At last, no more waiting to test your new
antennas. Winegard Company has a state of-the-art vertical planar near-field antenna measurement system on site.

The vertical planar near-field range is designed for testing medium to high gain antennas (gain higher than 15 dBi). It provides comprehensive and valuable information on the performance of the antenna under test (co- and cross-polarization patterns, gain, sidelobe, beam width, beam pointing, axial ratio, etc.).

Features:

• Frequency of operation is up to 40 GHz.
• Scan area of 5 ft. by 5 ft.
• Radiation patterns of up to +/- 70° in azimuth and elevation can be measured.
• Range is housed in a room which has RF absorber on the side walls to minimize multipath.
• Range consists of NSI robotic scanner, Agilent E8363B network analyzer, NSI antenna measurement software, other RF hardware, and a computer for data acquisition and processing.

Overview of Near-Field Measurement

In a planar near-field measurement system, the antenna under test (AUT) remains stationary during the test and the probe antenna is moved in both X and Y directions such that a grid of near-field samples is formed.

The robotic scanner carries the probe antenna, which is connected to the Agilent E8363B network analyzer (PNA) from one port. The other PNA port is connected to the AUT. The PNA measures the near-field grid samples, which are amplitude and phase measurements of the AUT response.

The size of the near-field grid or the scan size is determined from the AUT size, the probe antenna size, the probe-to-AUT spacing, and the maximum far-field angle. Once the measured near-field grid of the AUT is formed, a Fourier transform of the near-field grid results in the far-field pattern.

After measuring the AUT, the standard gain horn (SGH) antenna is measured. The measured SGH data is then used to determine the AUT gain by comparing the far-field level of the AUT to that of the SGH. The difference in signal level between the AUT and the SGH is the difference in gain between the AUT and the SGH.