Millimeter waves for short-range multimedia communication systems

A framework for the performance characterization of short-range communications systems is developed with the intention of investigating the feasibility of new multimedia wireless services at millimeter waves (MMWs). Both narrow- and wide-band systems are considered for mobile and/or fixed users. This paper aims at defining and evaluating proper metrics to characterize the service quality for the user and jointly takes the propagation characteristics, the transmission techniques, and the multiple access protocols into account. The definition of service-oriented metrics is emphasized. Three different real scenarios operating at MMW are investigated with a unified perspective: intelligent transport systems, wide-band local-area networks, and local multipoint distribution systems for interactive video services. The role played by the MMW band in the development of these services is discussed. In each scenario, accurate propagation analysis is carried out and suitable countermeasure techniques are pointed out in order to join suitable service-quality levels. The methodology considered is based on both analytical and semianalytical tools for performance evaluation     

Cellular effects: Millimeter waves and Raman spectra—Report of a panel discussion

On June 22, 1979, a panel discussion was held at the Bioelectromagnetics Symposium in Seattle, WA. In this report, we summarize the statements of the panel members and comment on several common suggestions. We also include written abstracts which correspond to the oral presentations of most of the panel members.     

Diplexing Millimeter Waves

The paper describes a band-splitting filter or diplexer, which splits the incoming spectrum into the sub-bands 120-139 GHz and 141-158 GHz. This diplexer is intended to separate the electron cyclotron emission of a magnetically confined plasma into two subbands and to feed two independent heterodyne radiometers. The construction principle of this diplexer has been used in the past for broadband communication systems. It is particularly suited to systems incorporating oversized waveguides.     

Millimeter wave antennas

Major advances in millimeter-wave antennas have been made in recent years, in particular in two areas. A new class of leaky-wave antennas based on open millimeter waveguides has been proposed and investigated, and substantial progress has been achieved in integrated antennas where active and passive circuits, possibly in monolithic form, are combined with the radiating elements in one compact unit. Interesting developments have taken place also in a third group of millimeter-wave antennas, that of microstrip antennas and printed circuit antennas in general. An attempt is made to summarize these developments     

砷化镓毫米波器件

叙述了GaAs MESFET、GaAs HEMT和GaAs耿氏器件等新一代GaAs毫米波器件的发展现状。     

Millimeter Wave Antenna Technology

Millimeter wave antenna technology has had a long history of development, and as millimeter wave systems evolve through planning to implementation, a significant amount of additional development work will be required. Millimeter wave antennas play a key role in the rationale for millimeter system designs because high spatial resolution can be achieved with modest physical dimensions. Reflector, lens, array, and horn technologies are surveyed. Multiple beam designs and adaptive processing antennas are described because these technologies afford high leverage opportunities to enhance electronic survivability and to extend communication capabilities. Ancillary components, such as radomes, are a necessary part of practical antenna designs and are discussed in some detail.     

Harmonics at Millimeter Wavelengths

Two techniques for obtaining millimeter waves with sufficient power to make physical measurements have been investigated at the Columbia Radiation Laboratory. The first in point of time was to use the harmonics of the fundamental frequency directly emitted by a magnetron when it is in oscillation. Harmonics up to wavelengths of 1.25 mm have been observed. The only advantage of the magnetron is in the ease of adjustment. An operator of moderate experience should be able to produce 1.5 mm radiation within a few hours using this technique. The other method in use is to frequency multiply the power emitted by a klystron by means of a silicon-tungsten contact used as a non-linear device. This method ps produced 1.5mm wavelength radiation at Columbia and wavelengths up to 0.77 mm at Duke University. It has the advantages that the radiation is stable in power and frequency, is monochromatic, and also is tuneable. The price paid is in a considerably greater time of adjustment and alignment, a few weeks being not at all uncommon.     

Millimeter Wave Subscriber Loops

Advantages and drawbacks of using millimeter waves in the telephone and data subscriber distribution network are listed. Fields in which it seems attractive to use millimeter wave loops are examined. For such applications, cost and reliability constraints led to the design of very simple systems. Two systems will soon be introduced into the French subscriber plant. The first one will be commissioned in 1983 to connect groups of remote subscribers, working at 31 GHz, using a homodyne millimetric front end. The second one, still under experiment, is designed for the connection of subscribers of the integrated service communication network; working at 23 GHz, it uses time-division multiplexing to assume duplex operation. The most drastic constraint when setting up such systems is the line-of-sight requirement. Investigations of that problem, using computer-aided coverage map plotting are discussed.     

毫米波衍射天线

衍射天线是一种新型天线，具有重量轻、体积小等特点，有广泛的应用。本文叙述了以标量衍射理论为基础的毫米彼衍射天线的设计和制作方法，报道了最近有关的研究成果．分析并评价了几种主要型式的透射式和反射式衍射天线。     

Millimeter wave self-mixing oscillators

Self-oscillating mixers in both dielectric and waveguide cavities have veen investigated in the 60 GHz frequency range. The deveces consist of negative resistance diodes of GaAs and InP material coupled to waveguide cavities or high resistivity dielectric cavities such as silicon or Al₂O₃. Experimental measurements show that these devices have a sensitivity in the order of ?80 dBm with the intermediate frequency at 60 MHz and an IF bandwidth of 120 MHz. Applications are suggested based on minimum detectable signal and RF power capabilities for systems requiring small size and low cost.     

Millimeter wave microstrip circulator

A new and unique microstrip “drop-in” type Y-junction circulator has been designed and developed for operation in the millimeter wave frequency region. This device utilizes NiZn ferrite as the gyromagnetic material which is mounted on a duroid substrate.     

低噪声毫米波接收机

几年来对固态器件已做了很大地改善(即雪崩二极管,耿氐二极管,变容二极管和混频二极管等等),这提高了毫米波接收机的整个性能和低噪声特性。由于器件的这些改善,目前完全能够制作固态低噪声毫米波接收机。由于在微波波段相似,低噪声参数,宽带低变频损耗混频器,固态本振都可使用。而且低温冷却参数和混频器也正在研制,其将要达到最佳系统灵敏度。由于这些全固态毫米波元件的灵活性,目前能设计出预卿应用的最佳系统结构,它或是一个先进的通讯系统,采用先进技术的EW应用,一个雷达系统,一个辐射测量系统,或满足正在发展的许多接收机的要求条件的任一条件。本文论述了毫米波波段以及其用于系统设计的正发展的趋向,并叙述了各种接收机系统的性能和其灵敏度的要求条件。本文还论述了系统工作噪声温度概念和其决定的方法及对低噪声元件的应用性,同时也论述了低噪声系统的目前技术水平及在毫米波波段所获得的试验数据。     

Millimeter Wavelength Frequency Multipliers

Mechanically tuneable millimeter wavelength frequency doublers typically exhibiting 10-percent conversion efficiency at any output frequency in the range 100-260 GHz have been fabricated. Output power varies from 10 mW at 100 GHz to 6 mW at 260 GHz, with a fixed tuned instantaneous 1-dB bandwidth typically 5 percent of the center frequency. A frequency tripler to 215-GHz output frequency is also described. For this device, a mechanically tuneable 3-dB bandwidth of 210 to 240 GHz was obtained, with a peak conversion efficiency of 6 percent at 4.8-mW output power.     

Millimeter Wavelength Resonant Structures

This paper discusses the construction of millimeter wave Fabry-Perot resonators, using both planar and spherical reflectors. It also discusses the equivalent circuits of planar reflectors and the method of obtaining efficient power transfer into the resonators.     

A Future Millimeter/Sub–Millimeter Radiometer for Satellite Observation of Ice Clouds

The instrument concept of a future spaceborne millimeter/sub-millimeter radiometer is proposed in this paper for the remote sensing of ice clouds from satellite. The proposed radiometer is expected to operate at a series of frequencies within the millimeter and sub-millimeter wave range from 150 to about 900 GHz. Five frequencies are selected in the atmospheric windows, i.e., 150, 220, 463, 683, 874 GHz, and at each frequency there are two orthogonally polarized channels. Three water vapor channels located close to 183.31 GHz are also included in this instrument, since they can provide water vapor information, which is needed for ice cloud parameter retrieval. To simplify system design and test, a modular design philosophy is followed in the receiver frontend design and two antennas are used separately for the millimeter and sub-millimeter channels. Overall, the instrument requirements can be met with today's technology, except for the channels at the highest frequencies, where the radiometric sensitivity can be larger than the required 1.0 K for the 10 km spatial resolution (2.5 ms integration time). However, this situation can be improved by averaging neighboring pixels in data processing if certain compromise in the spatial resolution can be made at these frequencies.     

Millimeter wave imaging lens antenna

The factors which influence the design of lenses suitable for imaging at millimetre wavelengths are discussed. Examples are given of optical designs for a military tracking application, firstly for use with an open ended waveguide array, and secondly for use with monolithic arrays, each covering a field of view of ±20°.