High performance oscillator with 2-mW output power at 300 GHz

Material structures and device structures of a 100-GHz InP based transferred-electron device are designed in this paper. In order to successfully fabricate the Gunn devices operating at 100 GHz, the InP substrate was entirely removed by mechanical thinning and wet etching. The Gunn device was connected to a tripler link and a high RF(radio frequency)output with power of 2 mW working at 300 GHz was obtained, which is high enough for applications in current military electronic systems.     

Experimental investigation of millimeter wave Gunn oscillator circuits in circular waveguides

Millimeter wave Gunn oscillator circuits using circular waveguides for 33–50 GHz and 75–110 GHz frequency bands are described. These oscillators are simpler to construct at millimeter wavelengths compared to the conventional rectangular waveguide circuits. The effect of various circuit parameters on the oscillator frequency and output power has been experimentally studied. The CW power and mechanical tuning range obtained from the circular waveguide Gunn oscillators are found to be comparable and sometimes even better than those obtained with conventional rectangular waveguide circuits using the same Gunn device.     

Low noise oscillator approaches at 140 GHz

Conclusion It was demonstrated that approaches towards oscillators with sufficient noise performance familiar up to frequencies of 100 GHz can be applied at 140 GHz with only minor modifications.Mostly due to the limitations imposed by the available InP Gunn diodes the power levels reached with second harmonic mode operation were less than at 94 GHz with GaAs devices. The two approaches employing IMPATT diodes deliver substantial output power at D-band. Which one is preferrable will be dependent on the application.     

Optimized design of quasi-optical source-array of solid state source power combiner at frequency 100 GHz

It is determined for the structure of the source-array located in inner surface of input quasi-optical resonator operating at frequency 100GHz using Type WT5731 GaAs Gunn diodes made in P.R. China (fundamental frequency 50 GHz). An adaptable phase coupling has been achieved and RF output power exceeded the sum of the individual diode outputs by from three to seven times.     

W-band 1/3 frequency dividers

In this article the theoretical and experimental performances of a Gunn harmonically synchronized frequency divider are presented. The results show that such a divider has a 96-32GHz division, with 15-mW output power over the operating band greater than 1400MHz at 10-mW input power level.     

A polystyrene cap for matching a silicon lens at millimeter wavelengths

A polystyrene cap for a silicon lens has been fabricated by thermal molding. The cap is 0.5mm thick, and it acts as a quarter-wave matching layer at 94GHz. The measured performance from 75GHz to 170GHz agrees with theory. The reflection loss at 94GHz is reduced by 1.5dB. This is an economical way to make a millimeter-wave anti-reflection coating. This makes a monolithic circuit with a gallium-arsenide substrate and a silicon lens much more attractive than before. The total absorption and reflection loss for a linch diameter lens with the cap should be 1.1dB.     

One-Circuit Stabilization of Millimeter-Wave Solid-State Oscillator by Quasi-Optical Resonator

The construction and operating characteristics of the highly stabilized millimeter wave IMPATT oscillator are described. The frequency stability is 8.1 × 10^-7 at 115 GHz. The output power is no less than 15 mW. The sphere-corner-echelette open resonator have been used for oscillator stabilization. This approach is also adaptable to the Gunn oscillator.     

A global optimization design for quasi-optics power combiner of 3mm wave solid-state sources

This paper describes a global optimization design for quasi-optics power combiner of solid-state millimeter-wave sources. The operating frequency is about 100 GHz and the oscillating sources are GaAs Gunn diodes. The source-array plane is a matrix consisting of NxN (N=3,5, ..., 2k+1, where k is positive integer) diodes. The radio frequency power of the combiner is from threefold to sevenfold larger than the sum total of the single diodes power. The global optimums of the array and the location in the cuvity of the suorce-array plane will be given by a global optimizition method.     

A 492 GHz Submillimeter-Wave Receiver

A 492 GHz submillimeter receiver was designed for application to the POrtable Submillimeter Telescope (POST). The receiver includes a Schottky diode mixer, a phase-locked Gunn oscillator at 82.3 GHz coupled with multipliers (×2×3), and low-noise amplifiers. In this paper, the system configuration and performance will be introduced.     

Thermistor controlled gunn oscillator at Ka-band

Frequency drift of Gunn oscillators is a major cause of concern in most of the Millimeter wave communication systems. This paper describes a simple and cost effective technique to arrest the frequency drift of a Ka band Gunn oscillator within 15 MHz for the operating temperature range of 0°C to 60°C as against a typical drift of about 50 to 100 MHz for free running Gunn oscillator for the same temperature range. At the ambient, the oscillator remains within ±1 MHz from switching on to stabilization. The temperature variation is sensed with a small thermistor bead placed close to the diode and a correction voltage is applied to the bias to compensate for the frequency drift. This compensation circuit also takes into account the non-linear behaviour of the thermistor and the Gunn oscillator with the temperature.     

Electron spin-echo spectroscopy at 95 GHz

An electron spin-echo spectrometer operating at 94.9 GHz is described. The experimental details of the microwave circuit are discussed and the performance is compared with that of more conventional spectrometers at 9.5 GHz.     

A G-band terahertz monolithic integrated amplifier in 0.5-μm InP double heterojunction bipolar transistor technology

Design and characterization of a G-band(140–220 GHz) terahertz monolithic integrated circuit(TMIC) amplifier in eight-stage common-emitter topology are performed based on the 0.5-μm In Ga As/In P double heterojunction bipolar transistor(DHBT). An inverted microstrip line is implemented to avoid a parasitic mode between the ground plane and the In P substrate. The on-wafer measurement results show that peak gains are 20 dB at 140 GHz and more than 15-dB gain at 140–190 GHz respectively. The saturation output powers are-2.688 dBm at 210 GHz and-2.88 dBm at 220 GHz,respectively. It is the first report on an amplifier operating at the G-band based on 0.5-μm InP DHBT technology. Compared with the hybrid integrated circuit of vacuum electronic devices, the monolithic integrated circuit has the advantage of reliability and consistency. This TMIC demonstrates the feasibility of the 0.5-μm InGaAs/InP DHBT amplifier in G-band frequencies applications.     

Generation of Submillimeter-Wave Radiation with GaAs Tunnett Diodes and InP Gunn Devices in a Second or Higher Harmonic Mode

Efficient second-harmonic power extraction was demonstrated recently with GaAs tunnel injection transit-time (TUNNETT) diodes up to 235 GHz and with InP Gunn devices up to 325 GHz. This paper discusses the latest theoretical and experimental results from second-harmonic power extraction at submillimeter-wave frequencies and explores the potential of using power extraction at higher harmonic frequencies to generate continuous-wave radiation with significant power levels at frequencies above 325 GHz. Initial experimental results include output power levels of more than 50 W at 356 GHz from a GaAs TUNNETT diode in a third-harmonic mode and at least 0.2–5 W in the frequency range 400–560 GHz from InP Gunn devices in a third or higher harmonic mode. The spectral output of these submillimeter-wave sources was analyzed with a simple Fourier-transform terahertz spectrometer and, up to 426 GHz, with a spectrum analyzer and appropriate harmonic mixers. Initial experimental results from a GaAs/AlAs superlattice electronic device at D-band (110–170 GHz) and J-band (170–325 GHz) frequencies are also included.     

Integrated image-line steerable active antennas

This paper reports a varactor-tuned Gunn oscillator constructed in an image-line circuit and integrated with a grating antenna. The combined circuit exhibited a 2 percent electronic tuning range corresponding to a frequency steerable range of 4 degrees. The active antenna demonstrated a clean spectrum with low side lobes. The beam angles agree very well with the prediction. The circuit can be produced at low cost and should have many applications at millimeter-wave frequencies     

A 94/47 GHz frequency halver using a GaAs Gunn device

This paper describes the basic principles and the set up of a new kind of frequency halvers suited for millimeter wave applications. A Ga As Gunn-device is used to act like a nonostable multivibrator having a hold time adequate to the domain transit time T_t of the Gunn-device.In a certain frequency range depending on the transit frequency f_T=1/T_T, bias voltage and circuit parameters a harmonic wave synchronized fundamental/2nd harnonic mode oscillator is able to perform as a frequency halver. An input power of only 1mW is sufficient to achieve a bandwidth of 5 GHz respectively 2.5 GHz centered around 94 GHz respectively 47GHz. Since the output power is 50 mW at fundamental frequency f_F, this halver offers 17dB conversion gain.     

A solid-state frequency source for radio astronomy in the 100 to 1000 GHz range

A compact Gunn oscillator-multiplier combination can provide the for SIS receivers necessary LO power up to 1000 GHz. Frequency multiplication factors of 2 to 8 are accomplished in a single step using a Schottky mixer diode in the varistor mode.     

Quasi-optical resonator for power combining at W-band

Laser resonator technique is employed for obtaining efficient, spectrally pure and narrow band output from a CW GUNN source operating around 94GHz. The same resonator configuration, used for two similar GUNN sources results in combined power output at W-band.     

A Gunn-Diode Active Leaky-Wave Frequency Scanning Antenna

A frequency tunable active leaky-wave scanning antenna using Gunn-diode voltage control oscillator (VCO) as source is developed. The frequency tuning controlled by changing either the varactor diode dc bias or the Gunn diode dc bias is demonstrated. The measured scanning angle of active antenna is close to 15 degree as the Gunn VCO frequency tuned from 12.58GHz to 12.98GHz. To excite the first higher order mode of the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the middle line of the microstrip leaky wave antenna. This is a prototype of frequency scanning antenna using two terminal device, which can be easily scaled up to millimeter wave frequency region.     

An efficient Schottky-varactor frequency multiplier at millimeter waves. Part I: Doubler

The efficiency of millimeter wave doublers with a wide tunable bandwidth was studied. The efficiency depends on the varactor parameters and the embedding impedances seen by the diode at fundamental and harmonic frequencies. Millimeter wave doublers were simulated with a nonlinear analysis program to find optimum embedding impedances for a given diode. Also the sensitivity of the efficiency to various diode and circuit parameters was evaluated. A scaled model was constructed in order to experimentally optimize the impedances. For experimental verification a doubler from 40–58 GHz to 80–116 GHz was constructed. The highest efficiency measured was 45% at 94 GHz with 5 mW input power. The highest efficiency obtained with 20 mW input power was 38%.     

70 GHz二次谐波倍频回旋速调管研究

 对70 GHz二次谐波倍频回旋速调管高频结构和电子与波互作用进行了研究。研究了TE02模腔体绕射品质因数及模式转化,解决了二次谐波倍频回旋速调管漂移段不能截止70 GHz的TE01模而引起的腔体间高频串扰的问题。分析了注电流、输入功率、电子横纵速度比和电子注引导中心半径等参数对输出功率、增益和效率的影响。针对二次谐波回旋速调管放大器工作频带窄、效率低,进行了高频结构优化设计,显著地展宽了工作频带,提高了互作用效率。在理论分析和高频计算的基础上,建立了注-波互作用PIC（粒子模拟）模型,进行了粒子模拟计算和优化,得到了70 GHz 的二次谐波倍频四腔回旋速调管放大器设计方案。粒子模拟结果表明：在工作电压70 kV,注电流13 A,电子注横向速度与纵向速度比为1.5时,中心频率69.81 GHz输出功率256 kW,带宽160 MHz,电子效率28%,饱和增益大于44 dB。