Designing Wideband Tapered-Slot Antennas: A novel method using SIW technology.

In this article, a novel method for the design of wideband tapered-slot antennas (TSAs) using substrate-integrated waveguide (SIW) technology is proposed. The proposed procedure includes modeling of TSAs by step lines, which are terminated in intrinsic impedance of free space, along with applying the theory of small reflections. To provide insight into the radiation mechanism of the designed antennas, the method is discussed in detail. Employing the proposed method, an initial antenna is designed with a central frequency of 37.5 GHz. This antenna, which is implemented on a single-layer substrate, is compact in size and has satisfying radiation characteristics. It provides 75% fractional bandwidth from 25 to over 55 GHz, with the peak gain variations between 2 and 5 dB in its operating band. To further verify the design principle, the proposed antenna is redesigned for a central frequency of 14 GHz, and its prototype is fabricated. The comparison of the simulated and measured results confirms the accuracy of the proposed method.