C波段单片有源环行器基本单元的研究

本文分析和研究了微波有源环行器所用的基本单元电路——放大器和定向耦合器.利用微波CAD欢件完成了放大器、定向耦合器和有源环行器的设计.模拟分析得出:在3.8～4.2GHz频率范围内,单片放大器的正向增益是6dB.反向隔离度为22dB:单片定向耦合器的正向插入损耗是4dB,反向隔离度为18dB.该有源环行器的隔离度是19dB,正向插损是5dB.实验结果为:放大器在3.5～4.0GHz频率范围内,正向增益是4.5dB,反向隔离度是23dB;定向耦合器在3.2～3.8GHz频率范围内,正向插入损耗是8dB,反向隔离度为23dB.     

Two-Tone and Nine-Tone Excitations in Future Adaptive Predistorted Linearised Basestation Amplifiers of Cellular Radio

Linearisation of a radio basestation amplifier using a third order, a fifth order and a seventh order predistortion scheme is studied. Adaptive predistortion using a third order predistorter improved the amplifier intermodulation distortion (IMD) by between 6.4 dB and 33 dB from the third IMD power level (i.e., maximum power amplitude variation of the IMD), provided by the raw amplifier, as measured by a two tone test. The variation in improvement is due to changes in the input power level. Improvement increases as the input power is backed off from the 1 dB compression point. A fifth order predistorter will give an IMD improvement of 8.7 dB and 48.4 dB if properly adjusted. A seventh order predistorter (with the fifth complex coefficient fixed to zero) will show the best performance, particularly throughout a window (approximately from 1.5 dB to 3 dB away from the 1 dB compression point). The IMD improvement throughout this window within the high input range measures between 9.1 dB to 21.7 dB over that achieved with a fifth order predistorter. For a nine-tone test (with uniformly distributed random phase), a third order predistorter will hardly improve the worst IMD power level, provided by the raw amplifier. A fifth order predistorter, if properly adapted will give an IMD improvement of between 8.8 dB and 41.5 dB from the worst IMD level while a seventh order predistorter will give a close performance to that of a fifth order one. Fixing the predistorter coefficients enables a comparative study of the IMD power level improvement between 5th order fixed and adaptive predistorters, for a nine-tone excitation. A 5th order predistorter with its coefficients fixed to those values obtained for optimum IMD level at a backed-off power input value of 8.5 dB from the 1 dB compression point is found to maintain an IMD power variation better than 55 dB from fundamental power level, throughout the input range, up to the backed-off value.     

A low phase shift attenuator

A PIN diode attenuator with an average of 0.25°/dB phaseshift between 2.5 GHz and 5.3 GHz has been modelled and constructed. In particular the attenuator has similar phase at 0 dB and 12 dB of attenuation to within 0.5° over most of the band. The input match is better than 10 dB over the attenuation range of 0 to 10 dB     

6～18GHz宽带正交混频器

介绍了一种6～18GHz小型化正交混频器。该正交混频器在所要求的频率范围内达到以下性能指标：变频损耗优于10dB,典型值8dB;镜像抑制度优于18dB,典型值25dB;LO到RF、RF到IF的隔离优于25dB,LO到IF的隔离优于20dB,典型值均为30dB。同时,测试结果表明该混频器具有良好的可靠性和一致性。     

High performance ion-implanted low noise GaAs MESFET's

Low noise GaAs MESFET's fabricated by ion-implanting into AsCl3VPE buffer layers have demonstrated not only excellent dc and RF performance, but also a highly reproducible process. The average noise figure and associated gain of four device lots at 12 GHz are 1.6 dB and 10.0 dB, respectively. The standard deviation of noise figure and associated gain from device lot to lot are 0.03 dB and 0.19 dB, respectively. And the standard deviation of noise figure and associated gain from device to device for 35 devices over four lots are 0.13 dB and 0.47dB, respectively. The best device performance includes a 1.25 dB noise figure with 10.46 dB associated gain at 12 GHz for a 0.5 µm × 300 µm FET structure. These results demonstrate the excellent performance and process consistency of ion implanted MESFET's.     

First heterodyne receiver frontend module including a polarizationdiversity receiver OEIC on InP

For the first time a packaged polarization diversity coherent receiver OEIC including detector units (photodetectors, JFET, load resistor) has been fabricated with the following data: waveguide loss 2 dB, 3 dB balance within 0.4 dB, polarization extinction >30 dB (TM) and >17 dB (TE), 3 dB cutoff frequency of 0.9 GHz, common mode rejection ratio 30 dB     

Wideband Bandpass Filter With Reconfigurable Bandwidth

this letter proposes a novel building block for developing tunable wideband bandpass filters. The proposed circuit block mainly consists of short circuit coupled lines and short circuit stubs with pin diodes as tuning elements. This work aims to demonstrate reconfigurable bandwidth of this type of filter. Two filters are designed and fabricated; one can be switched between a fractional bandwidth (FBW) of 16.3% and 35% at a center frequency of 1.9 GHz, and the other can be switched from a FBW of 27.8% to 37.4% at a center frequency of 1.9 GHz. The insertion loss and return loss in the first filter range from 4.17 dB to 0.4 dB and 27.54 dB to 19.04 dB. The second filter exhibits an insertion loss ranging from 0.73 dB to 0.43 dB and a return loss range from 31.1 dB to 27.7 dB. The tested filters show good agreement with EM simulations.      

F.E.T. mixer with the drain l.o. injection

Performance of a 6/4 GHz frequency convertor showed conversion gains up to 4.7 dB with 3.9 dB noise figure. On cooling to 200 K, a gain increase of 2.4 dB and a noise-figure decrease of 1.8 dB were measured.     

High-performance GaAs switch IC's fabricated using MESFET's withtwo kinds of pinch-off voltages and a symmetrical pattern configuration

GaAs MESFET switch IC's operating at low control voltages of 0/-3 V and +3/0 V have been developed for use in Personal Handy Phones using the 1.9 GHz band. The switch IC's have excellent RF characteristics, and have no need for external circuit installation. The unique points of these IC's are the use of GaAs MESFET's with two kinds of pinch-off voltages and a symmetrical source and drain pattern configuration with respect to the gate. The 0/-3 V IC had low insertion loss of 0.55 dB and 0.65 dB, and high isolation of 31 dB and 24 dB at receiving and transmitting operations, respectively. The +3/0 V IC also had excellent characteristics such as insertion loss of 0.73 dB and 0.95 dB, and isolation of 27 dB and 23 dB, respectively. Both IC's had an output power at 1 dB gain compression point of 25.4 dBm and 3rd order intercept point of more than 46 dBm     

High-gain mode-adapted semiconductor optical amplifier with12.4-dBm saturation output power at 1550 nm

A mode-adapted semiconductor optical amplifier (SOA) has been fabricated and packaged. At the gain peak, 1500 nm, the fiber to fiber gain was measured to be 32.5 dB. Statistics for eight packaged devices indicate that a fiber-to-fiber gain of 26.3 dB ± 1.3 dB and a saturation output power of 12.4 dBm ± 0.4 dBm are typical at a bias of 500 mA for λ = 1550 nm. Polarization sensitivity at 1550 nm was measured to be 1.1 dB ± 0.4 dB and the transverse electric (TE) polarization state noise figure (NF) was determined to be 7.0 dB ± 0.5 dB. The coupling loss was 1.3 dB ± 0.1 dB per facet. This SOA, with a 1.3-nm filter, was used as an optical preamplifier in a 10-Gb/s return-to-zero (RZ) system testbed with a pseudorandom binary sequence (PRBS) of 2³¹ -1. A 14.5-dB improvement in receiver sensitivity was observed at a bit error rate (BER) of 10^-11     

Polarisation insensitive 1.55 mu m semiconductor integrated optical amplifier with access waveguides grown by LP-MOCVD

A 1.55 mu m GaInAsP/InP optical amplifier integrated with access waveguides provides 0 dB fibre to fibre gain at only 47 mA bias current and a 5 dB saturation gain already high enough to design 0 dB integrated complex circuits. Polarisation gain dependence and gain ripple are less than 0.5 dB and 0.7 dB, respectively.<>     

84 dB 5.2 mA digitally-controlled variable gain amplifier

A digitally-controlled topology that reduces power dissipation to half that of the conventional one while occupying smaller die area and obtaining higher linearity is presented. In the 0.13 mum CMOS process, the VGA occupies an active area of 0.46 mm² and dissipates an average current of 5.2 mA at 1.5 V. The gain-variation range is -32 to 52 dB with a gain error of less than plusmn1 dB. The IIP3, P1 dB, NF at 52 dB of gain, and 3 dB bandwidth are -37 to +13 dBm, -42 to -2 dBm, 6.2 dB and 200 MHz, respectively.     

Extinction ratio improvement using the nonlinear optical loopmirror

We have investigated the nonlinear optical loop mirror operating as an extinction ratio (ER) improvement device. ER improvement and bit-error-rate measurements were made in a polarization insensitive mode. An ER of 3.8 dB can be improved to 10.8 dB with an improvement of the receiver power penalty from 4.1 dB to 1.6 dB     

基于SiGe工艺的高增益射频功率放大器

基于0.13μm SiGe HBT工艺,设计应用于无线局域网(WLAN)802.11b/g频段范围内的高增益射频功率放大器.该功放工作在AB类,由三级放大电路级联构成,并带有温度补偿和线性化的偏置电路.仿真结果显示:功率增益高达30dB,1dB压缩点输出功率为24dBm,电路的S参数S11在1.5～4GHz大的频率范围内均小于-17dB,S21大于30dB,输出匹配S22小于-10dB,S12小于-90dB.最高效率可达42.7%,1dB压缩点效率为37%.     

数字硅MOSFET微波特性的研究

利用国内先进的 0 .6μm数字 Si-MOS工艺 ,设计了射频 MOSFET,并研究了其 DC和微波特性 :I-V曲线、S参数、噪声参数和输出功率。研究发现 ,数字电路用 Si MOSFET的频率响应较高 :频率为 1 GHz时功率增益可达 1 0 d B,2 GHz时为 8d B,4GHz时为 5 d B。 1 .8GHz时 ,1分贝压缩输出功率 1 2 .8d Bm,饱和输出功率可达 1 8d Bm,且最小噪声系数为 3 .5 d B。用提取的参数设计并研制了微波 Si MOSFET低噪声放大器 ,以验证MOS器件的微波性能。此放大器由两级级联而成 ,单电源供电 ,输入输出电容隔直。在频率 1 .7～ 2 .2 GHz的范围内 ,测得放大器增益 1 5± 0 .5 d B,噪声系数 N F<3 .8d B,1分贝压缩输出功率 1 2 d Bm;在频率 1 .5～ 2 .5 GHz的范围内 ,放大器增益大于 1 3 d B。     

Performance of Pr-doped fluoride fibre amplifier for multichannel AM-VSB transmission

The system performance of a Pr-doped fluoride fibre amplifier was examined for multichannel AM-VSB video signal transmission for the first time. For a CNR of 51 dB, a loss budget of 15.1 dB was obtained with the amplifier, and for a CNR of 46 dB, the loss budget was expanded to 20.1 dB.<>     

低频高阻带抑制SAW有源滤波组件

介绍了一种低频高阻带抑制SAW有源滤波组件的设计方法，并介绍了最新研制的滤波组件的性能。其中心频率18MHz，通带波动0.5dB，近端阻带抑制达105dB，远端阻带抑制大于95dB（其中三次谐波抑制大于75dB)，增益8dB。     

GaAs衬底共面波导S参数标准样片研制

GaAs等固态微波裸芯片电性能测试需要采用探针将共面波导参考面过渡到同轴参考面。设计制作了用于微波探针校准的GaAs衬底的计量级标准样片,包括SOLT 和TRL 校准模块,以及匹配传输线、衰减及驻波等验证模块。提出了平衡电桥结构,兼具衰减驻波标准,带内平坦,且工艺适应性好。经过与国外校准片比对,验证了频率覆盖100 MHz ~50 GHz,驻波比测量范围:1.1,1.5,2.5,5,10;衰减测量范围:-1 dB,-2 dB,-3 dB,-10 dB,-20 dB,-30 dB,-40 dB;匹配负载反射损耗小于-30 dB。同时提取了SOLT校准模块的矢网校准用参数。     

Resonant-grid quasioptical diplexer

Measurements on a polarisation independent-resonant-grid diplexer are described. The grid transmits the 13·5 to 19 GHz band (loss < 1 dB). It reflects the 23 to 36 GHz band (loss < 1 dB) at an angle of 40° to the incident beam. Peak rejections exceed 44dB. Crosspolarised components are below 30dB.