A very-small-sized reversed-phase hybrid ring

This paper presents a design method of a reversed-phase hybrid ring based on the equivalent admittance approach, and successfully designs a very miniature hybrid ring with a 0.28-wavelength or less circumference by adding shunt capacitors at each port as a matching element. The present hybrid has a broad bandwidth comparable to the regular reversed-phase hybrid ring. The validity and usefulness of the design are demonstrated by electromagnetic simulation for a uniplanar hybrid.