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Showing papers on "Radio frequency published in 1981"


Journal ArticleDOI
TL;DR: The surface radio frequency power absorption in human head and torso nuclear magnetic resonance (NMR) imaging experiments is estimated as a function of the NMR frequency, the rf pulse length, and the pulse duty cycle.
Abstract: The surface radio frequency (rf) power absorption in human head and torso nuclear magnetic resonance(NMR)imaging experiments is estimated. The results are expressed as a function of the NMR frequency, the rf pulse length, and the pulse duty cycle, which are varied over six orders of magnitude for general applicability. The results are compared with average metabolic levels and the limits advised by the National Radiological Protection Broad of the United Kingdom. Heating due to time‐dependent magnetic field gradients is discussed.

143 citations


Patent
31 Jul 1981
TL;DR: In this article, the relative amplitudes of alternating currents in the conductive elements are controlled to generate a spatially uniform field, which can be used to detect magnetic field components oscillating at a radio frequency.
Abstract: Apparatus for generating and detecting magnetic field components oscillating at a radio frequency in a direction transverse to a static magnetic field in a nuclear-magnetic-resonance (NMR) system. The apparatus has a plurality of conductive elements spaced from one another and from the axis along which the static magnetic field is directed. The relative amplitudes of alternating currents in the conductive elements are controlled to generate a spatially uniform field. A preferred embodiment uses a standing wave in a coil assembly to control relative current amplitudes, which takes advantage of the current-phase characteristics of such waves. Detection of RF magnetic fields results from an EMF generated in the coil assembly in response to the time-varying magnetic field; the high Q of the coil assembly enhances detection properties.

73 citations


Patent
01 May 1981
TL;DR: In this paper, an oscillator for generating an electromagnetic field having an output frequency in the radio frequency range and a high Q passively tuned LC circuit which has a resonant frequency variable in the frequency range generated by the oscillator are used for monitoring respiration and detecting apnea.
Abstract: A method and assembly for monitoring respiration and detecting apnea. The assembly includes an oscillator for generating an electromagnetic field having an output frequency in the radio frequency range and a high Q passively tuned LC circuit which has a resonant frequency variable in the radio frequency range generated by the oscillator. The LC circuit responds to the electromagnetic field by absorbing electromagnetic energy from the field when the resonant frequency matches the output frequency of the oscillator. A band is positioned about the subject's chest or abdominal cavity to vary the resonant frequency of the LC circuit in response to the expansion and contraction of the subject's chest or abdominal cavity. A detecting means is also provided for detecting when the LC circuit is responsive to the electromagnetic field established by the oscillator. In one embodiment the output frequency of the electromagnetic field established by the oscillator is maintained constant and the detecting means includes reset timing means for providing a signal when the LC circuit fails to respond to the electromagnetic field within a predetermined time period. In a second embodiment the output frequency of the electromagnetic field established by the oscillator is varied within the predetermined frequency range and the detecting means includes reset timing means for providing a signal when the LC circuit fails to respond to the electromagnetic field at different resonant frequencies within the predetermined frequency range within a predetermined time period.

73 citations


Patent
01 Oct 1981
TL;DR: An anti-theft tag (34) containing a semiconductor diode (36) connected to a metal antenna loop (38) is configured to receive two distinct radio frequency transmissions.
Abstract: An anti-theft tag (34) containing a semiconductor diode (36) connected to a metal antenna loop (38) is configured to receive two distinct radio frequency transmissions. The diode (36) bridges a closed loop at one end of the antenna (38), forming a tank circuit resonant at twice a selected center frequency. A first transmitter (26) generates a tone modulated radio frequency (f) displaced on one side of the center frequency, and a second transmitter (30) generates a continuous wave radio frequency (f) displaced on the other side of the center frequency. Both signals are fed separately to respective dipole radiating antenna strips (18, 19, 20, 21) on opposite sides of a surveillance area. The dipole strips for the different frequencies are at right angles to each other on each side; those for the same frequency are at right angles to each other on opposite sides. This produces cross polarized transmission of both frequencies within the area. Diode (36) of tag (34) mixes the two frequencies received by the antenna loop (38), causing the tank circuit to resonate at the sum of the two frequencies (double the center frequency). That resonant frequency is reradiated to receiver antennae (22, 24) on each side for detection by a very narrow band receiver (42) responsive to the sum frequency. The modulating tone is derived from the received signal and processed to trigger an alarm (44) when the detected signal is of sufficient strength and duration.

63 citations


Patent
Robert L. Toellner1
19 Jan 1981
TL;DR: In this paper, a technique for radio frequency heating of hydrocarbonaceous earth formations in which a high power radio frequency transmitter is impedance matched to a transmission line including a plurality of conductors at least partially embedded in the formation to be heated is described.
Abstract: The disclosure relates to a technique for radio frequency heating of hydrocarbonaceous earth formations in which a high power radio frequency transmitter is impedance matched to a transmission line including a plurality of conductors at least partially embedded in the formation to be heated. The impedance matching may be effected by a "T" network having three variable reactances. In accordance with the teachings of the present invention, continuous variations of impedance, of the type encountered during the heating of the formation, may be matched in unambiguously defined Smith chart regions by varying two of the three reactances to minimize reflected power from the transmission line.

61 citations


Journal ArticleDOI
01 Feb 1981
TL;DR: In this article, the suitability, reliability, and the potential for interference are considered for frequencies in the 1- to 300-GHz range. But the authors do not consider the effect of interference on the reliability of the system.
Abstract: Propagation phenomena affect the design of radio frequency (RF) transmission systems. Propagation phenomena limit the suitability of portions of the frequency band for some applications, limit the reliability of RF transmission systems, and provide a means of coupling unwanted signals from one system to another with the potential of producing interference. The possiblity of interference is the fundamental limitation to the unrestricted use of the frequency band. Phenomena affecting suitability, reliability, and the potential for interference are considered for frequencies in the 1- to 300-GHz range.

59 citations


Patent
16 Sep 1981
TL;DR: In this paper, a TV receiver tuning system for selecting one of a plurality of receivable TV channels comprises a frequency selective radio frequency device including trimming elements for receiving TV signals, a local oscillator controlled by a first control signal and a mixer in which the TV signals and the local oscillators are heterodyned to develop an intermediate frequency signal.
Abstract: A television (TV) receiver tuning system for selecting one of a plurality of receivable TV channels comprises a frequency selective radio frequency device including trimming elements for receiving TV signals, a local oscillator controlled by a first control signal and a mixer in which the TV signals and the local oscillator signal are heterodyned to develop an intermediate frequency signal A first control device develops the first control signal in response to the selection of a TV channel to control the local oscillator frequency so that the mixer shifts the selected TV channel signal to the IF frequency A second control device including a PROM trims the frequency selectivity of the RF device using its trimming elements unaffected by selection of the TV channel whereby mechanical alignment of the TV tuning system can be avoided In other aspects of the invention, the second control device develops signals for adjusting tunable circuits in the IF amplifier, for adjusting the tracking of the local oscillator frequency in relation to its control signal, and, in a double-conversion tuner, for adjusting the frequency of a second local oscillator

38 citations


Patent
19 Aug 1981
TL;DR: In this paper, a multiband tuning system produces an IF signal from RF signals residing in, in the order named, a first broadcast band, an upper frequency portion of the first cable band, the second broadcast and the second cable bands in response to the tuning signal.
Abstract: A multiband tuning system produces an IF signal from RF signals residing in, in the order named, a first broadcast band, a first cable band, a second broadcast band and a second cable band. A control device generates a tuning signal having a magnitude determined by the frequency of a selected channel. A first filter selects RF signals corresponding to channels selected in a first tuning band including the first broadcast band and a lower frequency portion of the first cable band in response to the tuning signal. A second filter selects RF signals corresponding to channels selected in a second tuning band including an upper frequency portion of the first cable band, the second broadcast and the second cable bands in response to the tuning signal. A selection device enables operation of the first filter when the selected channel is within the first tuning band and enables operation of the second filter when the selected channel is in the second tuning band.

38 citations


Patent
21 Dec 1981
TL;DR: In this article, a compact antenna feed system for orthogonally polarized RF signals includes a waveguide feed with internal ridges, a pair of wave detectors coupled to the waveguide, and an amplifier housed as part of the feed system to amplify received RF signals.
Abstract: A compact antenna feed system for orthogonally polarized RF signals includes a waveguide feed having orthogonally disposed internal ridges, a pair of wave detectors coupled to the waveguide feed to receive orthogonally oriented RF signals, and an amplifier housed as part of the feed system to amplify received RF signals prior to communication of the signals outside the feed system. The system is readily switchable by remote control to receive RF signals in either orientation and angular alignment to the orientation of the incoming signals is easily accomplished.

36 citations


Patent
10 Dec 1981
TL;DR: In this article, an emitter responsive to the electromagnetic radiation for producing a beam of charged particles, an electrode spaced from the emitter to define a path for the particles, and a resonant structure for supporting RF oscillations and disposed with respect to the path to enable energy transfer between the charged particles and an RF field associated with the RF oscillation.
Abstract: A device for generating RF energy from electromagnetic radiation of another form, such as light, includes an emitter responsive to the electromagnetic radiation for producing a beam of charged particles, an electrode spaced from the emitter to define a path for the charged particles, and a resonant structure for supporting RF oscillations and disposed with respect to the path to enable energy transfer between the charged particles and an RF field associated with the RF oscillations. When biased, the devices operate in a multi-pass mode, wherein the charged particles undergo multiple oscillations while remaining in phase with the RF field. When unbiased, the devices operate in a half-cycle mode to produce RF oscillations with no externally applied input power other than the electromagnetic radiation.

34 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used modern digital computer techniques to calculate the field reradiated from a power line near an AM broadcasting tower and compared the results with scale model measurements.
Abstract: The encroachment of "civilization" on the site of a medium wave broadcasting array can give rise to distortions of its radiation pattern resulting in inadequate coverage of the service area, or even in the violation of licensing provisions. The radiation pattern distorts because RF currents are induced by the broadcasting antenna's field on any large metallic structures such as a highrise building or a high-tension power line. If the structure is resonant, these currents can be large and the reradiated field can be strong. This paper uses modern digital computer techniques to calculate the field reradiated from a power line near an AM broadcasting tower. The current distribution on the towers and "skywires" for a uniform power line is shown to exhibit distinct "off-resonance" and "resonant" behavior. The frequency dependence of the reradiated field is found to be simple loop resonance for a uniformly spaced power line, and so is a super-position of the resonant behavior of loops of many sizes for a complex site. The computer model is applied to analyze the azimuth pattern for a complex site near Hornby, Ontario where two power lines come close to an omnidirectional antenna. The computations are compared with scale model measurements. Since a perfectly conducting ground was used in the computations, the method may help to estimate the upper bound on the distortions of the azimuth pattern which could arise from the construction of a proposed power line near an existing broadcasting antenna.

Journal ArticleDOI
TL;DR: In this article, a phase-insensitive detector is used, comprised of two balanced mixers which are fed in quadrature phase by one of the RF inputs followed by a phase quadratures combiner.
Abstract: A coherent (homodyne) detection system is used to map field distributions in real time. A key feature is the use of an electrically modulated (10-kHz) dipole scatterer which is also mechanically spun (150 Hz) to create an amplitude- and phase-modulated backscattered field. The system is monostatic. The backscattered field is coherently detected by mixing with the CW reference. A phase-insensitive detector is used, comprised of two balanced mixers which are fed in quadrature phase by one of the RF inputs followed by a phase quadrature combiner. The resulting amplitude and phase of the 10-kHz output are proportional to the square of the RF field component along the instantaneous axis of the spinning dipole. Both are measured simultaneously and independently in real time. From these, the polarization properties can also be found, so the field is uniquely described. The system's application to scanning the E-field transmitted through Iossy, nonhomogeneous and anisotropic media (e.g., wood) is demonstrated. Other applications besides nondestructive testing are microwave vector holography, nearfield antenna measurements, and inverse scattering.


Journal ArticleDOI
TL;DR: In this article, the dependence on RF power of the large-signal S-parameter S/sub 22/ and the optimum load for maximum output power were investigated using a nonlinear circuit model of the device.
Abstract: The large-signal S-parameter S/sub 22/ and the optimum load for maximum output power are two parameters commonly used in the RF characterization of microwave power FET's. Using a nonlinear circuit model of the device, the dependence on RF power of each of these parameters is investigated. A method is given for computing the optimum load from the Iarge-signal S/sub 22/. Equivalent load-pull data can thus be obtained without the need for load-pull measurements. The gain compression characteristics of the transistor for arbitrary load can be computed from large-signal S/sub 21/, and S/sub 22/ data.

Patent
Robert M. Broton1
02 Nov 1981
TL;DR: In this article, a transmit-receive switching circuit is provided for switching a transmitter and a receiver to common antenna via a common signal path, where a circulator is employed to control the flow of transmitter RF energy and received RF energy.
Abstract: A transmit-receive switching circuit is provided for switching a transmitter and a receiver to common antenna via a common signal path. A circulator is employed in the common signal path. The flow of transmitter RF energy and received RF energy is controlled through the circulator by a selectively actuable impedance element coupled to the circulator.

Patent
23 Mar 1981
TL;DR: In this paper, a resonant metallic conductor having a nominal resonant frequency which varies inversely with temperature is temperature compensated by association with a predetermined proportion of dielectric material which acts to increase the nominal resonance frequency with temperature so as to substantially temperature compensate an antenna structure.
Abstract: A resonant metallic conductor having a nominal resonant frequency which varies inversely with temperature is temperature compensated by association with a predetermined proportion of dielectric material which acts to increase the nominal resonant frequency with temperature so as to substantially temperature compensate an antenna structure.

Patent
29 Jun 1981
TL;DR: In this paper, a solid state radio frequency high power generator for induction heating applications uses MOSFET devices controlled at radio frequency by a current loop which is automatically corrected against the possible occurrence of a leading phase shift by a voltage-current phase shift detection loop which responds to digital signals corrected against inherent time delays.
Abstract: A solid state radio frequency high power generator for induction heating applications uses MOSFET devices controlled at radio frequency by a current loop which is automatically corrected against the possible occurrence of a leading phase shift by a voltage-current phase shift detection loop which responds to digital signals corrected against inherent time delays.

Patent
Richard A. Meador1
16 Mar 1981
TL;DR: In this article, the phase difference in radio frequency signals between receiver coil pairs in each pad is measured, providing improved data resolution for computing formation dip, and making possible dip measurements in wells drilled with oil base mud or air (invert type muds).
Abstract: An improvement to dipmeter logs has very closely spaced radio frequency sensor coils mounted in pairs in each of the formation contacting pads. A transmitter mounted in a sonde emits the radio frequency energy, such as in the range of from two to one hundred megahertz. The phase difference in radio frequency signals between receiver coil pairs in each pad is measured, providing improved data resolution for computing formation dip, and making possible dip measurements in wells drilled with oil base mud or air (invert type muds).

Journal ArticleDOI
TL;DR: In this paper, a theoretical and experimental evaluation of the electromagnetic fields in the immediate vicinity of resonant dipole antennas is presented. And it is shown in the results that it is possible to detect relatively high intensity electromagnetic (EM) fields in close proximity to dipoles even for very low levels of radiated power (1 mW and less).
Abstract: The theoretical and experimental evaluation of the electromagnetic fields in the immediate vicinity of resonant dipole antennas is presented. This type of antenna is widely used with portable and mobile radio transmitters. The work presented herein has been motivated by the concern that future Radio Frequency Protection Guides with respect to human exposure to nonionizing electromagnetic radiation might be expressed strictly in terms of the intensity squared of the electric or magnetic fields. It is shown in the results that it is possible to detect relatively high intensity electromagnetic (EM) fields in close proximity to resonant dipoles even for very low levels of radiated power (1 mW and less). The paper is divided into a theoretical section and an experimental section because its goals are twofold. First, the formulas for the correct evaluation of the EM fields in the close proximity to dipole antennas are established. Second, it is shown that such EM fields, which can be theoretically predicted and experimentally verified with satisfactory accuracy, are indeed strong enough to violate proposed Radio Frequency Protection Guides even for very low levels of radiated power. Thus portable radios are rendered virtually useless, although the same guides permit exposures to much higher levels of power in the far field. Part I of the paper is essentially theoretical and expresses the fields near dipole antennas in terms of cylindrical waves, which lend themselves to closed form integration. The asymptotic expressions of some components of the field are particularly simple for close distances (in terms of wavelength) from the antenna. The correctness of the solution is checked by evaluating how closely boundary conditions are satisfied. Results have shown that previously used formulas for evaluating field intensity very near dipole antennas can give incorrect values.

Proceedings ArticleDOI
01 Aug 1981
TL;DR: The RFI s u s c e p t i b i l i t i e s o f b i p o la r BJT op amps in a u n i t y gain b u f f e r a m p l i f i e r c o n f i g u r a t i o n are determined from measurements o f demodulation r e s p o n s e s.
Abstract: The RFI s u s c e p t i b i l i t i e s o f b i p o la r BJT op amps in a u n i t y gain b u f f e r a m p l i f i e r c o n f i g u r a t i o n are a s s e s s ­ ed us ing a second order t r a n s f e r f u n c t i o n . Values f o r th e second order t r a n s f e r f u n c t i o n are determined from measurements o f demodulation r e s p o n s e s . The RF c a r r i e r frequency was v a r i e d from 50 kHz t o 100 MHz. The AM modulat ion freque ncy was 400 Hz. Experimental r e s u l t s show t h a t a t RF f r e q u e n c ie s above 1 MHz th e b u f f e r amp­ l i f i e r employing an LM10 op amp i s c o n s i d e r a b l y l e s s s u s c e p t i b l e t o RFI than i s a pA741 op amp. In the RF frequency range 10 MHz t o 50 MHz where the demodula­ t i o n i n t e r f e r e n c e e f f e c t s a re the most i n t e n s e , the d i f f e r e n c e in s u s c e p t i b i l i t y between t h e two b u f f e r a m p l i f i e r s i s about 15 dB. Computer s i m u l a t i o n s can ac co unt f o r th e d i f f e r e n c e in RFI s u s c e p t i b i l i t y , i f th e s i z e s o f p a r a s i t i c s u b s t r a t e c a p a c i t a n c e s in op amp macromodels a re a d j u s t e d . In cr e a s in g the v a l u e s f o r the p a r a s i t i c s u b s t r a t e c a p a c i t a n c e s cau ses the pr e d i c t e d RFI t o i n c r e a s e . Thus, the p a r a s i t i c sub­ s t r a t e c a p a c i t a n c e v a l u e s re qui re d f o r th e pA741 macromodel are l a r g e r than th o se req u ire d f o r the LM10 macromodel .

Journal ArticleDOI
TL;DR: In this paper, a LiNbO 3 :Ti directional coupler driven by an RF signal has been tested at 1.06 μm over a large modulation bandwidth, achieving a 16 dB extinction ratio with a driving power of approximately 50μW/MHz.
Abstract: A LiNbO 3 :Ti directional coupler driven by an RF signal has been tested at 1.06 μm over a large modulation bandwidth. An analytical model has been developed leading to simple usable expressions to describe the theoretical dependence of the frequency spectrum of sinusoidally modulated light. The frequency response has been measured with a scanning Fabry-Perot and also with a high-speed photodiode. Both methods provided results which are in good agreement. The 9 mm long switch exhibited a 2.5 GHz bandwidth; a 16 dB extinction ratio has been achieved with a driving power of approximately 50μW/MHz. The confirmation of practical modulation response expressions shows the advantage of the optical spectrum observation, which is a very simple measurement method without any bandwidth limitation. In addition, this method has the advantage of remaining quite accurate even for large modulation signals.

Journal ArticleDOI
TL;DR: In this article, a linac-collider operating at an energy gradient on the order of 100 MV/m was considered and a proper choice of an RF structure for such a collider can minimize the total RF power requirement and the effects of longitudinal and transverse single-bunch beam loading.
Abstract: The energy realistically attainable by an electron-positron storage ring is limited by the RF voltage and power requirements imposed by synchrotron radiation to about 100 GeV. To reach energies of 300 × 300 GeV and higher in a colliding beam machine of reasonable dimensions, we must look to the linac-collider operating at an energy gradient on the order of 100 MV/m. Proper choice of an RF structure for such a collider can minimize the total RF power requirement and the effects of longitudinal and transverse single-bunch beam loading. For an operating frequency in the range 4-6 GHz, the total RF power requirement for a 300 × 300 GeV collider with a luminosity of 1032 cm-2s-1 accelerating 1011 particles per bunch is on the order of 50 MW. To drive this collider, RF power sources are needed having a peak output power in the range 1-2 GW. Possibilities for attaining these peak power levels by direct generation and by energy storage and fast switching are discussed.

Journal ArticleDOI
TL;DR: In this article, the performance of optically coupled microwave switching devices for pulse generation or other applications is detailed and bias dependence of the RF power transfer is presented for a range of operating frequencies, thereby establishing the bias conditions required for a given ON/OFF ratio and insertion loss.
Abstract: The performance of optically coupled microwave switching devices for pulse generation or other applications is detailed The bias dependence of the RF power transfer is presented for a range of operating frequencies, thereby establishing the bias conditions required for a given ON/OFF ratio and insertion loss Limits on peak RF power level and pulse repetition rate, as well as limitations arising from harmonic distortion and shot noise, are also examined

Proceedings ArticleDOI
01 Aug 1981
TL;DR: In this paper, the authors investigated the susceptibility of IK bit memory with the intention of gaining understanding of the nature and consequences of electromagnetic interference (EMI) on complex digital devices.
Abstract: The investigation into the susceptibility of a IK bit memory as described in this paper was undertaken with the intention of gaining understanding of the nature and consequences of electromagnetic interference (EMI) on complex digital devices. The author is involved in the clearance of military aircraft for electromagnetic compatibility and this requires know­ ledge of system response to EMI. To have confidence in the hardness of an aircraft system it is necessary not only to design and build equipment capable of working in the severe electromagnetic environment encountered and created by modern military aircraft but also to be in a position to assess equipment hardness during manufacture and when installed in the aircraft.

Patent
23 Jan 1981
TL;DR: In this paper, a garage door opener system includes a radio receiver actuable by reception of a preselected radio signal for moving a door between opened and closed positions and a portable hand-held transmitter manually actuable to transmit such pre-selected radio signals to the receiver.
Abstract: A garage door opener system includes a radio receiver actuable by reception of a preselected radio signal for moving a garage door between opened and closed positions and a portable hand-held transmitter manually actuable to transmit such preselected radio signal to the receiver. The transmitter includes a radio frequency oscillator for producing the radio signal to be transmitted and a modulating means manually actuable to cause the oscillator to transmit a radio signal which is of the preselected form. An audio transducer is connected in parallel with the radio frequency oscillator to the output of the modulating means to produce an audio signal which corresponds in form to the electric signal modulating the radio frequency oscillator, which audio signal is audible to a person holding the portable transmitter.

Patent
10 Jun 1981
TL;DR: An adjustable phase shifter for adjustably providing a 360° range of phase shift to RF signals by dividing the RF signals into three equal parts, adjusting the relative amplitudes of the parts of the signals and combining the three parts at relative phase angles of 0°, 120° and 240° is described in this paper.
Abstract: An adjustable phase shifter for adjustably providing a 360° range of phase shift to RF signals by dividing the RF signals into three equal parts, adjusting the relative amplitudes of the parts of the RF signals and combining the three parts of the RF signals at relative phase angles of 0°, 120° and 240°.

Patent
16 Apr 1981
TL;DR: In this paper, the phase of the laser gating pulses of an acousto-optic Q-switch is synchronized electrically to the phase driven by the RF signal by applying the output of a repetition rate oscillator to the RF oscillator, whereby the leading edge of each output gating pulse from the flip-flop always occurs at a particular place on the RF waveform.
Abstract: The Q-switched laser gating pulses of an acousto-optic Q-switch are synchronized electrically to the phase of the RF signal driving the Q-switch by applying the RF oscillator output signals to the clock input of an integrated circuit D-type flip-flop and the laser gating pulses to the D input of the flip-flop, whereby the leading edge of each output gating pulse from the flip-flop always occurs at a particular place on the RF waveform In another embodiment, the RF signals are synchronized to the phase of the gating pulses by applying the output of a repetition rate oscillator to the RF oscillator

Journal ArticleDOI
01 Aug 1981
TL;DR: An overview of RF wave applications in magnetic fusion devices is given in this article, where a summary of the wave physics, the present experimental progress, and the technological development of RF heating is presented.
Abstract: An overview of RF wave applications in magnetic fusion devices is given. A summary of the wave physics, the present experimental progress, and the technological development of RF heating is presented. Particular emphasis is placed on the technological requirements of wave launchers, transmission systems, and RF generators for the three main frequency ranges: the ion cyclotron (ICRF), the lower hybrid (LHRF), and the electron cyclotron (ECRF). Some possible extrapolations of the present technology to CTR regimes are discussed.

Patent
17 Apr 1981
TL;DR: In this article, a circuitless particle beam device for relatively high frequency amplifierr oscillator applications that eliminates the requirement for an internal RF slow wave structure was proposed. But the beam was not designed to be an active dielectric waveguide serving the dual purpose of a slow wave circuit and amplification source.
Abstract: A circuitless particle beam device for relatively high frequency amplifierr oscillator applications that eliminates the requirement for an internal RF slow wave structure. A circularly polarized RF energy wave propagates on a relatively high density particle beam within an oversized waveguide and interacts with the beam which exhibits a relatively high dielectric constant. The high density beam acts as an active dielectric waveguide serving the dual purpose of a slow wave circuit and amplification source, and accordingly guides and amplifies the RF energy when a condition of beam and wave synchronism is met.

Patent
18 Dec 1981
TL;DR: In this article, a device mounted on a power transmission device of a vehicle is utilized for transmitting an RF signal when a predetermined parameter exists in the power transmission devices wherein the RF signal is capable of being received at a remote location.
Abstract: A device mounted on a power transmission device of a vehicle is utilized for transmitting an RF signal when a predetermined parameter exists in the power transmission device wherein the RF signal is capable of being received at a remote location. An electromagnetic transducer provides alternating voltage as power which is applied to an oscillator including a crystal filter, a junction field effect transistor and a resistor. The alternating voltage is applied across a drain and a source of the junction field effect transistor. The crystal filter is connected between the drain and the gate of the junction field effect transistor while the resistor is connected between the gate and the source of the junction field effect transistor. A wire antenna has a first end which is connected to the drain of the junction field effect transistor and a second end which is connected to the source of the junction field effect transistor to prevent transmission of any RF signal until the predetermined parameter is exceeded. Sensing elements mounted on the power transmission device indicate when any one of several parameters is exceeded and cause the second end of the wire antenna to be disconnected from the source of the junction field effect transistor to allow transmission of the RF signal.