Research Of Conformal Phased Array Antenna And Feed Network

Conformal phased-array antennas are becoming more and more important in the past few years. As it can be mounted on the aircraft surface, and will not impact the aerodynamics performance of the aircraft. Phased-array antennas use electric control scanning beam, so it has the performance of faster scanning velocity, flexible beam control and higher anti-interference ability. Thus it can realize target seeking, tracing, guidance at the same time, and can work in the complex and worsen condition. But the design and analysis of conformal antenna array has many difficulties in present time. Such as: the curvature of carrier will impact the performance of antenna array, most numerical methods will waste very long computation time when they are calculating electrical large-size structure, especially in millimeter-wave band, the problem will be predominant. So the investigation of conformal phased-array antennas has important engineering value.In this paper, the design and analysis of cylindrical conformal millimeter-wave phased-array antennas is discussed. First, an array element with an H-shaped coupling slot is designed, whose bandwidth is 10.9% while gain is 6.54dB. Furthermore, an element with double parasitic patch is designed, whose bandwidth is 22% while gain is 7.18 dB, so its bandwidth and gain can be improved by increasing parasitic patches. Then, compared with conventional microstrip antennas, two 2×2 planar microstrip antenna arrays and their feed networks are designed, the simulation results show that the spurious radiation influence of H-slot-coupled feed network is less than conventional coplanar feed networks, and easily integrated with other microcircuits. Based on the method of Isotropic Transformation from planar patch to conformal one, two 4×4 cylindrical conformal antennas array and their feed network are designed. The simulated results show that the bandwidth of H-slot-coupled, cylindrical conformal antenna arrays is over three times as the conventional microstrip conformal arrays, the side lobe level reduces 4.4 dB, the lobe width increases 4.6°, meanwhile, the gain decreased merely 1.63dB. Finally, based on the 4×4 conventional conformal array and 2×2 H-slot-coupled conformal array, the beam scanning capability of the array is analyzed in rolling surface and meridian plane, respectively. The results show that the scanning angle is 360°in rolling surface and±45°in meridian plane with the low-side lobe level.