Research On Ultra-Wideband Phased Array Antenna Based On Resistive Loading Technology

A phased array antenna is the key component of the modern wireless system,which can realize fast beam scanning.To realize more powerful functions,the wireless system demands more and more bandwidth of phased array antenna,and phased array antenna gradually develops towards the direction of ultra-wideband.At the same time,to achieve spatial coverage and platform installation,wide-angle scanning and low-profile characteristics are also very important for ultra-wideband phased array antennas.In this thesis,the ultra-wideband phased array antenna is studied and the role of resistive loading technology in improving the performance of the ultra-wideband phased array antenna is discussed.The research contents and achievements mainly include the following two parts:1.A 2-18-GHz balanced antipodal Vivaldi conformal phased array antenna is proposed.For Vivaldi arrays,it’s difficult to achieve a low profile and a wide bandwidth at the same time.The traditional Vivaldi array has a wide bandwidth but a high profile.BAVA arrays have a low profile but narrow bandwidth due to effects such as parasitic modes.To solve the problem,the BAVA elements are arranged in the way of proximity,and the working bandwidth limit is extended by capacitive coupling between adjacent elements,to lower the antenna profile.Then the parasitic mode in the band is eliminated by resistance and short-circuit column loading.Finally,the BAVA phased array antenna with both low profile(0.11λ_Low)and wide bandwidth（9:1）performance is realized.In the2-18 GHz operating band,the active VSWR is less than 2.5 within 60°scanning in E-plane and less than 3.8 within 45°scanning in H-plane.A 12×8 antenna array prototype is fabricated and tested to verify the correctness of the simulation results.2.A low-cost 0.8-12-GHz tightly coupled phased array antenna is proposed.For the tightly coupled array with more than ten-octave bandwidth,the height of the antenna from the ground usually exceeds half wavelength at the highest frequency,and the half-wavelength short-circuit points are introduced in the band.RFSS is often used to eliminate short-circuit points.However,the existing works usually use separate RFSS structures,which are not integrated with the array,resulting in difficult assembly,high cost,and difficult conformal with the application platform.In order to solve this problem,a vertically integrated RFSS is proposed in this thesis,which realizes the integration of the RFSS and the radiator,and all antenna array structures are integrated on the same single-layer PCB.At the same time,coupling-strengthening and FSS-loading techniques are used to improve the performance of the antenna,and the 15-octave-bandwidth tightly coupled phased array antenna is realized.In the operating band of 0.8-12 GHz,the active VSWR is less than 3.2 at broadside.The active VSWR is less than 2.9 when scanning to60°in E-plane and less than 4.3 when scanning to 60°in H-plane.Finally,a 17×17antenna prototype is fabricated and tested to verify the correctness of the simulation results.