Study On S-band Dual Circularly Polarized Antenna For Satellite Communication

Antenna is a key component in satellite communication and other wireless communica-tion systems.Its major responsibility is to receive and transmit electromagnetic wave.With the development of antenna for satellite communication,antenna is required for more than beam scanning but greater demands on wide operating bandwidth and multi-polarization.In this paper,the design and implementation of dual-port dual-circular polarization antenna for satellite communication system are expounded from the following aspects.1.In this paper,a dual-port dual-circular polarization microstrip patch antenna which is loaded with a U-shaped slot is proposed.The size of the antenna element is about 0.36?₀×0.36?₀×0.1?₀.To expand the operating bandwidth of the antenna,methods such as loading U-shaped slot as well as increasing the thickness of the radiation patch substrate are taken,leading to better simulation results.The simulation results show that the antenna element has a good broadband circular polarization performance.In the frequency ranging from 2.0 GHz to 2.3 GHz,the circular polarization gain at zenith is greater than 4.7d Bi,and the axis ratio at zenith is better than 3 d B.Meanwhile,in the range of elevation angle above 30°,the circular polarization gain at zenith is greater than-3d Bi,and the axial ratio is almost better than6.5 d B.In the higher frequency part and lower elevation angle,the range of the axis ratio is6 d B to 7.5 d B.2.Based on the broadband double circular polarized microstrip antenna element men-tioned above,an active phased array composed of six elements for anti-interference applica-tion is proposed.The array adopts the structure that one element is located at the center of a circle,while the remaining five elements are placed distributedly on a ring with equal space from the center.To improve the circular polarization performance of the array,the rotation feed technology is applied,which made the elements rotate around their respective geomet-ric centers.The array is placed on an aluminum circular plate with a size of?220 mm.The distance from the 5 elements on the ring to the center is about 0.5?₀.The simulation results show that the realized gain within the operating band at scanning point of|?|?60°is better than 6d Bi,and the axial ratio there is better than 6 d B,while the active SWR is almost better than 3.0.The relative bandwidth of the active scanning array is about 14%.Therefore,the simulated results coincide with the measured one.