A W-Band Quasi-TEM Waveguide Using Electromagnetic Crystal (EMXT) Surfaces

A W-band (75-110 GHz) quasi-TEM square waveguide is designed and realized utilizing two-dimensional electromagnetic crystal (EMXT) surfaces as its boundary walls. Because EMXT surfaces provide special boundary conditions, the waveguide size is not limited by the typical cut-off frequency associated with a regular metallic waveguide and free space like wave propagation can be achieved for both polarizations. Both eigenmode and full-wave EM simulations verify the quasi-TEM propagation at the designed frequencies. The S-parameters of the EMXT waveguide in a WR-10 fixture is measured and low insertion loss that agrees with simulation is obtained. This type of waveguides may be useful for applications including spatial power combining, low loss interconnects, and packaging for millimeter wave systems