MAGIC-T JUNCTION—A combination of the H-type and E-type T-junctions.
MAGNETIC FIELD—See H-FIELD.
MAJOR LOBE—The lobe in which the greatest amount of radiation occurs.
MARCONI ANTENNA—A quarter-wave antenna oriented perpendicular to the earth and operated with one end grounded. Also known as QUARTER-WAVE ANTENNA.
MAXIMUM USABLE FREQUENCY—Maximum frequency that can be used for communications between two locations for a given time of day and a given angle of incidence.
MEDIUM—The substance through which a wave travels from one point to the next. Air, water, wood, etc., are examples of a medium.
METALLIC INSULATOR—A shorted quarter-wave section of transmission line.
MICROWAVE REGION—The portion of the electromagnetic spectrum from 1,000 megahertz to 100,000 megahertz.
MINOR LOBE—The lobe in which the radiation intensity is less than a major lobe.
MULTIELEMENT ARRAY—An array consisting of one or more arrays and classified as to directivity.
MULTIELEMENT PARASITIC ARRAY—An array that contains two or more parasitic elements and a driven element.
MULTIPATH—The multiple paths a radio wave may follow between transmitter and receiver.
NEGATIVE ALTERNATION—The portion of a sine wave below the reference line.
NODE—The fixed minimum points of voltage or current on a standing wave or antenna.
NONDIRECTIONAL—See OMNIDIRECTIONAL.
NONRESONANT LINE—A transmission line that has no standing waves of current or voltage.
NORMAL—The imaginary line perpendicular to the point at which the incident wave strikes the reflecting surface. Also called the perpendicular.
NULL—On a polar-coordinate graph, the area that represents minimum or 0 radiation.}}
OMNIDIRECTIONAL—Transmitting in all directions. Also known as NONDIRECTIONAL.
OPEN-ENDED LINE—A transmission line that has an infinitely large terminating impedance.
OPTIMUM WORKING FREQUENCY—The most practical operating frequency that can be used with the least amount of problems; roughly 85 percent of the maximum usable frequency.
ORIGIN—The point on a graph where the vertical and horizontal axes cross each other.
OUTPUT END—The end of a transmission line that is opposite the source. Also known as RECEIVING END.
OUTPUT IMPEDANCE—The impedance presented to the load by the transmission line and its source.
PARALLEL RESONANT CIRCUIT—A circuit that acts as a high impedance at resonance.
PARALLEL-WIRE—A type of transmission line consisting of two parallel wires.
PARASITIC ARRAY—An array that has one or more parasitic elements.
PARASITIC ELEMENT—The passive element of an antenna array that is connected to neither the transmission line nor the driven element.
PERIOD—The amount of time required for completion of one full cycle.
AI-6
