A Technique for the Design of Microwave Transistor Oscillators (Short Paper)

A technique for the design of microwave transistor oscillators is presented in which measurements made on an experimentally optimized amplifier are used to calculate six basis oscillator circuits which yield maximum power output. The procedure has been experimentally verified by the construction of a silicon bipolar transistor test oscillator at 1 GHz.     

A generalized scattering matrix approach for analysis ofquasi-optical grids and de-embedding of device parameters

A generalized scattering matrix approach to analyzing quasi-optical grids used for grid amplifiers and grid oscillators is developed. The approach is verified by a novel method for de-embedding, in a waveguide simulator, the active device parameters of a differential pair high electron mobility transistor (HEMT) from the single unit cell of a grid amplifier. The method incorporates the additional ports presented to the active device into a method of moments solution of the embedding periodic array. The port(s) defined at the device or load location are within the plane of the array, and not terminated in a microstrip line with a known characteristic impedance. Therefore the generalized scattering matrix for the embedding array is normalized to the calculated input impedance(s) at these port(s). The approach described here uses a Floquet representation of the fields incident and reflected from the grid as the remaining ports in the generalized scattering matrix. The use of Floquet modes allows analysis of general geometries and nonnormal incident angles without the need for magnetic and electric wall assumptions. By developing a generalized scattering matrix for the embedding periodic array, this approach now allows conventional amplifier design techniques and analysis methods to be applied to quasi-optical grid amplifier and oscillator design. The major advantage of this unification for grid amplifier design being that the stability of the design can be predicted     

Design of a negative conductance dielectric resonator oscillator for X-band applications

An X-band tunable microwave low-phase noise planar oscillator employing a novel-fed dielectric resonator (DR) with a single transistor has been investigated and realized. A ZrSnTi oxide composite ceramic-based DR with dielectric permittivity of 95 enclosed in a metallic cavity with an unloaded Q factor of 5,000 at 10 GHz is proposed. The resonant frequency affinity with respect to geometric parameters is established by using the compensation technique based on dual negative conductance feedback, the outputs of which are combined via a Wilkinson power divider (WPD). The feedback parallel-coupled DR oscillator is incorporated into a laminate microwave board using the photolithographic technique. The oscillator includes a pseudomorphic low noise amplifier based on a high-electron-mobility transistor. Hence, the proposed oscillator with mechanic tuning is measured, and the results show that DR resonates at TE _01δ mode with frequency of 10 GHz. The measured phase noise of the oscillator is –81.03 dBc/Hz at a 100 kHz offset.     

Noise spectrum characteristics of low-noise microwave tubes and solid state devices

In this paper experimental data on the FM and AM noise of low-noise microwave tubes, "solid-state klystrons," and solid-state chains of the types used in Doppler radars are presented. The tube types include magnetrons, klystrons, and triodes. Data on solid-state chains of the type consisting of a VHF crystal-controlled transistor oscillator, followed by a VHF transistor power amplifier, and a varactor frequency multiplier are also presented. The spectral shape of the solid-state chain is shown to differ from those of the microwave tubes and that of the "solid-state klystron." Comparisons are made between the various devices.     

Class E high-efficiency tuned power oscillator

The class E high-efficiency transistor tuned power oscillator, based on the class E power amplifier, is presented. Theoretical conditions for optimum operation of the oscillator are formulated. A new feedback-loop circuit is proposed and a corresponding oscillator design procedure is given. Experimental results show that the collector-voltage and collector-current waveforms and the collector efficiency of the oscillator are the same as in the class E amplifier with the same transistor and operating at the same frequency. The measured collector efficiency was over 95 percent with 3 W output at 2 MHz. The proposed oscillator is especially applicable at high frequencies because it minimizes the power dissipated during the transistor off-to-on transition, even if the switching time is an appreciable fraction of the signal period.     

LDMOS微波功放器设计

文章首先从功放器的合理选择、功放器工作状态的确定和功放器匹配电路的设计三个角度讨论了在设计功率放大器电路方案时应该考虑的不同因素。然后以实际项目需要的微波功率放大器为例,根据产品的技术指标要求,结合在做微波放大器设计和生产中积累的经验,设计了一款工作在P波段,典型增益在15 dB的功率放大器,通过合理选择功放器及其工作状态,设计电路结构、阻抗匹配,最终该功放具有输出功率稳定、增益平坦度小、线性度高、可靠性高等特点。     

Feedforward-Regulated Cascode OTA for Gigahertz Applications

A very high-frequency operational transconductance amplifier (OTA) with a new feedforward-regulated cascode topology is demonstrated in this paper. Experimental results show a bandwidth of 10 GHz and a large transconductance of 11 mS. A theoretical analysis of the OTA is provided which is in very good agreement with the measured results. We also carry out a Monte Carlo simulation to determine the effect of transistor mismatches and process variations on the transconductance and input/output parasitic capacitances of the OTA. The linearity and intermodulation distortion properties of the OTA, which are of particular interest in microwave applications, are experimentally determined using a purpose-built single-stage amplifier. For high-frequency demonstration purposes we built a larger circuit: an inductorless microwave oscillator. The fabricated oscillator operates at 2.89 GHz and has a significantly larger output voltage swing and better power efficiency than other inductorless oscillators reported in the literature in this frequency range. It also has a very good phase noise for this type of oscillators: ${-}116$ dBc/Hz at 1-MHz offset.      

微波晶体管振荡器的计算机优化设计

本文用负阻概念分析了微波晶体管振荡器的基本工作原理及设计方法，着重讨论了微波振荡器的电路特性，给出了精确可靠的数学模型，并编写出最优化设计程序，从而提高了微波振荡电路的设计效率和精度。     

计算机辅助设计微波放大器

本文初步尝试用计算机辅助设计的方法设计微波晶体管放大器,经历了由源程序的编制、调试,至实验验证的全过程,取得比较满意的结果.编制的通用程序具有一定实用价值.本文介绍程序的算法原理、构成、使用方法,以及实验验证情况.     

基于ADS的微波低噪声放大器的设计与仿真

低噪声放大器包括输入匹配网络、微波晶体管放大器和输出匹配网络.微波晶体管放大器是设计中的核心部分.根据低噪声放大器设计的原理,提出技术指标要求,设计一个5GHz单级低噪声放大器,经过技术指标分析,采用Fujitsu公司的FHX35LG型HEMT场效应管晶体管.阐述了如何利用Agilent公司的ADS软件进行分析和优化设...     

L波段小信号放大器ADS设计与仿真

对小信号晶体管放大器的设计步骤、设计理论进行了阐述,利用ADS软件通过实例详细地设计了L波段小信号放大器,并给出了仿真结果.仿真结果表明,放大器匹配电路设计完全满足性能指标要求.本文提出的利用ADS软件对L波段的LNA和小信号功率放大器的设计方法可以加速放大器产品化进程,具有重要的实用价值.这种放大器主要应用于微波中继、数字音频卫星直播、全球定位系统等无线系统中.     

Mathematical Representation of Microwave Oscillator Characteristics by Use of the Rieke Diagram

This paper shows that the characteristics of oscillators can be phenomenologically expressed by a polynomial function of frequency and amplitude, provided the output signal is nearly sinusoidal, especially at microwave frequency. A method is presented of determining the coefficients of the polynomial from several points on the Rieke diagram, with two examples being shown. The characteristics of oscillators can consequently be represented by several parameters, as in the case of electron tubes and transistors, so that the design of an oscillator circuit may become easier with the aid of an electronic computer.     

Nonlinear optimization tools for the design of high-efficiency microwave oscillators

A new systematic method is presented for the design of high-efficiency microwave oscillators. It is based on the control of the transistor output-voltage waveform, through the combined use of a nonperturbing auxiliary generator and a substitution generator. The nonperturbing generator sets the oscillation frequency at the desired value during the entire design process. The combination of the two generators allows obtaining a quasisquare output-voltage waveform, with optimum harmonic components to maximize the efficiency. Attention is paid to the stability and phase noise of the implemented oscillator, which are analyzed versus technological parameters. A 6-GHz oscillator has been designed using these techniques, with good experimental results.     

Analysis of an experimental technique for determining Van der Polparameters of a transistor oscillator

The Van der Pol (VDP) model of a transistor oscillator describes the behaviour of the oscillator with three parameters. When operating in steady state, only two parameters can be determined by spectrum analysis, these being the oscillation frequency and amplitude of oscillation. In this paper, a technique for measuring the other VDP parameter is examined. In this approach, a periodically modulated voltage is added to the bias of the oscillator to perturb the operational state. A theoretical derivation shows that the power spectrum of the perturbed oscillator contains additional information for determination of the other VDP parameter. A simple analytical perturbation formula predicts the oscillator's response to the ramped bias. Our experimental results agree with the analytical perturbation solution and therefore, this allows one to read off the other VDP parameter from the experimental data. The VDP model allows one to predict the behaviour of coupled transistor oscillators more accurately and simply than does the traditional large-signal model of the transistor. This VDP model will simplify oscillator array design since the number of parameters needed to describe each oscillator is reduced from that which would be required using a large-signal circuit model     

Procedure for calculating microwave-amplifier matching circuits

A procedure for calculating the parameters of matching circuits in the case of complex-valued impedances of the generator and the load has been developed. The procedure has been tested by calculating the parameters of a microwave amplifier based on a Schottky-barrier field-effect transistor and by measuring the amplifier’s characteristics. The test results are presented.     

用于雷达的LDMOS微波功率放大器设计

硅LDMOS晶体管以其大输出功率和高效率等优点作为微波功率放大器广泛应用于雷达发射机中.在大信号S参数无法获得而厂家提供的1710 MHz～2110 MHz范围内的源阻抗和负载阻抗参数又不能用时,利用一公司的ADS软件,采用负载牵引法得到了输入和输出阻抗.在对晶体管绝对稳定性分析的基础上,运用共轭匹配,成功设计出P-1大于30W、功率增益在1580MHz～1650 MHz频率范围内、增益保持在30dB以上和PAE大于30%的2级LDMOS微波功率放大器.同时,得到了最终的版图并且运用MOMENTUM对它进行了2.5D仿真,得到了理想的结果.     

Notes on the Conjugate Matched Two-Port As an UHF Amplifier (Short Papers)

Because of the relative simplicity of measurement of scattering parameters of active two-ports at frequencies up to the lower microwave region, investigations have been made into the application of these parameters to the design of UHF amplifiers. The theory of generalized scattering parameters has been developed by Kurokawa, applied to two-port power-flow analysis by Bodway, and used in the design of a single-stage UHF amplifier by Froehner. In this last paper, the bandwidth limitations imposed by the matching networks were not considered, nor was the capacitive matching arrangement to a purely resistive load fully developed. Both of these topics are the subject of this short paper, in which the relevant design expressions are also given.     

一种具有深度二次谐波抑制的微波振荡器

微波振荡器作为通信系统中的关键器件,已经被广泛地研究和设计。因此,设计具有优秀性能的微波振荡器是至关重要的。提出一种具有深度二次谐波抑制性能的新型微波负阻型振荡器。该设计的新颖性在于利用一个装配于双极结型晶体管射极的并联结构(由一段短微带线和电容并联组成)来实现二次谐波抑制。该结构作为振荡器基波信号的反馈元件,同时作为二次谐波处的带阻结构。因为二次谐波没有反馈回路(接地),所以能被极大地抑制。更重要的是在振荡器的输出端无额外的滤波器来抑制二次谐波,这使得电路尺寸得以减小。给出了一个振荡器设计实例,并给出其测试结果来论证理论的正确性。测试结果表明相较于传统振荡器的二次谐波抑制度有25 dB 的提高。     

Use of Transistor-Simulated Inductance as an Interstate Element in Broadband Amplifiers

The properties of a transistor in the inverted common-collector connection, and the use of this connection as an interstage element in broadband amplifiers, are described. A simple amplifier synthesis procedure using a T model of the transistor, and experimental results obtained with a VHF amplifier, are presented. An extension of the synthesis using y-parameter characterization is also described; this procedure is useful in the synthesis of amplifiers consisting of many stages or when the validity of the simple T model is questionable. The use of the simulated inductance of the inverted common-collector connection in monolithic integrated circuits is considered and design examples of monolithic microwave amplifiers are given.