X Band Miniaturized 90° Hybrid Coupler

A miniaturized 90° hybrid coupler for X band using distributed capacitors in the inner area is designed. It is composed of high impedance transmission lines with reduced length and distributed capacitors. It is designed to increase the operating bandwidth and reduce the size as small as possible. To further increase the bandwidth a two section hybrid coupler is implemented. The miniaturized hybrid has amplitude imbalance of ± 0.5 dB, return loss and isolation of 15dB in the frequency range of 9.48GHz to 9.87GHz. The miniaturized broadband hybrid coupler has amplitude imbalance of ± 0.5 dB, return loss and isolation of 15dB in the frequency range of 9.46GHz to 12GHz. Both the design has broader bandwidth and minimum phase imbalance. The designs were simulated using Ansys HFSS.