Quiet Zone Implementation for VHF Antenna Measurement in Semi-Anechoic Chamber

Anechoic chambers (AECs) are increasingly used by research centers to obtain the characteristics of antenna systems necessary to compare them with the results of electrodynamics modeling. A review of the current publications on this topic has shown an increased interest in the general problems of AEC design, the choice of the shape and material of radar absorbing coatings that minimize reflections inside the chamber, as well as in the methods for measuring various antenna characteristics.

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Compact anechoic chamber and antenna measurement system for microwave teaching and research applications

Microwave and Optical Technology Letters ◽

10.1002/(sici)1098-2760(19960620)12:3<150::aid-mop8>3.0.co;2-g ◽

1996 ◽

Vol 12 (3) ◽

pp. 150-154

Author(s):

D. Geen ◽

D. Smith

Keyword(s):

Measurement System ◽

Anechoic Chamber ◽

Antenna Measurement ◽

Teaching And Research

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Ground-based Multichannel Microwave Radiometer Antenna Pattern Measurement using Solar Observations

10.5194/amt-2020-283 ◽

2020 ◽

Author(s):

Lianfa Lei ◽

Zhenhui Wang ◽

Jiang Qin ◽

Lei Zhu ◽

Rui Chen ◽

...

Keyword(s):

Point Source ◽

Microwave Radiation ◽

Microwave Radiometer ◽

Maximum Error ◽

Measurement Procedure ◽

Antenna Pattern ◽

Anechoic Chamber ◽

Solar Observation ◽

The Sun ◽

Antenna Measurement

Abstract. Ground-based multichannel microwave radiometers (MWRs) can provide continuous temperature and humidity profiles of the troposphere. MWR antenna pattern measurements are important for reliable and accurate antenna temperature measurement and are usually carried out in a microwave anechoic chamber. Measurement using an anechoic chamber is complex and expensive because the conventional measurement procedure requires a special situation and professional instruments. More importantly, the construction of the anechoic chamber and the installation method of the absorbing material can directly influence the performance of the anechoic chamber and the result of the antenna measurement. This paper proposes a new method of MWR antenna measurement by observing the sun, and this method can be used to measure other radar antenna patterns. During the measurement, the MWR observes the microwave radiation brightness temperature (TB) to measure the antenna pattern by high-resolution raster scanning of the azimuth and elevation of the sun under a clear sky in Xi'an, China. Analysis of the TB scanning data of the sun at four frequencies, 22.235, 26.235, 30.000 and 51.250 GHz, showed that the microwave radiation TB of the sun is strong enough to be observed by the MWR. Furthermore, the antenna pattern was illustrated and analyzed based on these data, which fully proves that the sun can be used to measure the antenna pattern. Finally, the antenna pattern derived from the solar observation was compared with the result of the far-field measurement with a point source in the microwave anechoic chamber at 30 GHz, the maximum error of the beamwidth is less than 0.1°, which showed that this pattern matched well to the pattern measurement using a point source in the microwave anechoic chamber. Therefore, the antenna pattern of the MWR can be measured by scanning the sun without a point source in the microwave anechoic chamber, and this method can be used for convenient MWR antenna measurements and can reduce the measurement complexity and cost.

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