Miniaturized CPW Rat-Race Coupler Using the Superformula

This paper presents a new design of a CPW rat race coupler at 1.8 GHz that employs the superformula to draw the shape of the coupler. The meander-shape like circumference of the coupler allows for around 83% reduction in the size of the coupler as compared with circular conventional coupler. Simulated results for the magnitude and phase of the S-parameters are provided using HFSS with good results.