The Declining Drain Line Lengths Circuit--A Computer Derived Design Concept Applied to a 2 26.5-GHz Distributed Amplifier

The principle of the "declining drain line lengths" has emerged as a successful concept in the pursuit of improved gain flatness and bandwidth. The optimized performance parameters of an "identical links" gain module are compared to those of a "declining drain line lengths" gain module, and the advantages of one design principle over the other are discussed. In addition, the paper studies the RF voltages and currents of the circuits' GaAs MESFETs and draws some qualitative conclusions as to the causes of gain limiting when approaching nonlinear operation. Finally, experimental results of a power module based on the "declining drain line lengths" principle are reported. The hybrid amplifier which incorporates five active devices with 0.25-µm gates achieves a small signal gain of G = 6.1+-0.6 dB from 2-27 GHz. Measurements of its output power, reflection coefficients and noise figure are afso discussed.     

Optical time-division multiplexed transmission at 8 Gbit/s using single laser and semiconductor optical power amplifier

The authors report transmission over 57 km of single-mode fibre in a two-channel, 8 Gbit/s optical time-division multiplexed system experiment using a transmitter with a single laser and a semiconductor optical power amplifier at the transmitter output. The amplifier operates with a net gain of 11.5 dB, which corresponds to 0.8 dB gain compression, and a fibre coupled output power of +6 dBm. The amplifier facet output power for which the gain is compressed by 3 dB is +13 dBm. The experimental system uses neither an isolator nor an optical filter.<>     

Analysis and Design of an X-Band Actively Compensated IMPATT Diode Amplifier

This paper shows how broad-banding of an IMPATT diode amplifier can be achieved using a circuit technique known as active reactance compensation. Theoretical analysis and experimental results both show that the gain-bandwidth products of an uncompensated IMPATT amplifier improves from G/sup 1/2/B = k to G/sup 1/4/B = 2k (where k is a constant) for the same amplifier actively compensated. The measured 3-dB bandwidth of 230 MHz for a 9.0-GHZ amplifier having a gain of 10 dB is improved to 700 MHz at the same gain.     

On Design and Performance of Lossy Match GaAs MESFET Amplifiers

The noise figure, the gain, and the reflection coefficients of lossy match amplifiers and their dependence on circuit elements are studied. Theoretical results are supported by measured data taken on a two-stage unit. In addition, the performance characteristics of a 100-8800 MHz four-stage lossy match amplifier are discussed. The unit exhibits 23.3 +- 1.1 dB of gain over the nearly 6-1/2 octaves. Its maximum noise figure is 10.9 dB from 100-8800 MHz and 6.6 dB from 2000-8000 MHz. The amplifier's overall circuit dimensions are 10 X 5.7 mm..     

Design and Performance of Microwave Amplifiers with GaAs Schottky-Gate Field-Effect Transistors

The design and performance of an X-band amplifier with GaAs Schottky-gate field-effect transistors are described. The amplifier achieves 20 /spl plusmn/ 1.3-dB gain with a 5.5-dB typical noise figure (6.9 dB maximum) over the frequency range of 8.0-12.0 GHz. The VSWR at the input and output ports does not exceed 2.5:1. The minimum output power for 1-dB gain compression is +13 dBm, and the intercept point for third-order intermodulation products is +26 dBm. The design of practical wide-band coupling networks is discussed. These networks minimize the overall amplifier noise figure and maintain a constant gain in the band.     

一种S波段低噪声放大器的设计

基于Siemens的NPN射频晶体管BFP420,设计出一款适合于S波段的低噪声放大器,本设计使用了宽带匹配技术,结合微带线和集总元件设计出宽带的匹配网络。放大器适用频率范围:1.8 GHz～3.2 GHz,可用带宽1.4 GHz,相对带宽56%,属超宽带低噪声放大器。测试结果表明,在可用频段范围内,放大器增益波动3.7 dB,输入驻波比VSWR<1.8 dB,输出驻波比VSWR<1.295 dB;1.8 GHz增益G=12.53 dB、噪声系数NF=1.128 dB;3.2 GHz增益G=8.79 dB、噪声系数NF=1.414dB。本设计可满足无线蓝牙、WIFI,Zigbee等多种2.4 GHz主流ISM无线设备的应用要求。     

毫米波大动态宽带单片低噪声放大器

利用0.25μmGaAsPHEMT低噪声工艺,设计并制造了2种毫米波大动态宽带单片低噪声放大器。第1种为低增益大动态低噪声放大器,单电源+5V工作,测得在26～40GHz范围内,增益G=10±0.5dB,噪声系数NF≤2.2dB,1分贝压缩点输出功率P1dB≥15dBm;第2种为低压大动态低噪声放大器,工作电压为3.6V,静态电流0.6A(输出功率饱和时,动态直流电流约为0.9A),在28～35GHz范围内,测得增益G=14～17dB,噪声系数约4.0dB,1分贝压缩点输出功率P1dB≥24.5dBm,最大饱和输出功率≥26.8dBm,附加效率约10%～13.6%。结果中还给出了2种放大器直接级联的情况。     

Low-power programmable gain CMOS distributed LNA

A design methodology for low power MOS distributed amplifiers (DAs) is presented. The bias point of the MOS devices is optimized so that the DA can be used as a low-noise amplifier (LNA) in broadband applications. A prototype 9-mW LNA with programmable gain was implemented in a 0.18-/spl mu/m CMOS process. The LNA provides a flat gain, S/sub 21/, of 8 /spl plusmn/ 0.6dB from DC to 6.2 GHz, with an input impedance match, S/sub 11/, of -16 dB and an output impedance match, S/sub 22/, of -10 dB over the entire band. The 3-dB bandwidth of the distributed amplifier is 7GHz, the IIP3 is +3 dBm, and the noise figure ranges from 4.2 to 6.2 dB. The gain is programmable from -10 dB to +8 dB while gain flatness and matching are maintained.     

A Low-Noise and Wide-Band Esaki Diode Amplifier with a Comparatively High Negative Conductance Diode at 1.3 Gc/s

This paper discusses the stability problem, output power, saturation level, and noise figure of Esaki diode amplifiers, and describes design considerations of the broadband circulator type amplifier with a large negative conductance diode. An experimental amplifier with a diode which has a negative resistance of -25 ohms is also described. The amplifier has a 3 dB bandwidth of 20 per cent, 18 dB gain, and a 3.6 dB noise figure including 0.3 dB insertion loss of the circulator. The output level for which the gain is 1 dB lower than the small signal gain is -17 dBm. These experimental results are in fair agreement with those estimated theoreticaly.     

Gain flattened Er3+-doped tellurite fibre amplifier forWDM signals in the 1581-1616 nm wavelength region

A gain-flattened Er³⁺-doped tellurite fibre amplifier (EDTFA) with an expanded L-band is presented. The amplifier has an average gain of 28 dB and a noise figure of <6 dB with a slight gain excursion of 1 dB over a wide wavelength range of 1581-1616 nm. The total output power of the EDTFA module was 20.5 dBm and its power conversion efficiency reached 25%     

A K-Band GaAs FET Amplifier with 8.2-W Output Power

An 8.2-W GaAs FET amplifier with 38.6+-0.5-dB gain over a 17.7-19.1 GHz frequency band has been developed. This amplifier combines the outputs of eight multistage amplifier modules utilizing a radial combiner. This state-of-the-art power level has been achieved with AM/PM of less than 2°/dB. The third-order intermodulation products at 1-dB gain compression were 20 dBc, and variation in group delay over the frequency band was less than +-0.25 ns. Tests show that the amplifier is unconditionally stable and follows the graceful degradation principle.     

A fully integrated 0.5-5.5 GHz CMOS distributed amplifier

A fully integrated 0.5-5.5-GHz CMOS-distributed amplifier is presented. The amplifier is a four stage design fabricated in a standard 0.6-μm three-layer metal digital-CMOS process. The amplifier has a unity-gain cutoff frequency of 5.5 GHz, and a gain of 6.5 dB, with a gain flatness of ±1.2 dB over the 0.5-4 GHz band. Input and output are matched to 50 Ω, with worst-case return losses on the input and output of -7 and -10 dB, respectively. Power dissipation is 83.4 mW from a 3.0 V supply, input-referred 1-dB compression point varies from +6 dBm at 1 GHz to 8.8 dBm at 5 GHz. From a circuit standpoint, the fully integrated nature of the amplifier on the given substrate results in a heavily parasitic-laden design. Discussion emphasis is therefore placed on the practical design, modeling, and CAD optimization techniques used in the design process     

Noise in Broad-Band GaAs MESFET Amplifiers with Parallel Feedback

The influence of the circuit elements of a single-ended feedback amplifier module on noise figure and gain, as well as on input and output reflection coefficients is discussed. Theoretical results are supported by tests performed on a five-stage single-ended amplifier. The unit exhibits 41.5+-0.8 dB of small-signal gain and a maximum noise figure of 4.0 dB between 2.4 and 8.0 GHz. Maximum reflection coefficients of 1.7:1 for the input and 1.5:1 for the output terminal were measured. The unit's overall circuit dimensions are 25x3.6 mm.     

反向泵浦光纤拉曼放大器的实现与传输实验

文章设计并实现了C L波段4泵浦光纤拉曼放大器(FRA),讨论了泵浦驱动电路的设计及掺铒光纤放大器(EDFA)与FRA 150 km混合传输的传输性能.实验结果表明,驱动电路可以稳定可靠地工作,当拉曼放大器的增益＜5 dB时,信号的误码性能不会得到显著提高.实验结果可为EDFA与FRA混合传输系统中增益的配置提供参考.     

超宽带低噪声放大器的计算机辅助设计

叙述了超宽带低噪声放大器的计算机辅助设计方法，提出了利用普通微带混合集成电路．工艺设计超宽带低噪声放大器的方法和关键技术，并且用带封装的ＢＪＴ和ＦＥＴ实现了两个超宽带低噪声放大器。实验结果和设计结果吻合较好。一个利用２ＳＣ３３５８，放大器为三级，频带为３０ｋＨＺ～１６００ＭＨＺ，增益Ｇ＝２０±１ｄＢ，噪声系数ＮＦ≤３．５ｄＢ；另一个利用ＡＴＦ１０２３５（６），放大器为二级，频带为５００ｋＨＺ～６０００ＭＨＺ，增益Ｇ＝２０±２ｄＢ，噪声系数ＮＦ≤２ｄＢ。     

L-band erbium-doped fibre amplifier with clamped- and flattened-gain using FBG

A gain clamped long wavelength band erbium-doped fibre amplifier (L-band EDFA) based on a ring laser cavity is demonstrated using a fibre Bragg grating (FBG) at the output end of the amplifier. This new design provides a good gain clamping as well as a gain flattening. The gain is clamped at 16.9 dB with gain variation of less than 0.1 dB from input signal power of -40 to -18 dBm by setting the VOA=5 dB. Also, the amplifier has the flattest gain spectrum at VOA=5. The gain variation is less than 1.0 dB within the wavelength range from 1570 to 1600 nm. This gain clamped amplifier also can support a 12 channel WDM system.     

Broad-band distributed amplifier impedance-matching techniques

A circuit concept is developed which allows impedance transformations to be performed over extremely broad bandwidths. The transformation is obtained by coupling one or more input or output lines of a distributed amplifier into several output or input lines, respectively. The circuit technique is demonstrated by results for an amplifier for a 1:2 impedance transformation over a 2-20-GHz bandwidth. The amplifier yields a voltage standing wave ratio (VSWR) of better than 1.7:1 into 25 Ω at the input and better than 1.5:1 into 50 Ω at the output while maintaining a gain of 9±1 dB. An application of the technique to the broadband impedance-matching problem of a laser diode driver is discussed. The circuit has a gain of 8.5±1 dB from 0.5 to 12.5 GHz and better than 10 dB return loss at both the input and output     

1.5 µm GaInAsP traveling-wave semiconductor laser amplifier

This paper presents a theoretical and experimental study in terms of small-signal gain, signal gain saturation, and noise characteristics of a 1.5 μm GaInAsP traveling-wave amplifier (TWA), realized through the application of SiOxfilm antireflection coatings. This TWA, having a residual facet reflectivity of 0.04 percent, exhibits a wide, flat signal gain spectrum and a saturation output power of +7 dBm at a 20 dB signal gain. The TWA also has a noise figure of 5.2 dB, which is the smallest value reported for semiconductor laser amplifiers. The experimental results are confirmed to be in good agreement with the theoretical predictions based on the multimode traveling-wave rate equations in conjunction with the photon statistic master equation analysis, which takes into account the amplifier material and device structural parameters. Signal gain undulation, saturation output power, and noise figure are also theoretically evaluated as functions of the facet reflectivity. The superior performance of the TWA demonstrates that the device is favorable for use in linear optical repeaters in fiber transmission systems.     

Miniaturised two-stage balanced Ku-band CPW MMIC amplifier using impedance transforming couplers

A two-stage balanced Ku-band coplanar waveguide amplifier design is presented which has been miniaturised by using impedance transforming couplers which considerably reduce the required matching networks to the MESFETs. The amplifier, measuring only 2*1.7 mm/sup 2/, exhibits a gain of 13.7 dB with less than +or-0.2 dB of ripple over the range 14-16 GHz.<>     

On Theory and Performance of Solid-State Microwave Distributed Amplifiers

The performance characteristics of n-link distributed amplifiers employing GaAs MESFET'S are studied. At first, formulas of tie symmetrical amplifier using lumped circuit elements are developed for the case of an idealized FET model. The theoretical analysis is then extended to distributed line elements and later to an S-parameter derived transistor model. In efforts to optimize amplifier performance, the restriction of circuit symmetry is subsequently removed and the performance characteristics of two concepts, that of equal characteristic impedances and that of equal line lengths, are proposed and compared. Based on this analysis and practical considerations, several three-link hybrid amplifiers utilizing the equal line lengths approach have been assembled and test results are reported. A gain of G = 5.5+-0.6 dB was measured over the bandwidth of 2-20 GHz. Across this frequency band a maximum VSWR of 2.2:1 for the input and 2.5:1 for the output terminaf have been reafized, while a minimum output power at the l-dB compression points of 19.3 dBm was achieved from 2-18 GHz. Agreement between measured and computed small-signal gain as well as reverse isolation is excellent.