New small size 3 dB microstrip 0o/180o coupler configurations are proposed and
discussed. The coupler can be fabricated in square or ring form. The ring may be
designed for symmetrical ports about either one axis or two axes. The proposed
configurations introduce significant size reduction, which is the most important
demand for microwave integrated circuits (MICs) and monolithic microwave
integrated circuits (MMICs). Different couplers are designed, and simulated at 900
MHz. The designed coupler in square shape is simulated and implemented.
Experimental results agree quit well with theoretical predicti