丝网印刷和烧结工艺对陶瓷基复合材料微带天线膜层结构与性能的影响

Effects of Screen Printing and Sintering Process on Film Structure and Properties of Ceramic Matrix Composite Microstrip Patch Antenna

目的 研究丝网印刷工艺参数(印刷压力、离网间距和印刷速度)和烧结制度(烧结温度和保温时间)对陶瓷基复合材料微带天线基板表面丝网印刷银膜层结构与性能的影响。方法 在石英纤维增强二氧化硅基复合材料表面,通过丝网印刷工艺,在指定温度下烧结制备银膜层。采用金相显微镜、扫描电镜、四探针测试仪和焊接法等测试手段,研究银膜层的微观形貌、方阻与附着力。采用矢量网络分析仪表征微带贴片天线的驻波性能。结果 当印刷压力为90N、离网间距为2.5mm、印刷速度为90mm/s时,银膜层的方阻最低,附着力最大。当烧结温度为850℃、保温时间为15 min时,银膜可以获得最好的致密结构和导电性,此时方阻为5.4 mΩ/□,附着力为2.25 N/mm^(2)。在上述印刷和烧结工艺条件下制作的天线板,其常温中心频点为1.869GHz,与设计中心频点(1.86GHz)的吻合度较好。结论 丝网印刷工艺参数通过影响印刷过程中银浆的转移率影响膜层的导电性和附着力,烧结制度显著影响银膜结构的致密性,进而影响银膜的导电性和附着力。在印刷压力为90 N、离网间距为2.5 mm、印刷速度为90 mm/s的印刷工艺条件和850℃保温15 min的烧结条件下,制备的陶瓷基微带贴片天线具有较好的驻波性能。

The effect of screen printing process parameters(printing pressure, off-screen distance and printing speed) and sintering system(sintering temperature and holding time) on structure and properties of screen-printed silver film on the surface of ceramic matrix composite microstrip patch antenna substrate were studied in this work. The silver film layer was prepared on the surface of the quartz fiber reinforced silica matrix composite material by screen printing process and sintering at a specified temperature. The microscopic morphology, square resistance and adhesion strength of the silver film layer were studied by metallographic microscope, scanning electron microscope, four-point probe tester and welding method, etc. The standing wave performance of the microstrip patch antenna is characterized by the vector network analyzer. When the printing pressure is 90 N,the off-screen distance is 2.5 mm, and the printing speed is 90 mm/s, the square resistance of the silver film layer is the lowest and the adhesion is the largest. The silver film with dense structure and good conductivity can be obtained when the sintering temperature is 850 ℃ and the holding time is 15 min. In above situation, the square resistance of the silver film layer is 5.4 mΩ/□ and the adhesion strength of the silver film layer is 2.25 N/mm^(2). The antenna plate fabricated under above printing and sintering process conditions has a center frequency of 1.869 GHz at room temperature, which is in good agreement with the design center frequency(1.86 GHz). Screen printing process parameters affect the conductivity and adhesion of the film layer by affecting the transfer rate of silver paste during the printing process. The sintering system profoundly affects the compactness of the silver film structure, which in turn affects the conductivity and adhesion of the silver film. Ceramic matrix composite microstrip patch antenna prepared under the printing pressure of 90 N, the off-screen distance of 2.5 mm, the printing speed of 90 mm/s, sintering temperature of 850 ℃ and holding time of 15 min has good standing wave performance.