Finding the Best Directional Antenna for Military Applications
A directional antenna (an antenna with a directional radiation pattern) can be viewed as analogous
to speaking with a particular person: your (the antenna's) aim is to speak only to (transmit signals to)
the other person, and to hear only from (receive signals from) the other person. In contrast to omnidirectional
antennas (which are designed for transmit and receive in all directions), a directional antenna is designed
for transmit and receive in the direction of the user's choice.
In military applications, when receiving signals emitted by an adversary, the adversary may
change their frequency of operation, thus limiting your ability to receive their signals with
as much signal strength. Hence, an ultrawideband constant aperture directional antenna can be advantageous.
Ultra wideband: An ultra wideband antenna has a frequency ratio
(maximum frequency divided by minimum frequency) of 10: 1 or greater,
typically with voltage standing wave ratio (VSWR) < 3 throughout, meaning
that it can operate efficiently (as defined by the VSWR condition) over a broad frequency range.
Constant aperture: An antenna whose gain increases with frequency will have nearly
constant effective aperture. Constant aperture means that the antenna will deliver the
same signal power at any frequency, for the same incident electromagnetic wave power density.
A further advantageous performance characteristic (for directional antennas in military use)
is time non-dispersive. To transmit or receive impulse-like signals (which are inherently low-probability
of detection and low probability of intercept) requires time non-dispersive ultrawideband antennas.
Emerging signal threats (such as ultra wideband radio signals) require the use of a time non-dispersive antenna.
Hence, a directional ultra wideband antenna which is time non-dispersive and has nearly constant aperture is recommended
for military applications such as tactical communications and information warfare. Further features to look for
in a directional antenna are compact size, light weight, ruggedness for operational use, low radar cross section/minimal visual profile, no groundplanes/baluns/impedance transformers needed, and ideally with customization/advanced capabilities (such as dual polarization) available as well.
Directional antennas are an important asset for military tactical communications and information warfare, hence
it is important to select the right directional antenna for your application to achieve performance, mechanical and operational advantages.
