Blazed gratings have so far been made tunable by mechanically changing the grating geometry, such as its periodicity. In this work, a low-profile planar blazed metasurface grating is demonstrated which is electronically tunable, with no moving or mechanically changing parts. The reflective metasurface is comprised of planar patch resonators with a cutting slot loaded with a surface mount varactor in each unit cell, and is demonstrated numerically and experimentally in Part 1. Coupling of the incident wave to the resonant surface provides a high efficiency back reflection or blazing. We show that by changing the DC bias, we are able to control the strip resonance, which in turn controls the Bragg blazing frequency and the reflection angle of the operation. This tuning has been confirmed by simulations and measurements for the Transverse Magnetic polarized incident wave within the X-band. In Part 2, several design are proposed to overcome the problems of the original design and improve the performance. The ground-slotted design, which maintains a simple strip resonator and places the bias on the ground plane, appears to achieve strong blazing using fewer varactors. Meanwhile, the separated bias system for ground-slotted design helps to identify defective varactors during fabrication. Future work is proposed in the final section to further refine the design and have a promised measurement result.
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