Efficient null broadening and steering using slot antenna array for radar applications

In this paper, an efficient null broadening is achieved by controlling amplitude excitations of the elements in an antenna array. A linear four-element array of slot antenna is preferred due to its higher immunity to spurious signals. Null steering is also demonstrated by controlling the bias voltage of PIN diodes. The proposed slot antenna array is fabricated on one side of the substrate with the microstrip feeding network on the opposite side. Two configurations of the slot array are designed, fabricated and tested. Experimental results showed good agreement with the simulated results. Broad nulls are achieved in the angular range of 30° in the First configuration and 45° in the second configuration with a null depth of ≤ -20 dB from peak in the direction of θ = ± 90°. Null steering is obtained in the direction of θ = 0° and 180°. The proposed antenna configurations can be used in the radar and commercial wireless communication applications due to its low cost and low profile properties.