A Simple Method for Continuous Beam-Steering in SIW based Leaky Wave Antenna

Planar microwave leaky wave antennas as a low-cost component are mostly used for microwave applications. In this paper, we provide a novel method to close the stopband issue in leaky wave antennas. The proposed method uses two radiation mechanisms per unit cell and needs just to optimize the dimension of two radiation mechanisms and the distance between them. The initial value for the optimization process is half of the wavelength for the period and a quarter of the wavelength for the dimensions of the radiation mechanism. The proposed method is useful for various types of LWA to obtain continuous beam steering. To confirm the presented method, an LWA is designed and fabricated. The prototype is SIW-based LWA with two radiation mechanisms (transversal and longitudinal slots) per unit cell. The LWA enables a wide steering range around the broadside direction including backward and forward directions. Nonetheless, with the exception of the frequency shift, the measured and simulated radiation patterns are identical. The measured result of S11 shows an almost perfect impedance matching for the LWA near broadside (around 15.82 GHz). The simulated result illustrates that the total efficiency is about 26% -57%. The prototype confirms the proposed method to overcome of open stopband issue.