Practical microwave circuits for groove waveguides

Groove guides have been known for many years. No practical microwave circuits have yet been described, although these types of transmission lines could be used in many cases. This paper discusses the physical realizability of some wide band designs such as matched load, directional coupler, hybrid coupler, bend and phase shifter. Both closed and open groove guides have been investigated. Optical-type components seem to be inappropriate for groove guide transmission. The best way to design components for these guides is to adapt those of standard rectangular guides, which perturb only the RF fields in the vicinity of the narrow walls, and to optimize the dimensions of the groove structure as a function of the losses and the symmetry of the induced spurious modes.