Dual-Band Combined-Aperture Variable Inclination Continuous Transverse Stub Antenna With Consistent Beam Direction

This article presents a Tx/Rx dual-band combined-aperture variable inclination continuous transverse stub (VICTS) antenna for low-earth-orbit (LEO) satellite-on-the-move (SOTM) applications. The beam directions for the Tx and Rx bands are kept consistent during beam scanning, so that the antenna allows a duplex link. The topology of the combined-aperture VICTS antenna is derived from the requirement for consistent beam directions. Nonuniform slow wave structures (SWSs) are used to achieve the required phase difference and phase-changing rate (PCR) between the radiation slots in the two bands, while maximizing the antenna efficiency. Predeflection technique is applied to the radiation slots to reduce the gain drop at a wide beam scanning angle. A prototype operating at K- and Ka-bands is designed, fabricated, and measured. Experimental results show that the antenna has a consistent beam direction during scanning in the frequency ranges of 19–21 GHz (Rx band) and 29–31 GHz (Tx band). The maximum beam directions in Tx and Rx bands exceeds ±47° at a relative rotation angle of 40°, and the gain drop during the beam scanning is reduced within 2.3 and 3.5 dB.