Radiation loss in dielectric waveguide Y-branch structures

Volume current method is used to calculate the radiation loss of dielectric waveguide Y-branch structures. Radiation loss of a Y-branch in the power-dividing mode of operation is calculated accurately for the first time, obtaining proper zero loss in the limit of the zero branching angle. Radiation loss of a Y-branch with parallel output guides is calculated and compared to the loss of a three guide coupler-divider; the Y-branch has smaller loss. Simple analytical formulas are given for approximate loss calculation in these structures.