1. [1] W.A. Sandrin, “The Butler matrix transponder,” COMSAT Tech. Rev., vol.4, no.2, pp.319-345, Fall 1974.
2. [2] S. Egami and M. Kawai, “An adaptive multi beam system concept,” IEEE J. Select. Areas in Commun., vol.SAC-5, no.4, pp.630-636, May 1987.
3. [3] K. Yamamoto and M. Tanaka, “50W class multi-port amplifier for multi-beam satellite communications,” in 1989 IEEE MTT-S Digest, PP-44, pp.1281-1284, 1989. 10.1109/mwsym.1989.38961
4. [4] M. Tanaka, K. Arai, K. Yamamoto, and K. Horikawa, “Ka-band and S-band transponder technologies for satellite on-board multibeam communications systems,” in 1992 Asia-Pacific Microwave Conference, 12-7, pp.261-264, 1992. 10.1109/apmc.1992.672030
5. [5] K. Horikawa, M. Tanaka, and K. Yamamoto, “A highly flexible and highly efficient 100W S-band transponder for multibeam mobile satellite communications,” in 14th AIAA-ICSSC, pp.148-154, 1992. 10.2514/6.1992-1823