A coaxial multi-slot antenna used for LEO-MSAT

It is foreseen that suburban areas and countryside will be covered by low-Earth-orbit mobile satellite communications (LEO-MSAT). In order to make LEO-MSAT commercially viable, its mobile terminal must be designed as a consumer product that is low-cost, light-weight, small-in-size, and robust. This is a tall order to be fulfilled because the mobile terminal for LEO-MSAT is more complex than its counterparts for GEO-MSAT although the former has a lower power rating. Comparing with a DBS antenna, a MSAT antenna must be equipped with a steerable main-beam for tracking the satellite position, preferably it is an automatic tracking system. Moreover, the antenna must be low-cost, high-gain, high-efficiency, small-in-size, and preferable low-profile. To this end, an innovative antenna that satisfies most of the aforementioned requirements has been conceived. The innovative antenna is an array comprising two to three antennas. Each antenna itself comprises a coaxial transmission line protruded from a ground plane. In this paper, an accurate analytical technique is developed for studying and designing the element of the novel LEO-MSAT antenna array, the multi-slot coaxial line antenna. The calculated and experimental radiation patterns show that the technique is successful.