High Input Power Levels Research Articles

Impact of dispersion-shifted fiber on optical communications link through orthogonal channels

Dispersion-Shifted Fiber (DSF) is essential for reducing chromatic dispersion in high-speed optical communication systems. This study investigates the influence of Four Wave Mixing (FWM) on the quality of signals in orthogonal channels. We examine the advantages of DSF technology and analyze the impact of modulation formats such as On-Off Keying with Return-to-Zero (OOK-RZ) and Duo Binary Modulation class-1 (DBM-1) on transmission performance at different distances. This research assesses the efficacy of orthogonal channels in mitigating four-wave mixing (FWM) effects and improving the overall performance of eight-channel systems at distances of 100 km and 200 km through computer simulations. The results of our study show notable enhancements, namely in optimizing the Q-factor (a metric for signal quality) and reducing bit error rates when employing orthogonal channels compared to previous work. By integrating orthogonal channels with OOK-RZ modulation, we achieved higher performance and reduced nonlinear impairments in a simulated eight-channel system with 50 GHz spacing and 80 Gb/s data rates. This effect was particularly pronounced at high input power levels. At an input power of 20 dBm and a distance of 200 km, this particular combination yielded a maximum Q-factor of 27.25 and a minimum FWM power of −54 dBm. In comparison, under the same conditions, the use of OOK-RZ alone resulted in an FWM power of −24 dBm and a Q-factor of only 1.63. This research provides vital insights into enhancing the efficiency and dependability of optical communication systems, hence facilitating breakthroughs in high-speed data transfer and network scalability.

A 170–230 GHz High-Power Frequency Doubler Based on a GaAs MMIC Process

This letter reports a high-performance frequency doubler operating at 170–230 GHz based on a GaAs monolithic microwave integrated circuit (MMIC) process. The frequency doubler was designed with a balanced structure and the MMIC was inserted between two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E$ </tex-math></inline-formula> -plane split-waveguide blocks. A “Pass-by” shaped biased filter was employed to improve the operation bandwidth. Measurement results showed that the doubler delivers continuous wave (CW) output power of 42–78 mW from 170 to 220 GHz with an efficiency of 14%–26%. With the increase of bias voltage, higher output power at higher frequency can be achieved, delivering a CW output power of 54–107 mW from 192 to 226 GHz at an efficiency of 18%–36%. At a very high input power level (600 mW), a maximum CW output power of 165 mW at 215 GHz with an efficiency of 27.5% has been demonstrated.

ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ ЗАЩИТНОГО УСТРОЙСТВА

The protective device (limiter) at the receiver input is an important component, as it ensuresthe safety of the receiver operation in conditions of receiving powerful signals. The results of anexperimental study of a protective device in the 1-4 GHz band are presented. It is shown that theminimum bandwidth losses at a low power level do not exceed 0.63 dB, the maximum bandwidthlosses are 1.23 dB. At an input power of 25 dBm, the protective device operates in a non-linearmode, therefore it creates harmonics of the input frequency. The experimental amplitudefrequencyresponse (AFC) of the protective device, as well as amplitude characteristics at threefrequencies are presented. The experiment to remove the frequency response was carried out on avector analyzer of circuits. The experiment to remove the amplitude characteristics was carriedout using a standard signal generator and a spectrum analyzer at three frequencies: 1 GHz;2 GHz; 4 GHz. Structurally, the protective device is a polycor substrate on which all elementsexcept connectors are placed. The substrate is placed in a frame-type housing and closed with twosealed lids. Type III sockets according to GOST13317- 89 are used as connectors. A schematicdiagram and a brief description of the design are given. The following main parameters have beenachieved: losses do not exceed 1.23 dB in the operating frequency range from 1 to 4 GHz, theoutput signal power at a high input power level (f = 1 GHz; Rvh = 25 dBm) does not exceed12 dBm. The protective device is recommended to be used in the input circuits of communicationreceivers, navigation, radar and electronic warfare.

Outside Front Cover: Plasma Process. Polym. 6/2022

Inside Front Cover: For a wide range of plasma processes, stable plasma ignition of remote plasma sources (RPSs) is essential to ensure the stability of the discharge, stable operating conditions, and high plasma density. An RPS operating at a gas pressure greater than 1 Torr relies on the reaction pathways leading to the high-level excited state to sustain the power balance and energy cascade at a high input power level. Further details can be found in the article by Cheongbin Cheon, Jung Hwan Yoon, Sanghyun Jo, Ho Jun Kim, and Hae June Lee (e2100251).

A 1.5–40 GHz frequency modulated continuous wave radar receiver front-end

AbstractThis study presents an ultra-wideband receiver front-end, designed for a reconfigurable frequency modulated continuous wave radar in a 130 nm SiGe BiCMOS technology. A variety of innovative circuit components and design techniques were employed to achieve the ultra-wide bandwidth, low noise figure (NF), good linearity, and circuit ruggedness to high input power levels. The designed front-end is capable of achieving 1.5–40 GHz bandwidth, 30 dB conversion gain, a double sideband NF of 6–10.7 dB, input return loss better than 7.5 dB and an input referred 1 dB compression point of −23 dBm. The front-end withstands continuous wave power levels of at least 25 and 20 dBm at low band and high band inputs respectively. At 3 V supply voltage, the DC power consumption amounts to 302 mW when the low band is active and 352 mW for the high band case, whereas the total IC size is $3.08\, {\rm nm{^2}}$.

Power dividing systems based on a rectangular coaxial line

L- and S-band phased array antennas are widely used in modern radiolocation systems. Existing power dividers for L- and S-band phased array antennas have several disadvantages. Waveguide based systems are sophisticated and have a large mass. Optical and conventional coaxial line based systems have a large size. Microstrip based systems are compact and have a low mass, but the maximum input power level is quite low. In this paper, the design of microwave devices based on a multilayer rectangular dielectric filled coaxial line is presented and the recommendations on its use in design of multichannel power dividers are given. The paper demonstrates that this type of power divider design results in lower mass, is compact and has high maximum input power level. Thus, multichannel power dividers based on a multilayer rectangular dielectric filled coaxial line are the most suitable for use in modern L- and Sband radiolocation systems.

Simple Adaptive Rectifier with High Efficiency over a Range of 21 dBm Input Power for RF Energy Harvesting Applications

This paper presents a novel simple adaptive and efficient rectifier for Radio Frequency (RF) energy harvesting applications. Traditional rectifiers have maximum RF-DC Power Conversion Efficiency (PCE) over a narrow range of RF input power due to diode breakdown voltage restrictions. The proposed adaptive design helps to extend the PCE over a wider range of RF input power at 2.45GHz using a simple design. Two alternative paths arecontrolled depending on the RF input power level. Low input power levels activate the first path connected to a single rectifier; low power levels make the diode operate below its breakdown voltage and therefore avoiding PCE degradation. High input power levels activate the second path dividing it into three rectifiers. This keeps input power at each rectifier at a low power level to avoid exceeding the diode break down voltage. Simulated PCE of this work is kept above 50% over a range of 21.4 dBm input power from -0.8dBm to 20.6dBm.

Self-Adaptive Rectenna with High Efficiency over a Wide Dynamic Range for RF Energy Harvesting Applications

This paper presents a novel simple adaptive and efficient rectenna with automatic power distribution to achieve high radio frequency-direct current (RF-DC) power conversion efficiency (PCE) over a wide range of RF input power. This design employs two rectifier paths operating at low and high-power levels, respectively. Automatic power distribution method exploits the power-dependent input impedance of the rectifier and routes the RF input power into the assigned path according to the input power level. A distinctive enhancement in the rectifier dynamic range is achieved when dividing the high path power equally into two or more parallel diode cells, which helps the high path to camouflage the diode breakdown voltage in case of high input power level. The proposed adaptive design applies two different rectifier topologies, one by using shunt diode topology and the other by using voltage doubler topology at 2.45 GHz. Simulated PCE of this work is kept above 50% over a range of 25.1 dBm from -5.7 to 19.4 dBm of RF input power using shunt diode topology and over a range of 30 dBm from -6.3 to 23.7 dBm of RF input power using voltage doubler topology.

Analysis, Design and Implementation of a Fully Integrated Analog Front-End for Microwave RFIDs at 5.8 GHz to Be Used With Compact MIMO Readers

In this paper we present the system and circuit level analysis and feasibility study of applying microwave Radio Frequency Identification (RFID) systems with multipleinput multiple-output (MIMO) reader technology for tracking machining tools in multipath fading conditions of production environments. In the proposed system the MIMO reader interrogates single-antenna tags, and a high RFID frequency of 5.8 GHz is chosen to reduce the size of the reader's antenna array. According to the requirements dictated by the performed system analysis at 5.8 GHz, a low power fully integrated analog frontend (AFE) is designed and fabricated in a standard 65-nm CMOS technology for low power passive transponders. Performance of the Differential Drive Rectifier (DDR) topology as the core of the energy harvesting unit is investigated in detail. A multi-stage DDR power scavenging unit is dimensioned to provide a 1.2 V rectified voltage for 20-30 kQ load range, with a high power conversion efficiency (PCE) for high frequency and low input power level signals. The rectified voltage is then converted to a 1 V regulated voltage for the AFE and the baseband processor with 30 to 50 μW of estimated power consumption. Transistors with standard threshold voltage (VT) have been used for implementation. Measurements of the fabricated multi-stage configuration of the circuit show a maximum PCE of 68.8% at -12.46 dBm, and an input quality factor (Q-factor) of approximately 10. Amplitude-shift keying (ASK) demodulator and backscattering modulator with 80% modulation index, operating according to EPC-C1G2 protocol are applied for data transfer. The AFE consumes less than 1 μW in the reading mode. The AFE tag chip is 0.55 × 0.58 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Design of Compact Dual-Band RF Rectifiers for Wireless Power Transfer and Energy Harvesting

In this paper, we propose a compact dual-band impedance matching network (DBIMN) for radio frequency (RF) rectifiers. The DBIMN is achieved with a single-stage T-type network, with only three segments of the transmission line. We investigate the closed-form design equations, as a design guideline of the DBIMN. In addition, we propose the design methodology of the rectifier using the DBIMN. For validation, we design two dual-band rectifiers (0.915 and 2.45 GHz), for different input power levels. The rectifier with high input power level, is designed for a wireless power transmission (WPT) system. With a 12 dBm input power, the measured power conversion efficiencies (PCEs) are 81.7 and 73.1% at the working frequencies. The PCEs becomes 69.2 and 64.1% (at −1 dBm input power) for the low-power input rectifier that can be used in an RF energy harvesting (RF-EH) system. The simulated and measured results match each other well. Compared with previous designs, the proposed designs have advantages in compactness and high efficiency.

Design, Analysis, and Performance Evaluation of a UHF RFID Forward-Link Repeater

The range of UHF-RFID systems, involving passive tags, is typically limited by the tag’s RF harvesting circuitry. In this paper a forward-link UHF RFID repeater is proposed. The repeater amplifies the reader-to-tag carrier signal. Then, a passive RFID tag can be successfully identified from a much larger distance, compared to current technology, by exploiting the sensitivity of the reader. The proposed repeater consists of low-cost components; namely a pair of antennas, a low-noise amplifier and passive electronics. The proposed design also accounts for out-of-band emissions and the limitations posed by the maximum effective isotropic radiated power of the EPC UHF Gen2 standard. In contrast to prior-art, it can be deployed with any commercial RFID reader. Link-budget analysis reveals i) that the location of the repeater is of great importance to the system, ii) the range depends on the reverse link and not on the forward, as in typical RFID technology and iii) optimum performance can be achieved with bistatic RFID readers and RFID tags, capable of harvesting RF power at higher input power-levels. It is shown that with common, commercial, monostatic RFID technology, a maximum range of 80m can be achieved. By deploying bistatic configurations, which allow for improved reader’s sensitivity, the read-range could be extended to 350m. By “tuning” the tag’s front-end to achieve good matching for increased incident power levels, the expected range could be increased to 2km. Experimental results validate the performance of the proposed repeater and reveal how the link budget is affected by the tag’s front-end. 73m measured range is experimentally achieved with commercial monostatic RFID equipment.

Langmuir probe characterisation of an Ar–H2 non-thermal plasma loaded with carbon nanoparticles

In this contribution, we describe the development of a test-bed for the characterisation of non-thermal dusty plasmas via Langmuir probe. This technique, while allowing the precise determination of plasma parameters and electron energy distribution function (EEDF), is notoriously difficult to apply in dust-forming chemistries. We overcome this limitation by utilising a two-plasmas system in which the particle precursor, in this case acetylene, is fully consumed and converted into nanoparticles in a first plasma reactor, followed by the injection of the dust into a second plasma reactor where the Langmuir probe measurement is performed. This approach allows studying the influence of the variation of process parameters on the dusty plasma properties, all while leaving the nucleation and growth phase of the particles unaffected and fully decoupled from the discharge in which the measurement takes place. We have applied this approach to the case of graphitic carbon nanoparticles dispersed in an argon–hydrogen mixture. We have monitored the quality of the Langmuir probe measurement, and found that it is minimally affected by the presence of the graphitic particles even after several EEDF measurements. Our measurements confirm the unipolar charging of nanoparticles in non-thermal plasmas, consistent with previous observations and theoretical predictions. We also observe an unexpected trend with plasma input power: the charge carried by the particles does not monotonically increase with increased power, instead starts decreasing at sufficiently high input power levels.

Supermode spatial solitons via competing nonlocal nonlinearities

We study spatial soliton formation in a system with competing nonlinearities. In doing so, we consider a specific nonlinear response that involves both focusing and defocusing nonlocal contributions. We demonstrate that at a sufficiently high input power level, the interplay between these nonlocal nonlinearities may lead to the formation of in-phase, two-hump, fundamental spatial solitons. The conditions required for the existence of these two-peak spatial solitons are also presented. Full Text: PDF ReferencesG. Stegeman and M. Segev, "Optical Spatial Solitons and Their Interactions: Universality and Diversity", Science 286, 1518 (1999). CrossRef Y. Kivshar and G. P. Agrawal, Optical Solitons: From Fibers to Photonic Crystals (Academic, San Diego, 2003).P. Varatharajah et al., "Stationary nonlinear surface waves and their stability in diffusive Kerr media", Opt. Lett. 13, 690 (1988). CrossRef G. Assanto and M. Peccianti, "Spatial solitons in nematic liquid crystals," IEEE J. Quantum Electron. 39, 13 (2003). CrossRef G. Assanto, ed. Nematicons: Spatial Optical Solitons in Nematic Liquid Crystals (Wiley, 2012). CrossRef O. Bang, W. Krolikowski, J. Wyller, J.J. Rasmussen, "Collapse arrest and soliton stabilization in nonlocal nonlinear media", Phys. Rev. E 66, 046619 (2002). CrossRef X. Hutsebaut, C. Cambournac, M. Haelterman, A. Adamski, K. Neyts, "Single-component higher-order mode solitons in liquid crystals," Opt. Commun. 333, 211 (2004). CrossRef C. Conti, M. Peccianti, and G. Assanto, "Route to nonlocality and observation of accessible solitons," Phys. Rev. Lett. 91, 073901 (2003). CrossRef U. A. Laudyn, P. S. Jung, M.A. Karpierz, and G. Assanto, "Quasi two-dimensional astigmatic solitons in soft chiral metastructures," Sci. Rep. 6, 22923 (2016). CrossRef U. A. Laudyn, P. S. Jung, M. A. Karpierz, G. Assanto, "Power-induced evolution and increased dimensionality of nonlinear modes in reorientational soft matter," Opt. Lett. 39(22), 6399–6402 (2014). CrossRef Y. V. Izdebskaya, V. G. Shvedov, P. S. Jung, and W. Krolikowski, "Stable vortex soliton in nonlocal media with orientational nonlinearity," Opt. Lett. 43, 66-69 (2018) CrossRef P.S. Jung, W. Krolikowski, U.A. Laudyn, M. Trippenbach and M.A. Karpierz, "Supermode spatial optical solitons in liquid crystals with competing nonlinearities", Phys. Rev. A 95, 023820 (2017) CrossRef P.S. Jung, W. Krolikowski, U.A. Laudyn, M.A. Karpierz and M. Trippenbach, "Semi-analytical approach to supermode spatial solitons formation in nematic liquid crystals", Opt. Express 25, 23893 (2017) CrossRef S. Jungling and J. C. Chen, "A study and optimization of eigenmode calculations using the imaginary-distance beam-propagation method", IEEE J. Quantum Electron. 30, 2098 (1994). CrossRef P.S. Jung, K. Rutkowska and M.A. Karpierz, "Evanescent field boundary conditions for modelling of light propagation", Journal of Computational Science 25, 115 (2018) CrossRef A.A. Hardy, W. Streifer, "Coupled mode theory of parallel waveguides," IEEE J. Lightwave Techn. LT-3, 1135 (1985) CrossRef M. Matuszewski, B.A. Malomed, and M. Trippenbach, "Spontaneous symmetry breaking of solitons trapped in a double channel potential," Phys. Rev. A 75, 063621 (2007) CrossRef

Investigation on Third-Order Intermodulation Distortions Due to Material Nonlinearities in TC-SAW Devices.

Nonlinearity can give rise to intermodulation distortions in surface acoustic wave (SAW) devices operating at high input power levels. To understand such undesired effects, a finite element method (FEM) simulation model in combination with a perturbation theory is applied to find out the role of different materials and higher order nonlinear tensor data for the nonlinearities in such acoustic devices. At high power, the SAW devices containing metal, piezoelectric substrate, and temperature compensating (TC) layers are subject to complicated geometrical, material, and other nonlinearities. In this paper, third-order nonlinearities in TC-SAW devices are investigated. The materials used are LiNbO3-rot128YX as the substrate and copper electrodes covered with a SiO2 film as the TC layer. An effective nonlinearity constant for a given system is determined by comparison of nonlinear P-matrix simulations to third-order intermodulation measurements of test filters in a first step. By employing these constants from different systems, i.e., different metallization ratios, in nonlinear periodic P-matrix simulations, a direct comparison to nonlinear periodic FEM-simulations yields scaling factors for the materials used. Thus, the contribution of the different materials to the nonlinear behavior of TC-SAW devices is obtained and the role of metal electrodes, substrate, and TC film are discussed in detail.

Robust Rectifying Circuits With FET Shunt-Mounted Voltage-Doubler Rectifier

Two robust rectifying circuits with a voltage-doubler rectifier (VDR) and reconfigurable matching stubs are proposed. Traditionally, if the rectifier diode in a VDR accidentally malfunctions at medium and/or high input power levels, the rectifying circuit would be mismatched or even not work. To improve the robustness of the rectifying circuit, a capacitor- or diode-shunted field-effect transistor, used as an adaptive switch and/or a rectifier diode, is installed in the VDR. Also, L-shaped reconfigurable matching stubs are adopted to automatically adjust the impedance of the rectifying circuit. Simulated and measured results demonstrate that the proposed topologies are robust, and optimal conversion efficiencies can be achieved.

Design data for quick development of folded H plane tee at high average power level

At high average power level, waveguide-based structures are indispensable in microwave systems due to their higher power handling capacity. These structures are often used to perform power division and combination operation. Folded H plane tee is one of the many components that can be used for the power division application. Its advantage is that the output arms and input arms are in a single plane along a single axis, thus taking less space in the overall system. However, their proper thermal management is indispensable for its use, as high surface temperature of the waveguide reduces its power handling capacity at high power level. This paper presents quick, easy design steps and methodology for obtaining the structure of a folded H plane tee at any given frequency of operation. Further, a scheme for the thermal management for high input power level (500 kW continuous wave) is presented. The proposed methodology is tested at various frequencies in COMSOL Multiphysics, CST Microwave Studio and HFSS with excellent results. A prototype structure was fabricated for use at 3.7 GHz, which exhibited good agreement with the simulation results.

Highly Integrated 3 V Supply Electronics for Electromagnetic Energy Harvesters With Minimum 0.4 V $_{\mathbf{peak}}$ Input

This paper presents a self-powered interface enabling battery-like operation with a regulated 3 V output from ac signals as low as 0.4 Vpeak, generated by electromagnetic energy harvesters under low frequency vibrations. As the first stage of the 180 nm standard CMOS circuit, harvested signal is rectified through an ac/dc doubler with active diodes powered internally by a passive ac/dc quadrupler. The voltage is boosted in the second stage through a low voltage charge pump stimulated by an on-chip ring oscillator. The output is finally regulated to 3 V at the last stage. The voltage doubling rectification stage deviates by less than 40 mV from ideal expectation for the validated 0.15–1 V input voltage range. The full system delivers 3 V output to 4.4 MΩ load for input voltage of 0.4 V peak, which is the lowest operable input voltage in the literature. The demonstrated system generates 9 μ W of dc power with 3 V stable output for 32 μ W input, whereas the circuit is able to supply even more output power for higher input power levels. The maximum efficiency of the rectification stage is 86%, while the full system efficiency is 37% and 28% for unregulated and regulated operation, respectively, when interfaced to an in-house electromagnetic energy harvester under 8 Hz 0.1 g vibration.

Link Optimization and Performance Analysis of a 40 Gbps DQPSK Modulated Ultra DWDM System with 32 Orthogonally Polarized channels

Abstract The demand for higher speed at a lesser transmission cost per bit resulted in growth of optical networks with improved spectral efficiency even at narrower channel spacing. Incorporation of multilevel modulation formats in DWDM system led to the exploration of the 25 GHz channel grid, popularly known as Ultra Dense Wavelength Division Multiplexed (UDWDM) systems, opening new research frontiers. At such channel spacing's, non-linear optical effects impose severe system impairments and hence robust modulation schemes are currently being investigated. This paper presents a simulative model to implement and analyze alternative polarized DQPSK modulated UDWDM system to evaluate its resilience to XPM and fiber nonlinearity. An UDWDM system supporting 32 channels, each operating at 40 Gbps and spaced at 25 GHz is studied numerically for long-haul optical communication system using OptiSystem simulator to estimate OSNR penalties to mitigate XPM effects. The major detrimental factors encountered in link design have been estimated to evaluate the system performance in terms of Q value for different number of channels and with varied input power. The analysis reports acceptable performance for DQPSK format up to a link distance of 1500 Km and also claims a better tolerance to dispersion and nonlinearities at higher input power levels.

Thermal saturation and its suppression in high-power, compact carbon nanotube thin-film thermophones

Carbon nanotube (CNT) thin-film thermophones, at sufficiently high input power levels, suffer from thermal saturation where an increase in the input power does not result in a corresponding increase in the sound pressure level generated. It is believed that high temperature air, trapped in and around the CNT film, inhibits the ability of the CNT film to cool sufficiently between heating cycles, thus limiting the sound pressure output and increasing in severity with both input power and frequency. Thermal saturation appears to be particularly acute for CNT thermophones designed for compactness or when placed inside a protective or loudspeaker enclosure, where natural convection or heat transfer from the film is inhibited. Fan cooling was integrated into a CNT thermophone and demonstrated to both reduce the temperature of the CNT film and suppress, almost entirely, the effects of thermal saturation.

Self‐biased anti‐parallel diode pair in 130‐nm CMOS

This Letter presents a self-biased anti-parallel diode pair (APDP) in a 130-nm standard digital CMOS process. The proposed device employs complementary polysilicon-gate-separated Schottky barrier diodes (SBDs). A parallel RC network in series with the n-well of n-type SBD connected in shunt is used to build-up the self-bias voltage that depends on the input power level. The device exhibits less roll-off in output harmonic power generation at a high input power level due to the automatic adjustment of the I–V curve. The measured cutoff frequency of the device reaches ∼530 GHz at zero-bias. Harmonic power measurements indicate that use of the self-biasing reduces saturation at high input power levels. The self-biased complementary-APDP (C-APDP) generates up to 5.7 dB higher third harmonic power than the cathode-tied C-APDP.