Design of a Vivaldi-Fed Hybrid Horn Antenna for Low-Frequency Gain Enhancement

This communication proposes the hybrid Vivaldi-fed horn antenna, which consists of the printed antipodal Vivaldi antenna (AVA) on an FR4 substrate for better matching performance in the low-frequency band and the horn antenna that surrounds the exterior of the AVA for increased gain performance in the high frequency. In order to verify the operating principle in the low-frequency band, an equivalent circuit of the proposed antenna is modeled and analyzed. The mode decomposition technique is then used to examine the radiation physics of the proposed antenna in high-frequency band. The measured reflection coefficients in the entire frequency range are less than -3 dB of the half-power reference (maximum of -4.11 dB). The measured gains of 2.12 dBi at 1 GHz and 7.84 dBi at 6 GHz are obtained. These results confirm that the better characteristics in low-frequency matching and high-frequency gain can be achieved by the proposed design.