By Topic

Antennas and Propagation Magazine, IEEE

Issue 6 • Date Dec. 1991

Filter Results

Displaying Results 1 - 7 of 7
  • Evolution of the large Deep Space Network antennas

    Page(s): 7 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1268 KB)  

    The evolution of the largest antenna of the US NASA Deep Space Network (DSN) is described. The design, performance analysis, and measurement techniques, beginning with its initial 64-m operation at S-band (2295 MHz) in 1966 and continuing through the present Ka-band (32-GHz) operation at 70 m, is described. Although their diameters and mountings differ, these parabolic antennas all employ a Cassegrainian feed system, and each antenna dish surface is constructed of precision-shaped perforated-aluminum panels that are secured to an open steel framework.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Circular sectoral waveguides

    Page(s): 20 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (650 KB)  

    Hollow cylindrical waveguides that have pie-shaped cross sections are described. The explicit equations for the field components of the TE (transverse electric) and TM (transverse magnetic) waves are given, and the modal patterns for a number of modes are plotted. The relation between the field distributions inside the circular and sectoral waveguides is discussed. It is shown that the electric and magnetic fields of the modes TE/sub 1n/ and TM/sub 1n/ display edge singularity when the sectoral angle is greater than pi . Formulas convenient for the evaluation of Bessel functions of fractional order on a personal computer are given.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SOUSY VHF radars and UV lidar for atmospheric research at MPAe

    Page(s): 28 - 32
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    A description is given of the SOUSY (sounding system) VHF radar, located in the Harz Mountains in Germany, which was constructed between 1974 and 1976 as one of the first-generation mesosphere, stratosphere, and troposphere (MST) radars. Its mobile counterpart, designed and built during the early 1980s for observational campaigns in remote locations, is also described. Some theoretical background on the use of such radar is provided, and representative studies are described. A UV ( lambda =351 nm) Rayleigh lidar added to the SOUSY Project in 1988 in order to provide supplementary measurements in the stratosphere and mesosphere in conjunction with radar observations is also described and some typical results reported.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Rapid evaluation of integer-order Bessel functions using an FFT algorithm

    Page(s): 33 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (227 KB)  

    A rapid, accurate, and stable method for computing integer-order Bessel functions is presented. In contrast to the iterative procedures normally used in the numerical evaluation of Bessel functions, this approach requires little more than a commonly available fast Fourier transform algorithm, and yet, for a given argument, can provide many J/sub n/s in a single pass.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Backyard Range-radio astronomy at Saint Mary's University, Halifax, Canada

    Page(s): 63 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    The Saint Mary's University (SMU) radio observatory, located on the roof of the university's McNally Administration Building, is described. The various antenna installations are used to conduct solar observations at the 21-, 7.5-, 5-, and 3-cm wavelengths. Facilities are also available for observations of the radio star Cassiopeia A. Two-element interferometer solar observations are routinely conducted by undergraduate physics students. Surprisingly good results for the angular extent of the Sun at the particular observing wavelength are obtained from these programs.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Antenna mechanic-more effective design of mechanical buffers for steerable antennas

    Page(s): 67 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (323 KB)  

    Discusses three true stories of catastrophes caused by antenna runaway, gives some design advice on mechanical buffers, and provides a worked example to illustrate the design methods. Although it may seem unlikely that certain events could happen concurrently (stuck limit switch, high wind, etc.), the consequences should be carefully weighed against the cost of designing buffers to prevent equipment damage. Conservation of energy is a very good method of identifying loads. It is also important that the energy balance equation be written with all events (wind torque, motor torque, peak velocity) happening simultaneously.<> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Antenna Designer's Notebook-simulation of slot array antennas using standard network analysis program

    Page(s): 45 - 47
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    It is shown how equivalent circuit models can be employed in a supercompact circuit simulation to investigate arrays of offset longitudinal broad-wall slots and tilted narrow-wall slots. An investigation of double broad-wall slots in a half-height waveguide is reported as an example of the use of the technique. The results can be used to optimize array bandwidth and to check the consequences of any changes introduced into the array design (tapering, tolerances, frequency offsets, etc.). It is noted that realistic radiation patterns can also be obtained using supercompact analysis View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Antennas and Propagation Magazine covers all areas relating to antenna theory, design, and practice.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
W. Ross Stone