频率负阻效应与复合振荡器

本文利用转动变换推导出五种典型放大电路的负阻条件;利用负阻效应特有的复合振荡现象取得了扩展振荡频带、增强振幅的效果;从而表明,在反馈振荡器与负阻振荡器之间存在可供实用的第三种振荡形式。     

新型砷化镓Z元件

本文报导了砷化镓材料制作的Ｚ元件,观察到Ｓ型负阻及相应的振荡波形,重点解决了Ｓ型负阻产生的原因及振荡机理,理论分析与实验相符。     

基于MEMS技术新型硅磁敏三极管负阻-振荡特性

介绍了-种新型硅磁电负阻-振荡器件--S型负阻-振荡硅磁敏三极管.该器件是基于MEMS技术在p型高阻单晶硅片上制作的具有立体结构的新型磁电转换器件,采用KOH各向异性腐蚀技术实现发射区及引线的制作.实验结果表明,集电极电流随外加磁场的变化而变化;在基极注入电流一定时,出现集电极电流受外加偏压VCE调制的负阻-振荡特性,且集电极电流振荡随外加磁场而变化.对该器件负阻-振荡特性的形成机理进行了讨论,结果表明,在集电区n+π结和基区与π区形成的p+π结均处于反偏条件下,当π区满足雪崩倍增效应产生的条件时,该磁敏三极管伏-安特性曲线中的Vp+x偏压相对应的基极注入条件下的集电极电流出现S型负阻-振荡特性.在发射极和基极间的n+π结和p+π结附近存在的大量深能级杂质将对负阻-振荡特性进行调制.     

负阻元件的设计与应用实验

在电路理论中,负阻元件在电子电路中主要用来产生振荡,其特性曲线都是严重非线性的。负阻元件典型的应用是间歇振荡,在缺乏高效供电时尤其有用。负阻振荡器结构简单、体积小、成本低,所以在一些需要初始触发时经常使用。     

基于MEMS技术新型硅磁敏三极管负阻-振荡特性

介绍了一种新型硅磁电负阻振荡器件——S型负阻-振荡硅磁敏三极管．该器件是基于MEMS技术在p型高阻单晶硅片上制作的具有立体结构的新型磁电转换器件，采用KOH各向异性腐蚀技术实现发射区及引线的制作．实验结果表明，集电极电流随外加磁场的变化而变化；在基极注入电流一定时，出现集电极电流受外加偏压VCE调制的负阻-振荡特性，且集电极电流振荡随外加磁场而变化．对该器件负阻振荡特性的形成机理进行了讨论，结果表明，在集电区n+π结和基区与π区形成的p+π结均处于反偏条件下，当π区满足雪崩倍增效应产生的条件时，该磁敏三极管伏-安特性曲线中的Vp+π偏压相对应的基极注入条件下的集电极电流出现S型负阻-振荡特性．在发射极和基极间的n+π结和p+π结附近存在的大量深能级杂质将对负阻-振荡特性进行调制．     

RC相移式振荡器的负阻法分析

利用负阻法推出了RC相移式振荡器的振荡条件和振荡频率公式，其结果与传统法推出的完全一致，且其物理概念更为清晰。     

变容管调谐微波压控振荡器

本文从晶体管等效电路入手,利用负阻法分析振荡器,导出了振荡管最佳反馈电容和最大等效负阻。指出了变容管串联及并联电调时等效电路及谐振频率的计算公式,提供了变容管调谐微波晶体管压控振荡器的设计步骤及方法。     

光电双向负阻晶体管的数值模拟与实验研究

光电双向负阻晶体管(PBNRT)是一种新型S型光电负阻器件.本文对它的光电负阻特性进行了数值模拟和实验研究,给出了器件等效电路.PBNRT在光电混合工作模式下具有光控电流开关效应,可通过光照和控制电压两种控制方式改变器件的S型负阻特性.模拟和实验结果均表明:光照强度增大,维持电压基本保持不变,转折电压减小,负阻电压摆幅减小;而增大控制电压,维持电压和转折电压均增大,输出负阻特性曲线右移.上述特点使得PBNRT可望在光电开关、光控振荡和光电探测等方面有很好的应用前景.     

光电双基区晶体管光控脉冲振荡器的实验研究

光电双基区晶体管（ＰＤＵＢＡＴ）是一种能产生“Ｎ”型光电负阻特性的新型光电负阻器件。通过对试制出的样管进行测试,发现ＰＤＵＢＡＴ在无外接电感的情况下即可发生脉冲振荡。脉冲振荡的频率和振幅均受到入射光强度的调制,即随光强的增大,振荡频率增加,振由减小。最后,对该器件的应用及发展前景进行了讨论。     

负阻提升的微波混沌振荡器的设计

将负阻提升技术引入到混沌振荡器的设计中,通过理论推导、数值计算和测试验证来优化电路结构,提供参数选取规则,从理论和实验两方面验证,在双电感的比值达到最优值时振荡器负阻能够得到大幅提升。并基于负阻提升技术提出了双电感结构的微波Colpitts 混沌振荡器。新结构电路的最高混沌振荡基频为1.78 GHz,较经典电路提升了39%;带宽达到4.60GHz(0.80～5.40 GHz),较经典电路提升了119%。测试结果表明,优化的双电感结构能有效提升混沌振荡基频和带宽。     

High-power punch-through avalanche-diode microwave oscillators

Two distinctive modes of oscillation are observed in specially profiled silicon avalanche diodes: transit-time mode at 3 to 7 GHz at lower bias current densities and an anomalous mode at around 1 GHz above certain threshold current levels. High pulsed power has been produced from both modes of operation. Space-charge-induced negative resistances are computed and their dependence on device parameters are discussed. Experimentally observed correlations between these two modes, including a locking behavior of the anomalous mode by the transit-time mode, and the computed and observed slight negative resistance at the anomalous-mode threshold suggest that the transit- time-mode oscillation and the space-charge-induced negative resistance are two possible pre-requisites for the initiation of the anomalous mode of oscillation.     

光电双基区晶体管的工作机理

通过分析光电双基区晶体管(PDUBAT)内部载流子的二维传输过程,获得它的物理模型,得出PDUBAT是个新型光控振荡器的结论,并依此模型给出了它的等效电路,利用SPICE程序得到的一系列计算结果与实验结果是一致的.结合这些计算结果,完整解释了PDUBAT产生耦合、负阻、振荡的物理过程.给出了起振电压(输出电流峰值电压)、振荡频率随光强变化的关系式,定性解释了相应的实验结果     

双向负阻晶体管动态伏安特性的实验研究

本文研究了双向负阻晶体管(Bidirectional Negative Resistance Transistor,简称BNRT)在张弛振荡电路中的动态伏安特性。借助动态伏安特性对BNRT张弛振荡电路的一些性质进行了分析。实验结果与计算结果一致。本文还对改进器件结构的设计,以便使器件达到更高的振荡频率提供了理论依据。     

Silicon pνn avalanche transit-time diodes

Negative resistance characteristics have been observed in the range 3-12 GHz in silicon pvn diodes using avalanche transit-time operation (IMPATT diodes). The diodes, made by a single boron diffusion into epitaxial wafers, had breakdown voltages from 40 to 100 volts. A few hundred diodes all showed, quite reproducibly, microwave negative resistance. Measurement by swept-frequency reflection showed that the negative resistance was present over wide frequency ranges. Oscillation was observed when the diode was put in the coaxial and waveguide "cavities." The oscillation could be tuned over a wide frequency range. The maximum output observed is 30 mW at 11 GHz with 1.7 percent efficiency. Cooling experiments indicated that substantially larger output is possible by proper engineering of the heat disposal. The spectrum width of oscillation, when the diode is reasonably well tuned, ranged from 100 to slightly below 5 kHz. The load impedance into which the diode can oscillate changes from capacitive to inductive, going through a maximum as the oscillation frequency increases. The diodes were found to have so-called microplasmas.     

Effect of External Circuits on Gunn Oscillation

The "resonant mode" of oscillation of a Gunn oscillator is analyzed. Experimental results show the frequency of oscillation of the "quenched dipole mode" depends on the load admittance. These characteristics can be explained by a proposed model which considers the formation and extinction of a dipole layer due to the RF voltage excited in a resonant cavity. The discussion accounts for the time constant of the growth and decay of a dipole layer and derives the susceptance and negative conductance components of the diode model.     

Optically controllable S-type negative resistance presented by a combinational connection of photocoupled FET's

A negative resistance circuit constructed with a combinational connection of photocoupled FET's is proposed, which indicates optically controlled S-type negative resistance characteristics. The circuit can be used as a reciprocal switching element with two external light inputs and an application to optoelectronic flip-flop operation is presented. Moreover, a bidirectional S-type negative resistance circuit is proposed, in which three external light inputs may change widely the bidirectional S characteristics. Applications of the circuit, phase control operation of an alternatively applied voltage, and bilateral relaxation oscillation are demonstrated.     

Comments on static negative resistance in avalanching silicon p+-i-n+junctions

The dependence of calculated static space-charge-induced negative resistance, in avalanching silicon diodes, upon the form of the ionization rate function is investigated. It is shown that the conversion efficiency calculated using a commonly employed function for the ionization rate is greatly overestimated. It is concluded that the mechanism of static space-charge-induced negative resistance is not the origin of high efficiency modes of oscillation.