The Narda Microwave Corp.

L-3 Communications Corporation

Edward E Aslan

Om P Gandhi

Adeline W Jahelka

The electromagnetic radiation monitor includes a low frequency surface charge sensor, a high frequency sensor, and a lossy material sandwiched between the two sensors. The surface charge sensor responds to electromagnetic radiation from about 100 KHz to about 1 GHz. The high frequency sensor responds to frequencies from about 300 MHz to about 100 GHz. An output signal from the low frequency sensor is detected, and provided to an adjustable gain amplifier. An output signal from the high frequency sensor is similarly provided to a second adjustable gain amplifier. Output signals from the two amplifiers are summed by a summing circuit, whose output signal is provided to one input of a comparator circuit. The output signal from the comparator circuit triggers an audible or visible alarm from the alarm circuit when electromagnetic radiation detected by either or both of the low and high frequency sensors causes the output signal of the summer circuit to exceed a threshold.

Ultra wideband personal electromagnetic radiation monitor

An electromagnetic probe for the detection of both E-field and H-field radiation includes a quasi-isotropic E-field antenna and a quasi-isotropic H-field antenna. The quasi-isotropic E-field antenna includes three mutually orthogonal surface area antenna elements which define three mutually perpendicular planes and an apex. Each surface area element is responsive to E-field radiation normal to the surface of that element and produces an output voltage signal proportional thereto. The quasi-isotropic H-field antenna includes three mutually orthogonal electrically small loop antenna elements. Each loop antenna element is responsive to H-field radiation which is incident normal to the plane of the element. Each loop antenna element produces an output voltage signal proportional to the field strength of the H-field radiation. The H-field antenna is affixed substantially proximate to the apex which is defined by the E-field antenna. Detection circuits receive the signals from each of the surface area antenna elements and loop antenna elements and produce output signals proportional to received field strength signals. Thus formed, the electromagnetic probe detects both E-field and H-field radiation over a frequency range of about 0.1 to about 300 MHZ with a substantially flat frequency response.

Electromagnetic probe for the detection of e-field and h-field radiation

A contact hazard meter used to measure electromagnetic field induced currents which would flow through a human body to ground upon physical contact with an item carrying such field induced currents includes a conductive contact, a human equivalent circuit coupled to the conductive contact and an electronic circuit coupled to the human equivalent circuit for measuring and displaying a measurement of current flowing from the item and through the human equivalent circuit when the conductive contact is placed in physical contact with the item carrying the field induced currents. The human equivalent circuit approximates the impedance of the human body at varying frequencies. The contact hazard meter has a plurality of range settings, one setting providing the resultant current as a percentage of a safety guideline maximum permissible exposure value.

Contact hazard meter having a human equivalent circuit

A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor assembly having a surface area sensor in the form of a conductive can-shaped or boss-like element. The surface area sensor detects the radial electric field component directly from the radiating antenna or a secondary radial field component created by the displacement current induced in the wearer of the personal monitor who is illuminated by the electromagnetic radiation. The radial field component is detected by a diode detector circuit and is provided to a comparator circuit which will trigger an alarm if the induced current exceeds a predetermined level.

Surface charge personal electromagnetic radiation monitor and method

A workstation mat used to monitor radio frequency, electromagnetic field induced currents flowing through the body of a person standing on the workstation mat. The workstation mat includes an upper and lower conductive plate residing in parallel planes. The upper plate is superposed in spaced apart relation over the lower plate. The mat also includes an electronic circuit coupled to the conductive plates. The electronic circuit senses the induced current flowing through a person's body and sounds an alarm to warn the worker when the induced body current meets or exceeds a predetermined current threshold. The threshold setting is variable and preset by the user. The workstation mat has a reset button switch mounted on one lateral side and contains connectors for a remote alarm and a remote reset switch.

Induced body current metering workstation mat

A wide power range radiation monitor includes a pair of diodes with their cathodes interconnected and with an additional capacitor coupled in parallel to one of the diodes. The detector, of the radiation monitor provides two outputs, a low power output and a high power output, which outputs are connected to the anodes of the detector diodes. The arrangement of dual diodes and capacitance provide the diode detector of the monitor with a greater than 40 dB square law region.

Wide power range radiation monitor

An antenna for use in measuring current induced in a human body from exposure to radio frequency, electromagnetic fields approximates the impedance the human body over a wide frequency band of operation. The antenna includes an elongated resistive strip secured to a rigid supporting member, the supporting member and resistive strip being mounted on a supporting base plate. The antenna obviates the need for a human subject to be exposed to electromagnetic fields which need to be assessed to determine whether the induced current exceeds permissible guidelines. The antenna is collapsible so that it is easily transported to any desired location.

Human-equivalent antenna for electromagnetic fields

A wide power range radiation monitor includes a pair of diodes with their cathodes interconnected and with an additional capacitor coupled in parallel to one of the diodes. The detector of the radiation monitor provides two outputs, a low power output and a high power output, which outputs are connected to the anodes of the detector diodes. The arrangement of dual diodes and capacitance provide the diode detector of the monitor with a greater than 40 dB square law region.

A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor in the form of at least one coil mounted on a rectangular form of lossy material. A first metal shield plate is situated adjacent to one side of the form on which the coil is mounted, and a second metal shield plate is situated on another side of the form. The metal shield plates have an impedance which varies substantially inversely proportional with the frequency of electromagnetic radiation sensed by the coil, and compensate for the variation in the magnitude of the induced current in the coil, which induced current, without at least one of the shields, would have varied in magnitude substantially directly proportional with the frequency of the electric field component of the electromagnetic radiation, so that the magnitude of an output signal generated by the sensor is relatively independent of the frequency of the sensed electromagnetic radiation.

Personal VHF electromagnetic radiation monitor

Personal electromagnetic radiation monitor

A personal electromagnetic radiation monitor includes an electromagnetic radiation sensor, a conductive shield spaced apart from the sensor and a backing of graduated lossy material. The electromagnetic radiation sensor includes thin film resistive thermocouples. The backing of graduated lossy material is interposed between the radiation sensor and the conductive shield. The layer is progressively more conductive through its thickness from the side which faces the sensor to the side which faces the conductive shield.

The present invention relates to a dipole antenna for monitoring electromagnetic radiation fields over an extended frequency range with essentially flat characteristics. The dipole antenna includes two arms, each of which is divided into two or more conducting elements. In one arm, a relatively low resistance is connected in series between the segments, and in the other arm, a relatively large resistance is connected in series between the segments.

Dipole antenna for monitoring electromagnetic waves over an extended

An electric field sensitive probe capable of measuring both CW and pulsed signals with consistent efficiency using a diode detector connected to a dipole antenna in which a shunt capacitor is connected in parallel with the dipole and one or more resistive elements are connected in series between the diode and the dipole.

Radiation monitor diode detector with constant efficiency for both CW

A unique diode sensor adapted for responding with pre-established sensitivity over a range of relatively low frequencies. A diode is connected to a dipole antenna having both conductive and resistive portions. Lumped impedances are connected in parallel with the diode and the values of these impedances are selected in coordination with the characteristics of the diode and antenna to control the sensitivity of the sensor as a function of the frequency of the illuminating energy.

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Plainview, NY, United States of America

Edward E Aslan