*SIW-Based Devices DOI: http://dx.doi.org/10.5772/intechopen.105421*

(EMI). The classical design methods of phase shifters based on SIW are mainly to control the equivalent dielectric constant of the transmission line [39–41], make selfcompensating wideband shifters [42–44], and take advantage of the slow-wave effect [45, 46]. Controlling the equivalent dielectric constant of transmission is the most widely used method. There are many designs such as using air-filled slabs and loading extra metallic posts. The designed phase shifters have good performance in a narrow band, but all of them are sensitive to frequency, which has poor performance in a wide bandwidth. Self-compensating technology is used to realize wide-band phase shifters. A phase shifter that takes advantage of the slow-wave effect can get a more compact size. In addition, dynamic tunable phase shifters are also popular. The main criteria for SIW phase shifter include insertion loss, operating bandwidth, phase deviation, and power handling capabilities. Next, we will introduce several phase shifters with excellent performance.
