Broad-Band Design of Lumped-Element 3 dB Quadrature Hybrid for Satellite Communications

위성통신용 집중정수형 3dB $90{\circ}$ 방향성 결합기의 광대역 설계에 관한 연구

Abroad-band design method of a lumped-element 3 dB quadrature hybrid without magnetic coupling is proposed and discussed, where techniques of cascading fundamental hybrids via second-order delay equializers and adding matching sections are adopted. It is shown that the designed broad-band lumped-element 3 dB quadrature hybrid can be easily constructed and its bandwidth reaches up to 54%. Furthermore, the experiments have been carried out, the results of which agree with the theoretical ones, and hence, the validity of the broad-band design method proposed here was confirmed.