1. Cohn, S. B., "Properties of ridge waveguide," Proc. IRE, Vol. 35, No. 8, 783-788, 1947.
doi:10.1109/JRPROC.1947.226277
2. Hopfer, S., "The design of ridge waveguide," IRE Transactions on Microwave Theory and Techniques, Vol. 3, No. 10, 20-29, 1955.
doi:10.1109/TMTT.1955.1124972
3. Rong, Y. and K. A. Zaki, "Characteristics of generalised rectangular and circular ridge waveguides," IEEE Trans. MTT, Vol. 48, No. 2, 258-265, 2000.
doi:10.1109/22.821772
4. Tsandoulas, G. N. and G. H. Knittel, "The analysis and design of dual-polarisation square waveguide phased arrays," IEEE Transactions on Antennas and Propagation, Vol. 21, 796-808, Nov. 1973.
5. Chen, C. C., "Quadruple ridge-loaded circular waveguide phased arrays," IEEE Transactions on Antennas and Propagation, Vol. 22, 481-483, May 1974.
doi:10.1109/TAP.1974.1140797
6. Chen, C. C., et al. "Modal characteristics of quadruple-ridge circular and square waveguide," IEEE Transactions on Antennas and Propagation, Vol. 22, 801-804, August 1974.
7. Chu, T.-T. and A. Larussi, Quad ridged feed horn with two co-planar probes, US Patent No. 6,624,792 B1, Sept. 23, 2003.
