An Integrated Wideband SIW Horn Antenna for Applications in X and Ku Bands

In this paper, an integrated broadband horn antenna for the X and Ku bands is proposed. By loading a double-sided parallel-strip line (DSPSL) structure with slots on the extended substrate of the Substrate Integrated Waveguide (SIW) horn antenna, the impedance characteristics at low frequencies are adjusted, and high-frequency resonant mode is introduced, effectively broadening the antenna’s operating frequency range. By integrating a Defected Ground Structure (DGS) around the horn aperture, the backward radiation of the antenna is significantly reduced, enhancing its radiation performance. Ultimately, the proposed antenna achieves a relative bandwidth of 70.3% in a compact size of 1.39λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>×0.79λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>×0.16λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf>, along with stable end-fire radiation performance and moderate gain. These features make the proposed antenna highly suitable for conformal integration on small aircraft.