A small size 3-dB 0/spl deg//180/spl deg/ microstrip ring couplers

A new small size 3 dB microstrip ring couplers suitable for microwave integrated circuits (MICs) and monolithic microwave integrated circuits (MMICs) are presented. Area saving more than 85% of that of the conventional ring coupler can be achieved using the proposed configurations. Small size couplers based on the proposed configurations designed at 900 MHz have been implemented on RT/Duroid 5880 dielectric material. The theoretical and experimental results show favorable comparison.