简讯

大功率GaAsFET目前所采用的三种主要结构是:日本电气公司的缓变凹栅结构,富士通公司的在源和漏电极下作n~ 层的结构和三菱电机公司的铜热沉上倒装片子的结构.日本电气公司的器件已达到6千兆赫,23瓦;8千兆赫,17瓦;18千兆赫,1.25瓦.三菱电机的器件已达到15千兆赫,1.9瓦.低噪声GaAsFET方面也展开了竞争.日本电气公司的窄凹栅结构已在12千兆赫下     

日本在可控热核反应中试用回旋管

在日本名古屋大学等离子体研究所的NBT中正研究用150千瓦(18.5千兆赫,100千瓦,10.5千兆赫,30千瓦,18千兆赫,20千瓦)的微波源产生、加热、封闭等离子体。最近在JIPPT-Ⅱ中开始用32只35千兆赫,5千瓦,5毫秒的速调管作全功率160千瓦的电子回旋加热实验,而原子能研究所今年秋季从美国暂惜了28千兆赫回旋管作电子回旋加热实     

Q波段砷化镓肖特基势垒碰撞雪崩二极管

据报导,以碰撞雪崩二极管模式工作的砷化镓二极管可工作在 J 或 X 波段。在 P-N 结器件中,刘氏在16千兆赫下获得1瓦的脉冲功率;奇姆和阿姆斯特朗报导,在11.1千兆赫下获得500毫瓦的连续波动率,效率为11.5%。李氏和奇姆利用砷化镓肖特基势垒碰撞雪崩二极管结构,在9千兆赫下获得2瓦的连续波功率,效率为9%。     

用于卫星地面站14千兆赫和30千兆赫的高功率耦合腔行波管

用于卫星地面站的14千兆赫、1千瓦耦合腔行波管和30千兆赫、800瓦耦合腔行波管已研制成功,14千兆赫的行波管采用设计得轻巧、紧凑的永磁聚焦装置,并在整个14.0～14.5千兆赫的频带内给出1千瓦输出功率。30千兆赫行波管采用螺旋管线包聚焦并在整个2.5千兆赫瞬时带宽范围内提供800瓦功率输出。这两只管子均为风冷式。在特殊情况下,为了冷却管体,30千兆赫行波管采用几段热导管。     

微波功率晶体管近几年来的发展水平

微波功率晶体管近几年来的发展速度保持着迅速的步子。以5瓦连续输出功率晶体管为例,1962年频率为0.25千兆赫,1964年为0.5千兆赫,1966年为1千兆赫,1968年为2千兆赫,1969年计3千兆赫,1972年为4千兆赫,1973年可达5千兆5瓦。在不久的将来连续输出5瓦的功率管每1～2年可望提高1千兆赫。     

GaAs场效应晶体管

<正> 日本电气公司窄凹栅结构的低噪声 GaAsFET 已在12千兆赫下达到噪声系数1.68分贝,在4千兆赫下为0.7分贝。而三菱电机公司的缓变凹栅结构的封装器件在12千兆赫下最小噪声系数已达1.3分贝,未封装的芯片在16千兆赫下噪声为1.8分贝,在18千兆赫下为2.1分贝。功率 GaAsFET 目前三种不同的主要结构是:日本电气公司的缓变凹栅结构,富士通公司的源、漏下做 n~+层的结构和三菱电机公司的铜热沉上芯片倒装的结构。日本电气公司已达到6千兆赫,23瓦;8千兆赫,17瓦;18千兆赫,1.25瓦。三菱电机公司已达到15千兆赫,1.9瓦。     

微波管的功率和效率达到了新水平

由于微波管设计师能动性的增强,已经使行波管在ku波段连续波功率超过1千瓦,在100千兆赫连续波功率超过100瓦,而使回旋管在140千兆赫产生接近200千瓦的连续波功率。     

砷化镓功率场效应晶体管的X波段性能

本文介绍 X 波段砷化镓功率场效应晶体管(FET)的测量结果。这些器件是用简单的平面工艺制作的。多个单元并联的器件在9千兆赫下,输出功率大于1瓦,增益大于4分贝。4分贝增益下,最大输出功率在9千兆赫下为1.78瓦,在8千兆赫下为2.5瓦。8千兆赫下,器件功率附加效率为46%。     

微波GaAsMESFET的功率和噪声性能达到新水平

在一月份举行的日本电子通信学会半导体、晶体管研究会上,日本电气中央研究所发表了微波GaAsMESFET的研究结果.功率器件在6千兆赫下输出达25瓦,增益3分贝;低噪声器件在4千兆赫下噪声系数为0.7分贝,在12千兆赫下为1.68分贝.该所用内部连接的器件已实现了在6千兆赫下输出15瓦,为进一步提高输出功率,由提高集成度、增加FET的单位栅宽,即栅条长度而获得成功.为设计在10伏偏压下输     

简讯

GaAsFET在功率和频率方面达到新的水平 德克萨斯仪器公司认为,在4～30千兆赫范围内,GaAsFET将是主要的微波功率源。在许多x波段系统中将代替耿二极管和崩越二极管。在空军资助下他们研制的GaAsFET在10千兆赫下输出3.2瓦、增益6分贝、效率22％,单个器件在8千兆赫下输出5.1瓦,增益5分贝、效率35％。 该公司将把8千兆赫1瓦的器件MSX803的单价由1000美元降到250美元(1～9只一批)。并予计在年内将能出售8千兆赫2瓦的器件,其价格可能是1瓦器件的2～3倍,大约是500美元到750美元。     

A 4-9 GHz 10 W wideband power amplifier

A 4-9 GHz wideband high power amplifier is designed and fabricated, which has demonstrated saturated output power of 10 W covering 6-8 GHz band, and above 6 W over the other band. This PA module uses a bal-ance configuration, and presents power gain of 7.3 ± 0.9 dB over the whole 4-9 GHz band and 39% power-added efficiency (PAE) at 8 GHz. Both the input and output VSWR are also excellent, which are bellow -10 dB.     

X-band performance of GaAs power f.e.t.s

The results of X-band measurements on GaAs power f.e.t.s are reported. These devices are fabricated with a simple planar process. Devices with output powers of 1 W or more at 9 GHz with 4 dB gain have been fabricated from more than a dozen slices. The highest output powers observed with 4 dB gain are 1.78 W at 9 GHz and 2.5 W at 8 GHz. Devices have been operated with 46% power-added efficiency at 8 GHz.     

Q and V band power InGaAs MESFETs

Excellent power performance at 44 and 60 GHz demonstrated by 0.25 mu m gate InGaAs MESFETs is reported. From small-signal S-parameter measurements, these devices typically have extrinsic f/sub t/ greater than 100 GHz. At 1 dB compression point, a 150 mu m wide MESFET shows a power added efficiency of 33% with an output power of 60.8 mW (0.43 W/mm) at 44 GHz. For 200 mu m wide devices, the power added efficiency was measured to be 19% with an output power of 82 mW (0.41 W/mm) at 60 GHz. These results indicate that InGaAs MESFETs are viable millimetre-wave power devices.<>     

A 1.7-1.9 THz local oscillator source

We report on the design and performance of a /spl times/2/spl times/3/spl times/3 frequency multiplier chain to the 1.7-1.9 THz band. GaAs-based planar Schottky diodes are utilized in each stage. A W-band power amplifier, driven by a commercially available synthesizer, was used to pump the chain with 100 mW of input power. The peak measured output power at room temperature is 3 /spl mu/W at 1740 GHz. When cooled to 120 K, the chain provides more than 1.5 /spl mu/W from 1730 to 1875 GHz and produced a peak of 15 /spl mu/W at 1746 GHz.     

Microwave Amplifier Using Several IMPATT Diodes in Parallel (Short Papers)

IMPATT diode amplifiers are described that use several packaged diodes in parallel in a coaxial housing. With a pair of GaAs Schottky-barrier diodes, a power output of 8 W (input locking power equals 300 mW) was obtained at 4 GHz without exceeding safe operating temperatures. Similarly, three-diode circuits produced 15 W (locking power equals 3.5 W) at 4 GHz and >10 W (locking power equals 2.7 W) at 6 GHz under safe operating conditions. The maximum power obtained from the pair was 11 W. The maximum power obtained from the 4 GHz three-diode circuit was 21 W. The efficiency of the diodes at the maximum power level was 12-13 percent. The characteristics of the pair are compared with those of the individual diodes and it is concluded that this power-combining scheme is very efficient and should be economically advantageous. The scheme permits the total diode area utilized in a single cavity to be increased significantly beyond that which is practical in a single diode package. The use of parallel operation permits efficient heat sinking of each diode package, which is impractical with series operation. The technique employed has been shown to be suitable for extension to three or more diodes for higher power. It is required that each set of diodes be matched for similar I-V characteristics. With this constraint, the close RF coupling of the diodes in conjunction with appropriate stabilizing resistor(s) assures that the diodes operate cooperatively as a unit capable of being powered from a single current-regulated source.     

Pulsed GaAs f.e.t. operation for high peak output powers

Significant increases in GaAs f.e.t. X-band power output are made possible by pulsed operation, using pulse durations sufficiently short that thermal limitations are alleviated. Significantly higher-voltage operation is also possible under these conditions, with further improvement in power output and gain. As much as 5.9 W of peak power output has been obtained at 8 GHz from a device capable of 2.5 W c.w. output at 6 GHz.     

High-power pulsed GaAs double-drift hybrid-read impatt diodes for X-band

Gallium-arsenide double-drift hybrid-Read Impatt diodes have been developed to deliver high peak and average powers in X-band. A peak power output of 35 W with 20% efficiency has been obtained at 8.3 GHz for 20% duty cycle. Peak power output of 32 W with 20% efficiency has been obtained at 8·6 GHz for a 25% duty cycle. Peak power output of 26 W with 21.5% efficiency has been obtained at 8.6. GHz for 33% duty cycle.     

High power reliability aspects on RF MEMS varactor design

A new kind of RF MEMS switched varactor for high power RF signals (P_input > 1W) has been developed on a simple and innovative design. This device is conceived to perform tuneable capacitor operations up to 10 GHz, in the 0-10W power range. The design principle is discussed in detail and measurement results validating our approach are reported. The fabricated components have undergone both lifetime reliability tests and maximum handled power tests. The measurement campaign has shown 1 billion cycle operations under 1W at 10 GHz, 250 million cycle operations under 5W at 3GHz at 2.5 kHz bipolar actuation, without any failure observed, and a maximum power handling capability up to 10W.     

Generation of Submillimeter-Wave Radiation with GaAs Tunnett Diodes and InP Gunn Devices in a Second or Higher Harmonic Mode

Efficient second-harmonic power extraction was demonstrated recently with GaAs tunnel injection transit-time (TUNNETT) diodes up to 235 GHz and with InP Gunn devices up to 325 GHz. This paper discusses the latest theoretical and experimental results from second-harmonic power extraction at submillimeter-wave frequencies and explores the potential of using power extraction at higher harmonic frequencies to generate continuous-wave radiation with significant power levels at frequencies above 325 GHz. Initial experimental results include output power levels of more than 50 μW at 356 GHz from a GaAs TUNNETT diode in a third-harmonic mode and at least 0.2–5 μW in the frequency range 400–560 GHz from InP Gunn devices in a third or higher harmonic mode. The spectral output of these submillimeter-wave sources was analyzed with a simple Fourier-transform terahertz spectrometer and, up to 426 GHz, with a spectrum analyzer and appropriate harmonic mixers. Initial experimental results from a GaAs/AlAs superlattice electronic device at D-band (110–170 GHz) and J-band (170–325 GHz) frequencies are also included.     

High-power-density 4H-SiC RF MOSFETs

The authors have made the first 4H-SiC RF power MOSFETs with cutoff frequency up to 12 GHz, delivering RF power of 1.9 W/mm at 3 GHz. The transistors withstand 200 V drain voltage, are normally off, and show no gate lag, which is often encountered in SiC MESFETs. The measured devices have a single drain finger and a double gate finger, and a total gate width of 0.8 mm. To their knowledge, this is the first time that power densities above 1 W/mm at 3 GHz are reported for SiC MOSFETs.