Aircraft Cavity-Backed Nonprotruding Wideband Antenna

A novel circular aperture antenna is presented. The proposed nonprotruding antenna is composed of a cylindrical cavity embedding an inverted hat antenna whose profile is defined by three elliptical segments. This profile can be used to control and shape the return loss response over a wide frequency band (31% at -15 dB). The present design combines the benefits of a low-profile antenna and the broad bandwidth of the inverted hat monopole. A parametric analysis of the antenna is conducted. Omnidirectional monopole-like radiation pattern and vertical polarization are also verified with measurements and simulations. This antenna constitutes a low drag candidate for a distance measurement equipment (DME) aircraft navigation system.