Circular Sector Patch Hybrid Coupler With an Arbitrary Coupling Coefficient and Phase Difference

This paper presents, for the first time, a patch coupler configuration that can be designed with an arbitrary coupling coefficient and phase difference at the output ports. Four circular sector patches are combined to form the patch coupler resulting in ease of design and fabrication. To demonstrate and verify this, a patch quadrature coupler configuration is proposed to realize a wide range of coupling coefficients by adjusting the radii of each quadrant. To extend this concept of an arbitrary coupling coefficient for 180° patch couplers, different patterns are etched underneath the circular patch to realize the required power division ratio while maintaining good impedance matching and desired phase characteristics at the input/output ports. Finally, a circular patch coupler is demonstrated to exhibit an arbitrary phase difference between output ports maintaining an equal power division.