The Design Of Sparse Array Based On Strong Mutual Coupling

Phased array antennas are extensively applied in variety of communication systemssuch as modern radar and satellite communication due to their much superiority, e.g.,abilities of vary rapid beam scanning, agile beams, multi-beam forming, whosedevelopments are motivated by requirements of detecting very far and high-speedtargets. T/R modes are connect with every cells in traditional architectures, which havebeen widely recognized as the most complex, sensitive, and perhaps expensive parts ofthe phase array systems. In recent years, phased arrays are being considered for newapplications such as commercial millimeter-wave automotive radars and robotic sensors.Typically, in such applications, a very precise pattern control and a wide scan angle arenot required. Instead, other commercial engineering measures such as low cost, lowcomplexity, integrativity and ease of manufacturing are the driving criteria. For thisreason, reduction of the cost of phased arrays is always of importance, for bothcustomers and developers. In order to reduce the cost of the array, using the strongmutual coupling between the elements reduces the amount of the RF componentsconnected to the elements in the array. The thesis mainly contains the following severalparts:Firstly, the advance and importance of the phase array are described. The tech-niques of reducing the cost of array in the past several decades are revealed.Secondly, the basic theory and the principle of the antenna array are introduced.The theory of sub-array is proposed in this paper, which makes use of the mutualcoupling between the elements. Linear array and planar array is builted based on thetheory.Thirdly, to demonstrate the proposed idea, several micro-strip patch antenna arraywhich are broadside array and tilted array, are built and measured. Comparisons to theirconventional counterparts are also given to highlight their advantages, in terms ofaperture efficiency, SLL, and the cost.Finally, a varactor diode based phase shifter connects each element in the sub-array is designed for cavity-backed dipole array, which realizes a high gain, wideband frequency band, and±30osteer angle. The gain of the proposed array is high than theone of the microstrip array, and only changing the phase of the feeding network canrealize the limited field of view.