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A Compact Antenna Test Range (CATR) is a facility which is used to provide convenient testing of antenna systems at frequencies where obtaining far-field spacing to the AUT would be infeasible using traditional free space methods. It was invented by Richard C. Johnson at the Georgia Tech Research Institute. [3]
For the relationship between the electric and magnetic fields, see the impedance of free space. For a 50 Ω load, knowing that P D A e = P r = V 2 /R and E 2 = μ 0 ε 0 {\displaystyle {\sqrt {\frac {\mu _{0}}{\varepsilon _{0}}}}} P D ~ 377P D (E and V noted here are the RMS values averaged over time), the antenna factor is developed as:
Ruze's equation is an equation relating the gain of an antenna to the root mean square (RMS) of the antenna's random surface errors. The equation was originally developed for parabolic reflector antennas, and later extended to phased arrays.
Forms of the reciprocity theorems are used in many electromagnetic applications, such as analyzing electrical networks and antenna systems. [1] For example, reciprocity implies that antennas work equally well as transmitters or receivers, and specifically that an antenna's radiation and receiving patterns are identical.
G/T is the figure of merit for a satellite system. G is the Receive antenna gain. T is the system noise temperature. System noise temperature = antenna noise temperature + Receiver noise temperature (LNA) Antenna noise temperature is the noise power seen at the receive output of the antenna. (To LNA) If we are not measuring with an LNA or ...
If a current, , injected into port A produces a voltage, , at port B and injected into port B produces at port A, then the network is said to be reciprocal. Equivalently, reciprocity can be defined by the dual situation; applying voltage, , at port A producing current at port B and at port B producing current at port A. [1] In general, passive networks are reciprocal.
When actual measurements of an antenna's gain are made by a laboratory, the field strength of the test antenna is measured when supplied with, say, 1 watt of transmitter power, at a certain distance. That field strength is compared to the field strength found using a so-called reference antenna at the same distance receiving the same power in ...
Measurement of AoA can be done by determining the direction of propagation of a radio-frequency wave incident on an antenna array or determined from maximum signal strength during antenna rotation. The AoA can be calculated by measuring the time difference of arrival (TDOA) between individual elements of the array.