晶体管渡越时间振荡器的效率

本文叙述了晶体管渡越时间负阻振荡器的简单原理。预计在微波频率工作可以得到低噪声。叙述了一个工作在10千兆赫的典型设计。并指出最大的理论效率大约是40％。     

“穿通”渡越时间振荡器

用穿通注入的空间电荷漂移二极管,可以获得高频负阻。对于理想结构,效率估计约为20％。这个器件适于低功率低噪声运用。     

渡越时间方法测量系统研究

载流子迁移率是半导体材料的一项重要参数,而有机材料的载流子迁移率较低,限制了一些传统方法的使用。文章建立了一套用于测量有机材料载流子迁移率的渡越时间(TOF)法实验系统,着重介绍了实验系统中各元件的作用及要求,实验关键技术参数等。该实验系统的主要特点是把激发光源同时作为外触发光源,消除实验中杂散信号的干扰,得到清晰的信号。同时利用实验系统对无机材料Se,有机共轭聚合物材料MEH-PPV的载流子迁移率进行测量,结果表明:该实验系统组建方便,快捷,可以较好用于测量有机材料低载流子迁移率,具有一定的实用价值。     

SiGe HBT基区渡越时间研究

对基于SiGe HBT基区本征载流子浓度和电子迁移率依赖于掺杂、基区Ge组分分布和速度饱和效应的基区渡越时间进行了研究。结果表明,相同Ge组分条件下,基区渡越时间bτ随WB由100 nm减薄到50 nm,降低了74.9%;相同WB,Ge组分为0.15比0.1 Ge组分的bτ减小了33.7%。该研究与其他文献的结果相吻合,可为SiGe HBT基区设计提供一定的理论指导。     

微波锁相振荡器

微波锁相振荡器在目前得到了很好的发展,并且受到了微波系统用户(如:通信、雷达、仪表等)的重视。这种锁相振荡器能为其他微波功率产生技术提供出很多的优点,即:——高频谱纯度     

锁相介质振荡器

锁相介质振荡器采用锁相稳频技术将介质振荡器的频率稳定在参考频率上。研制的一种X波段锁相介质振荡器,得到的性能指标如下：频率8.44GHz;相位噪声≤-80dBc/Hz@10kHz、≤-110dB/Hz@100kHz;输出功率≥10dBm;杂波≤-75dBc、谐波≤-30dBc。     

锁相介质振荡器

锁相介质振荡器采用锁柏稳频技术将介质振荡器的频率稳定在参考频率上。研制的一种Ｘ波段锁相介质振荡器,得到的性能指标如下：频率８．４４８ＧＨｚ;相位噪声≤ －８０ｄＢＣ／Ｈｚ＠１００ｋＨｚ、≤－１１０ｄＢ／Ｈｚ＠１００ｋＨｚ;输出功率≥１０ｄＢｍ;杂波≤－７５ｄＢｃ、谐波≤－３０ｄＢｃ。     

低温双极晶体管的正向渡越时间研究

分析了禁带变窄效应和少子陷阱效应对低温双极晶体管正向渡越时间的影响，在此基础上，建立了综合两种效应的正向渡越时间模型，理论计算结果与实测值一致。     

俘获等离子体雪崩触发渡越振荡器的器件物理

本文利用简单的物理模型来描述 TRAPATT(俘获等离子雪崩触发渡越)振荡器的工作。在计算精度方面作些让步,就提出了一个完全高效率的器件设计,并且阐明了工作与物理参数的关系。描述 TRAPATT 工作的精确微分方程是极为复杂的,这给单个二极管电路结构的计算造成了困难.然而,通过观察这个解的重要特征,就引出了一个给予现实解答的简单近似。引出了一个理论的器件设计方案。这个方案提出了器件宽度和杂质浓度与 TRAPATT 频率的关系,并指出了“穿通”程度随频率的增加而下降。此外,还得到了宽度和杂质浓度与二极管的反向饱和电流的明确的关系。雪崩区通过二极管的激励,特别是恢复到扫出(Swept-out)态的限制,对于其它类型的二极管,特别是 p-i-n 开关和“突变”(“Snap”)二极管,具有重大的意义。     

Computer Simulation of a 5.7GHz, 110kW Transit-Time Oscillator

A high-power transit-time oscillator producing 110kW at 5.7GHz in the TM₀₁₀ cavity mode is described. The device comprises a temperature-limited diode electron gun operating at 40A in the range from 28kV to 35kV and an intermediate coaxial cavity from which the microwave power is extracted through a TEM coaxial guide. The diode serves also as a resonant cavity, where electromagnetic oscillations are grown from noise. The effect of the applied voltage on both the output microwave power and the instability saturation time has been investigated leading to an optimal diode voltage of 33kV.     

Electronic Tuning of the Punch-Through Injection Transit-Time (PITT) Microwave Oscillator (Short Papers)

Experimental results of the dynamic resistance and capacitance of p+-n-p+ punch-through injection transit-time (PITT or BARRITT) diodes are presented. A method of predicting the oscillator electronic tuning from the change in the device capacitance is outlined and verified experimentally at X band.     

Nondegenerate Phase-Locking of a Semiconductor Laser by Sideband Injection

A semiconductor laser rate equation theory is presented that describes sideband injection locking under both weak optical injection and current modulation. By simultaneous optical injection and current modulation, control of both the phase and the frequency of a semiconductor laser is demonstrated. The phase-locked semiconductor laser operates at a different frequency to the optical injection source, with a frequency-difference given by the current modulation frequency. This method can be used to produce broadband sources, such as those producing ultrashort pulses and those required for coherent control, or to create high-frequency electronic oscillator sources with phase control by interference beating     

Varactor-Tuned Avalanche Transit-Time Oscillator with Linear Tuning Characteristics (Correspondence)

A circuit is described which uses an abrupt junction varactor to electronically tune an IMPATT oscillator. Linear voltage frequency tuning is obtained over a 10 percent frequency band.     

Chaotization of Oscillations in a Single-Frequency Millimeter-Band Impact Avalanche and Transit-Time Diode Oscillator under the Influence of a Low-Frequency Harmonic Oscillation

The change in the oscillation spectrum of an oscillator based on an impact avalanche and transit-time (IMPATT) diode of the 7-mm range under the action of a low-frequency harmonic oscillation (3 MHz) in the supply circuit of the diode is studied experimentally. It is demonstrated that, if the low-frequency oscillation amplitude exceeds the trigger negative voltage and the working point in the diode volt–ampere characteristic is located either near the trigger current (trigger negative voltage) or far from it, pulsed oscillation mode is established and, consequently, oscillations are chaotized.     

Maximum Phase-Locking Bandwidth Obtainable by Injection Locking (Short Papers)

A simple rule is presented for the determination of the locking region of an oscillator with a general tuning circuit.     

High Effective Subharmonic Injection Locking of a Millimeter-Wave IMPATT Oscillator

Abstract-Effective stabilization of an IMPATT oscillator in the millimeter-wave region can be achieved through subharmonic injection locking to a weak parasitic oscillating signaI. In subharmonic injection-Iocking experiments more than 19 dB of locking gain at 10-MHz locking range was obtained at a subharmonic ratio 1:2 of the main oscillating frequency. At the subharmonics 1:4 and 1:6, the locking gain was more than 12 and 13 dB at 10 MHz, respectively. Using the parasitic oscillating signal, higher than 32-dB gain and 10-MHz locking range at a subharmonic ratio 1:2 of the parasitic oscillating frequency was obtained. This locking gain was 13 dB higher than that for the main oscillating signal. At the subharmonic ratio 1:4, the gain was more than 15 dB higher. As measured with the spectrum analyzer, the oscillating signal which was locked by the subharmonic injection signal almost coincided with the injection signal. These data show that the subharmonic injection locking has high gain as compared with that using the main oscillating signal.     

Indirect Subharmonic Optical Injection Locking of a Millimeter-Wave IMPATT Oscillator

Large aperture phased-array antennas operating at millimeter-wave frequencies are designed for space-based communications and imaging. Array elements are composed of active transmit-receive (T/R) modules that are phase and frequency synchronized to a reference signal at the central processing unit by a fiber-optic (FO) distribution network. The implementation of FO links, synchronizing the millimeter-wave Iocal oscillators (LO's), imposes a great challenge. This paper presents results of indirect optical injection locking of a free-running 38-GHz (Ka-band) IMPATT oscillator over the Iocking range of 2-132 MHz, depending on the injected power level (amplifier gain). In the experiment, the nonlinearity of both the laser diode and the IMPATT oscillator is exploited to achieve 12th subharmonic injection locking. The overall system FM noise degradation of the reference signal is 16 dB at 500-Hz offset. The FM noise degradation is dominated by the theoretical limit of 20 log N, where N is the frequency multiplication factor used in subharmonic injection locking. Methods by which optical injection locking may be extended into 60 and 90 GHz are demonstrated.     

Analysis of Oscillator Injection Locking Through Phase-Domain Impulse-Response

This paper presents a novel approach to the analysis of oscillator injection locking due to weak external signals. From the intuitive concept of impulse-sensitivity function, a phase-domain macromodel is deduced which is able to capture high-order synchronization effects. Novel closed-form expressions for the synchronization regions are thus presented. The proposed phase-domain macromodel and the expressions derived for synchronization-regions are very general since they apply to any oscillator topology.     

Generation of a CW Local Oscillator Signal Using a Stabilized Injection Locked Semiconductor Laser

We explore the technique of injection locking a semiconductor laser with a portion of the received optical signal to regenerate a local oscillator for eventual use with a homodyne receiver. In addition, we show that the injection locking process can be electronically stabilized by using the Modulation Transfer Ratio (MTR) of the slave laser as a monitor, given either a DFB or Fabry-Perot slave laser. We show that this stabilization technique maintains injection lock (given a locking range of ~1 GHz) for laser drift much greater than what is expected in a typical transmission system. In addition, we explore the quality of the output of the slave laser, and analyze its suitability as a local oscillator signal for a homodyne receiver.