Design Of Broadband Planar Array Antennas With Wide Scannning Angle

With the rapid development of wireless communication technology,electronic warfare including electronic reconnaissance and electroniccountermeasures (ECM), is becoming more and more significant in themodern war. Also, these systems are faced with increasingly stringentrequirements, such as realizing multi-target and whole airspace tracking,full operation band and high efficiency electronic anti-interference, and etc.Phased array antenna is one of the key components in wireless systems, soits development should keep pace with that. Wide operation band, highgain, wide scanning range and low profile properties are highly needed.Existing phased array antennas mainly have mainly two types, one ofwhich is through mechanical scanning. The mechanical scanning arrayshave the obstacles of big volume, heavy structure, low scanning speed, andun-conformal with platform. The other type is the electronic scanning array,which is running into the problem of narrow scanning angle. Based on this,this thesis is in view of planar array with appropriate element spacing,through the study of the widebeam array element and mutual decouplingtechnology, to improve wide scanning range of the electronic scanningphased array.First, this paper summarizes the research background and significance,and reviewed current situation of broadband and widebeam antenna, arraydecoupling technique and broadband array with wide scanning angle.Second, a novel wide-angle scanning array antenna utilizing abroadband element design is proposed. Due to the design of a grid-typebacked cavity as a choke structure and the butterfly-structure decouplingdipole, the proposed array achieved wide scanning range and operation bandwidth on condition of the element space with0.44λ. The simulatedand measured results demonstrate that the proposed array has a5.5~7.5%relative bandwidth within the scanning range of±48degrees.Third, a novel coplanar waveguide fed rectangular slot antenna isproposed, which also has the advantages of unidirectional broadbeam-width and broad bandwidth. The antenna is optimized to a smallscale, consisting of a substrate layer of rectangular slot antenna and acomposite cavity, which achieves a broad impedance bandwidth andarray’s wide scanning angle. Simulated and measured results indicate thatthe antenna is well adapted8.12~11.64GHz (3.52GHz) operationbandwidth within the scanning range of±56degrees on condition of theelement space about0.5λ.Furthermore, a microstrip scanning array with U-shape isolation armis studied. Array elements are rectangular patches, and they adopt theU-shape isolation arm with the same resonance frequency to reducecoupling effect. Simulated result shows that, the array enhances themaximum beam scanning angle from±25°to±40°compared with thetraditionally rectangular array.Finally, the thesis was summarized and prospected.