Tham khảo tài liệu 'microstrip antennas part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Microstrip Antenna Arrays 379 Fig. 27 presents S11 results of the folded antenna results for different position relative to the human body. Explanation of Fig. 26 is given in Table 6. From results shown in Fig. 13 we can see that the folded antenna has better than 1 for air spacing up to 5mm between the antennas and patient body. If the air spacing between the sensors and the human body is increased from 0mm to 5mm the antenna resonant frequency is shifted by 5 . Sensor position Plot colure Shirt thickness Red Shirt thickness 1mm Blue Air spacing 2mm Pink Air spacing 4mm Green Air spacing 1mm Sky Air spacing 5mm Purple Table 6. Explanation of Fig. 26 Sensor position Colure Shirt thickness Red Air spacing body to shirt 1mm Blue Belt thickness 4mm Pink Air spacing shirt to belt 1mm Sky Air spacing shirt to belt 4mm Green Table 7. Explanation of Fig. 27 Fig. 27. S11 results for different belt thickness S11results in Fig. 27 presents the folded antenna matching when the belt thickness has been changed from 2 to 4mm. Explanation of Fig. 27 is given in Table 7. S11results are better than -10dB for belt thickness ranging from to 2 to 4mm. Computed S11 and S22 results was better 380 Microstrip Antennas than-10dB for different body tissues with dielectric constant ranging from 40 to 50. Computed S11 and S22 results were better than -10dB for different shirts and belts with dielectric constant ranging from 2 to 4. Medical applications An application of the proposed antenna is shown in Fig. 28. Three to four folded dipole antennas may be assembled in a belt and attached to the patient stomach. The cable from each antenna is connected to a recorder. The received signal is routed to a switching matrix. The signal with the highest level is selected during the medical test. The antennas receive a signal that is transmitted from various positions in the human body. Folded antenna may be also attached on the patient back in order to improve the level of
