This engineering study describes the design and validation of a reverberation chamber intended for large-scale animal carcinogenicity research with RF EMF relevant to 4G/5G. E-field uniformity was tested under four loading scenarios, including setups with 80 Sprague-Dawley rats. The chamber achieved better than 1.36 dB E-field uniformity across scenarios, and the authors report a method to predict composite E-field intensity for simultaneous multi-frequency exposures.