Reconfigurable radiation from a W-band trough waveguide antenna: trade-offs in impedance and radiation from tapered MEMS-based perturbations

This work examines tapered, variable-length, MEMS-based perturbations for fixed frequency beam steering of a W-band trough waveguide antenna. Tapered (non-rectangular) perturbation geometries are utilized to reduce the impedance mismatch due to phase accumulation while scanning through broadside (where perturbations are one-half a guided wavelength), improve the fixed-frequency and frequency-dependant scanning capabilities, and reduce the side-lobes during scanning operations. Three different perturbation geometries (rectangular, sinusoidal, and triangular) are used in this work to study non uniform, periodic, odd aperture distributions (antiphase constant, sine, and antiphase triangular, respectively) and determine the resulting trade-offs in radiation and impedance behavior of the antenna. By maintaining the impedance match over the range of reconfigured radiation patterns and improving the radiation behavior of the antenna, the capacity of the antenna to support multi-function mm-wave systems can be increased substantially.