Evaluation of Radio Anechoic Chamber
Khadka, Sushan (2017)
Metropolia Ammattikorkeakoulu
2017
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-201704275564
https://urn.fi/URN:NBN:fi:amk-201704275564
Tiivistelmä
The main goal of this project was to evaluate the radio anechoic chamber located on 6th floor of the electronics department building of Helsinki Metropolia University of Applied Sciences at Albertinkartu 40-42, 00150 Helsinki. From the results obtained, the performance of the anechoic chamber was determined; how well the chamber was absorbing the signals generated inside the chamber; if the antenna measurements that were being carried out inside the chamber were accurate.
The chamber was evaluated using APC method and VSWR method which are the two most common type of techniques used for determining the reflectivity of an anechoic chamber. In each method, two identical patch antennas tuned at 735 MHz frequency were used and the measurements were recorded using the network analyzer. The final value of reflectivity calculated from both methods were compared to the commercial standard and thus the evaluation of the chamber was realized.
From the calculated results, the reflectivity of the chamber was found to be quite supporting with the tested frequency and the performance of the pyramidal absorber. In addition, the anechoic chamber seems to be complying with the commercial standard for radiated emission test.
The main target of the project fulfilled the requirement of the frequency that was used for the measurements. However, an anechoic chamber cannot be evaluated relying on one frequency only. The reflectivity of the chamber can be investigated at various frequencies and proper evaluation of the chamber can be achieved. The reflectivity value of the anechoic chamber calculated during this project can give an individual idea to some extent regarding the performance of the chamber and inconsistency in the measurements that is being carried out inside the chamber.
The chamber was evaluated using APC method and VSWR method which are the two most common type of techniques used for determining the reflectivity of an anechoic chamber. In each method, two identical patch antennas tuned at 735 MHz frequency were used and the measurements were recorded using the network analyzer. The final value of reflectivity calculated from both methods were compared to the commercial standard and thus the evaluation of the chamber was realized.
From the calculated results, the reflectivity of the chamber was found to be quite supporting with the tested frequency and the performance of the pyramidal absorber. In addition, the anechoic chamber seems to be complying with the commercial standard for radiated emission test.
The main target of the project fulfilled the requirement of the frequency that was used for the measurements. However, an anechoic chamber cannot be evaluated relying on one frequency only. The reflectivity of the chamber can be investigated at various frequencies and proper evaluation of the chamber can be achieved. The reflectivity value of the anechoic chamber calculated during this project can give an individual idea to some extent regarding the performance of the chamber and inconsistency in the measurements that is being carried out inside the chamber.