Patent EA-003712-B1 (EA)
Title: Serially-fed phased array antennas with dielectric phase shifters
Inventor: ZHU YONGFEI
IPC: H01P1/18
Filed: 2000-09-13
Abstract: 1. A phased array antenna (10) comprising a plurality of radiating elements (12), a feed line assembly (16), a ground plane (18) positioned between the plurality of radiating elements and the feed line assembly and a phase shifter (32, 34, 36) coupled to said feed line assembly, characterized by: the ground plane having a plurality of pairs of orthogonal openings (20), each pair of orthogonal openings positioned adjacent to one of the radiating elements; and the feed line assembly (16) including a plurality of microstrip lines (28), each of the microstrip lines including a portion positioned adjacent to one of the pairs of orthogonal openings. 2. A phased array antenna as recited in claim 1, further characterized by a linear microstrip line (24) wherein said plurality of microstrip lines (28) extend perpendicularly from said linear microstrip line, and the portion of each of said plurality of microstrip lines having a length selected to provide a 90 degree phase shift between the openings of an adjacent one of the pairs of orthogonal openings. 3. A phased array antenna as recited in claim 2, further characterized in that said plurality of radiating elements are arranged in a plurality of rows and columns, and wherein said feed line assembly further comprises: additional linear microstrip lines and additional pluralities of microstrip lines extending perpendicularly from each of said additional linear, wherein a portion of each of said pluralities of microstrip lines includes a length selected to provide a 90 degree phase shift between the openings of an adjacent one of the pairs of orthogonal openings; and additional phase shifters (48), each of said additional phase shifters coupled to one of said additional linear microstrip lines. 4. A phased array antenna as recited in claim 1, further characterized in that the phase shifter comprises: a substrate (90); a tunable dielectric film (80) having a dielectric constant between 70 to 600, a tuning range of 20 to 60 %, and a loss tangent between 0.008 to 0.03 at K and Ka bands, the tunable dielectric film being positioned on a surface of the substrate; a coplanar waveguide (64, 66, 68) positioned on a surface of the tunable dielectric film opposite the substrate; an input (76) for coupling a radio frequency signal to the conductive strip; an output (78) for receiving the radio frequency signal from the conductive strip; and a connection for applying a control voltage to the tunable dielectric film. 5. A phased array antenna as recited in claim 4, further characterized in that the high dielectric constant voltage tunable dielectric film comprises a barium strontium titanate composite. 6. A phased array antenna as recited in claim 4, further characterized by: a first impedance matching section (76) of said coplanar waveguide coupled to said input; and a second impedance matching section (78) of said coplanar waveguide coupled to said output. 7. A phased array antenna as recited in claim 6, further characterized in that 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. 8. A phased array antenna as recited in claim 4, further characterized in that the connection for applying a control voltage to the tunable dielectric film comprises: a first electrode (66) position adjacent a first side of a conductive strip (64) of the coplanar waveguide to form a first gap between the first electrode and the conductive strip; and a second electrode (68) position adjacent a second side of said conductive strip to form a second gap between the second electrode and the conductive strip. 9. A phased array antenna as recited in claim 4, further characterized by: 10. A phased array antenna as recited in claim 1, further characterized in that a tunable dielectric film (80) comprises one of: BSTO-MgO, BSTO-MgA12O4, BSTO-CaTiO3, BSTO-MgTiO3, BSTO-MgSrZrTiO6, and combinations thereof. 11. A phased array antenna as recited in claim 1, further characterized in that the phase shifter comprises: a first substrate (162); a tunable dielectric film (154) positioned on a surface of the first substrate; a coplanar waveguide (146, 150, 152) positioned on a surface of the tunable dielectric film opposite the substrate; a second substrate (144) positioned adjacent to an end of the first substrate; a microstrip line (142) positioned on a surface of the second substrate; and a connection between the microstrip line and a conductive strip (146) of the coplanar waveguide.