Abstract: Apparatus for a nuclear resonance imaging (MRI) machine (100) that includes plasma elements (104, 106, 108). The MRI machine (100) includes gradient coils (104) that generate time-dependent gradient magnetic fields, transmitting elements (106) that excite target molecules (120) with RF energy (122), and receiving elements (108) responsive to RF energy (124) emitted by the excited molecules (120). The gradient coils (104) include plasma conductors (710) in which the plasma (716) is ignited by an exciter (208). The plasma conductors (710) are electrically connected to a gradient amplifier (206) that outputs a signal to produce the gradient fields. The transmitting elements (106) are plasma devices (710) configured to emit RF energy (122). The receiving elements (108) are plasma devices (710) responsive to emitted RF energy (124). An RF exciter (218) selectively and alternatingly ignites said plasma devices (710) to avoid coupling and interference between them.

Abstract: A plasma antenna assembly may include a plasma antenna element, a plasma density sensor operably coupled to the plasma antenna element to measure plasma density during ionization of the plasma antenna element, a driver circuit operably coupled to the plasma antenna element to selectively provide pulsed current to the plasma antenna element for ionization of plasma in the plasma antenna element, and a controller operably coupled to the driver circuit and the plasma density sensor to provide control of the plasma density of the plasma antenna element.

Abstract: A plasma antenna assembly may include a plasma antenna element, a plasma density sensor operably coupled to the plasma antenna element to measure plasma density during ionization of the plasma antenna element, a driver circuit operably coupled to the plasma antenna element to selectively provide pulsed current to the plasma antenna element for ionization of plasma in the plasma antenna element, and a controller operably coupled to the driver circuit and the plasma density sensor to provide control of the plasma density of the plasma antenna element.

Abstract: Apparatus for a nuclear resonance imaging (MRI) machine (100) that includes plasma elements (104, 106, 108). The MRI machine (100) includes gradient coils (104) that generate time-dependent gradient magnetic fields, transmitting elements (106) that excite target molecules (120) with RF energy (122), and receiving elements (108) responsive to RF energy (124) emitted by the excited molecules (120). The gradient coils (104) include plasma conductors (710) in which the plasma (716) is ignited by an exciter (208). The plasma conductors (710) are electrically connected to a gradient amplifier (206) that outputs a signal to produce the gradient fields. The transmitting elements (106) are plasma devices (710) configured to emit RF energy (122). The receiving elements (108) are plasma devices (710) responsive to emitted RF energy (124). An RF exciter (218) selectively and alternatingly ignites said plasma devices (710) to avoid coupling and interference between them.

Abstract: Apparatus for a nuclear resonance imaging (MRI) machine that includes plasma elements. The MRI machine includes gradient coils that generate time-dependent gradient magnetic fields, transmitting elements that excite target molecules with RF energy, and receiving elements responsive to RF energy emitted by the excited molecules. The gradient coils include plasma conductors in which the plasma is ignited by an exciter. The plasma conductors are electrically connected to a gradient amplifier that outputs a signal to produce the gradient fields. The transmitting elements are plasma devices configured to emit RF energy. The receiving elements are plasma devices responsive to emitted RF energy. An RF exciter selectively and alternatingly ignites said plasma devices to avoid coupling and interference between them.

Abstract: A plasma array of plural plasma containers of selected shapes and a selected spacial distribution, contain variable plasma density within each container and from one container to the next for establishing plasma frequency ranges from zero to an arbitrary plasma frequency. The plasma array is operating in a mode to transmit, receive, filter, reflect and/or refract radiation.

Abstract: A plasma device having low thermal noise, which results in a high signal-to-noise ratio (SNR) of the plasma device. The plasma device includes devices with a plasma that is responsive to electromagnetic radiation and/or electrical signals. In various configurations, the plasma device has a plasma in which the temperature, resistance, pressure, and/or collision frequency are at a level sufficiently low to produce an acceptable level of noise. In another configuration, the operating frequency of the plasma device is at a level sufficiently high to produce an acceptable level of noise. Decreasing the noise level results in increasing the signal-to-noise ratio and increasing the data rate. The plasma temperature is reduced by operating the plasma device in the afterglow state. The plasma electron temperature is reduced by confining high energy electrons in a potential well and by using an electron emitting filament.

Abstract: A plasma array of plural plasma containers of selected shapes and a selected spacial distribution, contain variable plasma density within each container and from one container to the next for establishing plasma frequency ranges from zero to an arbitrary plasma frequency. The plasma array is operating in a mode to transmit, receive, filter, reflect and/or refract radiation.

Abstract: A plasma device having low thermal noise, which results in a high signal-to-noise ratio (SNR) of the plasma device. The plasma device includes devices with a plasma that is responsive to electromagnetic radiation and/or electrical signals. In various configurations, the plasma device has a plasma in which the temperature, resistance, pressure, and/or collision frequency are at a level sufficiently low to produce an acceptable level of noise. In another configuration, the operating frequency of the plasma device is at a level sufficiently high to produce an acceptable level of noise. Decreasing the noise level results in increasing the signal-to-noise ratio and increasing the data rate. The plasma temperature is reduced by operating the plasma device in the afterglow state. The plasma electron temperature is reduced by confining high energy electrons in a potential well and by using an electron emitting filament.

Abstract: A reduced noise and selectively configurable plasma device is capable of interpreting electromagnetic signals having an operating frequency and has a plasma mechanism with a plasma that is ionizable to a plasma frequency. An ionizing mechanism for ionizing the plasma and a control that is operative to control the ionizing mechanism, ionize the plasma to the plasma frequency by application of plasma ionizing energy pulses. An interpreting mechanism operates to interpret the electromagnetic signals only in a period between ionization of the plasma with the energy pulses.

Abstract: An reconfigurable array of variable conductive elements is provided for reflecting, filtering and steering electromagnetic radiation across a wide range of frequencies. The reconfigurable array is combined with a transmitting antenna to make a steerable antenna. The reconfigurable array surrounds the transmitting antenna and reflects all transmissions except on selected radials where apertures in the reconfigurable array are formed for permitting transmission lobes. The reconfigurable arrays can be arranged in stacked layers to make transceiving multiband antennas. Communications networks using the steerable antennas and arrays are also disclosed.

Abstract: A plasma device serves as an antenna, single or stacked plasma frequency selective surfaces, single or stacked plasma antenna arrays, plasma lamps, plasma limiters, plasma switch, plasma windows or plasma phase shifters. An electromagnetic wave signal is controlled to have a plasma frequency matched as nearly as possible to the frequency of incident electromagnetic signals for maximizing the antenna aperture and efficiency. Matching the frequencies permits the plasma device to have a physical size and shape substantially independent of the conventional optimal size and shape for a given transceived signal frequency. The plasma device plasma frequency is adjustable for tuning to different incident signal frequencies, thereby providing flexibility not available from conventional metal antennas.

Abstract: A scanner has plasma loop or plasma window antennas for selectively scanning for ID tags along distinct radials of the scanner. Scanner elements are made electromagnetically invisible to adjacent elements by removing power or lowering plasma densities so that the scanner elements do not interfere with its own operation. Activatable ID tags and a shipping container suitable for scanning with electromagnetic energy are also disclosed.

Abstract: An reconfigurable array of variable conductive elements is provided for reflecting, filtering and steering electromagnetic radiation across a wide range of frequencies. The reconfigurable array is combined with a transmitting antenna to make a steerable antenna. The reconfigurable array surrounds the transmitting antenna and reflects all transmissions except on selected radials where apertures in the reconfigurable array are formed for permitting transmission lobes. The reconfigurable arrays can be arranged in stacked layers to make transceiving multiband antennas. Communications networks using the steerable antennas nas and arrays are also disclosed.

Abstract: A scanner has plasma loop or plasma window antennas for selectively scanning for ID tags along distinct radials of the scanner. Scanner elements are made electromagnetically invisible to adjacent elements by removing power or lowering plasma densities so that the scanner elements do not interfere with its own operation. Activatable ID tags and a shipping container suitable for scanning with electromagnetic energy are also disclosed.

Abstract: A plasma antenna includes a plasma column formed of an ionizable gas. A modulating carrier frequency produces Hertzian dipoles within the plasma that radiate RF energy at the modulating carrier. The antenna, which produces these dipoles, can be short and still produce significant gain when the modulating carrier frequency and the natural resonance frequency of the plasma are substantially equal. Other aspects of the invention include a method to produce such plasma antenna and a product by process embodiment of the plasma antenna.

Abstract: A near-field plasma reader detects magnetic induction interference with objects having corresponding sensed loops to provide detection and communication between the reader and objects incorporating the sensed loops. The plasma reader has two or more plasma loop sensors in different orientations that are sequentially switched to scan across a range of directions without interference from adjacent loop antennas. The plasma reader is used for inventorying items, store checkouts and other wireless transactions.

Abstract: A plasma antenna is provided having an ionizer, which when energized, generates a bounded or unbounded plasma column extending along a vertical axis. When ionization is initiated, the difference in the diffusion characteristics of ions and electrons and the resulting gas plasma produce a current pulse in a first direction. As the plasma extinguishes, the difference in relaxation times for the ions and electrons in the plasma produces a second current pulse of opposite direction. The alternating current pulses generate an electric field that radiates from the plasma column.

Abstract: An antenna system and method for a plurality of plasma antennas driven by means of an optical driver. In one embodiment the driver comprises one or more lasers which may be modulated by one or more electro-optical modulators to produce a modulated laser signal. The modulated laser signal may be supplied to the plasma antenna by optical fibers whereby the photons from the modulated signal impart momentum to the plasma particles. The plasma particles, which may include unbound electrons, oscillate in accord with the modulated laser signal to radiate electromagnetic energy. In one embodiment, the plasma antenna is operated at a frequency near the resonant frequency of the plasma to form a more efficient radiator requiring a smaller size than to a metallic antenna. In another embodiment a plurality of closely spaced plasma antennas are operated with different plasma resonant frequencies such that one plasma antenna is electrically invisible with respect to another plasma antenna.

Abstract: A scanner has plasma loop or plasma window antennas for selectively scanning for ID tags along distinct radials of the scanner. Scanner elements are made electromagnetically invisible to adjacent elements by removing power or lowering plasma densities so that the scanner elements do not interfere with its own operation. Activatable ID tags and a shipping container suitable for scanning with electromagnetic energy are also disclosed.