Voltage tunable coplanar phase shifters with a conductive dome structure
View Patent ↗A phase shifter includes a substrate, a tunable dielectric film 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 positioned on a surface of the substrate, a coplanar waveguide positioned on a surface of the tunable dielectric film opposite the substrate, an input for coupling a radio frequency signal to the coplanar waveguide, an output for receiving the radio frequency signal from the coplanar waveguide, and a connection for applying a control voltage to the tunable dielectric film. A reflective termination coplanar waveguide phase shifter including a substrate, a tunable dielectric film 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 positioned on a surface of the substrate, first and second open ended coplanar waveguides positioned on a surface of the tunable dielectric film opposite the substrate, microstrip line for coupling a radio frequency signal to and from the first and second coplanar waveguides, and a connection for applying a control voltage to the tunable dielectric film.
1. A phase shifter comprising:
a substrate;
a tunable dielectric film 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 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;
a connection for applying a control voltage to the tunable dielectric film, wherein the coplanar waveguide comprises:
a first electrode position adjacent a first side of said conductive strip to provide a first gap between the first electrode and the conductive strip; and
a second electrode position adjacent a second side of said conductive strip to provide a second gap between the second electrode and the conductive strip; and
a conductive dome electrically connected between the first and second electrodes.
2. The phase shifter according to claim 1 , wherein the high dielectric constant voltage tunable dielectric film comprises a barium strontium titanate composite.
3. The phase shifter according to claim 1 , 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.
4. The phase shifter according to claim 3 , 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.
5. The phase shifter according to claim 1 , further comprising:
a third electrode position adjacent a first side of said first electrode opposite said conductive strip to provide 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 provide a fourth gap between the second electrode and the fourth electrode.
6. The phase shifter according to claim 1 , wherein the substrate comprises one of:
MgO, LaAlO 3 , sapphire, Al2O 3 , and a ceramic.
7. The phase shifter according to claim 1 , wherein the substrate has a dielectric constant of less than 25.
8. The phase shifter according to claim 1 , wherein the tunable dielectric film has a dielectric constant of greater than 300.
9. The phase shifter according to claim 1 , further comprising:
a conductive housing covering the phase shifter.
10. The phase shifter according to claim 1 , wherein the tunable dielectric is selected from the group consisting of:
barium strontium titanate (BaxSr 1-x TiO 3 , BSTO, where x is less than 1), BSTO—MgO, BSTO—MgAl 2 O 4 , BSTO—CaTiO 3 , BSTO—MgTiO 3 , and BSTO—MgSrZrTiO 6 .