Terrestrial antennas (10A, 10B, 10C and 10D) which are capable of transmitting and receiving radio signals directly to and from satellites in low Earth orbit are disclosed. The preferred embodiment of the invention employs circularly polarized, dual-frequency printed circuit antenna elements (136) measuring...http://www.google.com.hk/patents/US5905466?utm_source=gb-gplus-share專利 US5905466 - Terrestrial antennas for satellite communication system
Terrestrial antennas for satellite communication system