Study On Phased Array Antenna Based On Metamaterial And Its Beam Scanning

With the increasing application of phased array antennas in the exploration of airspace,guidance,identification,and tracking,the research on phased array antennas with high-gain,wide scanning angle,and multi-band operation,whether in military or civilian applications,has become more and more active.Among them,extending the scope of beam scanning as much as possible and achieving multi-band operation have always been the two key issues that current phased array technology needs to break through and develop.In recent years,metamaterials have attracted widespread attention due to their ability to control the propagation characteristics of space electromagnetic waves.The combination of metamaterial with different structures and conventional phased array antennas has resulted in the new opportunity to resolve two key issues.For this reason,this thesis investigates the phased array antennas based on metamaterial and the characteristics of beam scanning.The main research of this thesis is divided into the following aspects:1.Firstly,the research status of traditional phased array antennas and phased array antennas based on metamaterials in wide scanning angle applications are introduced.Then,the working principle of the mushroom-like electromagnetic band gap?EBG?structures and its application in antenna design are expounded.Next,the application of metasurface?MS?in the transmitter antenna and the basic theory of the linear array antenna are summarized.These are the theoretical basis for the design of the dual-band metamaterial-based phased array antenna with wide scanning angle,and the high-gain transmitter antenna based on multilayer metasurfaces?MMS?.2.A dual-band slot antenna based on mushroom-like superstrate is proposed.The slot antenna based on mushroom-like superstrate can operate in two bands.The lower band is from 2.9GHz to 3.7GHz,with relative bandwidth of 24.2%,and the upper band is from5.3GHz to 6.1GHz,with relative bandwidth of 12.1%.The lower band of the proposed antenna is corresponding to zero-order resonant mode of the superstrate,and its upper band is excited by TM₁₀ and anti-phase TM₂₀ resonant mode.The proposed antenna has characteristics of low profile,compact structure and multiband operating.3.A dual-band phased array antenna based on a rectangular EBG superstrate is designed,which achieves a wide scanning angle from boresight to endfire direction.The proposed array unit structure consists of a rectangular mushroom-like patch array and a planar slot-coupled array antenna.The dual-band phased array antenna can operate in two bands,which lower operating band is from 3.1 GHz to 3.7 GHz,with-10dB bandwidth of 17.1%,upper operating band is from 5.2 GHz to 6.0 GHz,with a-10 dB bandwidth of 15.8.%,the average gain of the two bands are 10.56 dBi and 15.32 dBi,respectively.The radiation efficiency is higher than 70%at its operating bands.Scanning compensation from lower band is implemented on upper band when the array scans,which greatly broadens the scanning angle ranging from boresight to endfire direction,and the array achieves a full-angle scan range.4.A high-gain transmitter array antenna based on multilayer metasurface?MMS?is designed.The transmitter array antenna is composed of a five-element linear array antenna and a transmission array based on multilayer metasurface structure.By varying the transmission phase of the transmitter array unit,which can fit phase compensation of proposed transmitter array antenna,so that the beam synchronization control on the E-plane and the H-plane is achieved while increasing gain of antenna.The implementation of the E-plane beam scanning is mainly caused by the phase difference between the feeds of the 1×5 linear array antennas.A MMS high-gain transmitter array is designed for beam scanning on the H-plane.The main beam of the proposed transmitter array antenna can scan from 0°to 45°on the H-plane while the beam scans normally on the E plane.