Ceramic ferroelectric composite material-BSTO-magnesium based compound

• US 5,635,434 A
• Filed: 09/11/1995
• Issued: 06/03/1997
• Est. Priority Date: 09/11/1995
• Status: Expired due to Term

• Current Assignee: Blackberry Limited
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Sengupta, Louise
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US08/528,629
• Time in Patent Office: 631 Days
• Field of Search: 501/137, 501/121, 501/120, 501/135, 501/136, 501/138
• US Class Current: 501/138
• CPC Class Codes: C04B 35/465 based on alkaline earth metal titanates

Abstract

Ceramic ferroelectric composite material-BSTO-Magnesia based compounds hag a low dielectric constant, low loss tangent and high tunability are disclosed. The composite material comprises Barium Strontium Titanate (BSTO) and a magnesia compound selected from the group consisting, MgZrO₃, MgAl₂ O₄, and MgTiO₃. The preferred composite is represented by Ba_1-x Sr_x TiO₃ -magnesia compound, wherein x is greater than 0.00, but less than or equal to 0.75, and wherein the percent weight ratio between BSTO and magnesia compound ranges from approximately 99%-40% and 1%-60%, respectively. The novel materials possess superior electronic properties, and they may be employed in various antenna systems.

Claims

1. A ceramic ferroelectric composite material-BSTO based compound consisting essentially of:

Barium Strontium Titanate, said Barium Strontium Titanate represented as Ba_i31 x Sr_x TiO₃ ;

wherein x is greater than 0.0 but less than or equal to 0.75;

and a magnesia compound selected from the group consisting of a NgZrO₃, MgAl₂ O₄, and a MgTiO;

wherein said Barium Strontium and said magnesia compound having a low dielectric constant, low low loss tangent and high tunability.

2. The ceramic ferroelectric composite material-BSTO-Magnesia based compounds according to claim 1, wherein said Barium Strontium Titanate is Ba_1-x SrTiO₃, wherein x=0.40.

3. The ceramic ferroelectric composite material-BSTO-Magnesia based compounds according to claim 1, wherein the weight ratio of said Barium Strontium Titanate to said magnesia compound selected from the group consisting of said MgZrO₃, said MgAl₂ O₄, and said MgTiO₃, ranges from approximately 99%-40% said Barium Strontium Titanate to approximately 1%-60% said magnesia compound.

4. The ceramic ferroelectric composite material-BSTO-Magnesia based compounds according to claim 3, wherein the ratio of said Barium Strontium Titanate to said Magnesia compound selected from the group consisting of said MgZrO₃, said MgAl₂ O₄, and said MgTiO₃ is approximately 70% wt. said Barium Strontium Titanate to approximately 30% said magnesia compound.