Abstract: A circuit (C1-C4) is employed in a TWACS transponder (T) installed in an electric meter (M). The transponder generates inbound signals (IB) transmitted from the location of the electric meter to a central location (R). Firmware (F) within the transponder controls the flow of current for each pulse through the circuit by triggering a semi-conductor device such as a SCR (X1) or TRIAC (X2). The resulting current flow through the inductor for a subsequent pulse, regardless of the pulse's polarity, will be in the opposite direction to that of the previous pulse. The result is to maintain a constant level of magnetization of the inductor core which does not have to be overcome by energy in the subsequent pulse resulting in amplitude of all the pulses imposed on an AC waveform being substantially the same.

Abstract: The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

Abstract: A plasma processing system for use in fabricating electronic devices including an RF generator; a process chamber including an electrical load which produces a plasma within the chamber when powered by the RF generator; an electronically tunable matching network connected between the RF generator and the electrical load of the process chamber, wherein during operation the matching network couples power from the RF generator into the plasma within the process chamber; and a control circuit connected to the matching network, wherein during operation the control circuit electronically adjusts the matching network so as to control a transfer of power from the RF generator into the plasma in the process chamber. The matching network includes an electronically tunable variable inductor including a core made of a material which exhibits a non-linear relationship between magnetic field intensity, H, and magnetic flux density, B. The core is configured as a closed loop defining a central opening.

Abstract: The disclosure discusses impedance matching circuits based on parallel-resonant L-C tank circuits, and describes a low-loss design for an adjustable inductance element suitable for use in these parallel tank circuits. The application of an impedance matching circuit to a plasma process is also disclosed; in this context, a local impedance transformation circuit is used to improve power transfer to the plasma source antenna.

Abstract: An apparatus for dynamically matching a radio-frequency source for semiconductor processing to a load, and particularly adapted for plasma sputtering and etching processes, comprises an admittance matching network utilizing magnetically saturable inductors. A dc bias signal is provided to optimize the operating point of the saturable reactor with respect to the hysteresis characteristic of the core material. A control signal characterized by a phase error and a magnitude derived from the signal reflected from the load is applied to control the magnetizing current flowing through the inductors. The invention discloses a structure for the inductors which provides efficient coupling of the control current, while inherently rejecting rf currents reflected back from the load to the inductor current source.

Abstract: In a tuning circuit, use is made of a current-controlled type variable inductor comprising a tuning coil and a control coil for controlling the magnetic flux density of the tuning coil. The tuning coil is connected in series with the antenna; a tuning capacitor is connected to each end of tuning coil; and by controlling a current flowing through the control coil, magnetic flux induced in the tuning coil is increased, decreased or cancelled so that the magnetic flux density of the tuning coil is adjusted to control the inductance thereof, thereby permitting the tuning circuit to be tuned to any desired frequency in the receiving frequency band.

Abstract: An inductor is configured so as to wind a control coil on one of winding portions of first and second cores and to wind a tuning coil on the other winding portion to insert the second core into a hollow portion provided inside the first core, thereafter accommodating the first and second cores thus assembled into a pot-shaped core, wherein both winding portions of the first and second cores are arranged in parallel with each other and the winding portion of the first core is arranged perpendicular to a bottom surface of the pot-shaped third core. The control coil and the tuning coil are arranged so that their magnetic paths overlap with each other at the winding portion of the second core, thereby to control a current flowing through the control coil when energized to vary effective permeability of the core on which the tuning coil is wound, thus producing changes in inductance.