Diode Pair Research Articles

A simple anti-parallel diodes based chaotic jerk circuit with arcsinh function: theoretical analysis and experimental verification

This paper introduces a novel autonomous chaotic jerk circuit with an antiparallel diodes pair whose mathematical model involves an inverse hyperbolic sine function in the form: $$f\left( x \right) = k - 2x + 4\arcsin h\left( {mx} \right)$$ where $$k$$ (i.e. a constant excitation source) controls the symmetry of the model while $$m$$ represents the slope of the inverse hyperbolic sine. The presence of the inverse hyperbolic sine is unusual provided that such types of circuits are connected to hyperbolic sine nonlinearity. The analysis of the model indicates that in case of a perfect symmetry ( $$k = 0.0$$ ), the system undergoes spontaneous symmetry breaking, period doubling scenario to chaos, symmetry recovering crisis, coexistence of multiple pairs of symmetric attractors, and coexisting symmetric bubbles of bifurcation. More complex and incoherent nonlinear dynamic patterns occur in the presence of symmetry perturbation ( $$k\ne 0.0$$ ) including for instance non-symmetric Hopf bifurcations, coexisting point attractor and limit cycle, coexisting asymmetric bubbles of bifurcations, critical transitions, and coexisting (i.e. up to five) non-symmetric periodic and chaotic attractors. The space magnetization resulting from the presence of various coexisting attractors is examined and illustrated by using basins of attraction. The predictions of theoretical investigations are supported by laboratory experimental tests based on a prototypal electronic circuit mounted on a breadboard.

A wideband subharmonic passive image rejection mixer

This article presents a circuit topology for a wideband subharmonic image rejection mixer. The mixer circuit is realized by employing two identical subharmonic mixers based on Schottky antiparallel diode pair, a wideband 90° differential phase shifter and a band pass filter without involving bonding wires, high impedance or tightly coupled arms. To demonstrate the topology, a mixer with 1 GHz as the fixed intermediate frequency is fabricated for 6 to 10 GHz of RF frequency. The lower side band is considered as the undesired band. Measurement results exhibit a minimum conversion loss of 7.87 dB and a maximum image rejection ratio of 41 dB at a local oscillator drive level of 9 dBm. Measured 1 dB compression point is 3 dBm. There is no requirement of DC bias.

Wide Input Power Range X-Band Rectifier With Dynamic Capacitive Self-Compensation

A microwave rectifier composed of a pair of Schottky diodes with dynamic capacitive self-compensation is proposed in this letter. The impedance of a Schottky diode usually varies with the input power. A method using paired diodes for capacitive self-compensation is presented to enhance the rectifier’s dynamic power range. The imaginary part of one diode’s impedance is compensated using another identical diode with a section of transmission line by impedance transforming. The proposed method reduces the effect of the input power on the diode impedance. An $X$ -band rectifier using a pair of HSMS-286 Schottky diodes based on the proposed method is designed and fabricated. This rectifier, with a dc load of $300~\Omega $ , achieves power conversion efficiency of 64.5% at 9.7 GHz and has a 15.3-dB input power dynamic range with efficiency exceeding 50%. The rectifier is expected to be used in wireless power transmission systems with flexible distance requirements.

Harmonic Dual-Band Diode Mixer for the X- and K-Bands

This paper presents a new dual-band diode mixer for the X- and K-bands. The proposed mixer consists of a pair of series-connected diodes and a frequency-dependent delay line that operates at 180° and 360° at the X-band of 10.525 GHz and at the K-band of 24.15 GHz, respectively. Without reconfigurable devices such as switches, the proposed mixer operates as a single-balanced diode mixer at the X-band and a subharmonically pumped antiparallel diode mixer at the K-band simultaneously. The designed circuit was implemented in a hybrid microwave integrated circuit using discretely packaged RF components on a microwave printed circuit board. The measurement results showed conversion losses of 6.5 dB and 16.6 dB at the X- and K-bands, respectively.

Measurement of Microwave Signal Frequency by a Pair of Spin-Torque Microwave Diodes

A single resonance-type spin-torque microwave diode (STMD) can be used as a quadratic detector to determine the frequency f of an external microwave signal when the power P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rf</sub> of this signal is known. However, unless the signal's frequency f exactly coincides with the detector's resonance frequency f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">res</sub> , there exists a finite frequency determination error Δf. In this letter, we show theoretically and experimentally that if a pair of independent STMDs with different resonance frequencies connected in parallel is used for the signal frequency determination, knowledge of the signal power is not necessary, and the frequency determination error can be substantially reduced to Δf ≈ 30 MHz at the frequency of f ≈ 5.0 GHz.

Time-Domain Characterization and Detection of Open Circuit Faults for H-Bridge Power Cell

This article presents the time-domain characterization of semiconductor open-circuit switch faults (OCSFs), such as an open switch with a healthy diode and switch–diode pair open for the H-bridge power cell. The inverter fault signatures under diagonally opposite open switch fault conditions with a healthy diode are approximately similar; therefore, this article presents a detection algorithm with a unique identification of each faulty switch within the H-bridge power cell. The proposed algorithm is also designed to detect and identify multiple OCSFs. The nonideal characteristics of semiconductor switches are considered for the identification of switch faults. The well-known unipolar sinusoidal pulsewidth modulation technique is used for the switching of semiconductor devices for the single power cell. The mathematical expressions have also been derived to find out the effect of the switch fault using a double Fourier integral solution and the switching states. The analytical expressions have been developed for the switched output voltage waveforms under ideal switching conditions. The behavior of the switch faults has been analyzed using inverter output voltage, load current, and total harmonic distortion of the pulsewidth-modulated inverter output voltage.

In Vivo Evaluation of a Subcutaneously Injectable Implant with a Low-Power Photoplethysmography ASIC for Animal Monitoring.

Photoplethysmography is an extensively-used, portable, and noninvasive technique for measuring vital parameters such as heart rate, respiration rate, and blood pressure. The deployment of this technology in veterinary medicine has been hindered by the challenges in effective transmission of light presented by the thick layer of skin and fur of the animal. We propose an injectable capsule system to circumvent these limitations by accessing the subcutaneous tissue to enable reliable signal acquisition even with lower light brightness. In addition to the reduction of power usage, the injection of the capsule offers a less invasive alternative to surgical implantation. Our current prototype combines two application-specific integrated circuits (ASICs) with a microcontroller and interfaces with a commercial light emitting diode (LED) and photodetector pair. These ASICs implement a signal-conditioning analog front end circuit and a frequency-shift keying (FSK) transmitter respectively. The small footprint of the ASICs is the key in the integration of the complete system inside a 40-mm long glass tube with an inner diameter of 4 mm, which enables its injection using a custom syringe similar to the ones used with microchip implants for animal identification. The recorded data is transferred wirelessly to a computer for post-processing by means of the integrated FSK transmitter and a software-defined radio. Our optimized LED duty cycle of 0.4% at a sampling rate of 200 Hz minimizes the contribution of the LED driver (only 0.8 mW including the front-end circuitry) to the total power consumption of the system. This will allow longer recording periods between the charging cycles of the batteries, which is critical given the very limited space inside the capsule. In this work, we demonstrate the wireless operation of the injectable system with a human subject holding the sensor between the fingers and the in vivo functionality of the subcutaneous sensing on a pilot study performed on anesthetized rat subjects.

UltraLow Noise, High Bandwidth, Low Latency, No Overload 6-Axis Optical Force Sensor

In this article, we present a novel six-axis optical sensor that employs pairs of light-emitting diodes (LEDs) and bicell photodetectors, and corresponding slits that modulate the projected LED light onto the photodetectors in response to external forces. The sensor can be clamped on and off a structure and relies upon the compliance of the structure for force estimation; it has no flexible components, and therefore, it is robust to overload. The mechatronic design features low noise, wide dynamic range opto-electronics, and signal conditioning, coupled with colocated digital electronics based on a FPGA that samples all sensing channels synchronously, enabling very low noise displacement sensing with resolution of 1.62 nm, low measurement signal latency of 100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> s, high measurement bandwidth of 500 Hz, and high data transfer rates in excess of 11.5 kHz for transmission of six axis transducer data to a host computer. The transducer's resolution is better than 0.0001% of the full-scale. A sensor model has been derived and can be used to explore design tradeoffs. A calibration approach based on an external reference sensor and an approach to temperature compensation are presented and validated. A video is attached.

A Soft-Switching Transformer-Less Step-Down Converter Based on Resonant Current Balance Module

In this article, a soft-switching transformer-less step-down converter based on a resonant current balance module is proposed. An LED driver is taken as an example of the analysis and design of the converter. The converter is made up of a stacked half-bridge, resonant current balance modules, and pairs of light-emitting diode (LED) strings. The resonant current balance modules allow the proposed converter to realize automatic current sharing, soft switching, and extending to a 1/N converter. The proposed converter can operate in discontinuous conduction mode (DCM) or continuous conduction mode (CCM) mode by choosing different operation frequencies, and achieve zero current switching or zero voltage switching (ZVS), respectively. Also, by using frequency doubling technique in the half-bridge, the switching losses are reduced by half under the same conditions. A 15.8-W experimental prototype with 100 V input voltage and 25 V output voltage has been implemented in the laboratory, verifying the feasibility of the soft-switching transformer-less step-down converter.

A wireless, skin-interfaced biosensor for cerebral hemodynamic monitoring in pediatric care

The standard of clinical care in many pediatric and neonatal neurocritical care units involves continuous monitoring of cerebral hemodynamics using hard-wired devices that physically adhere to the skin and connect to base stations that commonly mount on an adjacent wall or stand. Risks of iatrogenic skin injuries associated with adhesives that bond such systems to the skin and entanglements of the patients and/or the healthcare professionals with the wires can impede clinical procedures and natural movements that are critical to the care, development, and recovery of pediatric patients. This paper presents a wireless, miniaturized, and mechanically soft, flexible device that supports measurements quantitatively comparable to existing clinical standards. The system features a multiphotodiode array and pair of light-emitting diodes for simultaneous monitoring of systemic and cerebral hemodynamics, with ability to measure cerebral oxygenation, heart rate, peripheral oxygenation, and potentially cerebral pulse pressure and vascular tone, through the utilization of multiwavelength reflectance-mode photoplethysmography and functional near-infrared spectroscopy. Monte Carlo optical simulations define the tissue-probing depths for source-detector distances and operating wavelengths of these systems using magnetic resonance images of the head of a representative pediatric patient to define the relevant geometries. Clinical studies on pediatric subjects with and without congenital central hypoventilation syndrome validate the feasibility for using this system in operating hospitals and define its advantages relative to established technologies. This platform has the potential to substantially enhance the quality of pediatric care across a wide range of conditions and use scenarios, not only in advanced hospital settings but also in clinics of lower- and middle-income countries.

A design of 210 to 235GHzfixed tuned mixer using planar Schottky diode

This paper presents the design of a fixed tuned 210 to 235 GHz subharmonic mixer (SHM). The mixer is designed using GaAs based planar antiparallel Schottky diode pair AP1/G2/0P95 from Rutherford Appleton Laboratory. 3D model of the Schottky diode is discussed and simulated to consider parasitic effects of the diode. Detailed design technique of each of its subsections as well as the integrated mixer circuit is presented. Nonlinear co-simulation of the designed mixer exhibits double sideband (DSB) conversion loss less than 9.2 dB over the frequency band 210 to 235 GHz with 4 dBm of local oscillator (LO) power while the area of the rectangular printed section is 4.224 × 0.35 mm.

Low‐local‐oscillator‐power sub‐harmonic mixing in 300‐GHz band by Fermi‐level managed barrier diode

An anti-parallel (AP) diode pair based on a Fermi-level managed barrier (FMB) diode was developed for the sub-harmonic mixing of terahertz waves. A quasi-optical module integrating an AP–FMB diode pair and a trans-impedance amplifier exhibited a very low noise-equivalent-power of 9 × 10−19 W/Hz at an input signal frequency of 304 GHz with a very low local oscillator power of 30 μW.

Asymmetry-Induced Dynamics for a Class of Diode-Based Chaotic Circuits: A Case Study

We consider the modeling and asymmetry-induced dynamics for a class of chaotic circuits sharing the same feature of an antiparallel diodes pair as the nonlinear component. The simple autonomous jerk circuit of [J. Kengne, Z. T. Njitacke, A. N. Nguomkam, M. T. Fouodji and H. B. Fotsin, Coexistence of multiple attractors and crisis route to chaos in a novel chaotic jerk circuit, Int. J. Bifurcation Chaos Appl. Sci. Eng. 26 (2016) 1650081] is used as the prototype. In contrast to current approaches where the diodes are assumed to be identical (and thus a perfect symmetric circuit), we examine the more realistic situation where the diodes have different electrical properties in spite of unavoidable scattering of parameters. In this case, the nonlinear component formed by the diodes pair displays an asymmetric current–voltage characteristic which induces asymmetry of the whole circuit. The model is described by a continuous-time 3D autonomous system (ODEs) with exponential nonlinearities. We examine the chaos mechanism with respect to system parameters both in the symmetric and asymmetric modes of operation by using bifurcation diagrams and phase space trajectory plots as the main indicators. Period doubling route to chaos, merging crisis, and multiple coexisting (i.e., two, four, or six) mutually symmetric attractors are reported in the symmetric mode of oscillation. In the asymmetric mode, several unusual nonlinear behaviors arise such as coexisting bifurcations, hysteresis, asymmetric double-band chaotic attractor, crisis, and coexisting multiple (i.e., two, three, four, or five) asymmetric attractors for some suitable ranges of parameters. Theoretical analyses and circuit experiments show a very good agreement. The results obtained in this work let us conjecture that chaotic circuits with antiparallel diodes pair are capable of much more complex dynamics than what is reported in the current literature and thus should be reconsidered accordingly in spite of the approach followed in this work.

PIN-Diode-Based High-Intensity Radiation Fields (HIRF) Protection of a Printed Dipole Antenna

In this article, a PIN-diode-based high-intensity radiation fields (HIRF) protection method was proposed and the sensitivity to the field intensity of incident wave has been verified by a printed dipole antenna loaded with three pairs of PIN diodes at S-band. To illustrate this method, an equivalent linear circuit was raised to analyze the basic operation principle of the proposed antenna. With a low-power incident wave, the PIN diodes are in off-state and the gain of the proposed antenna remains unaffected; while it drops considerably as the PIN diodes are triggered by HIRF. Furthermore, extensive parametric studies of the structure were analyzed by full-wave simulation to investigate the key factors affecting the performance of HIRF protection and antenna characteristics. Finally, a prototype was fabricated and experiments were implemented to verify the feasibility, which shows a high isolation of 19 dB. To the best of our knowledge, the proposed antenna is the first one to achieve HIRF protection through integrated antenna technology, which features with low cost and compact structure, providing a new perspective.

Phase characteristics of E class amplifier with various output networks

Phase shift of E class amplifiers with classical output network and output network that satisfies E class loading impedance conditions twice in the frequency band were studied by simulation and experimentally. The phase shift across switch in nominal operation mode was investigated analytically. The phase shift across switch in suboptimal class E operation mode that occurs while altering the operation frequency was investigated as well. The simulation method was the harmonic balance analysis using the switch model that considers the structure of power MOSFET device, namely, the existence of antiparallel diode pair that alters the switch current waveform. The input and transition capacitances of the transistor were considered. Experimental measurement of the phase shift was performed utilizing the recorded digitized waveforms of the switch input and output voltages by computing the phases of the voltages’ first harmonics with the help of Fast Fourier Transform. It was observed that characteristics of phase shift at switch output and amplifier output are dependent on the kind of load network. The relationship between the phase shift at the switch and hodograph of the loading impedance was demonstrated. For the network with double fulfilment of class E conditions that has a loop in the loading impedance hodograph the switch phase shift dependency has an extremum, which provides an opportunity to obtain the same phase shift at two frequencies within the operating frequency band. That facilitates control of the phase-frequency characteristic and the group delay of the amplifier. Knowledge of the phase-frequency dependency simplifies the conditions for calculation of the phase shift in the feedback network. The obtained results are useful for design of class E oscillator operating in a wide frequency band.

Silicon Integrated Subharmonic Mixer on a Photonic-Crystal Platform

This article presents a planar silicon integrated subharmonic mixer on top of a photonic-crystal (PC) platform. The local oscillator power is injected through a 2-D PC slab to a resonant cavity that effectively couples the signal to a planar bow-tie antenna. The same antenna, which is printed on the top of the PC cavity, contains an antiparallel Schottky diode pair, which performs the downconversion. The proposed design is a simple, easy-to-integrate, low-cost, low-profile device. Moreover, the described fabrication process is compatible with active component integration. The performance of the design has been experimentally demonstrated showing good agreement with the simulation and is comparable with the state of the art of planar mixers. The work presented here is based on concepts and technologies from electronics and photonics domains and may be a good starting point for the creation of new devices, allowing the integration and upgrading of existing techniques from both fields.

Area-Efficient Series-Connected Resonant Tunneling Diode Pair as Binary Neuron in Cellular Neural Network

In this letter, we propose an area-efficient series-connected resonant tunneling diode pair device (SCRTD) to utilize as a binary neuron device in cellular neural networks (CNNs). The proposed SCRTD (P-SCRTD) consists of two RTDs interconnected by a floating metal layer with a high-doped epitaxial layer. The P-SCRTD shows a 48 % reduction in area by eliminating the isolation area in the conventional SCRTD (C-SCRTD) owing to the symmetrical I-V characteristic of the RTD, without any performance penalty on the DC and RF characteristics by means of adopting the floating metal layer, compared to the C-SCRTD. CNN application of the P-SCRTD is investigated, showing inherent threshold operation and high-speed (12.5 Gbps) low-power (21 mW) performance, despite using the $2~\mu \text{m}$ technology node, for a unit cell for edge extraction.

D-Band Frequency Tripler Module Using Anti-Parallel Diode Pair and Waveguide Transitions

In this paper, D-band (110–170 GHz) frequency tripler module is presented using anti-parallel GaAs Schottky diode pair and waveguide-to-microstrip transitions. The anti-parallel diode pair is used as a nonlinear device generating harmonic components for Q-band input signal (33–50 GHz). The diode is zero-biased to eliminate the bias circuits and thus minimize the number of circuit components for low-cost hybrid fabrication. The anti-parallel connection of two identical diodes effectively suppresses DC and even harmonics in the output. Furthermore, the first and second harmonics of Q-band input signal are cut off by D-band rectangular waveguide. Input and output impedance matching networks are designed based on the optimum impedances determined by harmonic source- and load-pull simulations using the developed nonlinear diode model. Waveguide-to-microstrip transitions at Q- and D-bands are also designed using E-plane probe to package the frequency tripler in the waveguide module. The compensation circuit is added to reduce the impedance mismatches by bond-wires connecting two separate substrates. The fabricated frequency tripler module produces a maximum output power of 5.4 dBm at 123 GHz under input power of 20.5 dBm. A 3 dB bandwidth is as wide as 22.5% from 118.5 to 148.5 GHz at the input power of 15.0 dBm. This result corresponds to the excellent bandwidth performance with a conversion gain comparable to the previously reported frequency tripler operating at D-band.

Reconfigurable Low-Pass Filter With Sharp Roll-Off and Wide Tuning Range

A miniaturized reconfigurable low-pass filter (LPF) with a sharp roll-off, wide tuning range, and extended stopband is presented in this letter. The proposed LPF consists of two fixed low-pass (LP) cells and a tunable bandstop (BS) cell loaded with two pairs of varactor diodes. The BS cell with tunable stopband edges is employed to achieve the reconfigurable cutoff frequency and sharp roll-off characteristics in the whole LPF. The fixed LP cells are utilized to suppress the high passband of the BS cell, which obtain the tunable LP filtering response and wide stopband. For experimental demonstration purposes, a microstrip prototype of the proposed reconfigurable LPF with a wide fractional tuning range of 78.8% and roll-off rate over 103 dB/GHz is simulated, fabricated, and measured. The wide stopband is extended up to 10 GHz with a rejection level better than 15 dB, and the overall dimension is $0.078\lambda _{\mathrm {g}} \times 0.08\lambda _{\mathrm {g}}$ . This physical size is comparable to more compact, prior art reconfigurable LPFs while featuring among the sharpest roll-off rate ever reported.

Analytical Model to Study Hard Turn-off Switching Dynamics of SiC mosfet and Schottky Diode Pair

Fast switching transient of SiC mosfet may lead to prolonged oscillations, spurious turn on, large device stress, and high amount of electromagnetic interference generation. For an optimal layout and gate driver design, study of switching dynamics is important. This article presents an analytical model that captures the turn-off switching dynamics of SiC mosfet and SiC Schottky barrier diode (SBD) pair using parameters obtained from device and gate driver datasheets and the values of external circuit parasitics. Unlike linear approximation, a detailed model of channel current is considered that captures the gradual transition from ohmic to saturation region and the transverse electric field effect. A comprehensive model of the transfer capacitance is used and the effect of external gate-drain capacitance is considered. This results in a better estimation of switching transition time, actual loss incurred, (dv/dt), (di/dt), and transient overvoltage. The behavioral simulation and experimental results confirm the accuracy of the presented analytical model over a range of operating conditions for two 1.2-kV discrete SiC mosfet and SBD pairs of different current ratings.