A Shared-Aperture Helical-Array Antenna Set at L and S Bands for Navigation Satellite Systems [Antenna Applications Corner]

This article reports on the design and development of a novel sharedaperture antenna that is set at the widely separated L5 and S bands for navigation satellite systems with its concentric phase centers located at the two bands. The design of the radiating element and its performance is also detailed as well as the design of the critical sections, namely, the square-coaxialline and waveguide feed networks, in view of multipaction and average power handling capability. An innovative method of implementing a sequential rotation scheme for improving the array cross-polarization isolation is discussed, and, subsequently, this article also presents and compares the measured and analyzed results of the array antenna set at the L5 and S bands. After data analysis, it was found that the in-orbit test results of the antenna well agreed with its measured results acquired at the ground level.