Double-drift IMPATT diodes near 100 GHz

This paper reports the highestxpower (frequency)²IMPATTS produced to date. A CW output power of 380 mW has been achieved at 92 GHz with an efficiency of 12.5 percent. An all-implanted double-drift n⁺-n-p-p⁺silicon structure was fabricated, using a lightly doped epitaxial layer as the starting material. The newly made structure uses a more shallow n⁺contact than previous diodes, and therefore has more equal drift spaces. Small-signal admittance calculations show lower susceptance per unit area in the newly made structure. The shallow contact has allowed the study of unequal dopings in the n- and p-drift spaces. Unequal dopings up to 50 percent can be tolerated with less than 20 percent variation in measured efficiency and output power. Both admittance and breakdown voltage calculations based upon experimentally determined doping profiles and independently measured ionization coefficients were found to be in good agreement with experiment. The doping profiles on both sides of the depletion region were determined byC(V)analysis. The testing of both the old and new structures has been carried out in a microwave circuit having improved mechanical tuning accuracy due to the introduction of a newly designed tuning plunger.     

Reflectivity of absorbers in 100-200 GHz range

Different types (pyramidal, convoluted, wedge, flat) of absorber panel made by several manufacturers have been measured at 107 and 183 GHz. These measurements revealed a rapid degradation of the quality of absorbers from 107 to 183 GHz: reflectivity increased nearly 10 dB. The best absorbers have reflectivities below -40 dB at 107 GHz and about -35 dB at 183 GHz.<>     

A Comparison of IMPATT Oscillator Power and Frequency Above 100 GHz with Results Derived from Theoretical Models

A comparison is made of experimentally determined IMPATT oscillator frequency and power characteristics in the 90-140-GHz band with values obtained from detailed theoretical models. The results show encouraging agreement and demonstrate the potential of the modeling approach for oscillator design.     

High-power generation in IMPATT devices in the 100-200-GHz range

A silicon double-drift IMPATT diode with high uniform doping levels was simulated. Simulation results show that it is possible for silicon IMPATT diodes to generate extremely high pulsed output power for frequencies above 100 GHz under high current-density operation. The highest output power matched to a 1-Ω load resistance obtained at 150 GHz is 37.7 W with a DC current density of 200 kA/cm², although the calculated power conversion efficiency is low. It is also shown that the low-power conversion efficiency limits the diode's continuous wave power operation     

Reflections in anechoic chambers in 100-200 GHz range

Three anechoic chambers have been tested at 110 and 183 GHz. Typical sidewall reflectivity levels are about -60 dB at 110 GHz and -50 dB at 183 GHz measured with pyramidal horns which have a gain of 20 dB. Backwall reflectivity levels are about -35 dB at 110 GHz and -25 dB at 183 GHz.<>     

100mW8～12GHz微波FET宽带放大器

本文介绍了一种宽带大动态放大器及其电路设计和实验结果。其主要技术指标为:在8～12GHz频带范围内,G_p≥20dB,△G_p≤±1.5dB,P_0≥100mW。该场放具有体积小、重量轻、可靠性高等特点。     

Broad-Band Characteristics of EHF IMPATT Diodes

Measurements have been made of the oscillator characteristics when a GaAs EHF double-drift IMPATT diode designed for a frequency of 35 GHz is operated over an extended frequency range from 33-50 GHz. The diode which was designed for 35 GHz has a broad-band capability which allows it to produce 2.15 W at 44.1 GHz. An analytic model is shown to predict accurately the observed results. The model indicates that the upper limit in frequency can be increased by reducing the diode area or the series resistance as well as by reducing the length of the drift region.     

A Broad-Band Traveling-Wave Maser for the Range 40-46.5 GHz

A tunable traveling-wave maser (TWM) for the frequency range 40-46.5 GHz has been developed, which is characterized by an extended instantaneous bandwidth. Andahssite (Al/sub 2/SiO/sub 5/ ) doped with Fe/sup 3/ atoms is used as the active crystal. The slow-wave structure is a digit comb with broad-band matching particularly suitable for the millimeter range. The new type of isolator employed is based on textured hexagonal ferrite materials, namely BaNi/sub 2/Sc/sub x/Fe,/sub 16/-/sub x/O/sub 27/. The net gain within the tuning band is 20-35 dB. The instantaneous bandwidth at a --3-dB level is 150-100 MHz, dependhsg on the net gain. The noise temperature at the input does not exceed 25° K.     

A Broad-Band Second-Harmonic Mixer Covering 76-106 GHz

A broad-band second-harmonic millimeter-wave mixer has been constructed. The circuit consists of a single unencapsulated Schottky-barrier diode and embedding network which includes a wave absorber in the IF output terminal. The conversion loss of the mixer is 14.6/spl plusmn/0.9 dB over a frequency range of 76-106 GHz. The mixer is pumped by a Iocal oscillator that is tuned over the range of 37.15-52.15 GHz. The IF is kept constant at 1.7 GHz. The new mixer looks attractive for use in broad-band millimeter-wave measuring equipment, such as spectrum analyzers.     

GaAs IMPATT diodes for 60 GHz

High-performance GaAs double-drift Read IMPATT diodes have been demonstrated at 60 GHz. 1.24-W CW output power at 11.4-percent dc to RF conversion efficiency was obtained with a junction temperature rise of 225°C. The doping profiles and test circuits have not yet been optimized and we expect that still higher power and efficiency should be achievable.     

Free space video detection of harmonic content of 100 GHz IMPATT oscillator

The harmonic content of a commercial c.w. 20 mW 100 GHz IMPATT oscillator operating at ambient temperature has been determined at 200 and 300 GHz using free space techniques. The highest power levels observed at these frequencies were 16.6 and 37.5 dB below the fundamental, respectively, corresponding to power levels of 0.5 mW at 200 GHz and 4.5 ?W at 300 GHz at the oscillator.     

八毫米脉冲IMPATT振荡器

本文简述了脉冲IMPATT器件的设计考虑和制造工艺以及振荡器的微波电路结构和脉冲调制器的原理。对脉冲偏置期间产生的频啁效应作了原理性说明,并提出了减小频啁带宽的方法。目前所研制的八毫米IMPATT振荡器最大的脉冲输出功率在34.2GHz下为15.7W。     

Highly Stabilized Half-Watt IMPATT Oscillator

An X-band IMPATT oscillator having a stabilized output power of over 0.5 watt has been developed. The oscillator consists of a main cavity and a directly coupled reaction-type cavity for stabilization. The oscillator has a frequency stability of 2.6x10/sup -5/ over a temperature variation ranging from 0/spl deg/ to 50/spl deg/C and an rms noise deviation of 15 Hz/1-kHz bandwidth at 500 kHz from the carrier. Design considerations have been made concerning the admittance characteristics of the circuit and of the diode to determine preferable circuit conditions for stabilization. The output-power loss due to the stabilization is as small as 0.4 dB. The oscillator is capable of operation in a frequency range of 10.7 to 11.7 GHz.     

50 GHz gallium-arsenide IMPATT oscillator

Gallium-arsenide diffused-junction IMPATT diodes have been operated in F band (40?60 GHz), producing output powers up to 140 mW, with a conversion efficiency greater than 7%.     

Comparison of GaAs IMPATT designs for 20 GHz

GaAs IMPATT diodes have been developed to deliver high c.w. powers in K-band. Single-drift and double-drift flat profile and single-drift Read profile designs have been evaluated. The highest conversion efficiencies were obtained with the high/low Read doping profile. A maximum c.w. power of 3.1 W has been measured at 19.6 GHz with 18.6% efficiency for these devices.     

IMPATT oscillator for groove guide at 95 GHz

An oversized-cavity millimetre-wave IMPATT oscillator has been constructed which can be easily coupled to a groove guide via a simple transformer. A resonant-cap structure is used to determine the frequency of oscillation. The oversized-cavity results in the Q of the oscillator being greater than that of a conventional impatt oscillator, but the output power and frequency are nevertheless stable. The tuning characteristic is discussed and a frequency spectrum presented.     

C.W. oscillation with p+-p-n+ silicon IMPATT diodes in 200 GHz and 300 GHz bands

Submillimetre-wave silicon single-drift-region IMPATT diodes with a p+?p?n+ structure have been fabricated by ion implantation. C.W. output powers of 7.5 mW at 285 GHz and 78 mW at 185 GHz were obtained. The maximum c.w. oscillation frequency observed was 394 GHz.     

GaAs 50 GHz Schottky-barrier IMPATT diodes

Technological improvements have been made to realise high-efficiency GaAs Schottky-barrier IMPATT diodes in the 50 GHz band. Efficiency and output power have been increased by a factor of 1.5 over previous best results. Efficiency as high as 11.0% at 51 GHz and an output power of 420 mW at 53 GHz have been obtained.     

140 GHz GaAs double-Read IMPATT diodes

CW GaAs double-Read IMPATT diodes for D-band frequencies are designed and tested. For reproducible RF impedance matching, the module encapsulation technique is applied. Ohmic losses of the active device are reduced by a titanium-Schottky contact instead of an alloyed ohmic n ⁺-contact. At 144 GHz 100 mW RF power with a conversion efficiency of 5% is realised     

An Isotropic Electric-Field Probe with Tapered Resistive Dipoles for Broad-Band Use, 100 kHz to 18 GHz

A new broad-band electric-field probe, capable of accurately characterizing and quantifying electromagnetic (EM) fields, has been developed at the National Bureau of Standards (NBS). The probe's 8-mm resistively tapered dipole elements allow measurement of eleetric fields between 1 and 1600 V/m from 1 MHz to 15 GHz, with a flatness of +-2 dB. A mutually orthogonal dipole configuration provides an overall standard deviation in isotropic response, with respect to angle, that is within +-0.3 dB. Both the theoretical and developmental aspects of this prototype electric-field probe are discussed in this paper.