Compact 3 dB 0/180o microstrip couplers in
ring and square configurations are proposed and
discussed. In a ring form, the coupler 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 1 GHz. The
IE3D software is used in order to validate the design
procedure. The designed coupler in ring shape is
simulated and implemented. The experimental results
agree well with the theoretical prediction