Novel Low Profile Wideband Monopole Antenna for Avionics Applications

In this communication, a new broadband antenna with a very low profile is proposed. The antenna inherits the wide bandwidth of the blade antenna, while its height is considerably reduced to 0.03 λ₀, where λ₀ is the wavelength of the lowest operating frequency. This new design consists of a top loaded monopole with several shorting pins and an inductive loading. The antenna resonates at two distinctive frequencies determined by the shorting pins and inductive loading and the wideband characteristic is achieved by the control of the resonance separations. The inductive loading is created by a shorted metallic disk embedded into the antenna structure. This new method of inductive loading facilitates the antenna fabrication while the physical size of the antenna is kept compact. A prototype was fabricated and its VSWR and far field radiation pattern were measured. The antenna provides a bandwidth of 17% for VSWR smaller than 3. Also, a minimum realized gain of 1 dBi was achieved over the frequency bandwidth in which the antenna is well matched.