The influence of polarization on millimeter wave propagation through rain

The influence of polarization on millimeter wave propagation is investigated from both an experimental and a theoretical viewpoint. First, previous theoretical and experimental work relating to the attenuation and depolarization of millimeter waves by rainfall is discussed. Considerable detail is included in the literature review. Next, a theoretical model is developed to predict the cross polarization level during rainfall from the path average rain rate and the scattered field from a single raindrop. Finally, data from the VPI and SU depolarization experiment are presented as verification of the new model, and a comparison is made with other theories and experiments. Aspects of the new model are: (1) spherical rather than plane waves are assumed, (2) the average drop diameter is used rather than a drop size distribution, and (3) it is simple enough so that the effect which changing one or more parameters has on the crosspolarization level is easily seen

Localized low-frequency vibrational modes in a simple model glass

This is the publisher's version, also available electronically from http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.66.636We examine the vibrational spectrum of a glass of soft spheres produced by quenching an equilibrated liquid (produced via constant-energy molecular-dynamics simulation) to zero temperature. Normal-mode analysis shows clearly the existence of (quasi)localized modes at the low-frequency end of the vibrational spectrum. The modes are found to be localized around atoms whose neighborhood structure differs significantly from the average glass environment. The effective masses of these modes range upwards from 10 atomic masses

Localized low-frequency vibrational modes in glasses

This is the publisher's version, also available electronically from http://journals.aps.org/prb/abstract/10.1103/PhysRevB.44.6746.Using a larger data set and more detailed analysis, we continue our examination of the zero-temperature vibrational spectrum of a glass of soft spheres by computer simulation. As in our previous study [Phys. Rev. Lett. 66, 636 (1991)], a normal-mode analysis shows clearly the existence of (quasi-)localized modes at the low-frequency end of the vibrational spectrum. The modes are found to be localized around atoms whose neighborhood structure differs significantly from the average glass environment and is reminiscent of that associated with interstitial defects in crystals. The effective masses of these modes range upward from 10 atomic masses

Polarization effects in millimeter wave propagation through rain: A review of present theory and a discussion of current experiments

An attempt was made to calculate the depolarization effects of rain on linearly or elliptically polarized millimeter waves. Results are given in graphs and tables

The influence of polarization on millimeter wave propagation through rain

The measurement and analysis of the depolarization and attenuation that occur when millimeter wave radio signals propagate through rain are described. Progress was made in three major areas: the processing of recorded 1972 data, acquisition and processing of a large amount of 1973 data, and the development of a new theoretical model to predict rain cross polarization and attenuation. Each of these topics is described in detail along with radio frequency system design for cross polarization measurements

A 20 Ghz Depolarization Experiment Using the ATS-6 Satellite

A depolarization experiment using the 20 GHz downlink from the ATS-6 satellite was described. The following subjects were covered: (1) an operational summary of the experiment, (2) a description of the equipment used with emphasis on improvements made to the signal processing receiver used with the ATS-5 satellite, (3) data on depolarization and attenuation in one snow storm and two rain storms at 45 deg elevation, (4) data on low angle propagation, (5) conclusions about depolarization on satellite paths, and (6) recommendations for the depolarization portion of the CTS experiment

A depolarization and attenuation experiment using the CTS satellite. Volume 1: Experiment description

An experiment for measuring precipitation attenuation and depolarization on the Communications Technology Satellite (CTS) 11.7 GHz downlink is described. Attenuation and depolarization of the signal received from the spacecraft is monitored on a 24 hour basis. Data is correlated with ground weather conditions. Theoretical models for millimeter wave propagation through rain are refined for maximum agreement with observed data. Techniques are developed for predicting and mimimizing the effects of rain scatter and depolarization on future satellite communication systems

A depolarization and attenuation experiment using the COMSTAR and CTS satellites

Monthly statistical data are presented on ground rainfall rate and attenuation of satellite downlinks at 11.7 GHz, 19.04 GHz, and 28.56 GHz and on cross-polarization isolation at 11.7 GHz. Regression equations for relating isolation to attenuation, attenuation to rain rate, and attenuation at one frequency to attenuation at another frequency are also included. Longer-term statistics are also presented and discussed

A depolarization and attenuation experiment using the CTS satellite

Rain attenuation and depolarization data collected on the communications technology satellite 11.7 GHz downlink, and changes made in equipment following rain leak damage to the parametric amplifier are discussed. A 15 GHz radar system is described