摘要：A voltage-controlled oscillator（VCO） with dual stages of accumulation mode varactors for a multimode global navigation satellite system（GNSS） application,which adopts sigma-delta fractional-N technology in the synthesizer,is *** structure is selected to optimize the frequency coverage and tuning linearity, based on a general analysis of the parasitic capacitance in the coarse tuning switch bank cells,which cover the global positioning system（GPS） and Beidou（BD） *** VCO implemented in the 0.18μm CMOS process can cover the GPS L1,BD B1,B2 and B3 bands with sufficient margin,and exhibits low phase noise by using this tuning curve linearization *** equalized K_（vco）,characteristic behavior further offers a wide voltage tuning range and improves the stability of the closed loop.

摘要：83-nm T-shaped gate InP-based In0.52Al0.48As/In0.65Ga0.35As pseudomorphic high electron mobility transistors （PHEMTs） with excellent DC and RF performance as well as low noise characteristics are reported, including a maximum saturation current density/ass of 894 mA/mm, a maximum extrinsic transconductance gm, max of 1640 mS/mm, an extrapolated cutoff frequency ft of 247 GHz and a maximum oscillation frequency fmax of 392 GHz which were based on the measured S-parameters from 1 to 110 GHz. The minimum noise figure （NFmin） measured by the cold-source method is 1 dB at 30 GHz associated with a gain of 14.5 dB at Vds of 0.8 V and Ids of 17 mA. These results were obtained by the combination of increased InAs mole fraction in the channel, gate size scaling, parasitic reduction and the quantization channel. These excellent results make it one of the most suitable devices for millimeter wave （MMW） low noise applications.

摘要：A 72 mW highly integrated dual-channel multimode GNSS（global navigation satellite system） receiver with aΣ△fractional-N synthesizer which covers GPS L1 and the Compass B1/B2/B3 band is *** chip was fabricated in a TSMC CMOS 0.18μm process and packaged in a 48-pin 3×3 mm^2 land grid array chip scale *** work achieves NF≤5.3 dB without an external LNA,channel gain = 105 dB for channel one （Compass B2 and B3 band）,and channel gain = 110 dB for channel two（GPS L1 and Compass B1 band）.Image rejection（IMRR） = 36 dB,phase noise is -115.9 dBc @ 1 MHz and -108.9 dBc @ 1 MHz offset from the carrier for the two channels *** the low power consumption,multibands of GNSS are compatible in one chip, which is easy for consumers to use,when two different navigation signals are received simultaneously.

摘要：A complex-coupled DFB laser with sampled grating has been designed and fabricated. The method uses the ＋ 1 st order reflection of the sampled grating for laser single-mode operation. The typical threshold current of the sampled grating based DFB laser is 25 mA, and the optical output is about 10 mW at the injected current of 100 mA. The lasing wavelength of the device is 1.5385 μm, which is the ＋1 st order wavelength of the sampled grating.

摘要：In this paper, a numerical simulation of the traditional graded distributed Bragg reflector (DBR) and a design of the novel DBR with short period superlattices (SPSs DBR) used by vertical cavity surface emitting laser (VCSEL) are reported. First, the optical characteristic matrix of the graded DBRs is derived using the theories of thin film optics. Second, its reflective spectrum is numerical simulated and it is found that the simulative results are similar with the experimental data. The difference of the cavity mode position between the experimental and simulative data is discussed. Finally, based on the simulative results of graded DBR, a novel DBR with 4.5-pair GaAs/AlAs SPSs is designed, and its reflective spectrum is numerical simulated and analyzed.

摘要：90-nm T-shaped gate InP-based In_（0.52）Al_（0.48）As/In_（0.6）Ga_（0.4）As pseudomorphic high electron mobility transistors were designed and fabricated with a gate-width of 2×30 μm,a source-drain space of 2.5 μm,and a source-gate space of 0.75 μ***,RF and small-signal model characterizations were *** maximum saturation current density was measured to be 755 mA/mm biased at V_（gs）=0.6 V and V_（ds）=1.5 *** maximum extrinsic transconductance was measured to be 1006 mS/mm biased at V_（ds）=—0.1V and V_（ds）=1.5 *** extrapolated current gain cutoff frequency and maximum oscillation frequency based on S-parameters measured from 0.5 to 110 GHz were 180 and 264 GHz,*** inflection point（the stability factor k=1）where the slope from-10 dB/decade（MSG） to-20 dB/decade（MAG） was measured to be 83 *** smallsignal model of this device was also established,and the S-parameters of the model are consistent with those measured from 0.5-110 GHz.

摘要：报道了采用MBE外延生长方法制备的叠层阵列CW工作型高功率半导体激光器。激光器的生长结构采用经过优化的单量子阱渐变折射率分别限制波导结构 ,激光器芯片结构为标准的CM条 ,注入因子设计为 6 0 %。叠层装配采用了具有高效散热能力的水冷结构。经初步测试 ,叠层器件的阈值电流为 12A ,直流 30A驱动电流下的输出功率达 40W ,斜率效率为 2 2W /A。器件中心激射波长为 810nm ,光谱宽度 (FWHM )为 6nm。

摘要：系统设计师转向串行通信策略,以提高条件恶劣的工厂或工业环境下自动化设备设计的可靠性,延长其服务寿命。

摘要：随着负载电流、存储容量和控制带宽的增长,在功率转换设计中实现全方位保护已成为首要考虑因素。本文从电源保护中最常见的过电流、过电压和过热保护入手,介绍了如何用新技术解决上述问题。

摘要：使用具有超高性能和超小封装尺寸的可设置增益仪表放大器简化您的设计;DC耦合VGA集成无与伦比的增益和带宽为高电压和宽温度范围应用提供灵活性;适合高DC精度应用的16V精密运算放大器系列;