Design Of Highly Integrated Active Phased Array At Ku/Ka Band

With the development of communication technology,phased array antenna technology has been more and more widely used in target detection,civil aviation early warning,public security and other fields.Active phased array antenna has become the mainstream direction of antenna technology development because of its many advantages.In recent years,with the increasing development and maturity of monolithic microwave integrated circuit(MMIC)technology,the application field of active phased array is more and more extensive.It will gradually replace the existing passive phased array antenna.Therefore,this thesis focuses on the design methods of several active phased array antennas.Firstly,the radiation principle and physical characteristics of microstrip antenna are introduced,and the basic parameters of microstrip antenna are summarized in detail;Based on the basic equidistant N-element linear array,the beam scanning principle of one-dimensional phased array antenna and the conditions of grid lobe generation and suppression are discussed.On this basis,three active integrated phased array antennas are designed.The thesis mainly includes the following aspects:(1)Based on microstrip antenna and single channel RF link,a Ka-band circularly polarized active phased array antenna based on PCB substrate is designed.The array element adopts the form of double-layer chamfer patch antenna,the laminated structure widens the bandwidth,and realizes circular polarization by introducing chamfer.In order to improve the circular polarization performance of the array,the sequential rotation array is used to offset the asymmetry in the physical structure and form 2×2 miniature phased array antenna.According to the beam scanning principle of phased array,the phase and amplitude of energy transmitted by different RF channels are simulated and controlled in the electromagnetic simulation software.The simulation results show that the array can realize beam scanning of ±30° in both horizontal and pitch planes.Based on PCB substrate,a millimeter wave board level active array integrated with phased array antenna and feed network is designed,processed and tested.The measured results verify the reliability of the simulation.(2)Aiming at the world’s mainstream 5G millimeter wave commercial frequency band,a one-dimensional active phased array antenna with a central frequency of 28 GHz is designed.In order to broaden the bandwidth,the double-layer microstrip patch antenna is used as the array element.The array adopts the form of H-plane 8-element linear array and E-plane 8-channel phase control.The phase and amplitude of energy transmitted by different RF channels are simulated in the electromagnetic simulation software to realize the one-dimensional beam scanning of the antenna array at ±60° on the E-plane.The simulation results show that the working bandwidth of the phased array antenna reaches 15%,the maximum normal gain reaches 21.9d Bi,and the gain drop is less than 3.2d B when the working band is scanned to ±60°.Finally,taking the array as the radiating element and based on PCB substrate,the high integration design of active phased array is completed.(3)In order to reduce the transmission loss of antenna array,a Ku-band dual polarization one-dimensional active phased array antenna with novel structure is designed.The antenna unit adopts patch antenna with air cavity as medium,which has high radiation efficiency;The feeding network adopts the form of low loss air microstrip line,which reduces the transmission loss of the feeding line.On the elevation plane,a one to twenty power divider network is connected with twenty antenna units to form a linear array.The antenna units are arranged symmetrically in the form of central mirror image of the horizontal azimuth plane and simulated the beam scanning function of 16×20 large phased array under the master/slave boundary conditions in the electromagnetic simulation software.The simulation results show that when the antenna is scanned to ±60° in the working frequency band,the gain drop is less than 3.1d B,and the active return loss is less than-9d B.Processed and made 4×20 subarray samples,and the test results verify the feasibility of the antenna radiation unit transmission network.