An Optimal Design of Directional Coupler of Millimeterwave Integraed Dielectric Image Lines

The general optimization program by making use of a new direct optimization method for directional coupler of millimeterwave integrated dielectric image line are described. The optimal numerical results, in 8 mm wave range, 3-dB coupler of 26-percent bandwidth and flatness less than 0.5 dB, have been obtained.