Abstract: A portable bioelectric impedance monitor for monitoring extracellular fluid levels includes a tetrapolar electrode array lead with four electrodes arranged sequentially and axially along the lead, and circuitry coupled with the at least four electrodes configured to measure bioelectric impedance extracellular fluid in a human subject at a frequency of less than 15 kHz. The electrodes are adhered to a human subject/patient on the patient's torso or one of the patient's limbs. One embodiment includes a Tetrapolar Analog Front End Patient Interface circuit configured to convert two electrode operation of a commercial Impedance Converter, Network Analyzer into a tetrapolar operation for excitation and impedance measurement of the human subject.

Abstract: An antenna includes an antenna layer, a ground layer and a dielectric layer between the antenna layer and the ground layer. The antenna layer and the ground layer form a figure in the shape of two identical mirror image triangles joined together at a longest side of each one of the triangles where each side of each triangle is a different length.

Abstract: A method of evaluating or monitoring the medical state of a human subject on the subject includes the steps of: positioning an antenna side of a self-contained radio apparatus for non-invasive, thoracic radio interrogation of a human subject proximally to the heart of the human subject; providing a radio frequency interrogation interference signal from the human subject, the radio frequency interrogation interference signal being low frequency components of reflections of a radio interrogation signal transmitted into the thorax of the subject; and determining with the apparatus on the subject at least at least one stroke volume value of the subject from radio frequency interrogation interference signal generated by the apparatus.

Abstract: A relative positioning system and method has an adjoining pair of spaced apart receivers positioned proximal to an object causing a signal interference with a radio frequency signal detectable by each receiver of the adjoining pair. The radio frequency signal is associated with an emitter. Control electronics operatively couple the spaced apart receivers. The control electronics are configured to determine a direction of the emitter based on the signal interference. In an embodiment of the system and method the emitter is associated with an object of interest, the signal encodes information relating to the identity and status of the object, and information and heading of the object are cutaneously communicated to an operator by an article worn by the operator.

Abstract: A relative positioning system and method has an adjoining pair of spaced apart receivers positioned proximal to an object causing a signal interference with a radio frequency signal detectable by each receiver of the adjoining pair. The radio frequency signal is associated with an emitter. Control electronics operatively couple the spaced apart receivers. The control electronics are configured to determine a direction of the emitter based on the signal interference. In an embodiment of the system and method the emitter is associated with an object of interest, the signal encodes information relating to the identity and status of the object, and information and heading of the object are cutaneously communicated to an operator by an article worn by the operator.

Abstract: A relative positioning system and method has an adjoining pair of spaced apart receivers positioned proximal to an object causing a signal interference with a radio frequency signal detectable by each receiver of the adjoining pair. The radio frequency signal is associated with an emitter. Control electronics operatively couple the spaced apart receivers. The control electronics are configured to determine a direction of the emitter based on the signal interference. In an embodiment of the system and method the emitter is associated with an object of interest, the signal encodes information relating to the identity and status of the object, and information and heading of the object are cutaneously communicated to an operator by an article worn by the operator.

Abstract: A relative positioning system and method has an adjoining pair of spaced apart receivers positioned proximal to an object causing a signal interference with a radio frequency signal detectable by each receiver of the adjoining pair. The radio frequency signal is associated with an emitter. Control electronics operatively couple the spaced apart receivers. The control electronics are configured to determine a direction of the emitter based on the signal interference. In an embodiment of the system and method the emitter is associated with an object of interest, the signal encodes information relating to the identity and status of the object, and information and heading of the object are cutaneously communicated to an operator by an article worn by the operator.

Abstract: An antenna includes an antenna layer, a ground layer and a dielectric layer between the antenna layer and the ground layer. The antenna layer and the ground layer form a figure in the shape of two identical mirror image triangles joined together at a longest side of each one of the triangles where each side of each triangle is a different length.

Abstract: A radio apparatus and method for non-invasive, thoracic radio interrogation of a subject for the collection of hemodynamic, respiratory and/or other cardiopulmonary related data from the subject includes a antenna positionable proximally to the subject, a radio transmitter transmitting an unmodulated radio interrogation signal of a predetermined fixed frequency at a safe level of about 1 milliwatt or less from the antenna into the subject and a radio receiver capturing through the antenna, reflections of the transmitted radio interrogation signal returned from the subject. A Doppler component of the reflections contains the data that can be extracted from the captured reflections.

Abstract: A portable thoracic impedance monitor for monitoring thoracic fluid levels, an electrode array assembly having a single linear electrode array lead with first, second, third, and fourth electrodes arranged sequentially and axially along the linear electrode array lead, and a method of use of the thoracic impedance monitor. A measurement of the user's thoracic impedance is obtained by connecting the second electrode to the user's body at the junction of the clavicles, superior to the sternum, the third electrode to the user's body at the xiphoid-sternal junction, and the first and fourth electrodes to the user's body substantially along a centerline of the user's sternum respectively at a first pre-determined distance above the second electrode and a second predetermined distance below the third electrode, followed by initiating operation of the monitor.