A symmetrical SIW-based leaky-wave antenna with continuous beam scanning from backward-to-forward through broadside

In this paper, a leaky-wave antenna based on substrate integrated waveguide is introduced with continuous beam scanning from backward-to-forward through broadside. A new two-part unit cell has been used to achieve the continuous beam without drop of gain in the broadside. This suppresses the open stop-band, the broadside radiation gain would be without a drop, and the side lobe level is kept low. The wide operating bandwidth is obtained, which covers from 11.7 to 19.6 GHz. It is observed that S-11 is below - 10 dB from 11.5 to 20 GHz, and the average S-21 is - 8.5 dB from 11.5 to 20 GHz. Scanning of this antenna is continuous and covers all angles between - 61 degrees to + 34 degrees. The gain in the direction of the broadside beam is equal to 14.2 dB and without a drop. The gain changes are low in the operating frequency and the average gain is 14.1 dB in this antenna, also the average side lobe level is - 12 dB. The average radiation efficiency of this proposed antenna is 73%.