A measurement method for reflection coefficient of anechoic chamber using standing wave techniques

This paper presents the results of measurements of the reflection coefficient of the anechoic chamber in the microwave laboratory, Electronic Engineering Polytechnic Institute of Surabaya (EEPIS), ITS, in the frequency range of 1,000 MHz to 1,700 MHz. For this purpose, we made a pyramidal horn antenna especially for the required frequency range. This antenna is used as a matching device between space (air) and the transmission line. It is also used as a device for the measurement of transmitted waves and received waves reflected by the anechoic chamber. When a radio wave is transmitted by the antenna and reflected by the anechoic chamber, there is a standing wave along the transmission line. This technique is used to measure the reflection coefficient of the anechoic chamber. In this measurement, the wave is transmitted perpendicular (or normal) to the wall surface of the chamber. Radiowaves were transmitted in three different patterns based on the structure of the pyramid wall of the chamber. From the results of the experiments, it is found that the average reflection coefficients of the chamber are 0.0586 (-24.74 dB); 0.0785 (-22.20 dB) and 0.0969 (-20.36 dB) for 1,000 MHz to 1,700 MHz.