隔离器负载用微波吸收材料的研制

Development of microwave absorbing composite used in the load side of isolator

以环氧树脂为基体、羰基铁粉为吸收剂制备复合微波吸收材料。对获得的羰基铁粉/环氧树脂复合材料的击穿电压强度、密度和吸收损耗进行了测试,并对使用该材料的隔离器性能进行了研究。结果表明:羰基铁粉在树脂中分散性较好,颗粒之间的绝缘程度很高,吸收材料的吸收损耗大,承受功率高。密度为3.83g/cm3的试样,击穿电压强度达763V/mm,8～12GHz频率内吸收损耗在2.5～4.5dB/mm。隔离器负载中使用该材料,器件电压驻波比(VSWR)≤1.2时,隔离度≥20dB,相对带宽为25%,承受功率≥5W。

Microwave absorbing composite with epoxy resin as matrix and carbonyl iron powder as absorber was prepared. The breakdown voltage, density and absorption loss of prepared composite were measured, and the properties of isolator fabricated with this composite were studied. The results show that carbonyl iron powders are well dispersed in the epoxy resin matrix, and the insulation level among carbonyl iron powders is quite high. High absorption loss and high power handling capability are found for the prepared composite. For the composite sample with a density of 3.83 g/cm^3, its breakdown voltage is 763 V/mm, and its absorbing loss is 2.5-4.5 dB/mm when the frequency is in a range of 8 -12 GHz. When the voltage standing wave ratio is not above 1.2, the isolation, relative bandwidth and power handing capability of the isolator with prepared composite as load side is≥20 dB, 25% and ≥ 5 W respectively.