温度对AlGaN/GaN HEMT电学性能的影响

研究了蓝宝石衬底AlGaN/GaN HEMT器件直流和微波性能随温度的变化。研究结果表明,器件直流性能随着温度升高逐渐下降,350°C时直流性能依然良好,从350°C冷却到室温后,器件直流特性除欧姆接触电阻改善外,其他都得到了恢复;微波测试表明,器件fT,fmax都随温度升高而下降,180°C时,fT从室温的11.6GHz下降为7.5GHz、fmax从24.6GHz下降为19GHz,通过外推得到350°C时的fT为3.5GHz,fmax为12GHz。证明了AlGaN/GaN HEMT具有良好的热稳定性,适合在高温下进行高频工作。     

Liquid-nitrogen-cooled submillimetre-wave silicon IMPATT diodes

400 and 300 GHz c.w. oscillation characteristics for liquid-nitrogcn-cooled silicon IMPATT diodes are described. Output powers of 2.2 and 4.5 mW have been obtained at 412 and 295 GHz, respectively, and a highest oscillation frequency of 430 GHz observed.     

Dependency of the highest harmonic oscillation frequency on junction diameter of IMPATT diodes

The effect of series resistance and junction capacitance on the high-frequency limit of IMPATT diode operation is studied with a Read-type small-signal theory, and is confirmed experimentally. Oscillation frequencies from 30 to 400 GHz have been measured with Si p⁺-n-n⁺abrupt junction diodes with a depletion layer width of 0.2 µm. The highest oscillation frequency increases as the junction diameter is decreased, owing to reduced junction capacitance and increased bias-current density. The highest oscillation frequency observed is 423 GHz, which is obtained in the fifth harmonic mode with a diode of 16-µm junction diameter. Fundamental oscillation frequency is found to depend strongly on dc bias-current density, and to be close to the avalanche frequency of the small-signal theory.     

Low Voltage CMOS LC VCO with Switched Self‐Biasing

This paper presents a switched self‐biasing and a tail current‐shaping technique to suppress the 1/f noise from a tail current source in differential cross‐coupled inductance‐capacitance (LC) voltage‐controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 µm CMOS process. The measured phase noise is ‐117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.     

Integration of GalnP/GaAs heterojunction bipolar transistors andhigh electron mobility transistors

Integration of carbon-doped GaInP/GaAs heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs) is demonstrated by growing an HBT on the top of a HEMT. A current gain of 60, a cutoff frequency of 59 GHz and a maximum oscillation frequency of 68 GHz were obtained for a 5×15 μm² self-aligned HBT. The HEMT, with a gate length of 1.5 μm has a transconductance of 210 mS/mm, a cutoff frequency of 9 GHz and a maximum oscillation frequency of 22 GHz. It is shown that the GaInP/GaAs HBT on the HEMT is a simple Bi-FET technology suitable for microwave and mixed signal applications     

新型CMOS正交压控振荡器设计

通过对两个相同的LC振荡器进行交差耦合,用耦合系数来控制输出频率,设计了一种新型精准正交正弦波压控振荡器.由于其频率调节方式不再依赖于变容管,大大增加了输出频率的调节范围.基于TSMC18rf工艺库,采用Cadence的Spectre工具对电路进行仿真.在VDD=1.8V下,频率覆盖了1.78GHz到4.03GHz,可调控范围约为77%,1MHz处相位噪声约为-104dB/Hz.     

Wide-band VCOs in SiGe production technology operating up to about 70 GHz

Multipurpose VCOs with wide tuning range and oscillation frequencies up to 74 GHz (on wafer) and 69 GHz (mounted chip, with output buffer), respectively, have been fully integrated in a commercial SiGe production technology. To the best of the authors' knowledge these are record values for commercially available Si-based technologies, despite the moderate transistor f/sub T/ (62 GHz). The oscillation frequency can easily be dropped down to 41.5 GHz by cutting interconnection lines in the upper metallization layer. The phase noise obtained depends on the frequency range chosen and is sufficiently low for the intended applications.     

2．4GHz电压控制振荡器的设计与仿真

通过分析测量BJT的S参数与稳定因子定,并利用已测量的BJT输出阻抗ZOUT来设计输出匹配电路,使整体电路在2．4GHz的频率上产生振荡。利用ADS软件对电路进行仿真。达到在BJT特定的偏压下。仍在2．4GHz的频率上持续振荡。并可利用电压的变化来控制其振荡频率的目的。     

A Differentially-Tuned Voltage ControlledOscillator Using Symmetric Transformer

This letter proposes a new voltage controlled oscillator (VCO) topology that cancels common-mode noise by adoption of differential tuning varactor. To suppress common mode noise effectively, a symmetric three-coil transformer is proposed as a differential tuning resonator. The measured phase noise shows -128.7 dBc/Hz at 1 MHz offset frequency from the 1.2 GHz oscillation frequency. Over the whole frequency range, common-mode noise rejection is larger than 36 dB. Measured tuning range of the proposed VCO is about 204 MHz from the 1.18 GHz to 1.38 GHz while dissipating 1.2 mA at 1.8 V power supply.     

最大振荡频率为200 GHz的蓝宝石衬底AlGaN/GaN HEMT

本文报道了fmax为200GHz的基于蓝宝石衬底的AlGaN/GaN 高电子迁移率晶体管（HEMT）。外延材料结构采用了InGaN背势垒层来减小短沟道效应,器件采用了凹栅槽和T型栅结合的工艺,实现了Ka波段AlGaN/GaN HEMT。器件饱和电流达到1.1A/mm,跨导为421mS/mm,截止频率（fT）为30GHz,最大振荡频率（fmax）为105GHz。采用了湿法腐蚀工艺将器件的Si3N4钝化层去除后,器件的Cgs和Cgd减小,器件截止频率提高到50GHz,最大振荡频率提高到200GHz。     

T形电极晶体管

叙述了一种制作双极型晶体管的T形电极结构自对准工艺。利用该工艺已研制成微波T形电极晶体管(TSET)。最高振荡频率为10GHz,截止频率为6GHz;在3.2GHz下,输出功率1.1W,功率增益6dB。     

宽频率范围的单子带压控振荡器设计

基于TSMC 180 nm CMOS工艺,提出了一种振荡频率为2～3 GHz的宽频率范围、低相位噪声的单子带压控振荡器(VCO).采用双平衡吉尔伯特混频结构,将单子带5～6 GHz压控振荡器与固定频率3 GHz压控振荡器进行下混频,可得到振荡频率为2～3 GHz的单子带压控振荡器,实现相对带宽从18.18％到40％的展...     

Fully integrated dual-band VCOs with power controlled by body voltage in 130 nm CMOS/SOI for multi-standard applications

In this paper, the design of two VCOs for wireless multi-standard applications is presented. The oscillation frequencies are 5.2 and 3.3 GHz. These circuits have been produced using CMOS/SOI technology, with body voltage to control power consumption and phase noise performance. A new architecture for multi-standard applications is proposed. Five standards are covered by these structures: GSM (900 MHz), GPS (1.5 GHz), DCS (1.8 GHz), Bluetooth (2.45 GHz) and 802.11 a (5.8 GHz). The tuning range can vary from 2.45 to 5.8 GHz for the first VCO and from 850 MHz to 1.9 GHz for the second by using frequency divider. The main idea is to use only two MOS varactors to cover the entire frequency span. The first one is needed to get the matched frequency variation and the second to adjust the oscillation frequency. Such VCOs can be made thanks to CMOS/SOI technology advantages, high-Q passives and body voltage biasing that allow current change and power dissipation in the VCO core. These circuits were produced with a view to producing a single VCO covering all these standards. Switched resonators were therefore studied. At a frequency offset of 100 kHz, the single side band phase noise measurements were −89 and −93 dBc/Hz at 5.2 and 3.6 GHz respectively.     

带自适应体偏置的宽带LC VCO自动幅度控制策略

为了优化宽带LC型压控振荡器（LC VCOs）相位噪声性能,提出一种自动幅度控制策略。该策略结合了自适应体偏置和数字校准。当VCO开始工作时,自适应体偏置技术使VCO在不同的工艺角、电压和温度（PVT）情况下快速起振。当谐振频率变化时,在自适应体偏置和数字校准的作用下,VCO的谐振幅度被控制在最优值附近,达到优化相位噪声的目的。在TSMC 0.18μm CMOS工艺中,覆盖频率范围为1.6～3.2GHz的宽带LC VCO用来验证该幅度控制策略的可行性。基于SpectreRF的仿真结果表明LC VCO的幅度变化率降低90%,且在3.2GHz谐振频率,10kHz频率偏移处的相位噪声改善8.2dB。     

Waveguide/resonant-disc circuits for millimetre-wave devices

Bias circuits using resonant discs have been employed for millimetre-wave transferred-electron (TE) diodes operating at their second or third harmonic frequencies in the V (50?75 GHz) and W (75?110 GHz) bands. It is shown that this type of circuit exhibits resonances at frequencies in the lower millimetre-wave range, corresponding to the fundamental oscillation frequency of diodes typically used. In addition, the circuit provides efficient coupling to the waveguide circuit at the higher (harmonic) operating frequency. By tuning the fundamental oscillation frequency of a number of resonant discs, the power-frequency spectrum of the TE device can be determined, which is demonstrated for a device with its maximum third-harmonic power output at 94 GHz.     

AlGaAs/GaAs HBTs fabricated by a self-alignment technology usingpolyimide for electrode separation

A self-aligned HBT (heterojunction bipolar transistor) technology using polymide for insulating the emitter contact from the base contact is described. A 1-μm emitter-width HBT with maximum oscillation frequency of 86 GHz was successfully fabricated. This processing was also applied to fabricate frequency-divider ICs. An operating frequency of 18 GHz was obtained with good reproducibility     

270°C, 1 GHz oscillator-type active antenna

Reported is the first demonstration of an active antenna operating at 1 GHz and at temperatures above 200degC. A Clapp oscillator integrated with a slot-ring antenna generated and transmitted a 1 GHz signal from 25 to 270degC. The oscillation frequency varied by less than 4 over the temperature range.     

Millimeter-wave GaAs distributed IMPATT diodes

Millimeter-wave oscillations were obtained in distributed GaAs IMPATT diodes prepared by molecular beam epitaxy (MBE). Both single-drift-region and double-drift-region structures were used to fabricate various length devices, up to 1.25 mm, to investigate oscillation frequency dependence on device length. Output power levels of 1.5 and 0.5 W were obtained at 22 and 50 GHz, respectively, using 500-ns pulses. The highest frequency of oscillation observed was 89 GHz.     

A K-band monolithic oscillator integrated with a buffer amplifierusing a device-circuit interaction design concept

We report on a high power, high efficiency, and small-size monolithic coplanar waveguide oscillator incorporating a single-stage buffer amplifier on the same chip. For the oscillator design, by changing RF current level through the device, the optimum load line was chosen in order to have an oscillation frequency insensitive to the effect of the subsequently connected amplifier, based on a device-circuit interaction concept. The amplifier, on the other hand, which was driven directly by the oscillator, was designed to achieve an overall high power and high efficiency operation. At 21 GHz, the output power of the developed chip recorded 17 dBm with an overall DC-RF efficiency of 22%. By changing the length of a source feedback line, the oscillation frequency was varied from 21 GHz to 26 GHz. For all cases, the output power remained higher than 16 dBm     

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.