Conformal antenna

Advantages

In modern aircraft, a wide variety of antennas are needed for essential functions like navigation, communication systems, instrument landing, and radar altimeter. These antennas, often numbering between 20 and 70 on military aircraft, significantly increase aerodynamic drag and fuel consumption []. To reduce these negative effects, integrating antennas into the aircraft’s surface, known as conformal antennas, offers a highly effective solution []. Conformal antennas streamline the aircraft by embedding the antennas into the skin, preserving aerodynamics while maintaining functionality.

How it works

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 device which are all controlled by a microprocessor (computer). By controlling the phase of the feed current, the nondirectional radio waves emitted by the individual antennas can be made to combine in front of the antenna by the process of interference, forming a strong beam (or beams) of radio waves pointed in any desired direction. In a receiving antenna the weak individual radio signals received by each antenna element are combined in the correct phase to enhance signals coming from a particular direction, so the antenna can be made sensitive to the signal from a particular station and reject interfering signals from other directions.

In a conventional phased array the individual antenna elements are mounted on a flat surface. In a conformal antenna, they are mounted on a curved surface, and the phase shifters also compensate for the different phase shifts caused by the varying path lengths of the radio waves due to the location of the individual antennas on the curved surface. 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 of the waves is small enough that small antennas can be used.

References

References

1. (2001). "IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)". IEEE.
2. (2006-01-20). "Conformal Array Antenna Theory and Design". Wiley.