Step Recovery Diode Research Articles

Characterizing Dual-Band RF PAs Using Wideband Synchronization and Calibration Techniques of Nonlinear Vector Network Analyzer

This paper presents novel nonlinear vector network analyzer (NVNA)-based techniques for characterizing the harmonic and intermodulation nonlinearity of dual-band radio frequency (RF) power amplifiers (PAs). On the one hand, a wideband Schroeder-phase multisine is used to drive a step recovery diode comb generator, so that a novel multiharmonic-band NVNA phase reference on a dense spectral grid is obtained. On the other hand, a novel phase calibration approach is developed to synchronize the NVNA multiband measurements. To validate the NVNA testbed with novel techniques, an RF PA under two typical kinds of dual-band multisine stimulus is tested, where the NVNA measurement is compared with that of an oscilloscope. This paper can be easily adapted for various multiband conditions.

A Simple Picosecond Pulse Generator Based on a Pair of Step Recovery Diodes

A picosecond pulse generator based on a pair of step recovery diodes (SRD), leveraging the transient response of the SRD PN junction and controlling the pulse width by a resistor, is proposed. We first explain the operation principle of the device, decomposing the pulse generation into different phases, and then demonstrate an experimental prototype with two different resistance, and hence pulse width, values.

Characterization for Multiharmonic Intermodulation Nonlinearity of RF Power Amplifiers Using a Calibrated Nonlinear Vector Network Analyzer

This paper presents a novel realization of nonlinear vector network analyzer (NVNA) test-bed with a new phase calibration technique, in order to characterize the multiharmonic intermodulation nonlinearity of a radio frequency (RF) power amplifier (PA) under a large-signal modulated input. The NVNA test-bed uses a step recovery diode comb generator as the phase reference, which is driven by a pulsed-RF signal with a high duty cycle of over 99%. Hence all the multiharmonic intermodulation tones of interest can be measured at once. A multisine phase standard provided by a vector signal analyzer is used to calibrate the intermodulation tones at each harmonic on a dense spectral grid. Two harmonic phase standards with different fundamental frequencies are used to synchronize the phase calibration results at different harmonics. The validity of this paper is verified by comparing NVNA measurements with oscilloscope measurements of the same PA under test. This paper can be used to inspect the nonlinearity of RF amplifiers under large-signal modulated excitations in both the frequency and time domains.

Design of reconfigurable active integrated pulse generator‐antenna with pulse‐shape modulation for ultra‐wideband applications

A novel design of ultra-wideband (UWB) reconfigurable pulse generator (PG) active-integrated antenna (AIA) is introduced and discussed in this study. The reconfigurable structure of the proposed PG AIA provides pulse-shape modulation which is desirable for most UWB communication systems. The presented design utilises only a single step-recovery diode and just a single positive-intrinsic-negative diode in order to generate sub-nanosecond switchable monocycle/doublet pulse shapes. Since in UWB communication systems the design of source pulses and transmitting/receiving antennas should be optimal for the performance of overall systems both frequency domain and time domain characteristics of the designed PG AIA are carefully investigated under realistic conditions. The pulse distortion is insignificant in the operating band and is verified by the measured PG AIA performance with low ringing level, high signal fidelity, and virtually steady group delay. The presented design is a good candidate for UWB transmission because of its simplicity, low cost, and good performance.

A compact reconfigurable sub-nanosecond pulse generator with pulse-shape modulation

A new design of reconfigurable sub-nanosecond pulse generator (PG) with pulse shape selection ability is presented in this paper. Step recovery diode is used as the pulse sharpening device and the pulse shaping circuit consists of a controllable RC differentiator in which a single PIN diode is embedded, which provides two different switchable pulse shaping performances. The realized PG has a compact (10 × 12 mm2) simple structure and is easy to implement while generating Gaussian and monocycle pulses with 510 and 660 ps pulse width, respectively. The proposed pulse shaping method is versatile and can be effectively modified and reconfigured to generate more complicated pulse shapes such as polycycle signals. The measured results reveal that the proposed reconfigurable PG is suitable to be used in systems with pulse shape modulation that require sub-nanosecond pulses at low pulse repetition rates.

Temperature dependence of silicon carbide drift step recovery diodes injection electroluminescence

The experimental results of silicon carbide (SiC) drift step recovery diodes (DSRDs) temperature dependence of injection electroluminescence (IEL) spectra were presented. It was shown that in the forward current range If = 0,1...1 A the DSRD-dies temperature was raised from 327 K to 546 K correspondingly. While the short-wavelength maximum of IEL spectra - λmax1 shifts from 392.4 to 402.1 nm and possesses dependence close to linear. On the basis of obtained calibration curves it is possible the non-contact temperature measuring of SiC-DSRDs by electroluminescence spectra at their operation in the generator of high voltage pulses.

Validation of Fast Current Interruption Mechanism in Sub-Nanosecond High-Voltage Switching Diodes

The fast current interruption property of drift step recovery diodes (DSRDs) is utilized in high-voltage fast switches. Previously, using a physical device simulator, we have conducted a theoretical investigation of this mechanism in a p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> πn <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> structure and evaluated the expected dependence of device performances on its structure and driving conditions. In this letter, we experimentally validate these findings by presenting consistency between the theoretical results and the actual measured results. Diode structures with a uniform doping profile and abrupt junction were fabricated using thick layer epitaxy technology, which allows for improved control over the doping profile, compared with the traditional method of deep aluminum diffusion. The switching characteristics of the diodes were measured using a specially designed circuit. An outstanding switching time of 0.3 ns at 230 V per DSRD die was demonstrated by driving the diode with a reverse current density exceeding 1250 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . We conclude that a semi-empirical design of the diode and its driving conditions can be substituted by accurate modeling using the device simulator. By combining the physical understanding gained with accurate modeling capabilities and epitaxial growth technology, novel diode design and improved switching performance may be achieved.

Generating photon pairs from a silicon microring resonator using an electronic step recovery diode for pump pulse generation

Generation of photon pairs from compact, manufacturable, and inexpensive silicon (Si) photonic devices at room temperature may help develop practical applications of quantum photonics. An important characteristic of photon-pair generation is the two-photon joint spectral intensity, which describes the frequency correlations of the photon pair. Recent attempts to generate a factorizable photon-pair state suitable for heralding have used short optical pump pulses from mode-locked lasers, which are much more expensive and bigger table-top or rack-sized instruments compared with the Si microchip used for generating photon pairs, and thus dominate the cost and inhibit the miniaturization of the source. Here, we generate photon pairs from an Si microring resonator by using an electronic step-recovery diode to drive an electro-optic modulator which carves the pump light from a continuous-wave laser diode into pulses of the appropriate width, thus potentially eliminating the need for optical mode-locked lasers.

High-Voltage Ultra-Fast Pulse Diode Stack Based on 4H-SiC

The paper reports on the results of the studies of static and dynamic characteristics of 4H-SiC drift step recovery diodes (DSRDs) assembled in diode stacks. Switching performance of single dies has been simulated and experimentally confirmed. It was established that the switching process is determined primarily by the incomplete ionization of acceptors in 4H-SiC and by the bandgap narrowing in heavily doped emitters. Based on the simulation results the optimized die size has been selected. For DSRD stacks of 4 and 8 dies I-V and C-V measurements are reported. The stacks were dynamically tested in a special oscillator circuit. Repetitive voltage pulses of 10.5 kV with the leading edge length of 900 ps were demonstrated.

Electrical Performance of 4H-SiC Based Drift Step Recovery Diodes

Mesa-epitaxial 4H-SiC p+-p-no-n+-diodes were fabricated from commercial epitaxial wafers. Reverse recovery characteristics of the diodes were measured in pulse regimes to be relevant to operation of drift step recovery diodes (DSRDs) [1]. When injecting the minority carriers by forward current pulse followed by applying a reverse voltage pulse, the diodes are able to break the reverse current in a subnanosecond time (DSRD-mode). Different regimes of diode operation in DSRD-mode are investigated such as variable reverse voltage amplitude, forward current amplitude and duration, time delay between forward and reverse pulses.

Coherent cavity-enhanced dual-comb spectroscopy.

Dual-comb spectroscopy allows for the rapid, multiplexed acquisition of high-resolution spectra without the need for moving parts or low-resolution dispersive optics. This method of broadband spectroscopy is most often accomplished via tight phase locking of two mode-locked lasers or via sophisticated signal processing algorithms, and therefore, long integration times of phase coherent signals are difficult to achieve. Here we demonstrate an alternative approach to dual-comb spectroscopy using two phase modulator combs originating from a single continuous-wave laser capable of > 2 hours of coherent real-time averaging. The dual combs were generated by driving the phase modulators with step-recovery diodes where each comb consisted of > 250 teeth with 203 MHz spacing and spanned > 50 GHz region in the near-infrared. The step-recovery diodes are passive devices that provide low-phase-noise harmonics for efficient coupling into an enhancement cavity at picowatt optical powers. With this approach, we demonstrate the sensitivity to simultaneously monitor ambient levels of CO2, CO, HDO, and H2O in a single spectral region at a maximum acquisition rate of 150 kHz. Robust, compact, low-cost and widely tunable dual-comb systems could enable a network of distributed multiplexed optical sensors.

A modular drift step-recovery diode generator for nanosecond pulse technologies

A generator of nanosecond pulses with an energy of ~50 mJ, which provides switching of voltage pulses with an amplitude of ~17 kV and a rise time of ~4 ns at a repetition frequency of 8 kHz to a 75-Ω resistive load, is described. The load is matched to the generator output cable. The generator is based on an opening switch in the form of a unit of drift step-recovery diodes (DSRDs). The conditions for the efficient operation of DSRDs are provided by six self-contained modules each of which contains an IGBT transistor and a step-up saturable-core transformer. The results of an experimental study of the generator are presented. They indicate a high efficiency of the developed modular circuit, which makes it possible to increase the switched energy virtually in proportion to the number of used modules, and the possibility of reducing the switching energy loss in the DSRD unit in proportion to the number of diode assemblies connected in parallel. It is shown that the generator can be used for producing ozone and high-purity silicon tetrafluoride and also in an apparatus for purifying air of organic pollutants.

Design and Implementation of Impulse Radio Ultra-Wideband Transmitter

This paper illustrates the simulation, implementation and testing of an UWB transmitter based on Step Recovery Diode (SRD). For testing purposes, a square wave generator has been also implemented based on Colpitts oscillator and a clipping circuit that was used to trigger the monocycle pulse generator. The simulated output is a monocycle pulse waveform with 300 ps pulse width and acceptable symmetry in both amplitude and shape. Integrating the UWB transmitter and the Colpitts oscillator, the achieved output from this integration after implementation is a monocycle pulse waveform with 420 ps pulse width and acceptable symmetry in both amplitude and shape.

A Novel Picosecond Pulse Generation Circuit Based on SRD and NLTL.

Because of the importance of ultra-wideband (UWB) radar in various applications, short pulse generation in UWB systems has attracted a lot of attention in recent years. In order to shorten the pulse, nonlinear transmission line (NLTL) is imported, which expands the application of step recovery diode (SRD) for pulse generation. Detailed analysis and equations for this SRD and NLTL-based pulse generation are provided and verified by simulation and experimental results. Factors that could cause pulse waveform distortions are also analyzed. The generator circuit presented in this paper generates 130ps and 3.3V pulse, which can be used in UWB radar systems that require sub-nanosecond pulses.

Dynamic characteristics of 4H-SiC drift step recovery diodes

The dynamic characteristics of 4H-SiC p+–p–n0–n+ diodes are experimentally studied in the pulsed modes characteristic of the operation of drift step recovery diodes (DSRD-mode). The effect of the subnanosecond termination of the reverse current maintained by electron-hole plasma preliminarily pumped by a forward current pulse is analyzed in detail. The influence exerted on the DSRD effect by the amplitude of reverse-voltage pulses, the amplitude and duration of forward-current pulses, and the time delay between the forward and reverse pulses is demonstrated and accounted for.

High-Power Nanosecond Pulse Generator With High-Voltage SRD and GDT Switch

A high-power short-pulse generator based on the dual action of two coupled diodes, a high-voltage step recovery diode and a high-current diode, is presented. This is made possible using a gas discharge tube. Both analysis and SPICE simulation show about 20-dB peak power increment. This gives a high output power level of 5.7 MW with 1-ns pulsewidth and 450-kHz repetition rate obtained from an input average power of 7.1 kW. An efficiency of about 73% is obtained with more than 30 dB increase in the average power delivered to a 50- $\Omega $ load.

A Novel Low-Ringing Monocycle Picosecond Pulse Generator Based on Step Recovery Diode.

This paper presents a high-performance low-ringing ultra-wideband monocycle picosecond pulse generator, formed using a step recovery diode (SRD), simulated in ADS software and generated through experimentation. The pulse generator comprises three parts, a step recovery diode, a field-effect transistor and a Schottky diode, used to eliminate the positive and negative ringing of pulse. Simulated results validate the design. Measured results indicate an output waveform of 1.88 peak-to-peak amplitude and 307ps pulse duration with a minimal ringing of -22.5 dB, providing good symmetry and low level of ringing. A high degree of coordination between the simulated and measured results is achieved.

Mechanism of Fast Current Interruption inp−π−nDiodes for Nanosecond Opening Switches in High-Voltage-Pulse Applications

Pulsed-power applications supporting research in fusion, plasma, and particle physics require delivery of high voltages over very short times (nanoseconds, or less)---no mean feat of engineering. The authors study current interruption in a step-recovery diode (SRD), which could be a fast-opening switch for high-voltage pulsed electronics, and find the main governing parameters to be the diode's reverse current density and base doping concentration. This understanding allows the design of improved structures, taking advantage of modern semiconductor growth technology.

A nanosecond-pulse generator with an optimized diode switch

A diode-transistor generator of high-voltage nanosecond pulses, which is based on an inductive energy storage and an opening switch in the form of an assembly of drift step-recovery diodes (DSRDs) connected in series, is considered. It allows switching of a voltage pulse with an amplitude of 12 kV and a rise time of 4 ns into a load of 75 Ω at a frequency of 10 kHz. The results of investigations of the process of disabling DSRDs with different thicknesses of the base regions and different diffusion-layer profiles are presented. The design of optimized DSRDs with reduced energy losses during disabling is described. It is shown that the use of an assembly of optimized DSRDs in the developed generator provides a twofold increase in the limiting switched energy.

Temperature Dependence of Minority Carrier Lifetime in Epitaxially Grown p&lt;sup&gt;+&lt;/sup&gt;-p&lt;sup&gt;–&lt;/sup&gt;-n&lt;sup&gt;+&lt;/sup&gt; 4H-SiC Drift Step Recovery Diodes

In this paper we report on the effect of temperature and injection level on the effective lifetime of non-equilibrium charge carriers in p-base of 4H-SiC PiN diodes. Studies were carried out on 1kV drift step recovery diodes (DSRDs) with p+-p--n+. The lifetime of non-equilibrium charge carriers in 4H-SiC p+-p--n+ structures increases by an average of 6 times from 250ns to 1.4μs with the increase of the samples temperature from 300K to 673K. However, increase of the injection level in the drift region from 2.3·1016cm-3 to 5.9·1016cm-3 does not affect the lifetime indicating that Shockley-Read-Hall recombination processes are dominating.