This study presents a breast microwave radar imaging system designed for bistatic operation in air. The system operates in the range of 1-8 GHz and employs a double-ridged horn antenna array with four degrees of freedom. A hemispherical breast phantom with a tumor inclusion of 1.5 cm diameter was used for validation. Reconstructed datasets resulted in artifact-free images where the tumor presence was detected. Signal to clutter ratios greater than 30 dB and tumor to fibroglandular ratios of 3 dB were measured. The encouraging images obtained with the system validate its potential as a clinical tool for breast cancer detection.