A Low-Profile Beam-Steering Reflectarray With Integrated Leaky-Wave Feed and 2-Bit Phase Resolution for Ka-Band SatCom

A novel reflectarray (RA) with ultralow-profile and 2-bit phase quantization beam-steering ability is presented in this article. To reduce the profile, a Leaky-wave feed is used to excite the RA with enhanced illumination efficiency. Moreover, simultaneous sum and difference patterns are also obtained to provide beam flexibility. The entire thickness of the proposed RA is less than 3% of that of the conventional front-fed RA with the same aperture. To increase the efficiency of the RA, a novel unit cell consisting of a polarizer layer and a reflection layer is developed, which is configured to provide polarization rotation and 2-bit phase shifts by using a hybrid of tunable polarization and discrete resonator. The operation principle, theoretical explanation, and implementation of the proposed antenna are elaborated in this work. To prove the design concept and beam scanning performance, an array with 9 \times 7 unit cells operating at Ka-band is designed and simulated first. Two-dimensional beam scanning within the range of ±30° has been verified. Then, a passive prototype with 9\,\,\times67 unit cells is designed, fabricated, and measured. Experimental results show aperture efficiency of 35.1% and illumination efficiency of 43.4%. The developed RA is scalable, and it provides a viable low-cost solution to develop low-profile, high-gain and beam-steering array antennas for satellite applications.