| The non-contact vital sign radar detection system requires a development of the high gain, broadband, and beam steering patch antenna. The proposed design approach combines the advantages of the wideband antenna, the advantage of the parasitic patch, and the advantage of beam steering antennas within a single microstrip patch antenna. As a result, a 2.8--4.8 GHz beam steering broadband microstrip antenna was designed, fabricated, and measured. The proposed antenna can steer beam in broadband range (sampled at 3, 3.5, 4, and 4.5 GHz) by switching PIN diodes that connect stubs and a partial ground plane. Its broadband beam steering is suitable for a vital sign radar. The proposed antenna requires no array for beam steering but requires only two additional diodes. The wide frequency tuning range allows the radar system to be tuned for an optimum transmission frequency. In addition, effects of modifying the proposed antenna on the antenna characteristics such as reflection coefficient, radiation pattern, gain, or beam steering capability are investigated. |
