摘要:
A tracer material is embedded in a component of electrical equipment to detect excessive wear of the component when it is exposed to an electrical arc. As the component wears, the tracer material becomes exposed to the electrical arc and emits electromagnetic radiation, which is monitored continuously. The tracer material is selected so that it emits electromagnetic radiation when it is exposed to an electrical arc that is distinct from electromagnetic radiation emitted by any other parts of the component.
摘要:
A tracer material is embedded in a component of electrical equipment to detect excessive wear of the component when it is exposed to an electrical arc. As the component wears, the tracer material becomes exposed to the electrical arc and emits electromagnetic radiation, which is monitored continuously. The tracer material is selected so that it emits electromagnetic radiation when it is exposed to an electrical arc that is distinct from electromagnetic radiation emitted by any other parts of the component. A fluorescent tracer material may also be used.
摘要:
A reduced height monopole/slot antenna having generally parallel spaced ground planes, the upper one of which has a slot therein, a stripline located between the ground planes, and a monopole extending from the stripline through said slot generally orthogonally through the upper ground plane and being top hat loaded at the outer end thereof. The stripline is offset toward the slotted ground plane, and the slot is capacitively loaded with capacitance connected across the narrow dimension of the slot.
摘要:
A direction finding system utilizing a single monopole/crossed slot antenna in combination with associated electronic circuitry. Each of the four ports of the antenna are connected to amplitude varying elements whose outputs are combined by a power combiner. A microcontroller stores the signal. The microcontroller also generates the signals which control the amplitude variation supplied by each of the amplitude varying elements. Two configurations of the amplitude varying elements are provided by predetermined settings within the microcontroller. The two settings are selected to configure the antenna on two distinct reception patterns, each with a predetermined angular offset from a reference direction. In operation the antenna will be configured for a first reception pattern. The signals received will be detected, quantified, and stored by the microcontroller which subsequently reconfigures the antenna for a second reception pattern. A second signal is received by the antenna in the second configuration and again is detected, quantified, and stored by the microcontroller. The microcontroller determines the difference between the two signals and, based upon a predetermined calibration curve relating differences in the stored signals to the angle of arrival of the signals from the reference direction, determines the angle from which the signal arrived.
摘要:
An antenna which is adapted to have multiple fundamental resonances includes an outer conductor electrically connected to a feed network and having a generally tubular portion opening through one end to define an internal cavity therein. The antenna also includes an interior conductor electrically connected at a first end to a portion of the outer conductor within the internal cavity. The interior conductor extends through the opening defined in the outer conductor to a second end to thereby define an extended conductor portion which extends beyond the outer conductor. The antenna also includes decoupling means for electrically decoupling the extended conductor portion of the interior conductor from the antenna for signals having frequencies within the upper frequency band. In one embodiment, the internal conductor portion has a predetermined electrical length equal to an odd multiple of a quarter wavelength of a signal having a frequency in the upper frequency band of the antenna. Thus, the extended conductor portion is effectively electrically decoupled from the antenna for signals having frequencies within the upper frequency band.
摘要:
A reduced height monopole/crossed slot antenna having generally parallel spaced ground planes, the upper one of which has a capacitively loaded slot therein formed by crossed slot portions. A stripline is located between the ground planes offset toward the upper ground plane, and is formed by crossed stripline portions. A monopole extends from the intersection of the crossed stripline portions through the intersection of the crossed slot portions orthogonally to the upper ground plane, and is top hat loaded at the outer end thereof. The stripline is fed at selective ends thereof.
摘要:
A dual frequency stacked microstrip patch antenna is comprised of a pair of circular radiating patches separated by a layer of dielectric, the two upper patches being further separated by another layer of dielectric from a pair of separated ground planes. A modal shorting pin extends between the patches and ground planes, and the patches are fed through a pair of feed pins by a backward wave feed network. A pair of modified shape feed through holes in the lower patch through which the feed pins pass result in an extended bandwidth.
摘要:
A microstrap patch antenna with a substantially omni-directional radiation pattern includes an upper hemisphere microstrip patch radiator working against a ground plane and a lower hemisphere microstrip patch radiator working against a ground plane, the ground planes being oriented in close proximity and spaced apart from each other. One of the radiators is excited in left hand circular polarization and the other in right hand circular polarization such that their fields add constructively across their ground planes to achieve an omni-directional radiation pattern.
摘要:
A dual frequency stacked microstrip patch antenna is comprised of a pair of circular radiating patches separated by a layer of dielectric, the two upper patches being further separated by another layer of dielectric from a pair of separated ground planes. A modal shorting pin extends between the patches and ground planes, and the patches are fed through a pair of feed pins by a backward wave feed network. A pair of pear-shaped holes in the lower patch through which the feed pins pass balance the impedance between the patches and result in an extended bandwidth.