inputs (< 1 degree phase difference) is required.
In a phased array antenna with hundreds or
thousands of elements, where it is necessary to
characterize each element in a relative way to the
others, the ability to accelerate the test by using
multiple input channels is a significant benefit.
As technology evolves and antenna configurations continue to have higher densities, a scalable
platform that can accommodate additional channels in the future becomes equally important.
In addition, a digitizer with sufficient 3-dB analog bandwidth is also necessary in order to use
it to characterize signals across all of the different
functions possible in the phased array. Modern
active electronically steered array (AESA) antennas do not only transmit and receive continuous
wave (CW) tones, but also often have signals of
bandwidth as in the case of communications or
different types of modulation. For example, there
are several radar configurations that use pulsed
RF or Barker codes, or other forms of modulation, that increase the amount of bandwidth that
is used. Therefore, a digitizer that has enough
bandwidth to encompass a variety of high bandwidth test conditions is also required.
The Agilent M9703A AXIe High-Speed Digitizer with optional DDC provides eight synchronous acquisition channels. This 12-bit digitizing
solution is able to capture signals from DC up to
2 GHz at 1.6GS/s (or 3. 2 GS/s with interleaving)
into 4GB of internal memory.
Using a wideband multi-channel, coherent
digitizer to make relative phase and amplitude
measurements across the elements of an array
antenna definitely represents a different test
methodology than in the past. Narrowband
measurements are familiar and traditionally used
in antenna testing using one or more network
analyzers. But wideband signals that mimic the
signals of the operational system provide a more
realistic answer in the presence of nonlinearities.
The advantages of this technique are well worth