A Substrate-Integrated Waveguide Leaky-Wave Antenna Based on Eye-Shaped Transverse Slot

At present, there are few reports of broadside antennas based on the transverse slots in SIWs, because those slot structures often exist as open stopbands (OSB), which restrict radiation in the broadside direction. In this communication, a new type of transverse slot element, eye-shaped transverse slot element with a high phase shift, is proposed. The phase constant of this element can vary linearly, which can lead to continuous beam scanning from the backward-to-forward direction. The relationship between the phase difference and the element size is obtained by simulation. What is more, a leaky-wave antenna with element spacing slightly larger than half-waveguide wavelength is described, and its internal field distribution is analyzed. The measured results show that the main beam can scan from -56 degrees to 39 degrees when the frequency increases from 9.1 to 13 GHz, while the gain ranges from 9 to 11.7 dBi in the passband with an effective length of 110 mm. Because of its small antenna length, wide beam scanning range, and high gain, the antenna can be widely used in wireless communication or radar systems.