Study And Design Of Array Antenna Based On ADS

Antenna is an essential part of wireless communication system.The array antenna is widely applied due to its high gain,low sidelobe and beam control.However,the mutual coupling between the antenna elements will cause problems such as an increase in the sidelobe level of the array antenna pattern and a decrease in gain.Therefore,the mutual coupling between the antenna elements must be reduced in the design of array antenna.The traditional methods to reduce the mutual coupling include employing the defected ground structure,loading a resonator,loading a neutralization line,and so on.These methods are suitable for narrow band antennas and difficult to be applied for large scale array antennas because of their complicated structures.Array-antenna decoupling surface(ADS)is a new decoupling method,which has the advantages of maintaining the radiation characteristics and matching conditions of the original antenna unit,wideband decoupling,and easy to design.It is suitable for large scale arrays.The main contents of this paper are summarized as follows:1.A single band slot array antenna based on ADS is proposed.A half-wavelength bending slot is etched on the ground plane to produce a resonance at 2.4 GHz.ADS consists of four groups of metal reflection patches,which are employed to reduce the mutual coupling between the antenna elements.The results indicate that the relative bandwidth of the array antenna is 7.7% and the isolation is grater than 15 d B.It has good radiation characteristics.2.A dual band monopole array antenna based on ADS is presented.The radiating element of the antenna consists of two arc strips.The lower frequency is generated by the longer arc strip,and the upper frequency is produced by the shorter arc strip.ADS consists of four groups of metal strips,in which long and short strips are placed symmetrically.The mutual coupling at the lower and upper frequencies is reduced by the long and short metal strips,respectively.The results indicate that the relative bandwidth of the antenna in two bands is 5.2% and 20.2%,which covers the 2.4-2.484 GHz and 5.15-5.35 GHz of WLAN.The isolation between the antenna elements is grater than 15 d B.Good radiation characteristics are also obtained.3.A wideband monopole array antenna based on ADS is proposed.A circular patch is used as the radiating element of the antenna,and a defected ground structure is employed to improve the radiation pattern at the upper band.ADS is composed of four groups of metal strips.Each group consists of several strips with different lengths placed symmetrically,which are used to reduce the mutual coupling in the wideband.The results indicate that the relative bandwidth of the array antenna is 96.7%,covering the whole working band of WLAN and Wi MAX.The isolation between the elements is grater than 15 d B,and the antenna exhibits good radiation characteristics.