Conformal antenna

Lore & Background

Conformal antennas were developed in the 1980s as avionics antennas integrated into the curving skin of military aircraft to reduce aerodynamic drag, replacing conventional designs that project from the aircraft surface. Military aircraft and missiles remain the largest application, though they are also used in some civilian aircraft, military ships, and land vehicles. As the cost of required processing technology decreases, conformal antennas are being considered for civilian uses such as train antennas, car radio antennas, and cellular base station antennas, to save space and reduce visual intrusion by integrating into existing objects.

Conformal antennas are a form of phased array antenna. They are composed of an array of many identical small flat antenna elements—such as dipole, horn, or patch antennas—covering the surface. At each antenna, the current from the transmitter passes through a phase shifter controlled by a microprocessor. By controlling the phase of the feed current, the nondirectional radio waves emitted by the individual antennas combine through interference to form a strong beam in any desired direction. In receiving mode, the weak signals from each element are combined in the correct phase to enhance signals from a particular direction and reject interference.

In a conventional phased array, the antenna elements are mounted on a flat surface. In a conformal antenna, they are mounted on a curved surface, and the phase shifters compensate for the varying path lengths of radio waves due to the location of individual antennas on the curve. Because the individual antenna elements must be small, conformal arrays are typically limited to high frequencies in the UHF or microwave range, where the wavelength is small enough for small antennas.

Reader's Guide

The significance of conformal antennas lies in their ability to address a critical problem in modern aircraft: the large number of antennas needed for navigation, communication, instrument landing, and radar altimeter functions. On military aircraft, these antennas can number between 20 and 70, each projecting from the surface and significantly increasing aerodynamic drag and fuel consumption. By embedding antennas into the aircraft's skin, conformal antennas streamline the vehicle, preserving aerodynamics while maintaining full functionality. This integration reduces drag and fuel use, a major advantage for both military and civilian aviation.

The legacy of conformal antennas extends beyond aircraft. Their use in military ships and land vehicles demonstrates their versatility, and as processing costs decline, they are being considered for civilian applications such as train antennas, car radio antennas, and cellular base station antennas. In these contexts, conformal antennas offer space savings and reduced visual intrusion by integrating into existing objects. The technology represents a shift from protruding, drag-inducing designs to embedded, shape-conforming arrays that maintain performance while improving aerodynamics and aesthetics.

Did You Know?

• Conformal antennas were developed in the 1980s for military aircraft to reduce aerodynamic drag.
• Military aircraft can carry between 20 and 70 antennas, all of which increase drag and fuel consumption.
• Conformal antennas are a form of phased array that compensates for curvature using phase shifters.
• They are typically limited to UHF or microwave frequencies because the antenna elements must be small.