Abstract: An acoustic resonator includes a first electrode, a second electrode, and a barium strontium titanate (BST) dielectric layer disposed between the first electrode and the second electrode, where the acoustic resonator is switched on as a resonator with a resonant frequency if a DC (direct current) bias voltage is applied across the BST dielectric layer. The acoustic resonator is also switched off in no DC bias voltage is applied across the BST dielectric layer. Furthermore, the resonant frequency of the acoustic resonator can be tuned based on a level of the DC bias voltage, with the resonant frequency increasing as the level of the DC bias voltage applied to the BST acoustic resonator increases.

Abstract: A self-tuning variable impedance circuit provides improved performance. A variation in the power applied to the variable impedance circuit causes a corresponding change in the impedance of the circuit, resulting in improved performance. For example, the variable impedance circuit may be a matching circuit that “follows” the output power of a power amplifier, thereby increasing the power efficiency of the power amplifier.

Abstract: Ferroelectric thin film devices including a passivation structure to reduce or control a leakage path between two electrodes and along an interface between a ferroelectric thin film layer and a passivation layer are described. Methods for fabricating such devices are also disclosed. The passivation structure includes a first passivation layer that includes an opening exposing a portion of the ferroelectric thin film layer allowing a second passivation layer to contact the thin film layer through the opening. In an exemplary embodiment, the opening is a rectangular ring surrounding an active region of a capacitor. In another exemplary embodiment, the second passivation layer also contacts the second electrode, a portion of which is also exposed through the opening. In another exemplary embodiment, current flows along the interface between the thin film layer and the passivation layer in an integrated resistor.

Abstract: A tuning circuit for use in an electrical circuit network is disclosed. The tuning circuit includes a bridge circuit. The bridge circuit comprises a first adjustable capacitance grouping, a second adjustable capacitance grouping and a third adjustable capacitance grouping. Each adjustable capacitance grouping includes at least one tunable capacitor and a bias port. In one embodiment, the tunable capacitor is comprised of a tunable thin-film barium strontium titanate (“BST”) capacitor. A first lead and a second lead couple to, or extend from, the bridge circuit. The leads are configured to couple with a coupling element and a shunt element of the electrical circuit network so that when the leads are grounded, one adjustable capacitance group is grounded and the remaining adjustable capacitance group couple with a bias voltage to appropriately tune the electrical circuit to achieve desired electrical characteristics.

Abstract: A parallel-plate, voltage-variable capacitor is designed to have an increased current conducting perimeter relative to its area. In one approach, the perimeter is increased by changing the shape of the plates. In another approach, the varactor is implemented by a number of disjoint plates, which are coupled in parallel.

Abstract: A capacitive element includes two or more voltage-variable capacitors (varactors). The varactors are configured so that they are coupled in series with respect to an applied AC signal and are coupled in parallel with respect to an applied DC bias voltage. The effective capacitance of the overall capacitive element can be tuned by varying the DC bias voltage.