Hybrid Reflectarray Antenna of Passive and Active Unit Cells for Highly Directive Two-Direction Beam Steering

Abstract

A hybrid reflectarray antenna (RA) composed of passive and active unit cells that can steer a beam into two selected directions with high aperture efficiencies is designed and experimentally verified. The hybrid RA is implemented by a combination of one-bit active and passive unit cells, which enables the quantization of phase profiles of the reflection coefficients on the antenna surface to 120°. This combination can improve the quantization efficiency of the conventional one-bit reconfigurable RA quantized with 180°. A combination of the passive unit cells of which the phases of reflection coefficients are 180° is determined to be included simultaneously in two quantized phase profiles for two-direction beam steering. As a proof of concept, the hybrid RA is designed to steer the beam to the vertical angles 𝜃 of -18° and 18° on the E-plane. By comparing them with those of the one-bit RA, we confirmed that the aperture efficiencies are improved by 41.85% and 69.41% in simulations and by 37.19% and 60.19% in measurements for the vertical angles 𝜃 of -18° and 18°, respectively.

Broadband Parasitic Modeling of Diodes in the Millimeter-Wave Band

“…Another type of device packaging, named flip chip packaging, provides a broader frequency operating range. PIN diodes with this type of packaging have been selected for prototypes above 10 GHz [13][14][15][16][17][18]. With this packaging, the parasitic effects are mitigated, and the circuit model of the diode is extended in frequency to use it in the design process.…”