CRG is not superior to PG (p > 0.05). ConclusionsThere was no significant difference between the two groups. We thought positive results in the PG might attributed to doing exercise. As a result, capacitive-resistive diathermy is not superior to exercise, but can be used as an adjuvant modality in myofascial trigger points treatment.