Microstrip phase shifter

• US 6,621,377 B2
• Filed: 05/02/2001
• Issued: 09/16/2003
• Est. Priority Date: 05/02/2000
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Paratek Microwave Incorporated (Blackberry Limited)
• Inventors: Sengupta, Louise C., DuToit, Cornelis F., Osadchy, Vitaly, Kozyrev, Andrey
• Primary Examiner(s): Ham, Seungsook
• Application Number:
  US09/847,254
• Publication Number:
  US 20020014932A1
• Time in Patent Office: 867 Days
• Field of Search: 333/995, 333/156, 333/161, 333/205
• US Class Current: 333/161
• CPC Class Codes: H01P 1/181 using ferroelectric devices

Abstract

A phase shifter includes a substrate, a first electrode positioned on a surface of the substrate, a tunable dielectric layer positioned on a surface of the electrode, a microstrip positioned on a surface of the tunable dielectric layer opposite the substrate, an input for coupling a radio frequency signal to the microstrip, an output for receiving the radio frequency signal from the microstrip, and a connection for applying a control voltage to the electrode. In an alternative embodiment, a second electrode can be positioned on the surface of the substrate and separated from the first electrode to form a gap positioned under the microstrip.

Claims

1. A phase shifter comprising:

a substrate;

a first electrode positioned on a surface of the substrate;

a tunable dielectric layer positioned on a surface of the first electrode said tunable dielectric material operable at least at temperatures that include, room temperature and wherein the dielectric constant can be changed by 20% to 70% at 20 V/μ

m;

a microstrip positioned on a surface of the tunable dielectric layer opposite the substrate;

an input for coupling a radio frequency signal to the microstrip, the radio frequency signal in the K or Ka band;

an output for receiving the radio frequency signal from the microstrip; and

a connection for applying a control voltage to the electrode.

2. A phase shifter according to claim 1, further comprising:

a second electrode positioned on the surface of the substrate, said first and second electrodes being separated to form a gap therebetween, the gap being wider than a width of said micro strip.

3. A phase shifter according to claim 1, further comprising:

a first impedance matching section coupling said input to said microstrip; and

a second impedance matching section coupling said output to said microstrip.

4. A phase shifter according to claim 1, wherein the tunable dielectric layer comprises a material selected from the group of:

barium strontium titanate, barium calcium titanate, lead zirconium titanate, lead lanthanum zirconium titanate, lead titanate, barium calcium zirconium titanate, sodium nitrate, KNbO₃, LiNbO₃, LiTaO₃, PbNb₂O₆, PbTa₂O₆, KSr(NbO₃), NaBa₂(NbO₃)₅, KH₂PO₄, and combinations thereof.

5. A phase shifter according to claim 1, wherein the tunable dielectric layer comprises a barium strontium titanate (BSTO) composite selected from the group of:

BSTO—

MgO, BSTO—

MgAl₂O₄, BSTO—

CaTiO₃, BSTO—

MgTiO₃, BSTO—

MgSrZrTiO₆, and combinations thereof.

6. A phase shifter according to claim 1, wherein the tunable dielectric layer comprises a material selected from the group of:

Mg₂SiO₄, CaSiO₃, BaSiO₃, SrSiO₃, Na₂SiO₃, NaSiO₃-5H₂O, LiAlSiO₄, Li₂SiO₃, Li₄SiO₄, Al₂Si₂O₇, ZrSiO₄, KAlSi₃O₈, NaAlSi₃O₈, CaAl₂SiO₈, CaMgSi₂O₆, BaTiSi₃O₉ and Zn₂SiO₄.

7. A phase shifter according to claim 1, wherein the tunable dielectric layer comprises an electrically tunable phase and at least two metal oxide phases.

8. A phase shifter according to claim 1, wherein the substrate comprises a material selected from the group of:

MgO, LaAlO₃, sapphire, Al₂O₃, and a ceramic.