TUNABLE RESONATOR

Abstract

A tunable resonator includes at least one tunable capacitor coupled with at least one tunable inductor. The tunable resonator includes a mechanical tuning mechanism coupled with a connecting bridge and with first and second electrodes of the tunable inductor. The mechanical tuning mechanism also moves the first and second electrodes of the tunable inductor relative to an electrode of the tunable capacitor, and providing a force down onto or to pull up a connecting bridge to tune the tunable inductor.

Claims

1. A tunable resonator comprising: a tunable capacitor comprising: a first electrode and a second electrode, the first and second electrodes being formed of a conductive material; a third electrode between the first electrode and the second electrode; and a dielectric material interposed between the first electrode and the third electrode, and between the second electrode and the third electrode, the first electrode and the second electrode being movable relative to the third electrode to adjust and tune a capacitance of the tunable capacitor; and a tunable inductor coupled with the tunable capacitor, the tunable inductor comprising: a first wire coil having a first terminal lead; a second wire coil having a second terminal lead; a connecting bridge connecting the first wire coil with the second wire coil opposite the first and second terminal leads the connecting bridge being movable to respectively decrease a space between the first wire coil and the second wire coil to increase inductance, or increase the space between the first wire coil and the second wire coil to decrease inductance; and a mechanical tuning mechanism coupled with the connecting bridge of the tunable inductor and with the first and second electrode of the tunable capacitor, the mechanical tuning mechanism moving the first and second electrodes relative to the third electrode of the tunable capacitor, and moving the connecting bridge of the tunable inductor to tune the tunable inductor.

2. The tunable resonator in accordance with claim 1, wherein the second terminal lead of the second wire coil is arranged and oriented in the same direction as the first terminal lead.

3. The tunable resonator in accordance with claim 1, wherein the first wire coil and second wire coil are arranged in series and spaced side-by-side separated by the space.

4. The tunable resonator in accordance with claim 1, wherein the mechanical tuning mechanism provides a force to the connecting bridge of the tunable conductor to force down or pull up the connecting bridge.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other aspects will now be described in detail with reference to the following drawings.

[0015] FIG. 1 illustrates a shunt circuit using a resonator.

[0016] FIG. 2 illustrates a frequency range of a conventional tunable resonator.

[0017] FIG. 3 illustrates a tunable resonator in accordance with implementations of the present disclosure.

[0018] FIGS. 4A-4C illustrate various views of a tunable resonator in accordance with alternative implementations of the present disclosure.

[0019] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0020] This document describes a tunable resonator, and more particularly a mechanically tunable resonator having high accuracy in the designed range.

[0021] In preferred implementations, a tunable resonator is formed of a lumped inductor and a lumped capacitor. The tunable resonator has a wider tune frequency range due to simultaneous and synchronous change of both inductor value and capacitor value at the same rate, so that the ratio L/C stays constant. In other words, impedance Z stays constant. Referring again to the two formulas (1) and (2) above, in order to keep Z constant when f.sub.0 changes, both L and C must be tuned simultaneously, and the values of L and C must change at the same rate as well.

[0022] FIG. 3 shows the construction of a tunable resonator 100 in accordance with some implementations. The tunable resonator 100 includes a first electrode 3, a second electrode 4, and a third electrode 5. The first electrode 3 is fixed, but the second and third electrodes 4, 5 can move up and down along with coil leads 1 and 2. When a force from a stepper-motor is exerted on the top of the tunable resonator 100, both the inductor and the capacitor change their values: the inductor squeezes (increasing the inductor value) and the capacitor electrodes overlap a greater area (increasing capacitance value as well). The dimensions of the inductor and capacitor are chosen in such manner that the rate of change inductance value and the capacitance value stay unchangeable, keeping the impedance Z constant. These result in keeping the bandwidth and frequency response curve the same when tuning over a wide frequency range. The range is theoretically unlimited and depends only on dimensions of the inductor and capacitor. Also, the tunable range increases at least two times due to changes of both L and C.

[0023] In exemplary, preferred implementations, tuning a tunable resonator includes simultaneous tuning of the inductor and capacitor with the same rate. The uniqueness is also in the specific construction of the combination consisting of the spiral tunable inductor and the sliding electrode capacitor, which produces a non-distorted frequency response with the same bandwidth over a wider frequency range.

[0024] The tunable resonator as described herein has a wider frequency range, as would a tunable filter that utilizes the tunable resonator. The tunable resonator allows for a wider frequency range in tunable filters with constant bandwidth. Other advantages include a high level of RF power, and a high quality factor Q.

[0025] FIGS. 4A-4C illustrate various views of a tunable resonator. As shown in FIGS. 4A and 4B, the tunable resonator includes a first RF coil 10 and a second RF coil 20, a first terminal IN 30 and a second terminal OUT 40, and a tunable capacitor 50 provided between the first RF coil 10 and the second RF coil 20. The tunable capacitor 50 includes a first electrode and a second electrode, each being formed of a conductive material, and a third electrode between the first electrode and the second electrode. The tunable capacitor 50 further includes a dielectric material interposed between the first electrode and the third electrode, and between the second electrode and the third electrode. The third electrode is movable relative to the first electrode and the second electrode by a stepper motor to adjust and tune a capacitance of the tunable capacitor.

[0026] A mechanical tuning mechanism, such as the stepper motor, is coupled with a connecting bridge that connects the first and second RF coils 10, 20, and which also is coupled with an arm connecting the first and second electrodes of the tunable capacitor, as shown in FIGS. 4A and 4C. The mechanical tuning mechanism also moves the first and second electrodes relative to the third electrode of the tunable capacitor, and providing the force down onto or to pull up the connecting bridge to tune the tunable inductor.

[0027] Although a few embodiments have been described in detail above, other modifications are possible. Other embodiments may be within the scope of the following claims.