DF Antenna Array Technology for Military Applications
What is Direction-Finding (DF)?
There are 3 primary application areas in information warfare: signals intelligence (SIGINT),
direction-finding (DF) and electronic attack (EA). These can be thought of as "listen, locate and respond".
Listen: In signals intelligence, the objective is to monitor the environment for signals of interest and collect the signal information.
Locate: In direction-finding, the objective is to determine the direction that the signal of interest is coming from.
Respond: In electronic attack, the objective is to jam the signal of interest.
Why a DF Antenna Array?
Successful direction-finding requires a DF antenna array. In the past, DF antenna
arrays have been the limiting factor in DF systems. With high performance DF antenna arrays,
covering an ultrawideband frequency range and able to transmit and receive ultrawideband
(impulse-type) signals, high gain, accurate direction-finding is enabled.
DF antenna arrays are composed of multiple antenna elements in a single enclosure (radome).
To cover all azimuth angles at all times, one should use a circular DF antenna array.
The elements point in different directions, to pinpoint the direction of signal origin most
effectively. DF antenna arrays can be used for transmit and receive throughout an ultrawideband frequency range.
Custom DF Antenna Arrays
The development of a custom DF antenna array typically can be based on minimal
information from the end user: The volume (cylinder diameter and height) available for
the array, the maximum acceptable weight, number of elements (ports), whether an omnidirectional
element is needed, and whether the DF antenna array is for receive only, or for both receive and transmit.
Very compact and light-weight DF antenna arrays can be customized to the space available.
DF Antenna Array Selection
DF antenna arrays can be composed of omnidirectional or directional antenna elements.
With directional elements, the DF antenna array has the capability for true spatial filtering
and amplitude and phase DF. With omnidirectional elements, the DF antenna array has the capability
for phase-only based DF, which can lead to angle ambiguity and potentially even receiver overload.
Therefore, DF antenna arrays are most typically composed of directional elements, but with an integral omnidirectional element.
Conclusion
By providing the ability to effectively determine the direction of origin of a signal of interest, DF
antenna arrays, including customized, ultrawideband and lightweight/compact DF antenna arrays, are a
mission-critical technology for military applications, particularly information warfare.
