Reverberation chambers at low frequencies

This report documents the effects of corrugated walls on the uniformity of the electromagnetic environment within a small (1.8 m×1.2 m×0.8 m) reverberation chamber. The frequency band evaluated was 150 MHz to 650 MHz, taking 5 MHz steps. At each frequency 100 tuner steps were made, resulting in one complete tuner rotation. A small dual ridge horn antenna, designed for use above 800 MHz, was used as the transmit device. Field strength measurements were taken continuously using a three-axis, isotropic field measurement probe. The electric field intensity was measured in this way at sixteen different locations, once with flat, aluminum walls, and once with corrugated galvanized steel walls. The corrugated material was attached to the left, right, and rear walls, with extra corrugation randomly spread on the bottom. The data shows that corrugated material increases the uniformity of the electromagnetic environment within a reverberation chamber