Microwave testing of dielectric materials has recently become an increasingly important field. Dielectric materials such as composites are preferred over metallic counterparts, due to their light weight and superior strength. Because of the exponential growth in the use of such materials, a reliable method for testing is vital. This paper presents a novel microwave imaging system for the nondestructive detection of anomalies in dielectric materials. The system utilizes an active beam steering array that scans a wide circular sector of 150° where dielectric targets are positioned. The scattered field, measured on the arc of the sector, was used for image reconstruction and discontinuity detection by means of time reversal signal processing. Two types of anomalies are considered in the paper: discontinuities and metallic impurities. Experimental results of detecting these anomalies within dielectric samples are presented. Keywords: microwave testing, microwave imaging, antenna arrays, beam steering, time reversal signal processing.