Fahmi, M. M., J. A. Ruiz-Cruz, R. R. Mansour, and K. A. Zaki,  "Compact Ridge Waveguide Filters With Arbitrarily Placed Transmission Zeros Using Nonresonating Nodes",  IEEE Transactions on Microwave Theory and Techniques, vol. 57, no. 12, pp. 3354-3361, Dec., 2009.

Ruiz-Cruz, J. A., Y. Zhang, K. A. Zaki, A. J. Piloto, and J. Tallo,  "Ultra-Wideband LTCC Ridge Waveguide Filters",  IEEE Microwave and Wireless Components Letters, vol. 17, no. 2, pp. 115-117, Feb., 2007.

Zhang, Y., J. A. Ruiz-Cruz, and K. A. Zaki,  "Ridge Waveguide Divider Junctions for Wide-Band Multiplexer Applications",  2006 IEEE MTT-S International Microwave Symposium Digest, pp. 1225-1228, June, 2006.

Ruiz-Cruz, J. A., Y. Zhang, M. M. Fahmi, and K. A. Zaki,  "Ridge Waveguide Elliptic Filters in Narrow-Wall Canonical Configuration",  Proc. 36th European Microwave Conference, pp. 1080-1082, Sept., 2006.

Ruiz-Cruz, J. A., M. A. El Sabbagh, K. A. Zaki, J. M. Rebollar, and Y. Zhang,  "Canonical ridge waveguide filters in LTCC or metallic resonators",  IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 1, pp. 174-182, Jan., 2005.

Fahmi, M. M., J. A. Ruiz-Cruz, K. A. Zaki, and A. J. Piloto,  "LTCC wide-band canonical ridge waveguide filters",  2005 IEEE MTT-S International Microwave Symposium Digest, pp. 249-252, June, 2005.

Ruiz-Cruz, J. A., Y. Zhang, K. A. Zaki, A. J. Piloto, and J. M. Rebollar,  "Ridge waveguide branch-line directional couplers for wideband applications and LTCC technology",  2005 IEEE MTT-S International Microwave Symposium Digest, pp. 1219-1222, June, 2005.

Liu, Z. M., J. A. Ruiz-Cruz, C. Wang, and K. A. Zaki,  "An extremely wideband ridge waveguide filter",  2004 IEEE MTT-S International Microwave Symposium Digest, vol. 2, pp. 615-618, June, 2004.