Planar microwave integrated phase-shifter design with high purity ferroelectric material

Abstract

Ferroelectric materials (FEM's) are very attractive because their dielectric constant can be modulated under the effect of an externally applied electric field perpendicular to the direction of propagation of a microwave signal. FEM may be particularly useful for the development of a new family of planar phase shifters which operate up to X X X-band. The use of FEM in the microwave frequency range has been limited in the past due to the high losses of these materials tan = 0:3 at 3 GHz is typical for commercial BaTiO 3 (BTO) and due to the high electric field necessary to bias the structure in order to obtain substantial dielectric constant change. In this paper, how a significant reduction in material losses is possible is demonstrated. This is achieved by using a new sol-gel technique [1] to produce barium modified strontium titanium oxide [Ba10xSrxTiO3 (BST)], which has ferroelectric properties at room temperature. Also demonstrated is how the use of thin ceramics reduces the required bias voltage below 250 V, with almost no power consumption required to induce a change in the dielectric constant. A phase shift of 165 was obtained at 2.4 GHz, with an insertion loss below 3 dB by using a bias voltage of 250 V. Due to the planar geometry and light weight of the device, it can be fully integrated in planar microwave structures.

Investigation of the Characteristics of Barium Strontium Titanate (Bst) Dielectric Resonator Ceramic Loaded on Array Antennas

“…A dielectric ceramic that is not enclosed entirely by a conductive boundary can radiate as an antenna [21][22][23][24][25][26][27][28][29][30]. This was the first part of this investigation, which was conducted to determine the effectiveness of ceramic dielectric as a radiating element.…”

The Use of the FDTD Method for Electromagnetic Analysis in the Presence of Indepedently Time-Varying Media

“…There have already been a number of publications [2][3][4][5][6] describing the realisation of tunable components using bulk distributed properties directly rather than semi-lumped active components. We use the word "tunable" since the variation of the material properties is on a time-scale that is several orders of magnitude "slower" compared to the signal being controlled.…”

Technological evolution and performances improvements of a tunable phase‐shifter using liquid crystal

“…In planar technology, a phase-shifter using ferroelectric materials has been described in the literature [6]. Recently, few approaches have used LC for the dielectric substrate of a microstrip line [7][8][9][10].…”