Satellite MIMO Measurement With Colocated Quadrifilar Helix Antennas at the Receiver Terminal

An outdoor measurement campaign was undertaken with a dual circularly polarized (CP) contrawound quadrifilar helix antenna (CQHA) at the receiver terminal in a low-elevation land mobile satellite multiple-input-multiple-output (MIMO) system. The CQHA is a combination of two colocated miniaturized quadrifilar helix antennas and feeding networks. Performance of the CQHA was then evaluated and compared to spatially separated reference antennas in terms of measured correlation and capacity. Measurement results indicate that CQHA has the same performance as the reference antennas in non-line-of-sight (NLOS) environment, while in obstructed-LOS (OLOS) areas, proper orientation of the CQHA is required to achieve nearly the same capacity as the reference antennas .