RF power is widely used as an auxiliary heating method in fusion devices. This paper reviews the relevant theoretical considerations for the ion cyclotron, lower hybrid and electron cyclotron ranges of frequency, and presents the history, the state of the art, and the plans and prospects for antennas and transmission lines for RF heating. Reactor-relevant concerns are discussed, and the information needed to develop realistic antenna designs for a reactor environment is assessed.

Power transmission and coupling for radiofrequency heating of plasmas

Theory and Design of Diplexers and Multiplexers

A passive cancellation network may include a transmit input having a configuration that passively receives a transmit signal from a transmitter that is to be wirelessly transmitted; a transmit output having a configuration that passively delivers the transmit signal after processing by the passive cancellation network; a receive input having a configuration that passively receives a receive signal that includes undesirable leakage from the transmit signal; a receive output having a configuration that passively delivers the receive signal after processing by the passive cancellation network; and a passive feed forward cancellation circuit that passively cancels at least a portion of the undesired leakage from the transmit signal in the receive signal in a feed forward manner.

Passive leakage cancellation networks for duplexers and coexisting wireless communication systems

Recent advances in solid-state device technology for generating millimeter waves as well as advances in component design for IF and baseband portions of repeaters have renewed interest in millimeter-wave guided-wave communication systems. This paper describes a 306 Mb/s, all solid-state repeater which has been built using a 1.3-GHz IF and a form of differentially-coherent phase modulation. A signal-to-noise ratio of 13.6 dB is required for an error probability of 10−9 (compared with a theoretical value of 13.0 dB for an ideal differentially-coherent phase-modulated system). Sufficient gain for 15-mile repeater spacings (using two-inch circular waveguide) has been obtained with an LSA diode, an IMPATT diode, and a varactor multiplier as the millimeter-wave power source.

A solid-state regenerative repeater for guided millimeter-wave communication systems

Multi-port hybrid-based cancellation networks may be used to enable simultaneous transmit and receive in one or more co-existent communication systems. A multi-port hybrid-based cancellation network may include a first and second quadrature hybrid, a first and second two-port network, and other circuitry components. The second quadrature hybrid may be distinct from the first quadrature hybrid. The first two-port network may include a first filter or a first amplifier connected between the first and the second quadrature hybrids. The second two-port network may include a second filter or a second amplifier that is distinct from but essentially the same as the first filter or the first amplifier connected between the first and the second quadrature hybrids. The other circuitry components may be connected between or connected to a connection between one of the quadrature hybrids and one of the two-port networks. These other circuitry components may have a configuration that minimizes signal return loss at least one of the ports of the multi-port hybrid-based cancellation network. They may in addition or instead have a configuration that maximizes signal isolation between at least two of the ports of the multi-port hybrid-based cancellation network.

Enhancing isolation and impedance matching in hybrid-based cancellation networks and duplexers

A constant-resistance filter capable of dividing a very wide band into two subbands is described. It can handle one octave in the millimeter region with only 1.5 db insertion loss for each subband. The splitting transition takes place in a very narrow band (160 mc). Two of its components are important devices: an elbow and a hybrid junction. Both are quasi-optical and work with TE 01 ° mode in 2 inch diameter waveguide.

E. A. Marcatili

Papers

Band-splitting filter