Abstract: A high-speed data transmission system using half mode substrate integrated waveguide (HMSIW) is proposed and the single channel rate of 7.5 Gbps data transmission is realized. In this paper, the traditional SIW interconnection transmission system is improved. The channel transmission bandwidth and the system transmission rate are significantly increased by using the new HMSIW interconnect to replace the traditional SIW waveguide interconnection. The HMSIW has a dominant mode of TE_0.5,0 and the traditional SIW has a dominant mode of TE₁₀ . The single mode work bandwidth of the proposed HMSIW is two times larger than that of the traditional SIW, and the width of HMSIW is only half of that of SIW when the cutoff frequency of the dominant modes of the two waveguides are same. Comparison between the two systems based on HMSIW and SIW shows that the HMSIW based interconnect system has 1.5 times higher data transmission rate than that of SIW inter－connect system.