94 GHz phase-shift-keying modulator

This paper describes a kind of low insertion loss phase-shift-keying modulators used in 94GHz digital communications systems. A BPSK modulator with a insertion loss lower than 3.8dB has been achieved by connecting a circulator and a fin-line PIN diode phase shifter in series. The bandwidth is 2.5GHz given a phase error of ±5⁰. The circuits and experimental results are also given out.     

29 GHz E-plane biphase modulator

A biphase PSK modulator for use in 29 GHz radio equipment has been developed that gives state-of-the-art performance (less than 3 dB insertion loss across 7% bandwidth, including transition losses, and 70/100 Mbit/s data rate using PIN diodes as the switching elements). A drive amplifier has been developed for use with the modulator that allows beam lead PIN diodes with a long minority carrier lifetime to be used in the circuit up to 70 Mbit/s.     

Digital-to-RF conversion for a vector modulator

Digital technology lacks sufficient speed to support many high data rate applications at microwave frequencies. This is unfortunate since areas such as higher order modulation, predistortion, equalization, and demodulation could benefit in flexibility, modularity, and performance from digital architectures. However, use of radio frequency microwave technology permits the implementation of digital functions at these higher speeds and frequencies. This paper describes the implementation of a nonrecursive (finite-impulse response) filter in microwave technology     

110 GHz GaAs FET oscillator

A W-band GaAs FET oscillator has been demonstrated for the first time. A 75 ?m gate width device with sub-half-micrometre (0.2 ?m) electron-beam defined gates was used as a common-gate oscillator for operation in the 70 to 110 GHz frequency range. The highest oscillation frequency achieved was 110 GHz.     

A 110 GHz SIS receiver for radio astronomy

A 110 GHz superconductor insulator superconductor (SIS) tunnel junction receiver has been developed and used in regular astronomical observations on the 4m radio telescope at the Department of Astrophysics, Nagoya University. The SIS junction consists of a sandwich structure of Nb/AlOx/Nb, and is cooled to 4.2K with a closed cycle He-gas refrigerator. The receiver exhibits a best double side band noise temperature of 23±2 K at 110GHz. Additional measurements at 98–115 GHz indicate that the receiver has a good response over this input frequency range.     

Shifted-quadrant microwave vector modulator

A technique is presented whereby a four-quadrant microwave vector modulator can be realised using just two variable gain amplifiers or attenuators. This would normally produce only a single quadrant, so the technique uses a third, fixed, vector to shift the constellation and centre it on the origin. The technique has been demonstrated experimentally at 2 GHz using modular components.     

5.5 GHz multiple quantum well reflection modulator

The authors report the fabrication and operation of a high-speed reflection modulator using the quantum-confined Stark effect in GaAs quantum wells grown over a dielectric mirror. The modulator has a 5.5 GHz 3 dB response.<>     

0 to 3 GHz traveling-wave electrooptic modulator

A report is given on the construction and testing of a traveling-wave electrooptic modulator that requires a nominal 5-watt drive power to obtain 30 percent amplitude modulation from 0 to 3-GHz. The modulator employs potassium-dihydrogen-arsenate crystals and has been tested at 6328 Å with CW drive power.     

Microwave photonic vector modulator for high-speed wireless digitalcommunications

The authors present the design, realization, and experimental results of a microwave/photonic circuit suitable for high-speed direct digital modulation of microwave signals. The modulator employs a combination of microwave, photonic, and digital techniques to produce a discrete phase and amplitude (i.e., vector) modulated carrier signal. The proof-of-concept demonstration presented in this paper was performed using a carrier frequency of 1 GHz and supports BPSK, QPSK, and 16-QAM. The authors also discuss ways to modify the modulator to simultaneously achieve data rates on the order of several hundreds of Mbs and wideband frequency hopping     

Low-loss sapphire waveguides for 75-110 GHz frequency range

Low-loss dielectric waveguides are promising for use instead of metal ones, but problems in transitions have to be overcome. A simple and effective structure made of a monocrystalline sapphire waveguide has been designed. Experimental results at 75-110 GHz indicate good matching with metal waveguides (VSWR ⩽1.13) and low insertion loss (0.05-0.35 dB for 47 mm dielectric section)     

Rainfall attenuation at 110 and 890 GHz

Attenuation due to rainfall has been compared at 110 and 890 GHz over a 180 m path in the free atmosphere. It was found that the attenuation at 890 GHz is, on average, 25% higher than that measured at 110 GHz.     

110 GHz带通太赫兹滤波器设计

对滤波器的高精确度理论设计及小误差的工艺实现进行探讨与设计加工。总结了国内外的多种设计经验,讨论了多种类型的滤波器设计方案,选取适当的滤波器结构形式,设计加工了110 GHz的感性窗耦合波导滤波器,其中感性窗耦合结构采用传统机械加工技术实现,与法兰盘结构一并集成。基于高频结构仿真(HFSS)软件进行仿真,结果表明：设计并制作的110 GHz带通滤波器,其中心频率为110 GHz,相对带宽为5%,插入损耗小于1 dB,带内回波损耗大于 20 dB,距中心频率2倍带宽处,带外抑制大于40 dB。     

New methodology for adaptive vector quantisation

An image sequence coding scheme for low bit-rate video coding is presented. A new methodology is proposed for adaptive vector quantisation (AVQ), where the codebook is updated with new code-vectors. The new code-vectors replace less significant ones in the codebook, based on a novel scoring criterion that utilises a forgetting factor and codebook half-life. The proposed AVQ method gives rise to an additional performance enhancement of approximately 1 dB over frequency scoring techniques     

Low cost wideband I-Q vector modulator

One of the applications of QPSK modulators is to control the amplitude and phase of an RF signal, working as a vector modulator. Recently there are several monolithic commercial circuits that can be easily used to frequencies of >4 GHz. First, the input signal must be decomposed into two quadrature components, which is usually done in a 3 dB 90° hybrid coupler. Using microstrip techniques, this I-Q vector modulator exhibits narrowband characteristics, due to the degradation of the hybrid performances with frequency. The authors show how the working bandwidth can be extended up to an octave by means of a versatile control system as described here, as an alternative to a new design of the RF stage     

40 GHz optical pulse generation using sinusoidally-driventravelling-wave electroabsorption modulator

Optical pulse generation at a 40 GHz repetition rate using a sinusoidally-driven high-modulation-efficiency travelling-wave electroabsorption modulator is reported. Travelling-wave behaviour is demonstrated by comparing the pulse generation in the co- and counter-propagation configurations and confirmed by a theoretical model     

石墨烯太赫兹调制器及330 GHz无线通信系统

现有太赫兹无线通信系统通常采用微波倍频或直接调源的方式。本文从太赫兹波空间调制技术出发,研究了一种基于直接调制技术的太赫兹无线通信系统。重点探索了一种基于石墨烯/半导体硅的复合结构(GOS),研究出调制速率达到1 MHz,调制深度50%以上,工作频带覆盖0.2 THz~2 THz频段的新型全光学太赫兹调制器。在此基础上,构建了330 GHz载波频率的太赫兹无线通信系统,实现了1 Mbps的通信速率。     

CMOS and SiGe bipolar circuits for applications up to 110 GHz

Recently, CMOS has been demonstrated to be a viable technology for very-high-bit-rate broad-band and wireless communication systems up to 40 Gb/s and 50 GHz. Advances in device scaling and doping-profile optimization have also resulted in SiGe bipolar transistors with impressive performance, including cut-off frequencies of more than 200 GHz. This paper presents advances in circuit design which fully exploit the high-speed potential of a 0.13 µm CMOS technology up to 50 GHz and of a high-performance SiGe bipolar technology up to 110 GHz operating frequency. The combination of advanced circuit techniques and a state-of-the-art fabrication-process technology results in continuing the upward shift of the frequency limits.     

110 GHz gyrotron with a built-in high-efficiency converter

A 110 GHz 1 MW pulse gyrotron has been elaborated. A built-in electrodynamic duct consisting of a new type quasi-optical converter and three matching mirrors transforms operating mode TE_15,4 into a gaussian beam going through the output window. The efficiency of the duct (ratio of the gaussian beam power outside the gyrotron to the total microwave power at the output of the cavity) is about 95%. A system consisting of the gyrotron and an outer mirror transmission line is proved to have efficiency (ratio of the microwave power measured by calorimeter at the end of line to the power of the electron beam) more than 40%.     

0.1 - 110 GHz在片去嵌技术

研究了0.1 - 110 GHz S参数在片去嵌技术,给出了输入、输出端口非对称下的直通-反射-传输线（TRL）和传输线-反射-匹配（LRM）的去嵌算法求解结果。在 InP衬底上设计了TRL和LRM去嵌标准件,采用两种无源元件验证了去嵌结果的正确性,并且对TRL和LRM在0.1-110 GHz范围内的去嵌准确性进行对比。通过在0.1 - 40 GHz运用 LRM方法,和在75 - 110 GHz运用TRL方法,获得了有源器件HBT两频带内的本征S参数,并对去嵌前和去嵌后提取的小信号电流增益及单向功率增益进行对比。通过插值,可得出待测件0.1 - 110 GHz完整的S参数。     

Tropospheric emission and attenuation statistics at 110 GHz

The probability distribution of atmospheric emission noise from the zenith at 110 GHz has been measured by a radiometer at Slough, UK. The derived attenuations in the vertical direction exceed 13 and 6 dB for 0·5 and 5% of the time, respectively.