Abstract: Higher isolation solutions for printed circuit board mounted antenna and waveguide interfaces are provided herein. An example waveguide mounted onto a dielectric substrate can enclose around a periphery of an antenna and contain radiation produced by the antenna along a path that is coaxial with a centerline of the waveguide. The waveguide can have a first portion having a first cross sectional area that is substantially polygonal that transitions to a second cross sectional area that is substantially conical. A shape of the radiation produced by the antenna is altered by the first portion as the radiation propagates through the first portion. A second portion includes an elongated tubular member coupled with the first portion.