大功率连续波电子转移振荡器

描述大功率电子转移振荡器的连续波工作。获得了8.7千兆赫下0.78瓦的最大输出功率,其效率为2.5％。这是在这个频率范围内至今所报导的单个电子转移振荡器的连续波输出功率最高的。这样高的输出功率是由于改进了制造技术,致使0.015×0.015吋~2小片的热阻仅有8℃/瓦之故。     

声表面波调频振荡器

论述了声表面波调频振荡器的原理及设计方法，探讨了有关电路，并制作了中心频率３８０．８ＭＨｚ的声表面波调频振荡器。当调制信号频率区ＤＣ至８００ｋＨｚ变化，幅值为２．５Ｖ时，调频频偏大于５５０ｋＨｚ；当调制信号频率小于或等于２００ｋＨｚ，幅值为１．０Ｖ时，调频非线性失真小于３．５％。振荡器经过温度补偿，温度稳定性优于±１５０ｐｐｍ（－４０℃～＋５０℃）。     

无线传声器用调频振荡器

本文介绍了无线传声器用调频振荡器的技术概况,并以频率稳定性为中心,比较了各种调频振荡器的性能,进而给出了 LiTaO_3晶体振子调频振荡器的基本电路和性能。     

高效率、高峰值功率磷化铟电子转移振荡器

业已证明,用限流的阴极接触能够改善较厚汽相外延片的磷化铟电子转移器件的特性。用银-锡合金做接触的有源层为34微米厚的器件,在5千兆赫下已获得120瓦峰值功率和18％的效率。     

占空比调频式低频正弦振荡器

本文介绍一种带有周期性通断形状的振荡器电路，它是由两级积分器和一个倒相器组成的新式反馈型振荡器。在每个积分器中都有一个开关与积分电容串联，改变形状脉冲频率可使输出正弦波频率在较宽的低频范围内成正比变化，频率覆盖范围可达１０＾６倍。这种方法具有一般性，可用于任何普通ＲＣ振荡器。     

一种宽频带调频振荡器

一、前言由于调频制无线电通信的一系列优点,不少通信装备采用了这种调制制度。因此如何获得调频信号的问题,就显得特别重要。目前一般宽频带调频的方法是采用变容二极管的调制方法。采用变容二极管的调制方法当然可以获得较大的频偏,但是也存在不少问题。首先是变容二极管特性的一致性较差,即使同一型号的管子,其超突变中心电压值也有所不同,为了获得良好的调频所用的偏压E_0也应当有所不同,这样,调频振荡器的中心频率彼此不同,     

电子转移振荡器的稳定的频率—温度特性

在振荡器的设计中,常常需要振荡的频率在给定的温度范围内保持恒定。这样的频率稳定性,通常是通过补偿有源元件和外电路因温度变化引起的偏离而获得。本文将提出一些能使电子转移振荡器的频率-温度特性稳定的一些方法,它们可应用于任何微波电路中。众所周知,一个电路如果在某个频率上所有阻抗之和等于零就发生振荡。然而,研究有源元件和决定频率的微波电路元件在电路中阻抗的温度特性是有兴趣的。我们将分     

在脊波导电路中转移电子振荡器的工作

本文将描述大功率连续波转移电子振荡器(t.e.o.s)在波导电路中的实验结果,在标准、减高与脊波导谐振器中对这些器件的工作作了比较。实验结果表明,当波导阻抗从800欧减到50欧时,效率从2.5％提高到3.5％。另外,在脊波导电路中,在10千兆下连续功率高至1.0瓦,效率为2.5％,在20千兆下连续功率为500毫瓦,效率为3％。后者被认为在该频段内是迄今为止所报导的单片t.e.o.s的最大功率。 teo结构为n~+-n-n~+外延GaAs片。这些片子是以混合汽相合成的方法汽相外延生长     

高性能声表面波调频振荡器的研究

分析了声表面波谐振器的性能 ,论述了声表面波振荡器的工作原理及设计方法 ,最终完成中心频率为797.3 MHz的振荡电路 ,调频带宽 2 MHz(2 5 0 0 PPM)。文中对影响调频带宽、相位噪声的因素进行了分析讨论。本项目研究成果已获得实际应用     

Transferred Electron Amplifiers and Oscillators

The current status of transferred electron devices (TEDs) is surveyed. The physics of the transferred electron effect, the theory of amplifiers and oscillators, material growth, device fabrication, and the design of amplifier and oscillator circuits are discussed along with a presentation of the outlook for the near future.     

Frequency-Saturation Effects in Transferred Electron Oscillators

Frequency-saturation effects have been observed in the mechanical tuning characteristics of transferred electron (Gunn) oscillators operating in conventional waveguide cavities at frequencies from 12 to 40 GHz. Their existence leads to a restriction in oscillator tuning range and enhances frequency switching and hysteresis effects in the oscillators. Investigation of oscillator behavior in coaxial cavities as well as in waveguide cavities of varying height has shown that frequency saturation is caused by a coaxial resonance along the mounting post, which in the limit of fully reduced-height waveguide becomes the resonance of the diode with the encapsulation itself, or by a frequency limitation imposed by the diode thickness and operating voltage. The transverse coaxial resonance will occur in any waveguide size at a frequency near to if not within the band of interest. Simulation of the encapsulated diode by a localized reduction in mounting-post diameter shows that the frequency of transverse resonance can be increased by moving the encapsulation to a central position in the waveguide cross section. It is suggested that this technique and that of using cavities with a local reduction of height will make an important contribution to improving the performance characteristics of waveguide-mounted oscillators.     

A New Look at Noise in Transferred Electron Oscillators

Low-frequency current and voltage fluctuations have been measured, and it has been confirmed that noise in packaged transferred electron devices (TED's) is due to three distinct noise mechanisms: flicker, generation-recombination, antd thermal noise. For transferred electron oscillators (TEO's), this low-frequency noise is upconverted into the microwave frequency range and adds to the intrinsic RF noise. We have found that between 1 kHz and 1 MHz off the carrier, temperature-dependent generation-recombination noise is the main contributor to the total noise. A model of a noisy TEO is presented. This model permits the calculation of AM and FM noise spectra from device and circuit parameters for measured low-frequency noise or the derivation of device characteristics from noise and circuit parameter measurements.     

Microwave Circuits for High-Efficiency Operation of Transferred Electron Oscillators

Compact circuits for obtaining high-efficiency operation of high-power transferred electron oscillators (TEOs) in L-band are described. One is a coaxial resonator and the other employs coupled TEM lines. The circuits are shown analytically and experimentally to be capable of matching a wide range of fundamental device impedances. Provisions for independently tuning the second-harmonic impedance over a wide range are included in both types of circuits. Pulsed conversion efficiencies up to 32 percent have been obtained TEOs mounted in the coaxial resonators and up to 27 percent with TEOs in the coupled TEM-line structures. The impedance at the second harmonic has been shown quantitatively to be extremely important in controlling device efficiency. By varying the second-harmonic tuning the device performance can be varied from high-efficiency operation to no output. Oscillators using these cavities were temperature stable over a wide range. The operating frequency of TEOs in the coaxial cavity and the coupled-TEM-line cavity varied less than 30 and 40 kHz//spl deg/C, respectively, over the range from - 54/spl deg/C to +125/spl deg/C.     

Transferred Electron Amplifiers

The basic principles of operation of stable (non-oscillating) transferred electron amplifiers are reviewed with the aid of simple physical models.     

Frequency Tuning Of Microstrip TRAPATT Oscillators

This paper describes two methods of magnetically tuning the frequency of a microstrip TRAPATT oscillator. Tuning ranges in excess of 100 MHz at a center frequency of 2 GHz have been obtained at peak output power levels of typically 40 W with variations in output power of +-0.2 dB. In one of the methods the harmonics of the oscillator are separated which may enable additional diagnostic information to be obtained for the TRAPATT oscillator.     

温度调谐准相位匹配光学参量振荡器

对准连续泵浦的准相位匹配(QPM)光参量振荡器(OPO)进行了实验研究。利用二极管(LD)泵浦的Nd：YAG激光器，泵浦周期为29μm的周期极化LiNbO3(PPLN)晶体，得到信号光(1500nm)的高输出功率(平均功率＞100mW)，并且通过调谐晶体温度(80—250℃)，获得了信号光输出波长的调谐范围为1．48一1．54μm。     

Stabilized Supercritical Transferred Electron Amplifiers

GaAs transferred electron devices having nl products as large as 4 X 10/sub 12/ cm/sup -2/ have been stabilized by circuit loading to obtain linear reflection-type amplification. Peak output power in excess of 1 watt has been obtained at C band.     

Wide-Band Reflection-Type Transferred Electron Amplifiers

Stable CW and pulsed linear-reflection-type amplification at C- and X-band frequencies using epitaxial-GaAs transferred electron devices is described. These devices have a doping density-length product (nl) greater than 5 x 10/sup 11/cm/sup -2/. Criteria for avoiding the normal instabilities are discussed with specific regard for the circuit impedance, operating bias-voltage material characteristics, and the device temperature. The active impedance of a stable device has been measured, along with the effects of the package parasitic. These data were utilized to design multiple-tuned wide-band circulator-coupled coaxial-amplifier networks. Instantaneous CW bandwidths of nearly 1 octave have been measured in C-band, and instantaneous bandwidths of 4 GHz have been measured in X-band with single-stage Iinear gains from 6 to 12 dB. A -1-dB gain compression power output of 250 mW, with a saturated power output approaching 1 watt, has been realized from a single device. The noise figure of a single-stage amplifier has been found to be 15 dB. The phase response of a typical amplifier has been found to be linear with a differential phase shift of less than 20/spl deg/ /GHz. The amplitude linearity has been related to third-order intermodulation distortion and found to be comparable to that obtainable from traveling-wave-tube amplifiers (TWTAs). In a two-stage configuration a small-signal gain of 22 dB and a fractional bandwidth of 35 percent have been realized in C-band. A novel scheme for studying the gain response of pulse-biased devices using swept-frequency techniques has been developed. Pulsed amplification has been obtained with a power output of 2 watts at a 5-percent duty cycle with a conversion efficiency of 6 percent and a bandwidth of 1 GHz.     

A Dual Mode Tuning Circuit for Microwave Transistor Oscillators

A two-port circuit adjusting both even and odd mode fields, with orthogonal mode adjustment, can be used as an embedding circuit for a microwave transistor oscillator. The circuit, analyzed in TEM line, may also be realized in any other form of transmission line geometry, including two coexistent modes in a cavity. The resulting oscillator is stable, has low FM noise, and is readily tunable. Analyses of the tuning circuit and oscillator are presented, along with some experimental results and a discussion of methods using other than TEM transmission lines to produce the even and odd modes.