Gain Optimization Methods for SIW Leaky-Wave Antennas with Transverse Slots

Substrate integrated waveguides (SIW) with transverse slots on the top plane can be used as effective leaky-wave antennas with end-fire radiation capabilities. Such antennas have been investigated for maximum directivity conditions, but in practice the gain is decisive, which often drops down due to dielectric losses. Therefore we investigate such antennas considering the important loss mechanisms to get an optimized aperture illumination. For this goal a modal analysis is made to derive the phase and attenuation constant of the leaky mode for different slot length at a fixed frequency whereas the phase constant is fixed by an iterative procedure to get a main beam near end-fire. With this method, a look-up table is generated which is used for an optimization routine to get the slot length and the width of the SIW for a number of antenna sectors. The antenna is then simulated with a new magnetic/electric field fast integral equation framework we have developed in the last months.