Pulse Repetition Frequency Research Articles

A 94 GHz Pulse Doppler Solid-State Millimeter-Wave Cloud Radar

A 94 GHz pulse Doppler solid-state millimeter-wave cloud radar (MMCR), Tianjian-II (TJ-II), has been developed. It reduces the size and cost using a solid-state power amplifier (SSPA) and a single antenna. This paper describes the system design, including hardware and signal processing components. Pulse compression, segmented pulse, and dual pulse repetition frequency (PRF) technologies are employed to overcome the limitations imposed by the low power of the SSPA and the high frequency of 94 GHz. The TJ-II also features a dual-polarization, high-gain antenna for linear depolarization ratio detection and a time-division receive channel to improve channel consistency and save on costs. To achieve high flexibility and low interference in signal transmission and reception, the TJ-II uses software-defined radio technology, including direct digital synthesis, digital downconversion, and bandpass sampling. A series of Doppler power spectrum processing methods are proposed for detecting weak cloud signals and improving scene adaptability.

Estimation of the sea state bias error budget for pulse-limited satellite altimetry

Using an empirical, non-parametric sea state bias (SSB) modeling method, which was developed as a tool for SSB error analysis (Putnam, Alexa Forthcoming), we provide an error budget for overall SSB error, as well as the contributing sources of this error budget. The error analysis compares methods used to derive SSB models from observed altimeter measurements, collinear differences of measurements from adjacent repeat cycles, and methods using both collinear and crossover differences of measurements. Our error analysis reveals systematic error caused by ionosphere correction uncertainty in SSB models obtained from direct measurements, and wet troposphere correction uncertainty in SSB models generated using difference measurements. Results also expose a correlation to altimeter measurement error, with the backscatter coefficient accounting for over 20% of the SSB evaluation error and SWH accounting for approximately 50-60%. The error analysis presented here suggests SSB errors are lower than the often-used approximation of SSB error as 1% of SWH, except at SWH values less than 2 m where errors are likely larger. We find that increasing the pulse repetition frequency of the altimeter reduces SSB errors. The future for improving empirical, nonparametric SSB estimation primarily depends on improving measured SWH.

A novel convex acoustic lens-attached ultrasound drug delivery system and its testing in a murine melanoma subcutaneous model

Target-specific drug release is indispensable to improve chemotherapeutic efficacy as it enhances drug uptake and penetration into tumors. Sono-responsive drug-loaded nano-/micro-particles are a promising solution for achieving target specificity by exposing them to ultrasound near tumors. However, the complicated synthetic processes and limited ultrasound (US) exposure conditions, such as limited control of ultrasound focal depth and acoustic power, prevent the practical application of this approach in clinical practice. Here, we propose a convex acoustic lens-attached US (CALUS) as a simple, economic, and efficient alternative of focused US for drug delivery system (DDS) application. The CALUS was characterized both numerically and experimentally using a hydrophone. In vitro, microbubbles (MBs) inside microfluidic channels were destroyed using the CALUS with various acoustic parameters (acoustic pressure [P], pulse repetition frequency [PRF], and duty cycle) and flow velocity. In vivo, tumor inhibition was evaluated using melanoma-bearing mice by characterizing tumor growth rate, animal weight, and intratumoral drug concentration with/without CALUS DDS. US beams were measured to be efficiently converged by CALUS, which was consistent with our simulation results. The acoustic parameters were optimized through the CALUS-induced MB destruction test (P = 2.34 MPa, PRF = 100 kHz, and duty cycle = 9%); this optimal parameter combination successfully induced MB destruction inside the microfluidic channel with an average flow velocity of up to 9.6 cm/s. The CALUS also enhanced the therapeutic effects of an antitumor drug (doxorubicin) in vivo in a murine melanoma model. The combination of the doxorubicin and the CALUS inhibited tumor growth by ∼ 55% more than doxorubicin alone, clearly indicating synergistic antitumor efficacy. Our tumor growth inhibition performance was better than other methods based on drug carriers, even without a time-consuming and complicated chemical synthesis process. This result suggests that our novel, simple, economic, and efficient target-specific DDS may offer a transition from preclinical research to clinical trials and a potential treatment approach for patient-centered healthcare.

Effect of pulse parameters on ablation efficiency in dual-frequency HIFU therapy

High-intensity focused ultrasound (HIFU) has now been widely used to ablate various benign and malignant tumors. But it is still critical to increase the ablation efficiency in many clinical applications. Dual-frequency HIFU has been proven to be more efficient in ablation, but the principle on selecting the pulse parameters in this method remains to be explored. In this study, the in vitro lesion areas under different pulse repetition frequencies (PRFs), duty ratios, and frequency differences were compared, cavitation activity was also monitored during HIFU exposure. The results showed that different pulse parameters caused different types of lesions. In HIFU therapy, those pulse parameters that maximize the thermal effect, reduce heat dissipation and generate sufficient cavitation activities should be considered. But the method of evaluating or predicting the damage by using the cavitation dose is only applicable to mechanical damage.

Passively Q-switched erbium-doped fiber laser based on Ti3C2Tx saturable absorber

In this work, layer-structured MXene-Ti3C2Tx was successfully synthesized through chemical etching the Al in Ti3AlC2 using hydrochloric acid. The Ti3C2Tx was characterized in detail using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Additionally, a Ti3C2Tx-polyvinyl alcohol (PVA) thin film was prepared, which exhibited modulation depths of 3.8% and a saturation intensity of 418.61 MW/cm2. Passive Q-switched erbium-doped fiber laser built employing Ti3C2Tx-PVA thin film with saturated absorption characteristics. When the pump power is between 68 and 112 mW, Q-switched pulse outputs were achieved. By gradually enhancing the pump power, the pulse repetition frequency enhanced from an initial value of 29.47 kHz to a final value of 47.79 kHz, while the pulse width reduced from 6.1 μs to 3.45 μs. Correspondingly, the output power of the system enhanced from 1.063 mW to 1.847 mW. When the pump power is 112 mW, the maximum single-pulse energy can reach 38.64 nJ. The experimental results have demonstrated the promising potential of Ti3C2Tx-PVA as an effective saturable absorber.

Influence of CO2 laser beam modelling on electronic and electrochemical properties of paper-based laser-induced graphene for disposable pH electrochemical sensors

Laser-induced graphene (LIG) allows for the fabrication of cost-effective, flexible electrodes on a multitude of recyclable and sustainable substrates, for implementation within electrochemical biosensors. This work expands on current LIG research, by experimentally modeling the effects of several CO2 laser irradiation variables towards resulting conductive and electrochemical properties of paper-derived LIG. Instead of relying on the established paradigm of manipulating power and scan speed of the laser irradiation process for optimized outcomes, modeling of underlying laser operation principles for pulse modulation, regarding pulse repetition frequencies, pulse duration and defocus are presented as the key aspects dominating graphitization processes of materials. This approach shows that graphitization is dominated by appropriate pulse durations, dictating the time the substrate is exposed to each laser pulse, with laser fluence and irradiation defocus influencing the resulting conductive properties, with sheet resistances as low as 14 Ω sq−1. Similarly, fabrication settings controlled by these parameters have a direct influence on the properties of LIG-based electrochemical three-electrode cells, with optimized fabrication settings reaching electrochemically active surface area as high as 35 mm2 and heterogeneous electron transfer rates of 3.4 × 10−3 cm.s−1. As a proof-of-concept, the production of environmentally friendly, accessible, and biocompatible pH sensors is demonstrated, using two modification approaches, employing riboflavin and polyaniline as pH-sensitive elements.

Simulation of the N-MFSK Method Used for Laser-Induced Acoustic Communication

Laser-induced acoustic (LIA) technology is a possible way of communicating from an air platform to an underwater target. The present paper describes a modulation method of n-multiple frequency shift keying (n-MFSK) used for improving the communication rate of LIA technology. The thermal expansion mechanism was selected as a way of generating an acoustic signal by the pulse laser in this work. Thus, the technology of pulsed repetition frequency (PRF) can be used to realize n-MFSK modulation by controlling laser frequency and allocating periods in the time domain. The results of numerical simulation show that n-MFSK modulation can improve the communication rate and band utilization compared with the traditional n-frequency shift keying (n-FSK) modulation.

Ultrasonographic and Doppler characteristics of corpus luteum luteogenesis in Remonta Argentino jennies

The corpus luteum (CL) plays a crucial role in maintaining pregnancy and preparing the uterus for implantation of the fertilized egg. Transrectal Doppler ultrasonography of the ovary can be used as a diagnostic tool to assess the reproductive status and functionality of the CL. Our aim was to characterize size, echogenicity and degree of vascularization of the corpus luteum over five days after ovulation in Remonta Argentino jennies. Five healthy cycling jennies aged 9 to 14 years were monitored transrectally using the MyLabTMOne ultrasound (ESAOTE, InMed, Argentina) with a 5-10 MHz linear array transducer. After a preovulatory follicle was detected, jennies were monitored daily for ovulation (day 0) and ultrasonographic evaluation of the CL until day 5. Two ovulations and the respective CL formation were analyzed in each jenny (n=10 CL). Size and echogenicity were evaluated using B mode and CL vascularization using the Doppler-color function, with a pulse repetition frequency of 1.2 MHz. All ultrasound examinations were video recorded for analysis. Adobe Premiere Pro CS6® was used to collect three images from each video where the largest area of the CL and the highest Doppler signal were detected. Image J. version 1.52i software (National Institute of Health, USA) was used to analyze images and to determinethe area, number of gray pixels (echogenicity) and color area within the CL in Doppler mode. The average value from the three images was used to determine CL size (area in cm2), echogenicity (average gray pixel intensity) and the proportion of vascularized area (AV; area with blood flow/total CL area x 100). Spearman's test was used to correlate the variables and the changes recorded between days 1 and 5 of diestrus. The results obtained on each day were the following (values expressed as mean±SEM): Day 0: area 3.26±0.5; echogenicity 84.2±4.86; AV 5.54±1.75; Day 1: area 4.86±0.32; echogenicity 91.25±7.42; AV 1.84±0.26; Day 2: area 4.83±0.41; echogenicity 88.72±7.89; AV 3.51±0.81; Day 3: area 4.64±0.43; echogenicity 89.69±4.9; AV 4.54±0.67; Day 4: area 4.38±0.48; echogenicity 97.78±7.61; AV 5.8±1.06; Day 5: area 4.24±0.49; echogenicity 89.18±9.25; AV 8.66±1.15. No statistical correlation was observed either between variables or with the day of diestrus (p>0.05). Blood samples were collected daily between day 0 and day 5 of diestrus and progesterone determinations are ongoing. Our results contribute to a better understanding of CL formation in Remonta Argentino donkeys that could potentially be used to determine CL age and function.

Intensity Noise and Pulse Repetition Frequency Stability Measurements of a Passive Mode-Locked Cr:ZnSe Laser

Intensity Noise and Pulse Repetition Frequency Stability Measurements of a Passive Mode-Locked Cr:ZnSe Laser

ID: 202712 Loss of Conduction Fidelity in Dorsal Column Axons During Spinal Cord Stimulation With Conventional Frequencies

Epidural spinal cord stimulation (SCS) is an effective therapy for chronic pain, but there remains an opportunity to increase efficacy and response rates. Conventional paresthesia-producing SCS delivers pulse repetition frequencies < 200 Hz. SCS produces analgesia by activating large dorsal column axons which innervate inhibitory interneurons in the dorsal horn (Gate control theory). This understanding and contemporary research presume that dorsal column (DC) axons propagate faithfully every time a stimulation pulse is delivered. However, recent computational studies suggested that there may be a loss of conduction fidelity, or faithful propagation of an action potential for each stimulation pulse, depending on the stimulation frequency. We measured the response of single dorsal column axons to epidural SCS in healthy urethane-anesthetized Sprague-Dawley rats.

Dual-Link Synchronous Acquisition and Transmission System for Cabled Seafloor Earthquake Observatory

Seafloor observatories play a crucial role in acquiring continuous and precise submarine monitoring data, thereby holding significant implications for advancing major scientific advancements in marine science, particularly in the field of seafloor earthquake observation. This work mainly builds a dual-link observation system designed for observing seismic information on the seafloor based on a Zynq7000 system-on-chip and time synchronization module. The system is based on Zynq7000 SoC(MILIANKE; Changzhou, China) and AD7768(Analog Devices, Inc.; Norwood, MA, USA) to achieve eight-channel data (24 bit) synchronous acquisition, and the robustness of the system is improved by upgrading the link to full-duplex transmission and adding node data self-storage function. The P88 1588 PTP time synchronization single board(CoolShark; Beijing, China) is used to provide PPS (Pulse per second) signals for the system to realize microsecond timestamps to support subsequent seismic data inversion. An upper computer system based on the Qt framework is also developed to monitor the network condition in real time while visualizing the data transmission. For the acquisition of seismic signals, we employed triaxial seismic sensors. Additionally, a temperature and humidity monitoring module, along with an attitude detection module, was designed to enable real-time monitoring of the nodes. These modules not only facilitate the real-time monitoring of the nodes but also contribute to seismic data inversion. The experimental results indicate that the system provides a good synchronization of data acquisition, high accuracy, and reliability of inter-node transmission, which has good application prospects.

Numerical analysis of a nanosecond repetitively pulsed plasma-assisted counterflow diffusion flame

A computationally efficient model is proposed to analyze plasma-assisted combustion using nanosecond repetitive pulsed (NRP) plasmas. The NRP plasma discharge is placed in the oxidizer stream of a counter-flow diffusion flame. The effect of changing the flow rate and the pulse repetition frequency (PRF) of a continuous NRP plasma discharge on the temperature and species profiles of a counter-flow diffusion flame is investigated numerically. The results confirm that oxygen atom and nitrogen vibrational states are the most important species to enhance combustion. The results also show that kinetic effects are much more significant for higher PRF and lower pulse voltage. In addition, when steady plasma profiles are used instead of unsteady plasma profiles, the extinction strain rates increase by 25.8%, 21.1%, and 10.8% for PRF equal to 1, 2, and 4 kHz, respectively.

Deep-learning-assisted and GPU-accelerated vector Doppler imaging with aliasing-resistant velocity estimation

Vector flow imaging is a diagnostic ultrasound modality that is suited for the visualization of complex blood flow dynamics. One popular way of realizing vector flow imaging at high frame rates over 1000 fps is to apply multi-angle vector Doppler estimation principles in conjunction with plane wave pulse-echo sensing. However, this approach is susceptible to flow vector estimation errors attributed to Doppler aliasing, which is prone to arise when a low pulse repetition frequency (PRF) is inevitably used due to the need for finer velocity resolution or because of hardware constraints. Existing dealiasing solutions tailored for vector Doppler may have high computational demand that makes them unfeasible for practical applications. In this paper, we present the use of deep learning and graphical processing unit (GPU) computing principles to devise a fast vector Doppler estimation framework that is resilient against aliasing artifacts. Our new framework works by using a convolutional neural network (CNN) to detect aliased regions in vector Doppler images and subsequently applying an aliasing correction algorithm only at these affected regions. The framework’s CNN was trained using 15,000 in vivo vector Doppler frames acquired from the femoral and carotid arteries, including healthy and diseased conditions. Results show that our framework can perform aliasing segmentation with an average precision of 90 % and can render aliasing-free vector flow maps with real-time processing throughputs (25–100 fps). Overall, our new framework can improve the visualization quality of vector Doppler imaging in real-time.

Proapoptotic effect of nonthermal pulsed ultrasound on prostate cancer cells in a nude mouse model.

Ultrasound (US) can induce cell injury, and we have previously reported that adjusting the pulse repetition frequency (PRF) of ultrasound output can induce prostate cancer cell destruction without causing a rise in the temperature of the irradiated area. In this study, we examined the mechanism of nonthermal ultrasound cell destruction, which was not fully clarified in our previous reports. In vitro, we evaluated postirradiation cells immediately after treatment and examined membrane disruption by proliferation assay, LDH assay, and apoptosis assay. In vivo, we injected mice with human LNCaP and PC-3 prostate cancer cells and evaluated the therapeutic effects of US irradiation by H-E staining and immunostaining. Proliferation assays showed inhibition at 3 h postirradiation independently of PRF and cell line (p < 0.05). Quantitative assessment of apoptosis/necrosis by flow cytometry showed widely varying results depending on cell type. LNCaP showed an increase in late apoptosis at 0 h independent of PRF (p < 0.05), while PC-3 showed no significant difference at 0 h. The LDH assay showed an increase in LDH independent of PRF in LNCaP (p < 0.05 respectively), but no significant difference in PC-3. In vivo, tumor volume was compared and a significant reduction was observed at 10 Hz for LNCaP (p < 0.05) and 100 Hz for PC-3 (p < 0.001) at 3 weeks after the start of irradiation. The excised tumors were evaluated with Ki-67, Caspase-3, and CD-31 and showed a significant treatment effect independent of cell type and PRF (p < 0.001 respectively). Examining the mechanism behind the therapeutic effect of US irradiation revealed that the main effect was achieved by apoptosis induction rather than necrosis.

Simultaneous distributed acoustic and temperature sensing system based on ultra-weak chirped fiber Bragg grating array.

The quasi-static temperature and dynamic acoustic signals based on ultra-weak chirped fiber Bragg grating (CFBG) array is proposed and experimentally demonstrated, which can be employed to detect distributed acoustic and temperature signals simultaneously. Distributed temperature sensing (DTS) was realized by cross-correlation operation to measure the spectral drift of each CFBG, and distributed acoustic sensing (DAS) was achieved by gauging the phase difference between adjacent CFBG. Using CFBG as the sensor unit can protect acoustic signals from the fluctuations and drifts induced by temperature change without deterioration of signal-to-noise ratio (SNR). Applying least square mean adaptive filter (AF) can enhance harmonic frequency suppression ratio and increase the SNR of system. In the proof-of-concept experiment the SNR of acoustic signal is higher than 100 dB after the digital filter and frequency response is from 2 Hz to 1.25 kHz with repetition frequency of laser pulses of 10 kHz. Temperature measurement from 30°C to 100°C is achieved with demodulation accuracy of ±0.8°C. The spatial resolution (SR) of two-parameter sensing is 5 m.

Noninvasive mechanical destruction of liver tissue and tissue decellularisation by pressure-modulated shockwave histotripsy.

Boiling histotripsy (BH) is a promising High Intensity Focused Ultrasound (HIFU) technique that can be used to mechanically fractionate solid tumours at the HIFU focus noninvasively, promoting tumour immunity. Because of the occurrence of shock scattering phenomenon during BH process, the treatment accuracy of BH is, however, somewhat limited. To induce more localised and selective tissue destruction, the concept of pressure modulation has recently been proposed in our previous in vitro tissue phantom study. The aim of the present study was therefore to investigate whether this newly developed histotripsy approach termed pressure-modulated shockwave histotripsy (PSH) can be used to induce localised mechanical tissue fractionation in in vivo animal model. In the present study, 8 Sprague Dawley rats underwent the PSH treatment and were sacrificed immediately after the exposure for morphological and histological analyses (paraffin embedded liver tissue sections were stained with H&E and MT). Partially exteriorised rat's left lateral liver lobe in vivo was exposed to a 2.0 MHz HIFU transducer with peak positive (P +) and negative (P -) pressures of 89.1 MPa and -14.6 MPa, a pulse length of 5 to 34 ms, a pressure modulation time at 4 ms where P + and P - decreased to 29.9 MPa and - 9.6 MPa, a pulse repetition frequency of 1 Hz, a duty cycle of 1% and number of pulses of 1 to 20. Three lesions were produced on each animal. For comparison, the same exposure condition but no pressure modulation was also employed to create a number of lesions in the liver. Experimental results showed that a partial mechanical destruction of liver tissue in the form of an oval in the absence of thermal damage was clearly observed at the HIFU focus after the PSH exposure. With a single pulse length of 7 ms, a PSH lesion created in the liver was measured to be a length of 1.04 ± 0.04 mm and a width of 0.87 ± 0.21 mm which was 2.37 times in length (p = 0.027) and 1.35 times in width (p = 0.1295) smaller than a lesion produced by no pressure modulation approach (e.g., BH). It was also observed that the length of a PSH lesion gradually grew towards the opposite direction to the HIFU source along the axial direction with the PSH pulse length, eventually leading to the generation of an elongated lesion in the liver. In addition, our experimental results demonstrated the feasibility of inducing partial decellularisation effect where liver tissue was partially destructed with intact extracellular matrix (i.e., intact fibrillar collagen) with the shortest PSH pulse length. Taken together, these results suggest that PSH could be used to induce a highly localised tissue fractionation with a desired degree of mechanical damage from complete tissue fractionation to tissue decellularisation through controlling the dynamics of boiling bubbles without inducing the shock scattering effect.

Intraoperative ultrasound assessment of ureteral patency after uterosacral ligaments apical suspension for prolapse surgical repair: A feasibility study.

To prospectively compare power Doppler ultrasound diagnostic performance with reference standard cystoscopy in evaluating ureteral patency in a population at high risk of ureteral lesions. We analyzed 100 women who underwent pelvic organ prolapse repair. All ultrasound scans were obtained, at the end of the procedures, before cystoscopic evaluation. Bilateral simultaneous ureteral jet evaluation with power Doppler was performed at the level of the ureterovesical junctions with a pulse repetition frequency set to detect low flow for a maximum of 3 min. According to the reference standard urethrocystoscopy, at least one ureter not ejaculating was observed in 6% of patients, for a total of seven ureters jets not visualized. No false-negative results were obtained. Ultrasound with power Doppler showed 100% sensitivity and 95.9% specificity in detecting the lack of ureteral jet. The negative predictive value was 100%, and the positive predictive value was 46.7%. Ultrasound with power Doppler represents an effective and reliable non-invasive screening test to exclude ureteral kinking and reduce the need for intraoperative cystoscopy.

A compact ultra-wideband sub-nanosecond pulse generator with step recovery diodes

This article presents a compact ultra-wideband (UWB) sub-nanosecond monocycle pulse generator. The proposed circuit has a simple structure and low cost, and its core components are step recovery diodes (SRDs). It is composed of a power supply circuit, pulse drive circuit, short pulse-forming circuit, and pulse-shaping circuit. A transistor-based drive circuit is used to generate a drive pulse with sharp fall time. Then, a sub-nanosecond pulse width is realized through the combination of two SRDs in series and parallel. Finally, a monocycle pulse is directly formed by the inductance-based differentiator. This design achieves a full pulse width of 406 ps with a 260 mV peak-to-peak amplitude and a −10 dB bandwidth of 510 MHz to 6.1 GHz at a pulse repetition frequency of 10 MHz square waveform. The symmetry and ringing level are 96.9% and −25.3 dB, respectively, providing good symmetry and low ringing with a circuit size of 55 × 15 mm. In actual experiments, two identical UWB antennas with appropriate bandwidth are used to radiate a monopulse to breast phantoms. The results and uncertainty analyses of the test system show that there are distinguishable differences under diverse tumor phantoms and locations, proving that the proposed pulse generator is attractive for the application of UWB breast cancer detection.

Vessel Rupture Thresholds for Vessel-Bubble Interactions Using an Earthworm Vasculature Model.

Intravenous microbubble oscillation in the presence of ultrasound has the potential to yield a wide range of therapeutic benefits. However, the likelihood of vessel damage caused by mechanical effects has not been quantified as a function of the numerous important parameters in therapeutic ultrasound procedures. In this study, we examined the effects of microbubbles injected into the vasculature of the earthworm. It was found that the elastic properties of earthworm blood vessels are similar to those of arteries in older humans, and that earthworms are well suited to the large number of experiments necessary to investigate safety of procedures involving microbubble oscillation in sonicated vessels. Microbubbles were infused into earthworm vessels, and the rupture time during sonication was recorded as a function of ultrasound frequency, pulse repetition frequency and acoustic pressure. A modified mechanical index (MMI) was defined that successfully captured the trends in rupture probability and rupture time for the different parameter values, creating a database of vessel rupture thresholds. In the absence of bubbles, the product of MMI squared and rupture time was approximately constant, indicating a possible radiation-force effect. The MMI was an effective correlating parameter in the presence of bubbles, though the mathematical dependence is not yet apparent. The results of the study are expected to be valuable in designing more refined studies in vertebrate models, as well as informing computational models.

E–H transitions in Ar/O2 and Ar/Cl2 inductively coupled plasmas: Antenna geometry and operating conditions

Electronegative inductively coupled plasmas (ICPs) are used for conductor etching in the microelectronics industry for semiconductor fabrication. Pulsing of the antenna power and bias voltages provides additional control for optimizing plasma–surface interactions. However, pulsed ICPs are susceptible to capacitive-to-inductive mode transitions at the onset of the power pulse due to there being low electron densities at the end of the prior afterglow. The capacitive (E) to inductive (H) mode transition is sensitive to the spatial configuration of the plasma at the end of the prior afterglow, circuit (matchbox) settings, operating conditions, and reactor configurations, including antenna geometry. In this paper, we discuss results from a computational investigation of E–H transitions in pulsed ICPs sustained in Ar/Cl2 and Ar/O2 gas mixtures while varying operating conditions, including gas mixture, pulse repetition frequency, duty cycle of the power pulse, and antenna geometry. Pulsed ICPs sustained in Ar/Cl2 mixtures are prone to significant E–H transitions due to thermal dissociative attachment reactions with Cl2 during the afterglow which reduce pre-pulse electron densities. These abrupt E–H transitions launch electrostatic waves from the formation of a sheath at the boundaries of the plasma and under the antenna in particular. The smoother E–H transitions observed for Ar/O2 mixture results from the higher electron density at the start of the power pulse due to the lack of thermal electron attaching reactions to O2. Ion energy and angular distributions (IEADs) incident onto the wafer and the dielectric window under the antenna are discussed. The shape of the antenna influences the severity of the E–H transition and the IEADs, with antennas having larger surface areas facing the plasma producing larger capacitive coupling. Validation of the model is performed by comparison of computed electron densities with experimental measurements.