| The micro-Doppler effect is a common phenomenon in nature,human beings,animals and plants,so the successful research of the micro-Doppler effective radar will have a wide range of application prospects in the fields of surveillance,medical care,emergency response and biology.As a key component of the micro-Doppler effective radar,the performance of antenna will affect the reliability of the radar.Therefore,the micro-Doppler effective radar requires the antenna to have the features such as miniaturization,wide frequency band,high gain,strong directionality,conformality and beam controllability.Obviously,it is difficult for a single antenna to meet these demanding applications.The microstrip array antenna is a multi-antenna system.By selecting the type,number,and placement method of the elementary antennas,the spacing between the elementary antennas and the excited amplitude and phase of the elementary antennas can be set,which can make the radiation pattern enhanced at a specific angle,and weaken at a specific angle to resist the interference of other signals,improve the radiation efficiency,and can better meet the practical application requirements of the micro-Doppler effective radar.Therefore,the research on a variety of microstrip array antennas for the micro-Doppler effective radar will meet the application requirements of different special occasions,which will be of great significance to the development of the micro-Doppler effective radar.The first,the paper proposes a compact broadband endfire array antenna,which uses a single-layer substrate and introduces T-shaped slots to reduce the overall size of the array antenna,thereby achieving a compact planar design and making it easy to integrate into micro-Doppler effective radar.In addition,the proposed broadband endfire array antenna adopts a center-symmetric layout of elementary antennas,the same excitation amplitude,and the phase distribution of 90°,270°,0°,180°in the clockwise direction,which help to obtain good endfire performance.After processing and testing,the array antenna operates from 5.72 GHz to 6.71 GHz with an absolute bandwidth of 0.99 GHz,which satisfies the requirement of wideband characteristic.Then,the paper proposes a compact directional array antenna with slots that includes a novel inset-fed patch antenna with E-shaped slots,a center-symmetrical arrangement of elementary antennas,and a center-symmetrical feeding network,which help to achieve an oblique upward directional radiation.In addition,the proposed directional array antenna with slots adopts a compact planar design,which is easy to integrate into a micro-Doppler effective radar,and the lower processing cost is conducive to industrial promotion.Finally,the paper proposes a directional conformal array antenna,which is composed of an octant table model,the first sub-arrays,the second sub-arrays and a total feeding network.The first sub-array and the second sub-array are mounted alternately on the eight sides of the micro-Doppler effective radar so as to achieve a conformal design.Therefore,the proposed antenna has the characteristics of low profile,low air resistance,small volume,low cost,etc.which is suitable for high-speed radar applications.In addition,the proposed directional conformal array antenna adopts a symmetrical layout of elementary antennas,the same excitation amplitude and phase distribution of 0°,180°,270°,90°in the clockwise direction,and obtains good oblique downward directional radiation performance.It can be seen that the proposed directional conformal array antenna provides a new integrated method for the micro-Doppler effective radar,which can meet the special application requirements of the micro-Doppler effective radar.In summary,this paper proposes three kinds of microstrip array antennas for the micro-Doppler effective radar,which can meet the application requirements for different special occasions,and have extremely important significance for the development of the micro-Doppler effective radar. |
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