| Flexible and efficient radio wave coverage is the basic infrastructure for development of high-speed,stable,reliable,and green mobile communications.As an important part of the mobile communication system,the antenna plays a vital role in ensuring efficient and flexible radio wave coverage.Since the occurrence of smart antennas in the 1940 s,it has been widely used in mobile communications for its capability of flexible beam changing.However,for short distance and indoor mobile communication,the traditional smart antenna system is relatively discrete,large and expensive,which is not suitable for application in such kind of environments.In this paper,integrated intellectualized antenna with capability of automatic beam changing is studied in depth with the help of advanced electronic technology,for the development of short distance and indoor mobile communication.Advanced technologies such as Artificial-Intelligence(AI)and electromagnetic wave detection are used to achieve self-perception function of the intellectualized antenna;On this basis,the intellectualized antenna system integration with self-sensing function is realized.The research work in this paper will provide support for flexible and efficient radio coverage for short distance and indoor mobile communication.The main work and innovation of this paper are as follows:1.Based on the traditional antenna,two antenna arrays with the capability of three-beam switching in one-dimensional and four-beam switching in two-dimensional,respectively,are proposed,which can be used as the intelligent antenna radiation structure,and their radiation characteristics are analyzed and verified by experiments.An arbitrary two-dimensional beam changing antenna array based on cylindrical wave excitation are explored and studied,and the radiation field calculation model is established to study the optimal combination of feeding sets for the arbitrary beam direction.A database as a prior knowledge is established which can be called in the application according to the target information to realize the array pattern changing in real time.2.A planar annular leaky wave antenna structure that can radiate conical beam is proposed.By adjusting the antenna structure parameters,a flexible 2-D conical beam can be obtained,which provides a basic radiation structure for indoor 2-D intellectualized antenna covered by radio waves.On the basis of theoretical analysis,the design method of planar annular leaky wave antenna based on the substrate integrated waveguide is proposed,and the direction controllable conical beam and normal single beam are realized.At the same time,a compact slot coupling feeding structure is proposed to realize the feeding of the radiation layer and the absorption of the residual energy for the special structure of the planar annular antenna,and improve the uniformity of the far field.3.A planar double-loop leaky wave antenna array with capability of two-dimensional beam conversion is proposed,and its radiation field calculation model is established.The radiation characteristics of the double-loop leaky wave antenna array are analyzed,and the beam transformation results of the double-loop array under conditions of single feed of one element and co-feed of the two elements are obtained.On the basis of theoretical analysis,a planar double-loop leaky wave antenna array is designed and fabricated.The experimental results show that the designed beam switching antenna array can provide a good radiation structure for the two-dimensional integrated automatic beam switching intellectualized antenna.4.A one-dimensional integrated automatic beam transform intellectualized antenna based on FM continuous wave detection is proposed.The antenna consists of a sensing unit,a signal processing unit and a radiation unit.By using radar reflection mechanism and analog and digital electronic technology,a signal processing circuit is constructed,which can quickly obtain the distance information between the user and the antenna.The radiation unit uses a three-beam switchable antenna array which is integrated with two planar Yagi antennas and one microstrip antenna.The experimental results show that the integrated intellectualized antenna achieves a flatter one-dimensional radio coverage and a lower EVM distribution.5.A two-dimensional integrated automatic beam transform intellectualized antenna based on image recognition is proposed.By means of artificial intelligence technology and image recognition,the antenna can provide flexible and changeable radio coverage to the observation area in real time according to the user's position to ensure the quality of communication.Two kinds of integrated two-dimensional automatic beam transform intellectualized antennas are designed by using the four-beam switchable antenna array and the proposed double-loop leaky wave antenna array based on SIW(Substrate-Integrated Waaveguide),respectively.The experimental results show that the two 2D automatic beam switching antennas designed in this paper show good beam switchable capability,and can achieve more stable radio coverage and lower EVM distribution.Among them,the two-dimensional intellectualized antenna based on double-loop array has more stable radio coverage when spans over the boundary of adjacent regions. |
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