Research And Design Of Tightly Coupled Array Antenna Based On Reconfigurable Technology

As everyone knows,the ultra-wideband array antennas which are capable of achieving multi-function,high gain,low profile,and wide angle scanning performance is widely used in upgrading wireless communication systems.But the conventional array antennas are affected by the coupled effect between elements,resulting it difficult to improve the performance further.In order to solve this problem,combined with the current research status of the tightly coupled array antenna and the reconfigurable antenna at home and abroad,the main work has been carried out in the following two areas:1.A tightly coupled array antenna operating in 2-6GHz is designed.In the design process,firstly,the impedance characteristic of the periodic antenna element is analyzed.Secondly,according to the characteristic,a feed structure with the function of broadband impedance matching and balanced feed is designed.Thirdly,the performance of the periodic antenna element and a finite array antenna with 8×8 elements is simulated.The results show that the antenna can achieve ±45° angle scanning performance in the operating frequency band of 2-6GHz(VSWR≤3:1).Finally,according to the simulated results,the array antenna is processed and tested.2.A tightly coupled array antenna based on reconfigurable technology is designed,which can switch between 3-9GHz and 13-16 GHz.In the design process,firstly,selection of options,because of the low gain of the ultra-broadband tightly coupled array antenna at low frequency,in order to meet the requirements,a tightly coupled array antenna based on reconfigurable technology is proposed in this paper.A coupled part is added between the ordinary dipole antenna elements.By controlling the disconnection and connection of the coupled part,the switching of the two working modes is realized.And when disconnected,it is an ordinary dipole working mode.When connected,which not only prolongs the effective radiation length of the dipole antenna arms,but also enhance the coupled effect between the elements,so that the ordinary dipole antenna element is transformed into a tightly coupled antenna element,and the working frequency band of the array antenna is transferred to a lower frequency band,at the same time the bandwidth of the antenna is widened.Secondly,based on the analysis of the impedance characteristics of the two modes of the periodic antenna elements,a feed structure is designed,which can be applied to these two modes of antenna in the meantime.Thirdly,the performance of the periodic antenna element of two working modes and a finite array antenna with 8×8 elements are simulated.The results show that the antenna can achieve ±45° angle scanning performance in the operating frequency band of 3-9GHz(VSWR≤3:1)and ±30° angle scanning performance in the operating frequency band of 13-16GHz(VSWR≤3:1).Fourthly,using the boundary conditions of the Lumped RLC and Finite Conductivity in HFSS simulation software,the equivalent circuit model and the DC switching circuit of the PIN diode is arranged on the antenna.The simulated results of the model are basically consistent with the previous simulation results in the ideal state.Finally,according to the simulated results,the antenna element is processed and tested.