Dual-Gate MESFET Variable-Gain Constant-Output Power Amplifier

The use of a dual-gate GaAs FET as a broad-band variable gain and constant output power amplifier is described. A five-stage variable gain-constant output power amplifier has been realized which provides a constant output power of 3 dBm (/spl plusmn/2 dB) for a large dynamic range of input power of -45 dBm to 0 dBm over the 4-8-GHz band. The amplifier uses a feed-forward AGC circuit for preadjusting the gain of the amplifier stages depending upon the strength of the signal at the output of preceding stages. The amplifier has the capability of detecting two or more simultaneous RF pulses having different amplitudes and separated by more than 15-ns time intervals. Also it preserves any amplitude modulation of the individual pulse.     

A 77 GHz mHEMT MMIC Chip Set for Automotive Radar Systems

A monolithic microwave integrated circuit (MMIC) chip set consisting of a power amplifier, a driver amplifier, and a frequency doubler has been developed for automotive radar systems at 77 GHz. The chip set was fabricated using a 0.15 µm gate‐length InGaAs/InAlAs/GaAs metamorphic high electron mobility transistor (mHEMT) process based on a 4‐inch substrate. The power amplifier demonstrated a measured small signal gain of over 20 dB from 76 to 77 GHz with 15.5 dBm output power. The chip size is 2 mm × 2 mm. The driver amplifier exhibited a gain of 23 dB over a 76 to 77 GHz band with an output power of 13 dBm. The chip size is 2.1 mm × 2 mm. The frequency doubler achieved an output power of –6 dBm at 76.5 GHz with a conversion gain of ?16 dB for an input power of 10 dBm and a 38.25 GHz input frequency. The chip size is 1.2 mm × 1.2 mm. This MMIC chip set is suitable for the 77 GHz automotive radar systems and related applications in a W‐band.     

增益钳制掺铒光纤放大器特性研究

报道了一种新型基于环形激光腔的增益钳制掺铒光纤放大器。得到了较好的增益钳制效果和增益平坦度,利用980nm半导体激光器泵浦12m长掺铒光纤形成激光增益,观测到 30nm增益带宽。通过反馈1520nm 激光,在可变衰减器不同值测量了输入信号从- 40 ～10dBm的增益,其小信号增益被钳制在16dB。可为40个波分复用(WDM)信道波长提供增益钳制及平坦的放大功能。     

Tunable wavelength conversion in a semiconductor-fiber ring laser

A tunable wavelength converter is demonstrated using highly nondegenerate four-wave mixing in a semiconductor-fiber ring cavity with no external pump light and low input signal power requirements. This device allows continuous tuning of both pump and converted wavelengths over the semiconductor optical amplifier gain bandwidth. Results for 11.8-nm down- and 6.9-nm up-wavelength conversion with input signal power as low as -10 dBm have been obtained at 1 Gb/s with less than 1.6-dB power penalty     

High-gain 1310-nm reflective semiconductor optical amplifiers with low-gain uncertainty

A 1310-nm reflective semiconductor optical amplifier with a gain uncertainty of only 0.8 dB at an average gain level of over 30 dB has been demonstrated using a microoptic polarization reversing retroreflector. For this amplifier 3-dB saturation output powers of up to 10 dBm and a noise figure of 7.5 dB have been obtained. A low gain uncertainty for undefined input signal polarization states and input signal wavelengths (which may vary over several nanometers) is of primary importance in switching applications.     

120-nm bandwidth erbium-doped fiber amplifier in parallel configuration

A new S- to L-band erbium-doped fiber amplifier (EDFA) module, which reaches 120-nm gain bandwidth of 1480 to 1600 nm, has been experimentally investigated and demonstrated by using coupled structure. A 32.8-, 34.7-, and 38.1-dB peak gain is obtained at 1504, 1532, and 1568 nm, respectively, when the input signal power is -30 dBm. In addition, this proposed amplifier also provides a broad-band amplified spontaneous emission (ASE) light source of 1480-1606 nm with the output level above -40 dBm.     

30 dB optical net gain at 1.543 mu m in Er/sup 3+/ doped fluoride fibre pumped around 1.48 mu m

A 30 dB optical net gain and 12 dBm maximum output power for -1 dBm signal input have been measured at a signal wavelength of 1.54 mu m with an erbium doped ZBLAN fibre pumped at 1.47-1.48 mu m. The results confirm the great potential of ZBLAN fibres for hosting rare earth ions to generate optical amplification. The discussion points out the parameters to be studied to improve the fibre amplifier performance.<>     

250 W HVHBT Doherty With 57% WCDMA Efficiency Linearized to ${-}$55 dBc for 2c11 6.5 dB PAR

A two-way symmetrical Doherty amplifier exhibiting 250 W saturated power has been developed using high-voltage HBT (HVHBT) GaAs technology biased at 28 V on the collector. Greater than 57% collector efficiency at 50 W (47 dBm) average output power has been demonstrated while achieving -55 dBc linearized ACPR at 5 MHz offset using a two-carrier-side-by-side WCDMA input signal with 6.5 dB PAR measured at 0.01% probability on the CCDF. In addition, a two-stage HVHBT lineup exhibiting 450 W (56.5 dBm) peak power has been demonstrated. The output stage consists of a pair of 250 W two-way symmetrical Doherty amplifiers power combined using a low-loss branchline combiner and driven by a single-ended 100 W class AB high-efficiency amplifier. The lineup demonstrated 44% PAE at 100 W (50 dBm) average output power with 25 dB lineup gain while achieving - 55 dBc linearized ACPR at 5 MHz offset using a two-carrier-side-by-side WCDMA input signal with 6.5 dB PAR measured at 0.01% probability on the CCDF. The lineup exhibits 400 W (56 dBm) PldB at 60% PAE CW, with 45% PAE at 6 dB backoff.     

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。     

A power-efficient, low-distortion variable gain amplifierconsisting of coupled differential pairs

A variable gain amplifier incorporating a plurality of coupled differential pairs has been designed in a bipolar technology. By applying variable offset voltages to these differential pairs, the overall gain of the system can be varied. The linear input region is inversely proportional to gain, making the amplifier very well suited for automatic gain control circuits. Furthermore, the gain of the proposed amplifier is 0-25 dB, the signal bandwidth is 35 MHz, and the output IP3 is 24-30 dBm. It operates from a 5 V power supply and dissipates 40 mW. The active chip area is 0.15 mm² in a 1 μm bipolar technology     

19WC-波段MMIC多芯片合成功率放大器

报告了一个两级 C-波段功率单片电路的设计、制作和性能 ,该单片电路包括完全的输入端和级间匹配 ,输出端的匹配在芯片外实现 ,该放大器在 5.2～ 5.8GHz带内连续波工作 ,输出功率大于 36.6d Bm,功率增益大于 18.6d B,功率附加效率 34 % ,4芯片合成的功率放大器在 4 .7～ 5.3GHz带内 ,输出功率大于 4 2 .8d Bm( 19.0 W) ,功率增益大于 18.8d B,典型的功率附加效率为 34 %。     

Comparison between regenerative-feedback and cofeedback gain-clamped EDFA

The erbium-doped fiber amplifier (EDFA) with regenerative feedback is compared with the cofeedback scheme. Without the bandpass filter, the injected signal experiences regenerative amplification and results in a higher signal gain. Such an above-threshold regenerative amplifier also exhibits a lower noise figure due to a higher inversion for the transition corresponding to the signal wavelength of 1550 nm. A near quantum-limited noise figure of 3.1 dB is achieved at the maximum pump power of 134.5 mW, showing nearly complete inversion at the EDF input end in the regenerative-feedback scheme. A low (<10/sup -10/) bit-error rate has been achieved with saturation input signal power above -12 dBm.     

应用于C-X-Ku波段的宽带功率放大器

采用0.25μm AlGaAs/InGaAs/GaAs PHEMT工艺技术,研制出了6～18GHz三级MMIC全匹配宽带功率放大器单片.在6～18GHz的工作频率下,放大器的平均功率增益为19dB,输出功率大于33.3dBm,在10GHz处有最大输出功率34.7dBm,输入回波损耗S11低于-10dB,输出回波损耗S22低于-6dB.与报道的C-X-Ku频段宽带功率放大器相比,有较好的功率平坦度.     

Millimeter-Wave Power Amplifier Based on Coaxial-Waveguide Power-Combining Circuits

A millimeter-wave power amplifier based on a coaxial-waveguide power-combining circuit is presented in this paper. A coaxial stepped impedance transformer is used to provide an impedance transition from the 50- $Omega$ input coaxial line to the oversized coaxial waveguide, and its equivalent-circuit model has also been developed. A Ka-band four-device coaxial-waveguide power amplifier is fabricated and tested. The 10-dB return loss bandwidth of the fabricated amplifier is from 27.5 to 40 GHz, and the power amplifier has 17–25.9 dB gain over a wide bandwidth from 26 to 38 GHz. The measured output power at 1-dB gain compression is about 26.6 dBm at 30 GHz, with a power-combining efficiency of about 90%.      

A high-performance 2—18.5-GHz distributed amplifier—Theory and experiment

A high-performance 2-18.5-GHz monolithic GaAs MESFET distributed amplifier has been designed and fabricated. The distributed amplifier is analyzed theoretically using a normalized transmission matrix approach, and a closed-form gain equation is presented for the MMIC m-derived drain-line case. Theoretical predictions are compared to measured results and more complicated CAD models. The measured small, signal gain is typically 8.0±0.40 dB from 2-18.5 GHz at standard bias. Typical input return loss is greater than 12 dB, and the output return loss is greater than 15 dB. The saturated output power is in excess of 23 dBm over most of the band, and the noise figure is less than 7.5 dB.     

A variable gain amplifier with 50-dB control range for 900-MHz applications

A variable gain amplifier for 900-MHz applications has been designed and fabricated in a BiCMOS process with f/sub T/ = 24 GHz. The amplifier has linear-in-dB gain control with a 50-dB control range. The maximum gain is 28 dB and the third-order output intercept point (OIP3) is 13.7 dBm. The gain is achieved in one gain stage with a cascoded output. The amplifier bias network and the gain-control circuitry are temperature compensated for temperature-independent gain at any gain setting. The bias network also uses a feedback loop to cancel out undesired low frequencies present at the radio-frequency input. The maximum output power is +10 dBm and the output 1-dB compression point is +8.7 dBm. Active chip area is 0.1 mm/sup 2/. The amplifier is packaged in a SOT-363 and consumes 30 mA from a 2.8-V supply.     

An Experimental 50 Mb/s Fiber Optic PCM Repeater

An experimental repeater for amplification and regeneration of 50 Mb/s fiber-optical pulses has been built and tested. For the receiver either Si p-i-n or avalanche photodiodes are used in conjunction with a high impedance FET input amplifier. The high voltage for the avalanche photodiode is generated internally and controlled by the received signal. This AGC circuit is capable of compensating for temperature changes of the avalanche gain over the range of-40 - +60degC. The optical transmitter consists of either a GaAs light emitting diode or a GaA1As laser diode coupled to optical fibers and directly modulated by a current driver with 30 percent electrical efficiency. For 10^-9error rate, the required average optical signal power for a pseudorandom signal is p-i-n diode: -41.5 dBm; avalanche diode: -56.6 dBm. The optical output power into a fiber with 1 percent index difference is LED: -17 dBm; GaAlAs laser: 0 dBm. The repeater power requirement is about 2 W.     

X波段单片集成低噪声接收子系统

报道一种新型 X波段 0 .2 5 μm PHEMT全单片集成低噪声子系统。该子系统由开关衰减电路、采样检波电路和低噪声放大器三部分组成。开关插入损耗仅 0 .5 d B,放大器噪声系数小于 1 .5 d B。当开关控制电压为-2 V,输入电平 <-7d Bm时 ,此系统相当于一个低噪声放大器。在 8.5～ 1 0 .5 GHz频率内 ,整个系统增益大于2 4d B,噪声系数小于 2 .0 d B,输入输出 VSWR<1 .5 ;但当输入电平 >-7d Bm时 ,采样检波电路开始工作 ,打开主放大器前的开关衰减器 ,限制输入功率进入 LNA。输入功率越大 ,反射越大。在开关控制电压为 +2 V时 ,无论输入功率多大 ,开关关闭通道     

Low-noise Pr3+-doped fluoride fibre amplifier

The authors have constructed a Pr³⁺-doped fluoride amplifier (PDFA) module pumped by an Nd-YLF laser. The maximum signal gain and noise figure were 20 dB and 5 dB respectively. An output power of 19.2 dBm was achieved at an input signal power of 11.0 dBm. It was confirmed that this PDFA module has low-noise characteristics from experimental results on its use in a subcarrier multiplexed multichannel AM-VSB video signal transmission     

一种带功率检测和自适应偏置的CDMA功率放大器

设计了一款包含功率检测和自适应线性化偏置电路的CDMA功率放大器,功率检测器能根据输入信号的大小来调整功率管的偏置点,大幅提升低功率输出时的效率,从而提升系统整体效率;自适应线性化偏置能有效抑制功率放大器的增益压缩和相位失真,改善其线性度.采用2 μm InGaP/GaAs HBT晶体管工艺成功流片,测试结果表明,与普...