Abstract
This paper proposes a multiple-input multiple-output (MIMO) antenna array with four RXs and three TXs designed in a certain geometry configuration to achieve obstacle detection ability in both horizontal and vertical planes for an anti-collision radar system, which can enable visually impaired people to perceive the environment better in their everyday lives. An aperture coupled wide-beam patch antenna with two parasitic patches is proposed for each channel of RXs and TXs, which is utilized on a four-layer flexible printed circuit board (PCB) to ensure its compactness and wearability. The proposed MIMO antenna array achieves well-matched impedance in the frequency range of 76-81 GHz and the realized gains of 4.2 dBi and 2.4 dBi in each RX and TX channel respectively. It also realizes a wide 3dB beamwidth of larger than 90 degrees in the horizontal plane which improves the radar system angular coverage.