电磁混响室搅拌器不同工作状态对局部场强影响的初步研究

Influence of electromagnetic reverberation chamber stirrer working in different modes on local field strength

目的通过改变电磁混响室(RC)内搅拌器的工作状态,研究其对有效工作区域中场强的影响,为深入研究电磁辐射的生物效应和医学防护提供参考。方法在固定频率900 MHz、功率绝对值为-27 d Bm下,将直流稳压电源分别设置为0. 0、0. 4、0. 8、1. 2 A等不同档位,采用微波检测设备以网格法对RC有效工作区域内72个测试点进行场强测量并分析。结果在搅拌电流为0. 0、0. 4、0. 8、1. 2 A状态下,有效工作区域场强分别为(187. 44±46. 94)、(194. 61±36. 84)、(197. 05±36. 09)和(203. 69±39. 07) V/m,其中0. 0 A和1. 2 A状态所对应的场强之间相比,差异具有统计学意义(P <0. 05)。随着搅拌器转速的增加,场强呈逐渐增加趋势,但0. 4、0. 8和1. 2 A所对应的场强之间相比差异均无统计学意义。此外,在0. 0、0. 4、0. 8和1. 2 A 4种搅拌状态下,有效工作区域的场强变异系数(CV)分别为(9. 62±5. 43)%、(9. 37±5. 94)%、(9. 66±6. 61)%和(9. 21±5. 01)%,各组间差异均无统计学意义。结论在相同频率、相同功率绝对值和不同搅拌状态下,RC内有效工作区域场强分布均匀性都较好,混响室总体状态稳定。在搅拌器转速为零时,场强比1. 2 A状态较低,且搅拌器转速≥0. 4 A时,场强呈逐渐增加趋势,但不显著。从场强CV来看,4种搅拌状态对应的有效工作区域内场强波动情况总体稳定,表明该设备用于电磁辐射损伤效应和医学防护研究具有较好的可靠性。

Objective To describe the design of a new electromagnetic reverberation chamber(RC)and to study the influence of field strength on the working area by changing the working states of the electromagnetic stirrer.Methods At a fixed frequency of 900 MHz and an absolute power value of-27 d Bm,the direct current stabilized power supply was set at0.0,0.4,0.8 and 1.2 A,et al,and the microwave detection equipment was used in the electromagnetic RC.Field test points were measured and analyzed.Results In the state where the stirring current was 0.0 A,the local area field strength was(187.44±46.94)V/m compared with(194.61±36.84)V/m in the 0.4 A state,(197.05±36.09)V/m in the0.8 A state and(203.69±39.07)V/m in the state of 1.2 A.There was statistically significant difference(P<0.05)between the 0.0 A and 1.2 A states.Field strength increased gradually with the stirrer rotation speed in the states of 0.4,0.8 and 1.2 A,but there was no statistically significant difference between them.In the four stirring states of 0,0.4,0.8 and 1.2 A,the local field average field strength coefficient of variation(CV)was(9.62±5.43)%,(9.37±5.94)%,(9.66±6.61)%and(9.21±5.01)%,respectively.There was no statistically significant difference in CVs between the groups.Conclusion Under the same frequency,the absolute value of the same power and different agitation conditions,the uniform distribution of field strength in the effective working area of the electromagnetic RC is good,and the overall state of the RC is stable.When the stirrer rotation speed is zero,field strength is lower than 1.2 A,and when the stirrer rotation speed is≥0.4 A,field strength gradually increases,but not significantly.In terms of the field strength CV,the four stirring states are generally stable.Our data shows that the electromagnetic RC is stable for biomedical studies.