双漂移崩越二极管的渡越角分析

在考虑载流子的空间电荷效应、扩散效应和注入电流脉宽情况下,推导了双漂移崩越二极管的渡越角表达式.用于计算35GHz崩越管渡越角,与计算机模拟结果符合良好.     

State-Space Analysis of General IMPATT Diode Small-Signal Lumped Models

The development of a lumped model for small-signal carrier-field interactions in an IMPATT diode results in a set of state equations. Using state-space analysis techniques, the equations are solved for the small-signal impedance of a general IMPATT diode as a function of dc bias current and frequency. Read, p-n, and p-i-n diodes are studied using realistic values for saturation carrier velocities and carrier-ionization rates. Curves indicating the influence of diode physical properties on the small-signal impedance are presented. By combining state equations describing the behavior of the external microwave circuit with the diode state equations, the small-signal oscillation frequency and threshold dc bias current of a coaxial IMPATT oscillator are determined.     

Theory of Noise and Transfer Properties of IMPATT Diode Amplifiers

A theory is formulated which describes quantitatively the noise and transfer properties of IMPATT diode reflection-type negative resistance amplifiers. This theory is based on the method used in the large-signal theory of noise in IMPATT diode oscillators by the present authors. The theory takes into account the signal dependence of the noise generation in the diode, the noise and/or modulation present in the input signal, and also the intermodulation effects occurring between the various frequency bands. The equations are conveniently arranged in matrix form; such a formulation makes it easier to obtain quantitative results in terms of measurable noise and modulation parameters. Agreement between measured and theoretically predicted AM and FM noise of injection-locked oscillators is good. The usefulness of the theory is illustrated by results of calculations on minimum attainable noise of a given amplifier, maximum noise allowable on the input signal, AM-FM conversion, phase distortion, bias modulation, and the correlation between various types of noise.     

Computer optimisation of double-drift-region IMPATT diodes

Design parameters for double-drift-region silicon IMPATT diodes for frequencies from 10 to 100 GHz are presented. The design is based on extensive large-signal computer simulations at one frequency of two different diode structures in a simple circuit. From these simulations, a simple design criterion was derived which permits the calculation of optimised impurity profiles for any desired frequency, with a small computer effort.     

Nonlinear Behavior and Bias Modulation of an IMPATT Diode Oscillator

Experimental results of the nonlinear behavior of an IMPATT diode oscillator under free-running and bias-modulated conditions are presented and correlated with theoretical results. Amplitude and frequency behavior of a free-running IMPATT diode oscillator such as: 1) power-frequency characteristic, 2) jump and hysteresis, 3) temperature dependence, 4) harmonic content, and 5) electronic tuning characteristics are discussed. The bias-modulation properties and their relation to the free-running behavior are described. The effects of the operating point, external Q, and injection locking on the modulation properties are presented.     

SiC/GaN IMPATT二极管的交流性能研究

利用p型宽带隙材料SiC替代p型GaN,制作了一种p-SiC/n-GaN异质结双漂移(DDR)IMPATT二极管.对器件的交流大信号输出特性进行数值模拟仿真.结果表明,相比传统GaN单漂移(SDR)IMAPTT二极管,p-SiC/n-GaN新结构DDR器件的击穿电压、最佳负电导、交流功率密度和直流-交流转换效率都获得了...     

GaN基同型异质结IMPATT二极管噪声特性研究

针对p型GaN IMPATT制造工艺仍未成熟,提出了一种In0.4Ga0.6N/GaN n-n型异质结构来取代常规p-n结构,使GaN IMPATT二极管工作在IMPATT模式下。研究了这种n-n型In0.4Ga0.6N/GaN碰撞电离雪崩渡越时间(IMPATT)二极管的噪声特性,与同等条件下的传统GaN基p-n结IMPATT二极管作比较。结果表明,在不同偏置电流密度和不同InGaN层厚度下,该器件的噪声特性均好于传统p-n结构。结合器件交流输出特性可以得知,In0.4Ga0.6N/GaN同型异质结IMPATT器件不仅在功率效率上优于GaN p-n结构,其噪声性能表现亦优于传统GaN p-n结构,特别是在高频段的噪声特性优势更加明显。该研究可以为GaN基IMPATT器件的设计提供更多的思路和参考。     

Cavity Stabilization and Electronic Tuning of a Millimeter-Wave IMPATT Diode Oscillator by Parametric Interaction

A new technique is proposed by which both noise reduction and electronic tuning of a millimeter-wave solid-state oscillator can be realized by injecting an arbitrary low-frequency (several hundred megahertz or beyond) signal to the oscillator element which is provided with an additional high-Q cavity. This method has much wider tuning bandwidth than that of the conventional subharmordc injection locking technique. Presented are both experimental results and some theoretical interpretations by using an IMPATT diode oscillator.     

Diamond-Like Carbon Films Obtained by the Method of High-Frequency Diode Sputtering

Conditions for fabrication of diamond-like carbon films on the surface of oxidized single-crystalline silicon using the technique of high-frequency diode sputtering of graphite target are determined. It has been found that the deposited films have amorphous structure. The Raman spectroscopy technique has been used to show the presence of carbon phases with sp²- and sp³-hybridization, the ratio between which can be controlled by the growth conditions.     

Analysis and Design of an X-Band Actively Compensated IMPATT Diode Amplifier

This paper shows how broad-banding of an IMPATT diode amplifier can be achieved using a circuit technique known as active reactance compensation. Theoretical analysis and experimental results both show that the gain-bandwidth products of an uncompensated IMPATT amplifier improves from G/sup 1/2/B = k to G/sup 1/4/B = 2k (where k is a constant) for the same amplifier actively compensated. The measured 3-dB bandwidth of 230 MHz for a 9.0-GHZ amplifier having a gain of 10 dB is improved to 700 MHz at the same gain.     

L、S波段俘越二极管性能参数的实验研究

在以击穿电压V_b和结电咨C_j(-60)作为器件低频参数的基础上,研究了器件低频参数与高频性能的关系,增添电容比C_r(=[C_j(-1)]/[C_j(-60)]作为低频参数.实践表明,L、S波段俘越二极管各有相应的C_r最佳范围,凡具有最佳C_r范围的器件有好的俘越振荡性能.本文还介绍了器件C_r与外延材料的杂质浓度N的关系.可据此关系选抒外延材料的杂质浓度N来制造器件,使得80%以上批次的器件部具有好的俘越振荡性能.     

Field Analysis of a Millimeter-Wave GaAs Double-Drift IMPATT Diode in the Traveling-Wave Mode

An analysis of a realistic model of distributed lMPATT structures is described. Wave equations are solved with all losses included. The results show that net gain is produced at frequencies just above the avalanche resonance, while the propagation becomes slow at high frequencies. The results compare favorably with experiment.     

Experimental demonstration of a silicon carbide IMPATT oscillator

Silicon carbide (SiC) is an excellent material for high-power and high-frequency applications because of its high critical field, high electron saturation velocity, and high thermal conductivity. In this letter, we report the first experimental demonstration of microwave oscillation in 4H-SiC impact-ionization-avalanche-transit-time (IMPATT) diodes. The prototype devices are single-drift diodes with a high-low doping profile. DC characteristics exhibit hard, sustainable avalanche breakdown, as required for IMPATT operation. Microwave testing is performed in a reduced-height waveguide cavity. Oscillations are observed at 7.75 GHz at a power level of 1 mW     

有源光纤环形腔进行频率调谐窄线宽激光的方法

本文提出用有源光纤环形腔来获得精确调谐窄线宽激光的新方法，理论分析结果表明：幅值（或相位）调制产生的频宽扩展对腔带宽的影响很小，滤波输出激光的线宽约等于入射光随机初相位决定的线宽，有源腔对滤波输出激光还有光放大作用。     

Optimal Parameters of Photonic-Crystal Vertical-Cavity Surface-Emitting Diode Lasers

We investigate the modal characteristics of a 1300-nm InP-based photonic-crystal (PC) vertical-cavity surface- emitting diode laser. To this aim, we apply the plane-wave admittance method and analyze a broad range of PC parameters such as hole etching depth, distance between the holes, and their diameters. We determine a range of technologically feasible PC parameters providing an optimal laser performance.     

快恢复二极管软度参数的调整

探讨了快恢复二极管制造过程中,选择适当的复合中心能级去调整快恢复二极管软度因子和软度的可行性。实验结果说明,选用σｐ／σｎ比值较小的复合中心能级可以改善二极管的软度参数。     

3C-SiC功率肖特基二极管特性的计算机分析

由描述功率肖特基二极管电学特性的基本方程出发，结合对典型整流电路效率、器件正向压降、反向耐压及温度特性等参数的数值分析，给出3C－SiC功率肖特基二极管折衷优化设计的理论依据。     

计算机有源音箱的设计

就计算机有源音箱电路的设计,分别介绍了双电源电路、双声道立体声电路、超重低音电路以及静噪和保护电路的设计方法.提出了若干设计理念:如电源设计中采用简单串联武稳压,提高了设计的灵活性;双声道立体声前置采用反相放大形式,可有效减小噪声,提高信噪比;超重低音电路采用独有的高低通滤波器进行分频,可有效减小低频噪声,使超重低音浑...