Substrate integrated hybrid Butler matrix

In this paper, a substrate integrated hybrid Butler matrix is proposed and experimented making full use of the mode-to-mode coupling effect between a half mode substrate integrated waveguide (HMSIW) and a conductor-backed slotline etched on its broad wall. Several microstrip-to-slotline transitions are employed to connect such four hybrid HMSIW-slotline structures and also offer required phase shifts. This type of hybrid Butler matrix not only keeps a compact and small physical dimension, but also associates the HMSIW´s excellent property with the planar structure´s flexibility and integrated circuit compatibility. Thus it is believed that this substrate integrated hybrid circuit (SIHC) technology has great potentialities for microwave and millimeter-wave applications.