3-D -Printed Dielectric Slab Rectangular Waveguide for TE10 and TE20 Mode Equalization

The dielectric slab rectangular waveguide (DSRW) has been widely studied and used for increasing the single-mode bandwidth (BW) of rectangular waveguides. This work presents a DSRW for equalizing the group velocity of the first two propagating modes in the structure. Suitably scaled, this DSRW design can be used in chip-to-chip communications to yield interconnects that avoid dispersion while enhancing the BW density of these systems. A theoretical analysis is introduced to show the equalization BW attained depending on the slab dimensions with regard to the rectangular waveguide width and the dielectric permittivity of the materials that fill the waveguide. A proof of concept slab rectangular waveguide is designed to meet a 45% equalization BW around a center frequency of 10.0 GHz. The design is scalable and can be adapted to fit the dielectric permittivity of available materials. Several waveguide sections were fabricated using additive manufacturing (AM) techniques and two dielectric materials with different permittivities. Simulations and measurements confirm the waveguide behavior at the design frequency range. TE10 and TE20 modes exhibit the same group velocity of
$0.36\times c_{0}$
at 7.95 GHz.