High-Speed Testing of Microwave Antennas
Author: Joseph H. Pape
Publication: AMTA 1990
Copyright Owner: NSI-MI Technologies
State-of-the-art microwave antennas often incorporate the ability to operate in many operating states and over wide frequency ranges. Adaptive arrays and electronically scanned antennas may have programmable beam shapes, configurations or scan positions resulting in several thousand operational states. In addition, these antennas may also require testing at many frequencies. To be properly characterized, these antennas may require testing in all these states. The amount of data required to characterize these antennas, coupled with the requirement to maximize antenna range throughput and minimize costs, puts ever increasing demands on the test equipment designed to perform these measurements. This paper describes a new automated microwave measurement system utilizing a high speed measurement receiver and an 80386 PC based computer to rapidly test these new generation antennas. The recently introduced Scientific-Atlanta Model 2095 Microwave Measurement System incorporates a unique data acquisition coprocessor (DAC) for high speed test device control, instrument timing, frequency control, data buffering and transfer to the system controller. Antenna measurements on multi-beam and multi-port antennas can be made in a fraction of the time associated with other types of test systems. The various timing parameters of the Model 2095 are described with special emphasis on how these independent and variable factors inter-relate to each other. A method is presented to calculate total test time, given the test requirement and timing for state changes of the AUT. Examples of typical test scenarios are presented as a further aid in understanding system timing.