Resistive Termination Research Articles

Low power RF rectifiers based on class-E/F2 architecture for energy harvesting applications

This article introduces a new low-power Class-E/F2 shunt rectifier and voltage doubler (VD) for energy harvesting (EH) applications, employing RO4003C substrate. These circuits achieve high efficiency and produce a substantial DC voltage. The proposed designs are suitable for LTE, IoT, WSN, GSM 900, and low-power EH systems. The innovative designs are depending on a Class-E/F2 circuit structure, which combines Class-E and inverse Class-F configurations with a second harmonic resonance circuit. This configuration effectively eliminates the second harmonic current component by employing a λ/8 transmission line (TL) linked to the anode terminal of the diode. At low values of input power (Pin), the voltage and efficiency-boosting are achieved by designing two coupling transmission lines (CTLs). The proposed rectifier and voltage doubler circuits include a DC-pass filter designed to eliminate high-frequency components. The rectifier and VD circuits are manufactured using the HSMS-285x series Schottky diodes. When a radio input power (Pin) is equal to −10 dBm, the rectifier and VD circuits demonstrate experimental conversion efficiencies larger than 40 %. The DC voltage is 0.6 V at both 650 MHz and 900 MHz, with terminal resistances (RL) of 4.3 kΩ and 8 kΩ for rectifier and VD, respectively. The rectifier design achieves a maximum measured efficiency equal to 50 %, maintaining a constant DC-voltage equal to 1.7 V atRL = 4.3 kΩ and 900 MHz. Additionally, the proposed VD demonstrates a peak experimental efficiency equal to 57 %, with a constant DC-voltage equal to 3.2 V at Pin=0dBm and RL=8KΩ, operating in two bands of 650 MHz and 900 MHz. It also achieves a measured efficiency equal to 45 % at Pin=-10dBm. Finally, the PCB sizes of the suggested rectifier and VD are 3 cm2 and 3.37 cm2, respectively.

Fivefold increased power handling in waveguide UTC-PDs using dual-injection shared CPW PD-arrays.

This work presents two circuit-based solutions to enhance the power handling capabilities of waveguide-integrated uni-travelling carrier photodetectors (WG-UTC-PDs). Compared to a baseline WG-UTC-PD, these solutions achieve a fivefold increase in photocurrent before thermal breakdown. First, dual-injection improves the optical power distribution within a baseline WG-UTC-PD, raising the photocurrent threshold before thermal breakdown. Second, an array of four optically parallel WG-UTC-PDs, electrically connected to a single coplanar waveguide (CPW) line, further increases the maximum photocurrent by distributing the input optical power across multiple PDs. The design omits a termination resistor, as the arrays do not rely on a traveling wave configuration, maximizing photocurrent without a 50% reduction of bandwidth. Both 4-PD single-injection and dual-injection arrays were designed, fabricated, and characterized. Compared to a baseline UTC-PD, with a maximum photocurrent of 1.8 mA at a 3 dB bandwidth of 55 GHz, the 4-PD single-injection circuit achieved 5.1 mA at 43 GHz. The dual-injection array further increased the photocurrent to 9.2 mA at a bandwidth of 35 GHz. Electrical reflection measurements confirmed the negative effects of CPW losses on RF performance. These power handling improvements enable compact, high-power integrated solutions for microwave photonics.

Internal Electrostatic Discharge Modeling: Validation and Fitting Using Tests on Insulated Wires

Electron beam tests were conducted to observe the internal electrostatic discharge behavior of four wire samples arcing into three termination resistors. The charging environment during the test was also simulated using 3-D NUMIT to calculate the expected voltage development within each wire. The impedances of the wires and the test setup were measured and included in a circuit model of the discharging wire connected to the measurement circuit. The circuit model was fit to the largest discharge observed on a 50 Ω load. The circuit model was then used to simulate discharges into 5 kΩ and 10 MΩ terminations, and the simulated pulses were compared to observed pulses on those terminations. Simulated peak voltages agree with observed voltages to within a factor of 1.6 and simulated decay times agree with observed decay times to within a factor of 2.3. For large pulses, derived source voltages range from 3.7 to 15.5 kV, derived source capacitances range from 4 to 11 pF, and derived source resistances range from 1100 to 3500 Ω.

Quench protection for high-temperature superconductor cables using active control of current distribution

Superconducting magnets of future fusion reactors are expected to rely on composite high-temperature superconductor (HTS) cable conductors. In presently used HTS cables, current sharing between components is limited due to poorly defined contact resistances between superconducting tapes or by design. The interplay between contact and termination resistances is the defining factor for power dissipation in these cables and ultimately defines their safe operational margins. However, the current distribution between components along the composite conductor and inside its terminations is a priori unknown, and presently, no means are available to actively tune current flow distribution in real-time to improve margins of quench protection. Also, the lack of ability to electrically probe individual components makes it impossible to identify conductor damage locations within the cable. In this work, we address both problems by introducing active current control of current distribution between components using cryogenically operated metal-oxide-semiconductor-field-effect transistors (MOSFETs). We demonstrate through simulation and experiments how real-time current controls can help to drastically reduce heat dissipation in a developing hot spot in a two-conductor model system and help identify critical current degradation of individual cable components. Prospects of other potential uses of MOSFET devices for improved voltage detection, AC loss-driven active quench protection, and remnant magnetization reduction in HTS magnets are also discussed.

Numerical Analysis on the Current Distribution and the Loss in HTS Stacked Tapes Considering Termination Resistances

Numerical Analysis on the Current Distribution and the Loss in HTS Stacked Tapes Considering Termination Resistances

Review on Resistive Termination Techniques Driven by Wireline Channel Behaviors

Review on Resistive Termination Techniques Driven by Wireline Channel Behaviors

Low‐frequency noise model development of MoS2 field effect transistor and its analysis with respect to different traps

AbstractIn this paper, an analytical drain current model of double gate MoS2 FET Transistor for low‐frequency noise (LFN) power spectral density is developed, and compared its response with the device simulation of the proposed device structure. The developed low‐frequency noise power spectral density (PSD) model is analyzed with respect to different Trap densities, Oxide thicknesses, and high K‐dielectric materials using the TCAD Device simulation tool. Low‐frequency noise is one of the most important noises in any device since it degrades the device's performance. So, in this paper, we used a unique charge‐control model for analyzing the low‐frequency noise by considering the mobility degradation, trapping, and de‐trapping effects caused by trap densities and device lattice structure. Usually, all the previous studies on drain currents with low frequency are based on fluctuations caused by mobility and carrier variations. In our paper, we even considered the charge density fluctuation to analyze the drain current equation. Using a Charge Control Model, we can compute the parameters like gate capacitance (Cgs, Cgd), channel length modulation, and body effect. While other LFN models like the DC model, small signal model, and hybrid model will focus mainly on the static characteristics of the device such as its DC current–voltage (I‐V) relationship, terminal resistances, and input/output conductance of the devices. All the analytical model results were calibrated with the device simulation and it is observed that both are matches each other. Further, it is observed that with an increase in Trap density, the low‐frequency noise increases and low‐frequency noise is dominant at lower frequencies only (1–10 Hz), and after this frequency range the thermal noise will be the dominant noise factor.

Compact dielectric impulse radiating antenna with a flat feed arm structure for low‐frequency gain enhancement

AbstractA compact dielectric impulse radiating antenna (IRA) with flat coplanar conical plate (CCP) feed arms was proposed for low‐frequency gain enhancement. An empirical equation was proposed to predict the characteristic impedance of the CCP arms submerged in a dielectric half‐space. The predicted value was used to determine the termination resistors that connect the feed arms to the reflector. Both the dielectric‐filled and conventional air‐filled IRAs were fabricated, and their performances were measured. The gain of the proposed dielectric‐filled IRA is shown to be higher at frequencies lower than 3 GHz, where the diameter of the reflector is one wavelength.

60 GHz Analog Radio-Over-Fiber Single Sideband Transmitter Chipset With 55nm SiGe BiCMOS Driver RFIC and Silicon Photonics Modulator PIC

An all-silicon analog radio-over-fiber transmitter chipset is presented for narrowband operation in the unlicensed 60 GHz V-band for use in low-cost and low-power distributed antenna systems. The chipset consists of a low-noise high-speed quadrature driver RFIC and an EAM based single-sideband I/Q modulator PIC. Resonant matching is used to drive the EAMs which provides 6 dB more gain compared to an on-chip 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\Omega$</tex-math></inline-formula> resistive termination. A further 6 dB improvement is had by placing the quadrature hybrid on the RFIC before the output stages compared to implementations that place the hybrid on the PIC. The RFIC consists of a low-noise input stage, gain stages, a hybrid coupler and two output stages while the PIC consists of parallel electro-absorption modulators and thermo-optic phase shifters. A sideband suppression ratio of 25 dB is demonstrated with a full chipset size of 1.1 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> and a power consumption of 45 mW. Succesful optical back-to-back experiments were conducted using various QAM signals.

A Low-power DRAM Controller ASIC with a 36% Reduction in Average Active Power by Increasing On-die Termination Resistance

A low-power DRAM controller ASIC is proposed for point-to-point interconnects such as deep learning applications. The termination resistance of the DRAM controller is increased to 160 Ω and infinity during the write and read modes, respectively, to reduce power consumption with no transmission errors. Short-reach interconnects of 25 mm DQ/DQS lines are used to avoid signal integrity issues. The proposed DRAM controller is implemented in a 65 nm process with an active area of 1.64 mm², 16 DQ 8 Gb configuration, and a data rate of 800 Mbps per DQ pin. The DRAM interface using the proposed controller and a commercial DDR3 DRAM chip consumes 379 mW on average; this is 64% of the power with the default termination of the JEDEC standard. Derived equations for the TX and RX current of the DRAM interface reveals that the TX current of a clock signal is minimized when the time of flight of the PCB channel is integer multiples of the half period of the clock signal with large TX and RX terminations.

Position linearity analysis of circular arc terminated resistive anode using finite element method for photon-counting imaging detectors.

This study proposes a comprehensive model of the circular arc terminated (CAT) resistive anode based on the finite element method to explore the dynamic process of charge diffusion on this anode and its position linearity performance. The waveforms of charges of the electrodes on the anode are calculated for different electrical parameters and their influence on positional linearity is investigated. The influence of the signal development time and the non-uniformity of the resistance per square of the anode on positional linearity is also analyzed. The results of simulations show that the non-linearity of the image varies monotonically with the termination resistance and the non-uniformity of the resistance per square of the anode, but has a non-linear relationship with the signal development time and the ratio of the resistance per square. A CAT resistive anode with capacitance c and a resistance per square of the sensitive area of R▱ can be used to recover an image with a root mean-squared non-linearity of 2%, when the charge signals of the electrode are collected for at least 0.6R▱c s. The reliability of the results of the simulations was verified with experimental measurements.

Extraction of a SPICE Model for Investigating the Cable Discharge Event in Flat Ribbon Cables Based on Transmission Line Theory

Imagining a specific SPICE model for the Cable Discharge Event (CDE) is impossible because the model depends on the cable length, material, and type. This paper aims to propose an instruction to extract a SPICE model for Flat Ribbon Cables (FRCs), which have a wide range of applications in electronics. This work introduces general information and considerations about the CDE in FRCs, and the conductor of the FRC considers a transmission line which to Extract its equivalent circuit; a technique based on S-Parameter measurement and transmission line theory is demonstrated. Also, this work regards the mutual capacitance between the conductor of FRC in the extracted SPICE model. In this work, the analytical technique and the 3D full-wave software synergize with each other to increase the reliability of the proposed SPICE model. This work evaluates the effect of cable length and termination resistance on the discharge waveform. The proposed instruction can be expanded to the other cables. It helps the designers observe the CDE impacts besides other transient events on their circuits and systems without spending much time and expense.

Real‐time simulation multi‐point decoupling method of power systems based on terminal resistor

Real‐time simulation multi‐point decoupling method of power systems based on terminal resistor

Development of the Characterization Methods Without Electrothermal Feedback for TES Bolometers for CMB Measurements

Superconducting Transition-Edge Sensor (TES) bolometers are used for cosmic microwave background (CMB) observations. We used a testbed to evaluate the thermal performance of TES bolometers in regard to the saturation power Psat and intrinsic thermal time constant tau0. We developed an evaluation method that is complementary to methods with electrothermal feedback. In our method, the antenna termination resistor of the bolometer is directly biased with DC or AC electric power to simulate optical power, and the TES is biased with small power, which allows Psat and tau0 to be determined without contribution from the negative electrothermal feedback. We describe the method and results of the measurement using it. We evaluated Psat of five samples by applying DC power and confirmed the overall trend between Psat and the inverse leg length. We evaluated tau0 of the samples by applying DC plus AC power, and the measured value was reasonable in consideration of the expected values of other TES parameters. This evaluation method enables us to verify whether a TES has been fabricated with the designed values and to provide feedback for fabrication for future CMB observations.

Capacitively-Loaded Thin-Film Lithium Niobate Modulator With Ultra-Flat Frequency Response

Traveling-wave electro-optic (E-O) modulators based on thin-film lithium niobate (TFLN) have attracted much attention recently, as low half-wave voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }$ </tex-math></inline-formula> ) and wide modulation bandwidth can be realized with a small footprint. A flat E-O response of the modulator relies on low microwave loss, perfect velocity match and suitable terminal resistance. In this Letter, we present velocity-matched TFLN modulator based on low-loss capacitively-loaded traveling-wave electrodes (CL-TWEs) with an on-chip terminal resistor. The effect of termination resistance on the E-O frequency response is theoretically analyzed and experimentally confirmed. The TFLN modulator with 6-mm modulation length exhibit a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\pi }$ </tex-math></inline-formula> of 2.7 V and a 6.4-dB electrical bandwidth over 160 GHz. By adopting a termination resistance slightly lower than the characteristic impedance of the CL-TWEs, an ultra-flat E-O response has been demonstrated with fluctuation less than 1-dB up to 50 GHz, consistent with the theoretical prediction.

Key factors affecting contact resistance in coplanar organic thin-film transistors

We present a comprehensive numerical analysis of contact resistance in coplanar organic thin-film transistors. A large number of hole-transporting organic transistors are investigated through two-dimensional finite-element simulation, by deliberately changing the channel length, source/drain electrode thickness, and hole-injection energy barrier heights. Gate-field-dependent terminal contact resistances of these devices are fully estimated and electrostatic distributions inside the organic semiconductor film are visualized for the understanding of physical mechanisms. It is found that the relationship between source/drain electrode thickness and contact resistance does not follow any simple trend and is also strongly associated with the injection energy barrier. Moreover, the origin of negative contact resistance in organic transistors featuring a minimal charge-injection barrier is elaborated. Finally, a direct impact of the semiconductor charge-carrier mobility on contact resistance is addressed, revealing a linear dependence of contact resistance on inverse mobility over a broad parameter range.

Receiver Analog Front-End Cascading Transimpedance Amplifier and Continuous-Time Linear Equalizer for Signals of 5 to 30 Gb/s

A 5–30 Gb/s receiver analog front-end (AFE) cascading transimpedance amplifier (TIA) and continuous-time linear equalizer (CTLE) were implemented using a Taiwan Semiconductor 180 nm process. The system comprises a two-stage differential input pair CTLE, TIA, and a differential termination resistor Rm. A source-degenerated transconductance stage was adopted in the CTLE, and source follower and shunt feedback resistor stages were adopted in the TIA. The proposed CTLE could achieve high frequencies by altering the tail current with fixed degenerate capacitance CS and resistance RS. The proposed AFE achieved high bandwidth, and the use of a feedback resistor Rf and inductor Lf improved its high-frequency performance. Simulation results revealed that the CTLE can compensate for 16 dB of channel loss at a 3 GHz Nyquist frequency and can open closed eyes in a 6 Gb/s non-return-to-zero signal with a bit error rate of 0.16 × 10−12 for a 231 − 1 pseudorandom binary sequence input. The AFE could compensate for 12 dB of channel loss at a 15 GHz Nyquist frequency and can open closed eyes in a 30 Gb/s PAM4 signal from a pseudorandom binary sequence input; it consumed 27 mW of power at 1.8 V.

Clinical diagnostic algorithm in defining tuberculous unilateral pleural effusion in high tuberculosis burden areas short of diagnostic tools.

BackgroundEmpirical treatment was introduced when pathological or microbiological results of tuberculosis (TB) were not available. This report was designed to evaluate an algorithm based on empirical treatment in defining tuberculous pleural effusion (TPE) in high burden areas but short of diagnostic tools.MethodsIn this retrospective study, a total of 924 eligible patients were enrolled and 203 (22.0%) were primarily diagnosed as TPE by our diagnostic algorithm based on effusion characteristics [adenosine deaminase (ADA) and exudate] and immunoassays [purified protein derivative (PPD), M. tuberculosis antibody (TB-Ab) and interferon-gamma release assay (IGRA)]. All diagnosed cases received World Health Organization (WHO) standard anti-TB treatment and 187 of them had at least one year of follow-up. The final diagnosis and prognosis of these patients were traced and recorded.ResultsA total of 177 (94.65%) cases benefited from standard treatment, 5 (2.67%) failed due to early termination or drug resistance, and 5 (2.67%) were finally confirmed as misdiagnosis. Regarding diagnostic efficacy, 72 (30.13%) patients received four TB tests, and the combination of the four tests could increase the diagnosis of TPE. Besides, receiving operating characteristics curve (ROC) analysis revealed that our algorithm was the best method to differentiate TPE from malignant pleural effusion (MPE) with higher sensitivity and specificity than other serum markers.ConclusionsThis clinical diagnostic algorithm was an efficient and available method for the diagnosis of TPE. This diagnostic algorithm should be implemented in regions with high TB prevalence but short of diagnostic tools.

A Thermoelectric MEMS Microwave Power Sensor with Inline Self-Detection Function.

In this paper, the design, fabrication and measurement of a thermoelectric MEMS microwave power sensor with the terminal load inline self-detection function is proposed. The structure of the sensor mainly includes a coplanar waveguide, a thermopile, two terminal load resistors and two calibration resistors. In order to realize the inline self-detection function, the load and calibration resistors are designed to form a voltage divider circuit. The fabrication of this sensor is compatible with the GaAs MMIC technology. The on-chip performance is tested by using a microwave experimental platform. The measured reflection loss is less than −10 dB at 0.1–10 GHz. When the bias voltage is not applied, the sensitivity of the sensor is 47.39 μV/mW@5 GHz and 32.58 μV/mW@10 GHz, respectively, and when the bias voltage is applied, the sensitivity is 47.50 μV/mW@5 GHz and 32.73 μV/mW@10 GHz, respectively. The difference between the two cases is less than 0.5% at the same frequency, which indicates that whether or not to apply the bias voltage has little effect on the sensitivity. In addition, when the calibration resistance is increased from 50 to 100 Ω, the current flowing through the load resistance is decreased under the same bias voltage. Therefore, the DC power consumed on the load resistance will be significantly reduced. This makes the measured and theoretical results show better agreement, thus verifying the validity of the design.

Intrinsic Influence of Dynamic Resistance on Current Distribution of Two HTS Parallel Branches Without Terminal Contact Resistance

If a superconductor carries DC transport current and exposes to an alternating current (AC) magnetic field whose amplitude is more than its threshold field, a DC resistance so called dynamic resistance occurs on the superconductor because of the dissipative interaction between the DC transport current and the external magnetic field, which possibly appears in many kinds of high temperature superconductor (HTS) apparatus, such as linear synchronous motors. Occurrence of the dynamic resistance significantly affects the current distribution of the HTS components connected in parallel such as cables and conductors except for increasing the AC loses. In this paper, we employ a partially slit second-generation (2G) HTS tape with two branches to study the influence of dynamic resistance on current distribution such that the terminal contact resistances can be avoided. In experiment, DC transport current is applied to the whole 2G HTS tape and branch 1# is only exposed to an applied AC magnetic field. In addition, we use an analytical formulation of the dynamic resistance of branch 1# based on Bean critical state model and voltage calculation of branch 2# relies on E-I curve to build analytical model by using Newton Iteration. It is shown that DC current value of branch 1# decreases and branch 2# increases with the increasing of the dynamic resistance of branch 1#. The results are important for HTS DC devices with carrying ripple current or exposed to AC magnetic field.