analysis was limited to basic equations which were used to size the elements of antennas such as the monopole, dipole, long wire, and a few other configurations. These equations were also modified using rules of thumb, intuition, and field trials. For example, it was known that using tubing rather than thin wires for dipoles increased their bandwidth, which might be good or bad depending on the application; the amount of this increase versus tubing diameter was estimated using guidelines based on experience and basic measurements. Even academic discussions of antenna designs and their operating principles had few equations beyond basic arrangement versus wavelength discussions, as made clear in the 1926 technical paper for the classic Yagi-Uda antenna (Reference 1) (Figure 3).
the availability of models and algorithms that captured antenna attributes, which could be executed on computers to solve the electromagnetic field models and equations in a reasonable amount of time, as long as the models were not too complicated.
These “field solvers” allowed designers of new antenna configurations to use the
combination of antenna theory and field-experience insight to propose new arrangements, model them, and finally quantify their performance “on paper”, without need for a physical model and field tests in their initial design stages. This approach worked to some extent, but it was still somewhat of a hit-or-miss arrangement. It did, however, enable engineers to focus on an antenna design and iteratively adjust and tweak it until it met the project objectives. An extraordinary example of this was seen in the development of the first stealth aircraft, the F-117 Nighthawk, at Lockheed’s
legendary Skunk Works (References 2 and 3). Much the of theoretical work on reducing its radar signature by many orders of magnitude was based on analytical solutions and complex equations. These equations analyzed the reflection of electromagnetic energy fields on the aircraft as it was bathed in radar signals. The project’s objective was to use unique and unconventional choices in skin-panel material, shape, size, angles, joints, and other design elements to minimize the inherent tendency of these surfaces to act as an antenna. This, in turn, caused the aircraft to re-radiate and reflect energy in an antenna-like mode, and thus be invisible to the radar system receiver. Figure 2: The basic dipole is a balanced, symmetrical antenna without a ground reference (top), as shown in the illustration (bottom). Image sources: TCARES.net (top) and Tutorials Point (bottom)
The second phase The second wave of antenna- design innovation began with
Figure 1: The long wire or whip antenna arrangement is a single-element design using a ground plane (here, the car’s surface) (left); the illustration of the antenna shows its simplicity (right). Image sources: Lihong Electronic (left); Electronics Notes (right)
Third phase is very different
We are now entering a new wave of
we get technical
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