Wideband High Directivity Microstrip Couplers for Microwave Integrated Circuits

Microstrip loosely coupled quarter-wave directional couplers with broadband improved directivity can be obtained by technique in current use, merely adding a slight capacitance between the coupled lines. Additional computations or corrections are not required. The simple method was applied to many prototypes at different frequencies ranging from 1 to 7 GHz with interesting results.