Beam-Steering SIW-Based Slot Antenna with Filtering Function for X-Band

A Substrate Integrated Waveguide (SIW)-based slot antenna with filtering and beam rotation properties for radar band is presented. The tapered structure used for the feed line, contribute to better impedance matching. By etching two semicircular slots on the patch with SIW structure, we could rotate the main beam angle between 5° and 55°, eliminating the requirement for any phase shifter. In fact, the proposed antenna shows filtering characteristics in bandpass between 9.9 and 11.7 GHz with the average gain of 6dB, in the lower band between 8 and 11.5 GHz and the higher band from 12 to 13 GHz with a gain below 3dB without using any extra filtering circuits. The proposed antenna has a size of $\boldsymbol{\lambda}_{0}\times 0.8 \boldsymbol{\lambda}_{0}$, The main lobe of the antenna has a maximum gain of 6.5 dB in the frequency of 11.22GHz. Ansoft HFSS has been employed to simulate the antenna and the results reveal that the antenna has a simple structure and high gain which is appropriate for radar systems.