Abstract: An eVC including coarse and fine tuning networks. The coarse tuning network includes a circuit: receiving a RF input signal from a RF generator; outputting a RF output signal to a reference terminal or load; and receiving a DC bias voltage. The circuit is switched between first and second states. A capacitance of the circuit is based on the DC bias voltage while in the first state and is not based on the DC bias voltage while in the second state. The fine tuning network is connected in parallel with the coarse tuning network and includes a varactor. The varactor includes: a first diode receiving the RF input signal; and a second diode connected in a back-to-back configuration with the first diode and outputting a RF output signal to the reference terminal or load. A capacitance of the varactor is based on a second received DC bias voltage.

Abstract: An eVC including coarse and fine tuning networks. The coarse tuning network includes a circuit: receiving a RF input signal from a RF generator; outputting a RF output signal to a reference terminal or load; and receiving a DC bias voltage. The circuit is switched between first and second states. A capacitance of the circuit is based on the DC bias voltage while in the first state and is not based on the DC bias voltage while in the second state. The fine tuning network is connected in parallel with the coarse tuning network and includes a varactor. The varactor includes: a first diode receiving the RF input signal; and a second diode connected in a back-to-back configuration with the first diode and outputting a RF output signal to the reference terminal or load. A capacitance of the varactor is based on a second received DC bias voltage.

Abstract: A power amplifier (PA) adjustably operable between two classes of operation. The range of operation lies in a range of operation between a conventional, linear, conjugately matched Class AB characteristic amplifier and a higher efficiency switching Class E characteristic amplifier. A circuit topology having a push-pull configuration that allows a Class E characteristic of operation.

Abstract: A radio frequency (RF) sensor that measures RF current includes a substrate that has an inner perimeter that defines an aperture. A conductor extends through the aperture. Sensor pads are arranged on the aperture and are connected to form two sensor loops. The loops generate an electrical signal that represents RF current flow through the center conductor. Additionally, a plurality of circular conductive rings may be included in the RF sensor to generate a signal representing the voltage of the conductor.

Abstract: A power amplifier (PA) adjustably operable between two classes of operation. The range of operation lies in a range of operation between a conventional, linear, conjugately matched Class AB characteristic amplifier and a higher efficiency switching Class E characteristic amplifier. A circuit topology having a push-pull configuration that allows a Class E characteristic of operation.

Abstract: A radio frequency (RF) sensor that measures RF current includes a substrate that has an inner perimeter that defines an aperture. A conductor extends through the aperture. Sensor pads are arranged on the aperture and are connected to form two sensor loops. The loops generate an electrical signal that represents RF current flow through the center conductor. Additionally, a plurality of circular conductive rings may be included in the RF sensor to generate a signal representing the voltage of the conductor.

Abstract: A high efficiency stable RF power amplifier with frequency tuning capability is disclosed. The present invention includes a novel circuit configuration which allows the drain or collector terminal of the power transistor to be at ground potential eliminating the need for an electrical insulator between the transistor and the heatsink. In an alternative embodiment, the source or emitter terminal of the power transistor is allowed to be at ground potential. In either case, the amplifier is operated in a switched mode to provide high efficiency amplification at a predetermined frequency band. Additionally, despite the switched mode operation, the amplifier is stable because properly controlled impedances are provided for baseband, sub-harmonic and harmonic frequencies.

Abstract: An apparatus is disclosed wherein a dual directional harmonics dissipation filter includes an input terminal coupled to a RF power amplifier providing a radio frequency signal in a predetermined frequency range, an output terminal for providing the radio frequency signal to a load at the predetermined frequency range, a low pass filter connected between the input terminal and the output terminal, and a plurality of high pass filters coupled to the low pass filter wherein the plurality of high pass filters receive and dissipate signals in excess of the predetermined frequency range and wherein the plurality of high pass filter's effect on the impedance is offset at the input and output of the low pass filter.

Abstract: A high efficiency stable RF power amplifier with frequency tuning capability is disclosed. The present invention includes a novel circuit configuration which allows the drain or collector terminal of the power transistor to be at ground potential eliminating the need for an electrical insulator between the transistor and the heatsink. In an alternative embodiment, the source or emitter terminal of the power transistor is allowed to be at ground potential. In either case, the amplifier is operated in a switched mode to provide high efficiency amplification at a predetermined frequency band. Additionally, despite the switched mode operation, the amplifier is stable because properly controlled impedances are provided for baseband, sub-harmonic and harmonic frequencies.

Abstract: An apparatus is disclosed wherein a dual directional harmonics dissipation filter includes an input terminal coupled to a RF power amplifier providing a radio frequency signal in a predetermined frequency range, an output terminal for providing the radio frequency signal to a load at the predetermined frequency range, a low pass filter connected between the input terminal and the output terminal, and a plurality of high pass filters coupled to the low pass filter wherein the plurality of high pass filters receive and dissipate signals in excess of the predetermined frequency range and wherein the plurality of high pass filter's effect on the impedance is offset at the input and output of the low pass filter.

Abstract: A high power grounded-drain source follower RF amplifier circuit employs a high voltage MOSFET. The RF signal at the input is applied with respect to ground via an isolation transformer whose secondary feeds the signal between gate and source. The output is taken from the source with respect to drain, which is grounded. A 13.56 MHz 3 KW power amplifier topology with isolated RF input drive for each MOSFET die uses a pair of kilowatt power transistors or KPTs, in which there are multiple large area MOSFET dies, with the drain regions of the dies being formed over a major portion of the die lower surface. The drain regions are in direct electrical and thermal contact with the conductive copper flange. The source and gate regions are formed on the dies away from the flat lower surface. One or more pairs of multi-chip KPTs can be configured to design stable 2.5 KW, 5 KW and 10 KW RF plasma generators at 13.56 MHz.

Abstract: A linear RF power amplifier employs push-pull pairs of high voltage mosfets. A minimum of transformers is employed, with an impedance matching transformer feeding an input balun supplying the input signal in push-pull to the gates of the mosfets. The drains are coupled to balanced legs of an output balun, followed by an output impedance matching transformer. Thermal sensors are employed for control of gate bias and also for control of drain voltage. The temperature sensors are mounted in the air inlet path and on the spreader plate of the heat sink. An aluminum or fiberglass strap is used to press the transistors against the spreader plate thereby ensuring good thermal contact with the transistor dies.

Abstract: A high power radio frequency amplifier employs a power stage in which a bank of push-pull stages are connected in parallel. These power stages employ relatively low-cost high voltage MOSFETs. Because the devices are operated in their active regions, these MOSFETs are susceptible to drops in gain during operation due to heating of the transistor die. The gain fluctuation has a first, slower component that varies over a time of several minutes, and a second, faster component that varies over a span of seconds. The amplifier has B+ or drain voltage control to compensate for short-term (minutes) gain degradation and preamplifier gate voltage control to compensate for short-term (seconds) gain degradation.

Abstract: A linear RF power amplifier employs push-pull pairs of high voltage mosfets. A minimum of transformers is employed, with an impedance matching transformer feeding an input balun supplying the input signal in push-pull to the gates of the mosfets. The drains are coupled to balanced legs of an output balun, followed by an output impedance matching transformer. Thermal sensors are employed for control of gate bias and also for control of drain voltage. The temperature sensors are mounted in the air inlet path and on the spreader plate of the heat sink. An aluminum or fiberglass strap is used to press the transistors against the spreader plate thereby ensuring good thermal contact with the transistor dies.

Abstract: A harmonic and subharmonic filter is coupled between a high power RF energy source and a non-linear RF load via a matching network, such as a plasma chamber. The filter passes high power RF energy in a band centered on a predetermined radio frequency, i.e., 13.56 MHz, but blocks and attenuates out-of-band energy at frequencies which are multiples of or fractions of the predetermined frequency. The harmonic and subharmonic filter comprises an input terminal, an output terminal, a series LC resonance path connected between the input and output terminals, and tuned to the predetermined radio frequency, a series resistive path formed of first and second resistors, and a parallel LC resonance path between the junction of the two resistors and ground.