A GaAs MESFET Oscillator Quasi-Linear Design Method

A simplified quasi-linear method is proposed to design a GaAs MESFET oscillator. By expressing the generated power P/sub gen/ as a function of FET gate and drain RF voltages, it is possible to maximize P/sub gen/ under the limiting conditions on intrinsic FET terminal voltage amplitudes. The feedback circuit elements to realize a GaAs MESFET oscillator are derived. An X-band GaAs MESFET oscillator was designed by the quasi-linear method and was fabricated by using microwave integrated-circuit technology.     

Noise characteristics of GaAs and Si IMPATT diodes for 50-GHz range operation

Direct comparison of noise behaviors between GaAs Schottky-barrier junction and Si diffused p⁺-n junction diodes operating in the 50-GHz range is reported by using the same circuitry. In the oscillator operation, the GaAs diode exhibits excess "1/f^m" noise near carrier, whereas the Si diode shows flat spectrum. Far from the carrier, and AM-DSB-NSR of -133 dB in a 100-Hz bandwidth and an FM noise measure of 27.1 dB are observed for GaAs diodes. Corresponding values obtained for Si diodes are -125 and 36.2 dB, respectively. As a reflection amplifier, minimum noise figures of 27.5 and 38 dB are achieved for the GaAs and Si devices, respectively. These results indicate that the GaAs IMPATT is superior in noise behavior to the Si diode also in the 50-GHz frequency range by about 10 dB. It is emphasized that the noise induced in the bias circuit of the IMPATT oscillator is a replica of the sideband noise of the output power and can be used as an indicator to obtain a low-noise tuning condition of the oscillator.     

Development of a GaAs monolithic surface acoustic wave integratedcircuit

An oscillator technology using surface acoustic wave (SAW) delay lines integrated with GaAs MESFET electronics has been developed for GaAs-based integrated microsensor applications. The oscillator consists of a two-port SAW delay line in a feedback loop with a four-stage GaAs MESFET amplifier. Oscillators with frequencies of 470, 350, and 200 MHz have been designed and fabricated. This oscillator technology is most suitable for sensor applications but can logically be extended to radio-frequency oscillator and filter applications by methods well known for other piezoelectric substrates     

Design and Performance of X-Band Oscillators with GaAs Schottky-Gate Field-Effect Transistors

The circuit construction and design of an X-band oscillator with a GaAs Schottky-gate FET have been studied. The oscillation characteristics including stability and noise performance have been examined in order to clarify the position of a GaAs FET as a microwave solid-state oscillator device. The experiments have revealed that 1) the GaAs FET simultaneously possesses the most desirable features of both Gunn and IMPATT oscillators, i.e., low bias voltage operation and fairly high efficiency, and 2) it is situated between Gunn and GaAs IMPATT oscillators with respect to noise properties. The results indicate that the GaAs FET oscillator will soon be joining the family of microwave solid-state oscillators as a promising new member.     

Molecular orbital topology and optical properties of galliumarsenide clusters

The oscillator strength is expressed in terms of a density matrix formulation for optical absorption and is calculated for a GaAs cluster by using the self-consistent-field Xα-scattered wave cluster molecular orbital method. The discrete value of oscillator strength due to optical excitation defined by the selection rule leads to a model of the fundamental nature of the excitonic absorption behavior in GaAs bulk material and quantum well structure. Calculated results of band-to-band transition and exciton states are found to agree well with absorption spectra published in literature. The implication of the excitonic states for the nonlinear-optical behavior observed in GaAs quantum well structures is discussed. The presence of excitonic states may cause a `saturation' phenomenon which will lead to the optical nonlinearity     

HBT电压控制振荡器的相位噪声

研究了电压控制振荡器（ＶＣＯ）的相位噪声与构成该振荡器的有源器件的低频噪声的关系,测试了ＳｉＢＪＴ、ＡｌＧａＡｓ／ＧａＡｓ ＨＢＴ和ＧａＩｎＰ／ＧａＡｓ ＨＢＴ的低频噪声,并分析了各自低频噪声产生的原因,提出了选择ＧａＩｎＰ／ＧａＡｓ ＨＢＴ ＶＣＯ来实现微波固体振荡器低相位噪声化这一发展方向。     

Characteristics of a GaN-based Gunn diode for THz signal generation

A generalized large-signal computer simulation program for a Gunn oscillator has been developed.The properties of a Gunn diode oscillator based on the widely explored GaN,are investigated using the dev...     

DC magnetic field effects on a real space transfer heterojunction oscillator

The effect of a dc magnetic field on the voltage threshold of a AlxGa1-xAs/GaAs heterojunction oscillator wherein the applied voltage is parallel to the junction layers is shown to have different characteristics than a correspondingly biased Gunn oscillator. In particular, for one orientation of the magnetic field where the Lorentz force is directed from the GaAs to the AlxGa1-xAs layer, the threshold voltage can be decreased and the power output of the oscillator increased in contrast to Gunn behavior. These experiments strongly support reverse real space electron transfer by hot electrons as the dominant oscillator process.     

GaAs FET large-signal model and its application to circuit designs

A large-signal GaAs FET model is derived based on dc characteristics of the device. Analytical expressions of modeled nonlinear elements are presented in a form convenient for circuit design. Power saturation and gain characteristics of a GaAs FET are studied theoretically and experimentally. An oscillator design employing the large-signal model is demonstrated.     

Monolithically integrated Gunn oscillator at 35 GHz

A fully planar monolithically integrated Gunn oscillator for 35 GHz has been constructed on a GaAs substrate. An output power of about 1.5 mW, corresponding to an efficiency of 0.5%, is obtained from the oscillator in its present unoptimised form. The device is intended for use as a local oscillator in integrated millimetre-wave receivers. Measurements are made by means of quasi-optical output coupling.     

Cross-coupled differential oscillator MMICs with low phase-noiseperformance

LC-tank oscillators in the 5~6 GHz frequency range have been designed and implemented in a commercial 0.6 μm GaAs MESFET technology. One is a voltage-controlled oscillator (VCO), and the other is an oscillator without a controlling element. The output frequency range of the VCO is from 5.44 to 6.14 GHz, and the measured phase-noise is -101.67 dBc/Hz at an offset frequency of 600 KHz from the 5.44 GHz carrier. The phase-noise of the 6.44 GHz oscillator is -108 dBc/Hz at an offset frequency of 600 KHz, and the phase-noise curve, in the offset frequency range between 100 KHz and 1 MHz, shows a -20 dB/decade slope. These phase-noise characteristics are comparable to, or better than, those of the reported 5~6 GHz-band CMOS oscillators. To our knowledge, this is the first GaAs MESFET-based oscillator which has a cross-coupled differential topology and a capacitive coupling feedback to suppress the up-conversion of 1/f noise. Also, it is first reported that the GaAs MESFET-based oscillator shows 1/f² phase-noise behavior across the offset frequency range from 100 KHz to 1 MHz     

Design Theory for Broad-Band YIG-Tuned FET Oscillators

Design techniques that have been succcessfully used on the development of X-band GaAs FET YIG-tuned oscillators are presented. The design procedure results in the maximization of the oscillator bandwidth. Small-signal device characterization is utilized and accurately predicts the oscillator bandwidths. Spurious oscillation conditions are discussed, and design techniques are prescribed for eliminating spurious oscillations in both the active circuit and resonator. The operation of an experimental oscillator verifies the design procedure.     

Co-integration of GaAs MESFET and Si CMOS circuits

Co-integration of GaAs MESFET and Si CMOS circuits is demonstrated using GaAs-on-Si epitaxial growth on prefabricated Si wafers. This is thought to be the first report of circuit-level integration of the two types of devices in a coplanar structure. A 2-μm gate Si CMOS ring oscillator has shown a minimum delay of 570 ps/gate, whereas on the same wafer a 1-μm gate GaAs MESFET buffered-FET-logic (BFL) ring oscillator has a minimum delay of only 70 ps/gate. A composite ring oscillator consisting of Si CMOS invertors and GaAs MESFET invertors connected in a ring has been successfully fabricated     

Reduction of FM noise in impatt oscillators by optical illumination

Experiments are described in which laser illumination of the active device has reduced the FM noise output by up to 5 dB for a GaAs impatt oscillator and 2 dB for a Si impatt oscillator. A qualitative explanation of the observed results is given, and the effect of laser amplitude noise on the maximum noise reduction obtainable is shown.     

High peripheral power density GaAs f.e.t. oscillator

Peripheral power density (p.p.d.), i.e. the output power per Unit gate width is defined as a figure of merit for GaAs f.e.t. oscillators. An X-band oscillator circuit using series and shunt feedback is described and its performance characteristies indicated. It is shown that this GaAs f.e.t. oscillator circuit configuration has the highest peripheral power density.     

超导共面波导谐振腔稳频振荡器的实验研究

对共面波导谐振腔稳频振荡器进行了实验研究。在对不加谐振腔的简单振荡器研究的基础上，设计并制作了反馈型和传输型谐振腔稳频振荡器。首先，稳频谐振腔分别用常规导体介质基片和在ＺｒＯ衬底上的金膜来实现。然后，用ＬａＡｌＯ３介质衬底上的ＹＢＣＯ超导薄膜制作的共面波导稳频谐振腔嵌入振荡器电路，利用其高品质因数取得较好的稳频效果。所有电路的有源器件均采用ＮＥ７２０８４ＧａＡｓＭＥＳＦＥＴ。     

Stable monolithic GaAs FET oscillator

A monolithic X-band GaAs FET oscillator has been developed. Passive circuit components are lumped capacitors and inductors on semi-insulating GaAs; the chip size is 1.2 × 1.4 mm2. Stabilised with a Ba2Ti9O20 dielectric resonator, the oscillator delivers more than 30 mW output power at 10.8 GHz with a maximum chip efficiency of 20%. The frequency drift is better than 1 × 10?6/K from ?20°C to 80°C.     

A low-noise K-Ka band oscillator AlGaAs/GaAsheterojunction bipolar transistors

The design considerations, fabrication process, and performance of the first K-Ka-band oscillator implemented using a self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT) are described. A large-signal time-domain-based design approach has been used which applies a SPICE-F simulator for optimization of the oscillator circuit parameters for maximum output power. The oscillator employs a 2×10-μm² emitter AlGaAs/GaAs HBT that was fabricated using a pattern inversion technology. The HBT has a base current 1/f noise power density lower than 1×10^-20 A²/Hz at 1 kHz and lower than 1×10^-22 A/²/Hz at 100 kHz for a collector current of 1 mA. The oscillator, which is composed of only low-Q microstrip transmission lines, has a phase noise of -80 dBc/Hz at 100 kHz off carrier when operated at 26.6 GHz. These results indicate the applicability of the HBTs to low-phase-noise monolithic oscillators at microwave and millimeter-wave frequencies, where both Si bipolar transistors and GaAs FETs are absent     

Common-gate GaAs f.e.t. oscillator

Frequency tuning, power and noise characteristics of a common-gate GaAs f.e.t. oscillator were investigated. By changing the common-gate lead inductance, the frequency was changed by almost two octaves. The f.m. noise of the low-Q factor f.e.t. oscillator was at the same level as that of a medium-Q factor GaAs impatt oscillator.     

Stability analysis of self-injection-locked oscillators

This paper addresses the stability analysis of the self-injection-locked oscillators. The analysis is developed for arbitrary self-injection feedback loops and illustrated with the specific case of a simple time-delay cable. It is shown that the output phase stability in self-injection-locked oscillators depends on the feedback loop delay and the types of oscillator circuits, which are represented by equivalent parallel- or series-resonant oscillator models. The self-injection-locked technique can also be used to test the oscillator circuit model when the self-coupling phase is known. The theory is verified by using a self-injection-locked GaAs MESFET oscillator operating at X-band with delay loops.