A novel hybrid coupler design based on the concept of balanced loaded transmission lines

We propose a novel design for compact hybrid couplers. The concept of loaded transmission lines is exploited for the synthesis of a 2-stage hybrid coupler which is comparable in size with a canonical 1-stage coupler. The latter result is obtained exploiting the concept of balance between inductive and capacitive loads. Furthermore, a sinuous design for the longer lines is exploited to enhance compactness. Simulation results confirm that the proposed device outperforms the reference 1-stage device in terms of band of operation despite the comparable size.