One construction uses optical waveguides, while the other is inspired by fractal geometry.

The Schwinger reversed-phase coupler is another design using parallel waveguides, this time the long side of one is common with the short side-wall of the other.

Other evanescent wave biosensors have been commercialised using waveguides where the propagation constant through the waveguide is changed by the absorption of molecules to the waveguide surface.

Above about 400 Hz the low-frequency cones become directional, again violating the theory's assumptions, and at high frequencies, many practical systems use directional waveguides whose behavior cannot be described using classical line array theory.

In April 2010, scientists published a paper in Nature showing that they had used zero-mode waveguides to perform real-time observation of ribosomal translation.

Many klystrons use waveguides for coupling microwave energy into and out of the device, although it is also quite common for lower power and lower frequency klystrons to use coaxial cable couplings instead.

Vuzix is currently working on a system for PCAS that will use holographic waveguides to produce see-through augmented reality glasses that are only a few millimeters thick.

Planar lightwave circuits are either optical integrated circuits (ICs) or optical circuit boards made using the same manufacturing techniques as their electronic counterparts, using optical waveguides to route photons the same way that metal traces are used to route electrons in electronic ICs and circuit boards .

He used waveguides, horn antennas, dielectric lenses, various polarisers and even semiconductors at frequencies as high as 60 GHz; much of his original equipment is still in existence, now at the Bose Institute in Kolkata.