Serially-fed phased array antennas with dielectric phase shifters

• US 6,377,217 B1
• Filed: 09/13/2000
• Issued: 04/23/2002
• Est. Priority Date: 09/14/1999
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Paratek Microwave Incorporated (Blackberry Limited)
• Inventors: Sengupta, Louise C., Zhang, Xubai, Kozyrev, Andrey, Zhu, Yongfei
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/660,719
• Time in Patent Office: 587 Days
• Field of Search: H01/Q.138, H01/Q 2.100, 343/700.MS, 343/767, 343/770, 343/771, 343/778, 343/829, 343/846, 343/853, 343/872
• US Class Current: 343/700.0MS
• CPC Class Codes: H01P 1/181 using ferroelectric devices
• CPC Class Codes: H01Q 21/0075 Stripline fed arrays H01Q21/065 takes precedence
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

A phased array antenna includes a plurality of radiating elements, a feed line assembly, a ground plane positioned between the plurality of radiating elements and the feed line assembly, with the ground plane having a plurality of openings positioned between the plurality of radiating elements and the feed line assembly, and a plurality of voltage tunable dielectric phase shifters coupled to the feed line assembly.

Claims

1. A phased-array antenna comprising:

a plurality of radiating elements;

a feed line assembly;

a ground plane positioned between the plurality of radiating elements and the feed line assembly, said ground plane having a plurality of openings positioned between the plurality of radiating elements and the feed line assembly; and

a plurality of voltage tunable dielectric phase shifters coupled to said feed line assembly.

2. A phased array antenna as recited in claim 1, wherein each of the plurality of voltage tunable dielectric phase shifters comprises:

a substrate;

a tunable dielectric film having a dielectric constant between 70 and 600, a tuning range of 20 to 60%, and a loss tangent between 0.008 and 0.03 at K and Ka bands, the tunable dielectric film being positioned on a surface of the substrate;

a coplanar waveguide including a conductive strip positioned on a surface of the tunable dielectric film opposite the substrate;

an input for coupling a radio frequency signal to the conductive strip;

an output for receiving the radio frequency signal from the conductive strip; and

a connection for applying a control voltage to the tunable dielectric film.

3. A phased array antenna as recited in claim 2, wherein the tunable dielectric film comprises a barium strontium titanate composite.

4. A phased array antenna as recited in claim 2, further comprising:

a first impedance matching section of said coplanar waveguide coupled to said input; and

a second impedance matching section of said coplanar waveguide coupled to said output.

5. A phased array antenna as recited in claim 4, wherein the first impedance matching section comprises a first tapered coplanar waveguide section;

and

wherein the second impedance matching section comprises a second tapered coplanar waveguide section.

6. A phased array antenna as recited in claim 2, wherein the connection for applying the control voltage to the tunable dielectric film comprises:

a first electrode positioned adjacent a first side of said conductive strip to form a first gap between the first electrode and the conductive strip; and

a second electrode positioned adjacent a second side of said conductive strip to form a second gap between the second electrode and the conductive strip.

7. A phased array antenna as recited in claim 6, further comprising:

a third electrode position adjacent a first side of said first electrode opposite said conductive strip to form a third gap between the first electrode and the third electrode; and

a fourth electrode position adjacent a first side of said second electrode opposite said conductive strip to form a fourth gap between the second electrode and the fourth electrode.

8. A phased array antenna as recited in claim 6, further comprising:

a conductive dome electrically connected between the first and second electrodes.

9. A phased array antenna as recited in claim 2, wherein the substrate comprises one of:

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

10. A phased array antenna as recited in claim 2, wherein the substrate has a dielectric constant of less than 25.

11. A phased array antenna as recited in claim 2, wherein the tunable dielectric film has a dielectric constant of greater than 300.

12. A phased array antenna as recited in claim 2, further comprising:

a conductive housing covering each of the plurality of voltage tunable dielectric phase shifters.

13. A phased array antenna as recited in claim 2, wherein the tunable dielectric film comprises one of the group of:

barium strontium titanate (Ba_xSr<sub>1−

x</sub>TiO₃, BSTO, where x is less than

     1), BSTO—

MgO, BSTO—

MgAl₂O₄, BSTO—

CaTiO₃, BSTO—

MgTiO₃, BSTO—

MgSrZrTiO₆, and combinations thereof.

14. A phased array antenna as recited in claim 1, wherein:

said openings are elongated; and

orthogonal pairs of said openings are positioned adjacent to each of said radiating elements.

15. A phased array antenna as recited in claim 14, wherein said feed line assembly comprises:

a first microstrip line and a plurality of additional microstrip lines, wherein each of said plurality of additional microstrip lines extends perpendicularly from said first microstrip line and lies adjacent to one of said pairs of said openings.

16. A phased array antenna as recited in claim 15, wherein each of said plurality of additional microstrip lines provides a 90°

phase shift between the openings of an adjacent one of said orthogonal pairs of said openings.

17. A phased array antenna as recited in claim 1, wherein each of said radiating elements has a square shape.

18. A phased array antenna as recited in claim 1, wherein said plurality of radiating elements are arranged in a plurality of rows and columns, and wherein said feed line assembly comprises:

a first microstrip line and a plurality of additional microstrip lines for each column of said radiating elements, wherein each of said plurality of additional microstrip lines extends perpendicularly from said first microstrip line.

19. A phased array antenna as recited in claim 18, wherein:

said openings are elongated; and

orthogonal pairs of said openings are positioned adjacent to each of said radiating elements.

20. A phased array antenna as recited in claim 1, wherein each of the voltage tunable dielectric phase shifters includes a dielectric film comprising one of the group of:

barium strontium titanate (Ba_xSr<sub>1−

x</sub>TiO₃, BSTO, where x is less than

     1), BSTO—

MgO, BSTO—

MgAl₂O₄, BSTO—

CaTiO₃, BSTO—

MgTiO₃, BSTO—

MgSrZrTiO₆, and combinations thereof.

21. A phased array antenna as recited in claim 1, wherein each of the voltage tunable dielectric phase shifters includes a dielectric film comprising a barium strontium titanate composite.

22. A phased array antenna as recited in claim 1, wherein each of the voltage tunable dielectric phase shifters comprises:

a substrate;

a tunable dielectric film positioned on the substrate;

a coplanar waveguide including a conductive strip positioned on a surface of the tunable dielectric film opposite the substrate;

an input for coupling a radio frequency signal to the conductive strip;

an output for receiving the radio frequency signal from the conductive strip; and

a connection for applying a control voltage to the tunable dielectric film.