Common-Drain Flip-Chip GaAs FET Oscillators

GaAs FET oscillators with flip-chip mounted devices in a novel common-drain configuration are described. It is shown how common-drain oscillators can achieve low thermal resistance while at the same time minimizing parasitics. It is also shown that broad-band negative resistances can be generated without external feedback elements. This paper also reports experimental results where output powers of 390 mW with 22-percent efficiency at 8.5 GHz and 230 mW with 26-percent efficiency at 11.7 GHz have been demonstrated.     

X波段砷化镓场效应振荡管

X波段GaAs场效应振荡管是一种专门用于各种微波固体振荡电路的新型器件,尤其对X波段GaAsFET电压控制振荡器(VCO)和介质谐振器振荡器(DRO)更为适合。 本文在对有关资料分析的基础上,提出了设计这一器件的基本原则;概述了器件的基本结构;介绍了器件的参数研究结果和电路应用情况。用该器件制作的X波段FET VCO,得到了800MHz以上的电调范围,在整个电调范围内,输出功率为30～50mW,功率起伏小于1.5dB。     

Injection Locking of Klystron Oscillators

If certain criteria are met, a microwave oscillator may be synchronized by the injection of a controlling signal into the oscillator cavity. Synchronization is dependent upon oscillator circuit parameters, the ratio of injected power to oscillator power, and frequency difference between the free-running oscillator and the injection signal. Locking has been observed with injection signals 70 db below the oscillator output and 30-db ratios have been demonstrated to be easily realizable. Injection locking may be considered a form of amplification that permits taking advantage of the fact that microwave oscillators are smafler, lighter, less expensive and more efficient than amplifier devices. The low-frequency theory of Adler is shown to describe accurately the locking phenomena in reflex klystron oscillators and the transient response is extended to determine limitations on the amplification of modulated signals. Experimental verification of the theory is shown for 180/spl deg/ phase modulation of the locking signal at rates up to 100 kc for a VA-201 klystron. Design relations and curves are presented and applications and improvements are discussed.     

Optical Injection Locking of Baritt Oscillators

Optical injection locking of BARITT oscillators is investigated. Preliminary experimental results are presented for the first time. A sirmple first-order locking theory gives reasonable agreement with measurements.     

Injection Locking in Concurrent Dual-Frequency Oscillators

In a separate paper, the authors show that a nonlinear active core with a fourth-order resonator can generate two stable independent frequencies simultaneously. In this paper, the effect of injecting two frequencies into such a concurrent dual-frequency oscillator is analyzed and experimentally verified. It is shown that, for weak injection, the effect of injection at one frequency is decoupled from the effect of injection at the other frequency. The differential equation describing the effect of injection at either of the two frequencies is similar to the Adler's injection-locking equation for single-frequency oscillators. A theoretical analysis for a linear array of coupled concurrent dual-frequency oscillators is provided. It is shown that a linear phase progression at both frequencies can be achieved independently by detuning the array's end elements. Dual-frequency quadrature signal generation using two coupled concurrent dual-frequency oscillators is also demonstrated. To verify the theoretical derivations, an integrated circuit in a 0.18-$mu$m SiGe BiCMOS process is designed and fabricated. Measurement results closely match the theoretical predictions. The application of concurrent coupled oscillator array in dual-frequency beam forming with steering capability is also demonstrated.      

GaAs FET Applications for Injection-Locked Oscillators and Self-Oscillating Mixers

Injection-locked oscillators (ILO's) using GaAs FET's are described experimentally and theoretically, showing that a wider locking range can be obtained with transmission-type ILO's than with reffection-type, assuming Q/sub ext/, to the load to be the same in each case. Frequency-stabilized FET oscillators are discused in terms of the advantages gained by terminating the gate port by a 50-Omega load. Functioning as a self-oscillating mixer, the circuit showed a 9.5-dB (DSB) noise figure.     

Large-Signal Technique for Designing Single-Frequency and Voltage-Controlled GaAs FET Oscillators

A systematic procedure is described for designing fixed-frequency and voltage-tuned GaAs FET oscillators for optimum large-signal performance. The approach is based on the use of a large-signal FET model for de-embedding dominant device nonlinearities, leading to a method which is both accurate and simple to apply. The viability of the technique is demonstrated with a 17-GHz fixed-frequency oscillator and a 7.4 to 13.1-GHz varactor-tuned oscillator. Design considerations as well measured performance characteristics are discussed in detail.     

K波段介质谐振器稳频GaAs FET谐波振荡器

本文对介质谐振器稳频GaAs FET谐波振荡器进行了研究;分析了场效应管中的非线性源产生二次谐波分量的情况,利用两种不同类型的场效应管设计制作了两个介质谐振器稳频场效应管谐波振荡器,在22GHz和18GHz分别得到了5.4mW和305mW的二次谐波功率。     

Large Signal Design of GaAs FET Oscillators Using Input Dielectric Resonators

A dielectric resonator may be placed at the input of an active two-port device (FET or microwave transistor) yielding a stable frequency source. For this input configuration, a large signal design is presented. The method is simple, and power output prevision is also reached. The practical results obtained with an X-band medium-power oscillator are presented.     

Optical Injection Locking of BARITT Oscillators (Comments)

We were interested to read the above short paper, but would like to point out that experimental results on the optical injection locking of IMPATT oscillators have indeed been obtained. Over the last few years, reports of such experiments have appeared in the literature from groups in both Europe and the U.S.A.     

A Time-Domain Model for Predicting the Injection Locking Bandwidth of Nonharmonic Oscillators

A delay-based model in the time domain is introduced to describe injection locking in nonharmonic oscillators, such as ring or relaxation oscillators. Using this model, the locking bandwidth of differential ring oscillators is derived. The model predictions are verified against simulations and measurements of a four-stage ring oscillator circuit built using discrete components     

Criterion for Nonreciprocal Injection Locking of Bilateral Microwave Oscillators (Correspondence)

A criterion is presented for establishing the required degree of isolation between injection-locked microwave oscillators to prevent reverse Iocking. In particular, the effect of circulator directivity and oscillator harmonics on the performance of the locking circuit is discussed. The injection-locked performance of pulsed and CW transferred electron oscillators is used as an example.     

Highly Stable Dielectric Resonator FET Oscillators

The long-term frequency drift of GaAs FET oscillators with temperature has been analyzed theoretically and experimentally in view of stabilization using dielectric resonators. It was found that the dielectric material stability and quality factor should be within certain limits, and, in addition, that the resonance frequency over the temperature characteristic should be quite linear. Such a material has been developed on the basis of BaTi/sub 4/O/sub 9/ and Ba/sub 2/Ti/sub 9/O/sub 20/ , and ultra-stable DRO's with frequency drifts of around +- 100 kHz for -50 to 100°C at 11 GHz (ap +- 0.06 ppm/K) have been realized.     

功率GaAs FET

本文叙述了目前在研制功率GaAs FET过程中对器件的输出功率有比较重要影响的诸多因素,例如器件的几何结构、源引线寄生电感、热阻、击穿电压等等,以及对这些因素加以克服或限制的技术。折衷的结果将使所研制的器件具有良好的微波性能。     

Conversion Loss in GaAs Schottky-Barrier Mixer Diodes

In this paper, the intrinsic conversion loss of GaAs Schottky-barrier mixer diodes is analyzed in light of a more accurate diode model. This analysis resolves the discrepancy between the predictions of an earlier intrinsic conversion loss model and expefimental results. In particular, it is shown that a) cryogenic cooling should not degrade the conversion loss, and b) the diode diameter can be smaller than previously predicted before conversion-loss degradation begins to occur, Evidence is also presented which indicates that mixer diodes must be pumped beyond flat-band if the minimum, possible conversion loss is to be obtained. A more complete model of the conversion loss, which includes the parasitic circuit elements, is discussed and found to be in agreement with the qualitative results of the intrinsic conversion-loss model.     

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.     

GaAs microwave power FET

A design consideration for an X-band GaAs power FET, features of the fabrication process, and electrical characteristics of the FET are described. Interdigitated 53 source and 52 drain electrodes and an overlaid gate electrode for connecting 104 Schottky gates in parallel have been introduced to achieve a 1.5-µm-long and 5200-µm-wide gate FET. A sheet grounding technique has been developed in order to minimize the common source lead inductance (L8= 50 pH). The resulting devices can produce 0.7-W and 1.6-W saturation output power at 10 GHz and 8 GHz, respectively. At 6 GHz, a linear gain of 7 dB, an output power of 0.85 W at 1-dB gain compression and 30-percent power added efficiency can be achieved. The intercept point for third-order intermodulation products is 37.5 dBm at 6.2 GHz.     

GaAs FET distributed amplifier

The design and construction of a GaAs FET distributed amplifier with a bandwidth of 6 GHz is described The amplifier provides an input VSWR of less than 1.8:1 and noise figure of 3?6 dB The possibility of bandwidth extension is discussed.     

GaAs FET RF switches

The device parameter dependences of GaAs FET switch performance have been determined analytically and by two-dimension simulation. FET switch design would maximize the value of the switch quality factor while retaining the power handling capacity. Expressions for both the quality factor and power handling capacity are derived in terms of device parameters, and would enable such optimization to be performed.     

Dual-gate GaAs FET switches

A set of multi-pole, multi-throw switch devices consisting of dual-gate GaAs FET's is described. Included are single-pole, single-throw (SPST), double-pole, double-throw (DPDT), and single-pole four-throw (SP4T) switches. Device fabrication and measurement techniques are discussed. The device models for these switches were derived based on an equivalent circuit of a duff-gate FET. The devices were found to have substantial gain in X-band and low Ku-band.