Abstract: Two new compact enhanced-bandwidth hybrid rings using composite right/left-handed transmission lines are designed. The replacement of the 270° branch by ±90° ones results in at least 75% reduction in size of the hybrid ring compared with the conventional one. At the same time, the bandwidths of the first hybrid ring operating at 2GHz are enhanced by 50% in the in-phase operation, and 49% in the 180°-out-of-phase operation. The introduction of the 0° transmission line branches makes it possible that the second new hybrid ring be used as a mixer of two signals with -90°, 0°, 90° or 180° phase difference. The bandwidth is enhanced by 38% in the in-phase operation.

Key words: hybrid ring, left-handed materials, composite right/left-handed transmission lines