EDGE-GUIDE MODE DIRECTIONAL COUPLER
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-08
Microstrip directional couplers are inherently directivity limited due to the dissimilarity of the even-mode and odd- mode impedances. The impedance variation results in unequal forward and reverse propagation velocities which leads to incomplete cancellation of energy in the reverse direction. In many instances the limitation in directivity is uacceptable and complex structures (multiple dielectric laminations) are used to offset the impedance variations.