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。     

Temperature Stabilization of GaAs MESFET Oscillators Using Dielectric Resonators

A simple model of the temperature stabilization of dielectric resonator FET oscillators (DRO's) is presented. Deduced from the oscillation condition, the model furnishes relations for oscillation power and frequency stability with temperature. A stack resonator with an appropriate linear resonance frequency/temperature characteristic has been developed and used to stabilize a DRO: frequency stability of +- 120 kHz over - 20°C to 80°C (/sup delta=/+- 0.1 ppm/K) at 11.5 GHz has been achieved.     

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。     

GaAsFET大信号模型与参数提取

提出适用于功率ＧａＡｓＦＥＴ的新的大信号模型以及脉冲Ｉ－Ｖ和小信号Ｓ参数相结合的整体化参数提取方法。用研制出的大信号建模软件提取了功率ＦＥＴ的大信号模型参数，并用该模型模拟和测量了器件大信号Ｓ参数，结果完全一致。     

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.     

Design of Microwave Oscillators and Filters Using Transmission-Mode Dielectric Resonators Coupled to Microstrip Lines

A more detailed model for the transmission-mode dielectric resonator coupled between microstrip lines is given. Novel design approaches for parallel feedback oscillators and bandpass filters are discussed. For oscillators, the design mainly takes into account zero phase shift loop considerations, as in the classical low-frequency approach. Oscillators of this type may offer low phase noise. For filters, the spatial separation between dielectric resonators favors multipole designs. Using the same microstrip layout, different shapes and bandwidths may be obtained by simple tuning.     

X波段砷化镓场效应管介质振荡器

本文介绍了反馈型介质振荡器,给出了介质谐振器尺寸的计算方法.该振荡器在8GHz下,温度范围-40～+70℃,频率稳定度为0.6ppm/℃,输出功率16～30mW,在+55℃下连续工作8 小时,频率漂移小于50kHz,推频系数小于10kHz/V,在偏离载频100kHz的FM噪声为-110dBc/Hz.该振荡器在无人值守中继系统中作上下变频器的本振源,使用良好.这类振荡器在10.7GHz下,温度范围-40～+55℃,频率稳定度0.6ppm/℃,输出功率大于5mW.     

Transmission-Type Injection Locking of GaAs Schottky-Barrier FET Oscillators

Transmission-type injection-locked oscillators equipped with both signal-input and power-output ports are studied. A comparison with traditional reflection-type injection-locked oscillators, in which a signal is injected into the output port of the oscillator, is presented theoretically. It is shown that the Iocking range of transmission types always differs from the reflection type by a factor of G/sub s// G/sub p/ where G/sub s/ represents the maximum stable gain of the two-port oscillator and G/sub p/ represents the square root of the output power ratio of the two ports. Experiments on common-source injection-locked oscillators using GaAs FET chips are described and show that, with transmission types, a 1.8 times wider Iocking range can be obtained than with reflection types. Furthermore, investigation of FM noise for both types of injection revealed lower off-carrier FM noise for transmission types than reflection types, even though the Iocking gain of the transmission types was kept the same as that of reflection types. Thus overall features of transmission-type injection locking were found to be advantageous for FM signal amplification even though there is a minimal power loss at the signal input port.     

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 GaAs MESFET Oscillator Design

Techniques for large signal GaAs MESFET oscillator design are described which do not require repeated large signal measurement. In the first technique, small signal S-parameter measurements are used with a computer program to compute the packaged and mounted device equivalent circuit. Large signal measurements are made to determine a mathematical relationship between only those parameters which vary under large signal conditions. These relationships are included in the computer program. Then, once the equivalent circuit has been computed from the small signal S-parameter measurements, those parameters varying under large signals are incrementally altered until large signal S parameters are obtained which correspond to maximum oscillator output power. These values are used to calculate embedding element values for six oscillator topologies. A coaxial cavity FET oscillator was built and tested using the large signal design theory, and it substantially verified the design technique. The second design technique is based on the fact that S/sub 21/ varied more than other S parameters under large signals. By making design calculations based on S/sub 21/ reduced to the point corresponding to maximum oscillator power, it was possible to get usable design information for an FET oscillator.     

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.     

低相噪锁相介质振荡器研究

针对高的相位噪声指标要求,对取样锁相介质振荡器进行了研究.通过相位噪声分析,明晰了采用介质振荡器与取样锁相技术降低相位噪声的机理,并分别对介质振荡器与锁相环路进行了设计.设计中,应用HFSS与ADS对介质振荡器进行了联合仿真,体现了计算机辅助设计的优势.最终研制出17 GHz锁相介质振荡器,测试结果为:输出功率13.1 dBm;杂波抑制>70 dB;谐波抑制>25 dB; 相位噪声为-105 dBc/Hz@1 kHz,-106 dBc/Hz@10 kHz,-111 dBc/Hz@100 kHz,-129 dBc/Hz@1 MHz.     

Design of Microwave Dielectric Resonators

The resonant frequencies for the fundamental modes in circular cylindrical and rectangular parallelopiped high dielectric resonators have been calculated by computer for a range of values of physical dimensions and relative dielectric constant. The frequency range extends from zero to 50 kMc/s, the relative dielectric constant from 50 to 1800, and physical dimensions from zero to 500 roils. Results are presented in graphical form with frequency plotted vs. resonator length for parametric values of relative dielectric constant and cross-sectional dimensions. A brief review of earlier work with high dielectric resonators is included. Expressions for the resonant frequency and fundamental mode field configurations are given.     

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.     

Precise Design of a Bandpass Filter Using High-Q Dielectric Ring Resonators

A precise design is presented for a bandpass filter constructed by placing TE/sub 01delta/ dielectric ring resonators coaxially in a TE/sub 01/ cutoff circular waveguide. On the basis of a rigorous analysis by the mode- matching technique, the interresonator coupling coefficients are determined accurately from the calculation of two resonant frequencies f/sub sh/ and f/sub op/ when the structurally symmetric plane is short- and open-circuited. For the TE/sub 01delta/ ring resonator,the resonant frequency f/sub 0/, the temperature coefficient tau/sub f/, the unloaded Q(Q/sub u/), and the other resonances are also calculated accurately in a similar way. From the calculations, the optimum dimensions are determined to obtain the maximum Q/sub u/, as F/sub r/ = f/sub r/ /f/sub 0/ is kept constant, where f/sub r/ is the next higher resonant frequency the ring resonator using low-loss ceramics (epsilon/sub r/ = 24.3, tan delta = 5 x 10/sup -5/) has Q/sub u/ = 16800 at 12 GHz and tau/sub f/ = 0.1+-0.5 ppm/° C, while the rod one has Q/sub u/ = 14700. A four-stage Chebyshev filter having ripple of 0.04 dB and equiripple bandwidth of 27.3 MHz at f/sub 0/ =11.958 GHz is fabricated using these resonator; the measured frequency responses agree well with theory. The insertion loss is 0.9 dB, which corresponds to Q/sub u/ = 9800.     

介质谐振器反馈型GaAs FET振荡器

本文扼要分析了高Q介质反馈型FET振荡器的原理,认为介质反馈型振荡器类同于高Q介质谐振器与FET栅极耦合的反射型振荡器。实验表明,在-40～+55℃范围内,频率稳定度达2.0ppm/℃,最佳可小于0.2ppm/℃。同时,介质温度系数对振荡电路的过补偿比欠补偿更有利于提高输出功率温度稳定性。     

New Design Approach for Wide-Band FET Voltage-Controlled Oscillators

A new, computer-assisted method, based on small-signal "S" parameters, is described for the systematic design of wide-band VCO's. The method has been applied to design 6-12-GHz and 12-18-GHz GaAs FET VCO's, and it has shown an excellent capability to predict the maximum obtainable tuning bandwidth. The tuning linearity of the VCO's has also been optimized Delta f/f <= +-0.4 percent over a 3-GHz bandwidth.     

Design of Broad-Band Power GaAs FET Amplifiers

A model is presented for the drain-gate breakdown phenomenon of GaAs FET's, based on experimental results. this breakdown model is added to a previously published large-signal model and incorporated in a powerful computer-aided design program called LSFET. The program is capable of searching for the optimum power load for an FET and simulating the power performance of multistage amplifiers. The design of power amplifiers is discussed in detail, using the knowledge gained from LSFET. Data is presented from a fabricated monolithic broad-band power amplifier chip showing good agreement between measured results and simulated curves.