Ferroelectric phase shifters for electronically steerable antenna systems

It is shown that ferroelectric phase shifters for electronically steerable antenna systems can be realized by using an appropriate composition (e.g., Ba/sub 0.45/Sr/sub 0.55/TiO/sub 3/) of barium strontium titanate material in a suitable transmission line medium (waveguide, coaxial line, or microstrip line). Ferroelectric phase shifters will have several advantages over other types of phase shifters, including high power handling capacity, simple driver circuitry, low drive power, and low cost. Because of the large variation (more than 50%) of dielectric constant with DC biasing voltage, the development of low-loss tangent materials due to the addition of small quantities of Fe or Hi or Mn, and sol-gel processing of ultrapure and fine ceramic powders, (Ba-Sr)TiO/sub 3/ materials are particularly suitable for ferroelectric phase shifter applications.<
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