Browse Prior Art Database

Determination of Far Field Antenna Patterns

IP.com Disclosure Number: IPCOM000091083D
Original Publication Date: 1969-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Mitchell, SH: AUTHOR [+3]

Abstract

This system measures the far field radiation pattern of a microwave antenna by processing the received energy signals at the near field of the antenna. Fresnel probe measurements are used.

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Determination of Far Field Antenna Patterns

This system measures the far field radiation pattern of a microwave antenna by processing the received energy signals at the near field of the antenna. Fresnel probe measurements are used.

Focusing lens 1 collimates the wavefront signal received from the transmitting source of wave energy 2 by focusing the received signal at a point on plane 3. At this focal plane, sampling probe 4 is positioned by a variable coordinate frame system not shown. Probe 4 which can be a dipole, loop or equivalent sensor device is used to detect illumination at plane 3. Standard horn feed 5 is positioned adjacent to the antenna under test and provides a reference signal to network analyzer 6. The latter creates an output signal representative of the sampling that is detected at probe 4. Horn 5 presents an input into analyzer 6 that provides a reference for amplitude and phase that is utilized for appropriate adjustment of the output signal by such analyzer. The output of probe 4 is also introduced into strip recorder 7 to provide a visual output for operator monitoring of the system.

The signal output of analyzer 6 is passed through computer interface 8, a standard analog-to-digital converter. Conversion is necessary so as to make the sampled data compatible with a general purpose digital processor. After conversion of the data, the output of interface 8 is introduced into a convolution process device 9. This process is performed by a genera...