High resolution absolute frequency measurement of rotational transition 195,15 ← 184,14 in sulphur dioxide SO2 at 820 GHz

A submillimeter spectrometer using the concept of generating continuosly tunable difference-frequency sideband by beating the HCN laser radiation and millimeter wave klystron radiation in the non-linear Schottky barrier diode has been developed for the accurate frequency measurement on³²S¹⁶O gaseous sample at 820.151 GHz. The strength of the reradiated signal has been investigated as a function of generating laser and klystron power as well as of the d.c. bias applied externally to the diode.     

Fabrication and performance of GaAs p+n junction and Schottky barrier millimeter IMPATT's

A recently developed procedure, incorporating both preferential electrochemical etching for wafer thinning and electroplating for heat sink formation has been applied to the fabrication of Kaband (26.5-40 GHz) GaAs IMPATT's. Both epitaxially grown GaAs p⁺n junction and Cr Schottky barrier diodes have been fabricated. This procedure makes possible the batch fabrication of small area diodes (<2 times 10^{-5}cm²) over a large wafer area. The diodes have been operated both in the oscillator and stable-amplifier mode. Power, efficiency, and noise performance of the devices is reported. The p⁺n diodes, which could withstand junction temperature of over 300°C, gave the best power and efficiency. Powers as high as 680 mW with 12.4 percent efficiency at 34.8 GHz and an efficiency as high as 16 percent with 390 mW at 29.5 GHz have been achieved. The Cr Schottky diodes were unable to withstand junction temperatures in excess of 200°C and therefore produced less power despite the potentially better power handling capability. The highest power obtained from a Cr Schottky is 470 mW with 12.5 percent efficiency at 34 GHz. Comparable oscillator noise performance has been obtained with both types of diode. The best AM (DSB) double sideband NSR obtained is -135 dB in a 100 Hz window at 1.5 MHz from the carrier. An rms frequency deviation as low as 13 Hz in a 100 Hz window has been observed with a power output of 164 mW at 35.4 GHz by raising the external Q to 138. A lowest FM noise measure of 23 dB was achieved by reducing output power to 16 mW. The amplifier noise figure measured for both p⁺n and Cr Schottky diodes is 26 dB.     

(英) 基于石英基片工艺的D频段平衡式二倍频器设计

设计了一款D频段基于商用平面肖特基二极管DBES105a以及石英基片的二倍频器.通过对传统的用于平衡式混频器及倍频器的鳍线/悬置微带线巴伦耦合器进行改进,提出了一种方便为肖特基二极管外加偏置的平衡式倍频结构.首先,提出了一种适用于石英基片的波导/鳍线过渡结构,并且通过仿真及实验对该结构进行了验证,测试结果表明,这种过渡结构的损耗只有0.15 dB.在驱动功率为26.3 mW、外加反偏电压为0.4 V时,倍频器的测试最大输出功率为3.39 mW,对应倍频效率为12.9%.在外加偏置电压偏离最佳偏置点时,倍频器的输出功率从3.1mW降低到2.0 mW.这也说明:为了达到最大倍频输出功率,也需要为肖特基变阻二极管倍频器提供外加直流偏置.     

0.2 THz二倍频器研究

基于六阳极结反向串联型GaAs平面肖特基二极管,设计并实现了0.2 THz大功率二倍频器。肖特基二极管倒装焊接在50m石英电路上。采用电磁场和电路联合设计仿真获得了二倍频器的倍频效率。当入射功率在100 mW时,输出频率在190~225 GHz带内效率大于5%。在小功率（Pin100 mW）和大功率（Pin300 mW）注入条件下,测试了倍频电路的输出功率和倍频效率。在100 mW驱动功率下采用自偏压测试,最大输出功率为14.5 mW@193 GHz,对应倍频效率为14%;在300 mW驱动功率下采用自偏压测试,在188~195 GHz,输出功率大于10 mW,最大输出功率为35 mW@192.8 GHz,对应倍频效率为11%。     

Frequency-doubled monolithic master oscillator power amplifierlaser diode

Single-pass frequency doubling of laser diodes extends the wavelength range of infrared laser diodes to blue-green wavelengths. We describe the first experiments of frequency doubling of a coherent, high-power, monolithic master oscillator power amplifier (M-MOPA) laser diode. The output from a l-W M-MOPA is frequency doubled in a single pass through an 8.2-mm-long KNbO₃ crystal. We obtained 3.7-mW diffraction-limited output power at a wavelength of 491 nm and modulation at 20 MHz was demonstrated     

基于肖特基二极管的反射式可调预失真电路

为解决传统反射式预失真电路可调性不高、对功率放大器的邻信道泄漏比(ACLR)改善量小的问题,文 中提出了一种基于肖特基二极管的反射式可调模拟预失真电路。该电路由90°电桥、肖特基二极管以及偏置电路组 成。每条支路采用两个并联肖特基二极管产生非线性信号,以抵消功放的非线性失真。每一个肖特基二极管都有独立 的偏置电路,从而可以增加电路调节的自由度。通过改变每个肖特基二极管的偏压,可实现更大动态范围的幅度和相 位的补偿。基于此原理加工的S 波段模拟预失真电路对中心频率为3. 5 GHz 的Doherty 功率放大器进行线性化测试, 实验结果证明:加上提出的模拟预失真电路后,在输出功率为-28 dBm 时被测功放的ACLR 改善了14. 6 dBc 以上。     

Glass reinforced GaAs beam lead Schottky diode with airbridge for millimetre wavelengths

We describe the fabrication and measurement of a glass reinforced beam lead Schottky diode with an airbridge for use at millimetre wavelengths. We report an extremely low single sideband (SSB) noise figure for these diodes of 7.9 dB at 94 GHz, including a 1.5 dH IF (30 MHz) contribution.     

A RF to DC Voltage Conversion Model for Multi-Stage Rectifiers in UHF RFID Transponders

This paper presents a RF to DC conversion model for multi-stage rectifiers in UHF RFID transponders. An equation relating the RF power available from the antenna to the DC output voltage produced by a multi-stage rectifier is presented. The proposed model includes effects of the nonlinear forward voltage drop in diodes and impedance matching conditions of the antenna to rectifier interface. Fundamental frequency impedance approximation is used to analyze the resistance of rectifying diodes; parasitic resistive loss components are also included in the analysis of rectifier input resistance. The closed form equation shows insights into design parameter tradeoffs, such as power available from the antenna, antenna radiation resistance, the number of diodes, DC load current, parasitic resistive loss components, diode and capacitor sizes, and frequency of operation. Therefore, it enables the optimization of rectifier parameters for impedance matching with a low-cost printed antenna and shunt tuning inductor, in order to improve the RF to DC conversion efficiency and the operational distance of UHF RFID transponders. Three diode doublers and three multistage rectifiers were fabricated in a 130 nm CMOS process with custom no-mask added Schottky diodes. Measurements of the test IC are in good agreement with the proposed model.      

双端抽运的30 W光纤激光器实验研究

报道了双端抽运连续输出的掺Yb^3 双包层高功率光纤激光器。实验采用了中心波长在975nm附近的两种输出形式的半导体激光器(LD)作为抽运源，测量了不同抽运条件下的输出功率特性和光谱特性。在仅尾纤输出的半导体激光器抽运下获得了斜率效率为42％，峰值波长为1103．8nm的9．2W激光输出；在仅准直输出的半导体激光器抽运下获得了斜率效率为57％，峰值波长为1104．4nm的20．0W激光输出；当两个半导体激光器在双端同时抽运时，获得光纤激光最大输出功率为30．6W，输出峰值波长为1108．4nm，以及49％的总体光一光转换效率。     

Low frequency characteristics of a quasioptical Schottky diode detector part II: Experimental results

A detailed experimental study of the low frequency (video) response of a quasioptical Schottky diode detector over the microwave and FIR wavelength range is presented. An optimization of the responsivity versus the bias current is proposed and a generalized curve of the saturation power versus the FIR wavelength is given. This curve defines for any antenna point-contact Schottky diode detector, suitable for FIR detection, the power range for a linear detector response. A simple method is also described to calculate the coupling efficiency of the laser radiation into the antenna reception pattern.     

基于肖特基势垒二极管三维电磁模型的220GHz三倍频器

采用阻性肖特基势垒二极管UMS DBES105a设计了一个太赫兹三倍频器.为了提高功率容量和倍频效率,该倍频器采用反向并联二极管对结构实现平衡式倍频.根据S参数测试曲线建立了该二极管的等效电路模型并提取了模型参数.由于在太赫兹频段二极管的封装影响到电路的场分布,将传统的二极管SPICE参数直接应用于太赫兹频段的电路设计存在一定缺陷,因此还建立了二极管的三维电磁模型.基于该模型研制出的220 GHz三倍频器最大输出功率为1.7 mW,最小倍频损耗为17.5 dB,在223.5 GHz~237 GHz输出频率范围内,倍频损耗小于22 dB.     

Monolithic watt-level millimeter-wave diode-grid frequency tripler array

Thousands of solid-state diodes are monolithically integrated by a metal grid as a highly efficient frequency multiplier which promises watt-level CW output power throughout the millimeter and submillimeter wave region. Different devices such as GaAs Schottky diode, thin MOS diode, and GaAs Barrier-Intrinsic-N⁺ diode are employed in this study. The approach also results in low-cost fabication and small-size realization.     

Frequency-shifting submillimeter single-sideband receiver

A single sideband (SSB) receiver has been developed and implemented for use with a submillimeter sideband generator. While the sideband generator emits both an upper and lower sideband, and even some unshifted laser radiation, the receiver responds to only one sideband. The operator of the system can choose which sideband to receive. Rejection of the undesired signal is accomplished through selective frequency shifting coupled with the use of a commercially available single-sideband microwave mixer.     

Performance of W-InSb Metal-Semiconductor Point-Contact Diodes as Detectors and Mixers in the Near Infrared

Metal-Insulator-Metal (MIM) and Schottky-barrier diodes have been used extensively in the past years as harmonic generators and mixers for frequency measurements in the spectral range from the far-infrared to the visible. MIM diodes present a very low fabrication cost and are easy to handle, while Schottky diodes are mechanically more stable and long-lived. In the present work we discuss the performance of a metal-semiconductor point-contact diode for the radiation around 1 μm. This device, which may be viewed as a hybrid between a MIM and a Schottky diode, combines the simplicity and easiness of fabrication of the MIM diode with the stability and the long contact life typical of the Schottky diode. It proved to be very efficient even for visible light.     

Schottky diode design for low-voltage rectification

Barrier height and impurity concentration of a power Schottky diode are optimized for maximum rectifying efficiency in DC-DC converter operation. An optimum barrier-height-impurity-concentration combination is calculated for a given output voltage and diode temperature. For a 1.5 – 2 V output converter, the optimum combination is found to be 17 kT/q and 1.5 × 10¹⁶ cm^?3. Based on the theoretical prediction, titanium- and hafnium-barrier diodes were fabricated as suitable diodes for low-voltage converters and compared with conventionally used molybdenum-barrier diodes. In the experiment on a 2-V output DC-DC converter, the new diodes show higher efficiency than molybdenum diodes at up to 85°C. They are fit for use in encapsulated converters because of their smaller heat generation.     

A Long-Range UHF-Band Passive RFID Tag IC Based on High- $Q$ Design Approach

We present a fully integrated long-range UHF-band passive radio-frequency-identification tag chip fabricated in 0.35-$muhbox{m}$ CMOS using titanium (Ti/Al/Ta/Al)–silicon Schottky diodes. The diodes showed low turn-on voltages of 95 and 140 mV for diode currents of 1 and 5 $muhbox{A}$, respectively. In addition, the Schottky diodes exhibited low-resistive loss, and a high-$Q$ -factor design approach was exploited to achieve a long read range for the tag integrated circuit (IC). An optimized voltage multiplier resulted in an excellent sensitivity of $-$ 14.8 dBm and corresponding power-conversion efficiency of 36.2% for generating an output voltage of 1.5 V at 900 MHz. The range analysis of the measured multiplier performance indicated an operating range of more than 9 m at 4-W Effective Isotropically Radiated Power reader power. The subthreshold-mode operation of an ASK demodulator allowed ultralow power operation. Under power consumption as low as 27 nW, the demodulator supported a data rate of 150 kb/s and a modulation depth of 40%. A new architecture for generating a stable system clock (2.2 MHz) for the tag IC was employed to deal with supply voltage and temperature variations. Measurements showed that the clock generator had an error of 0.91% from the center frequency owing to an 8-b digital calibration scheme.      

基于平面肖特基二极管的平衡式亚毫米波倍频器芯片

基于标准的平面肖特基二极管单片工艺设计了一款平衡式亚毫米波倍频单片集成电路。依据二极管实际结构进行电磁建模,提取了器件寄生参数,并与实测的器件本征参数相结合获得了二极管非线性模型;依据该模型,采用平衡式拓扑结构以实现良好的基波抑制,设计了三线耦合巴伦电桥,并与肖特基二极管集成在同一芯片上,实现了单片集成,提高了设计准确度。芯片在片测试结果表明,在输入功率17 dBm 下,输入频率75~105 GHz范围内,倍频器芯片峰值输出功率达到2.67 dBm。芯片整体尺寸为0.80 mm×0.50 mm。     

0.2THz宽带非平衡式倍频电路研究

基于四阳极结反向串联型GaAs平面肖特基二极管,设计并实现了0.2 THz宽带非平衡式二次倍频电路。肖特基二极管倒装焊接在75 m石英电路上。在小功率和大功率注入条件下,测试了倍频电路的输出功率和倍频效率。输入功率在10~15 mW时,通过加载正向偏置电压,在210~224 GHz,倍频效率大于3%,在212 GHz处有最高点倍频效率为7.8%。输入功率在48~88 mW时,在自偏压条件下,210~224 GHz带内倍频效率大于3.6%,在214 GHz处测得最大倍频效率为5.7%。固定输出频率为212 GHz,在132 mW功率注入时,自偏压输出功率最大为5.7 mW,加载反向偏置电压为-0.8 V时,输出功率为7.5 mW。     

A High Power 320-356GHz Frequency Multipliers with Schottky Diodes

A 320-356GHz fixed-tuned frequency doubler is realized with discrete Schottky diodes mounted on 50μm thick quartz substrate.Influence of circuit channel width and thermal dissipation of the diode junctions are discussed for high multiplying effficiency.The doubler circuit is flip-chip mounted on gold electroplated oxygenfree copper film for grounding of RF and DC signals,and better thermal transportation.The whole multiplying circuit is optimized and established in Computer simulation technology (CST) suite.The highest measured multiplying efficiency is 8.0％ and its output power is 5.4mW at 328GHz.The measured typical output power is 4.0mW in 320-356GHz.     

高效170 GHz平衡式肖特基二极管倍频器

太赫兹源的输出功率是限制太赫兹技术远距离应用的重要参数。为了实现高效的太赫兹倍频器,基于高频特性下肖特基二极管的有源区电气模型建模方法,利用指标参数不同的两种肖特基二极管,研制出了两种170 GHz平衡式倍频器。所采用的肖特基二极管有源结区模型完善地考虑了二极管IV特性,载流子饱和速率限制,直流串联电阻以及趋肤效应等特性。通过对两种倍频器仿真结果进行对比,完备地分析了二极管主要指标参数对倍频器性能的影响。最后测试结果显示两种平衡式170 GHz倍频器在155~178 GHz工作带宽内的最高倍频效率分别大于11%和24%,最高输出功率分别大于15 mW和25 mW。从仿真和测试结果表示,采用的肖特基二极管建模方法和平衡式倍频器结构适用于研制高效的太赫兹倍频器。