The artificial microwave volume hologram technique has been applied to design a new microwave spatial beam splitter/combiner. It uses the multiplexing concept and has multiple holographic gratings integrated into a single hologram slab. A prototype has been fabricated and measured to verify the design concept.
Electronics Letters
Carleton University

Zhu, W., Shaker, J., Wight, J. S, Cuhaci, M., & McNamara, D.A. (2006). Microwave spatial beam splitter/combiner using artificial microwave volume hologram technology. Electronics Letters, 42(24), 1406–1408. doi:10.1049/el:20063038