To investigate possible health effects of mobile phone use, we conducted a double-blind, cross-over provocation study to confirm whether subjects with mobile phone related symptoms (MPRS) are more susceptible than control subjects to the effect of electromagnetic fields (EMF) emitted from base stations. We sent questionnaires to 5,000 women and obtained 2,472 valid responses from possible candidates; from these, we recruited 11 subjects with MPRS and 43 controls. There were four EMF exposure conditions, each of which lasted 30 min: continuous, intermittent, and sham exposure with and without noise. Subjects were exposed to EMF of 2.14 GHz, 10 V/m (W-CDMA), in a shielded room to simulate whole-body exposure to EMF from base stations, although the exposure strength we used was higher than that commonly received from base stations. We measured several psychological and cognitive parameters pre- and post-exposure, and monitored autonomic functions. Subjects were asked to report on their perception of EMF and level of discomfort during the experiment. The MPRS group did not differ from the controls in their ability to detect exposure to EMF; nevertheless they consistently experienced more discomfort, regardless of whether or not they were actually exposed to EMF, and despite the lack of significant changes in their autonomic functions. Thus, the two groups did not differ in their responses to real or sham EMF exposure according to any psychological, cognitive or autonomic assessment. In conclusion, we found no evidence of any causal link between hypersensitivity symptoms and exposure to EMF from base stations.

An optimized ink-reducing hollowed-out arm meander dipole antenna structure for printed RFID tags adi m. j. marindra, pornanong pongpaibool, werayuth wallada and siwaruk siwamogsatham This paper presents an optimized ink-reducing meander dipole antenna structure suitable for implementing printed radio frequency identification (RFID) tags. The proposed antenna designs contain empty ink-reducing hollowed-out areas along the antenna's arms such that the resulting antennas require much less conductive ink to produce yet still achieve decent antenna performance compared with the conventional solid-arm dipole antennas. The simulation results demonstrate that when the ratio between the width of the hollowed-out areas and the width of the antenna arms is about 0.6, the resulting RFID tag experiences a slight read range performance degradation of ,10%, while it offers a sizeable ink consumption reduction of almost 50%.

simulated frequency responses between the proposed and the conventional dual-mode DGW resonator filter. The resonant frequency of the DGW resonator can be reduced by the loading element by about 48%.Charge distributions of this designed DGW resonator are shown in Figure 3. It is interestingly found that the high-density distributions are located on the corners of resonator. Also, the phase difference of the high-density distributions between two degenerate modes is about 90 . The fabricated filter is given in Figure 4. A comparison between the simulated and measured frequency responses is described in Figure 5. Results show that the proposed filter has a fraction bandwidth of 4.6% at central frequency of 1.30 GHz, and its insertion loss in passband is less than 2 dB. There are two transmission zeros on the sides of the passband. They are À48 and À34 dB at frequencies of 1.21 and 1.42 GHz, respectively. They are close to the passband edges and can greatly improve the selectivity and stopband suppression of the proposed filter. Measured results agree well with the simulated ones and prove the validity of the introduced design principles to produce the dual-mode characteristics. Some discrepancy can be attributed to the inaccuracy in fabrication and implementation. CONCLUSIONS

In this paper, we study the performance of radio frequency identification (RFID) tags in ultra-high frequency (UHF) band placed in the protective package for animal traceability application. We examine the RFID tag performance by varying the air gap between the tag and the package, both on the top and bottom of the RFID tag. Two types of RFID tag antenna, dipole and meandered dipole antennas, and two types of RFID tag material, FR4 and polyester (PET), are used. The calculation results show the effects of the air gap size on the read range and resonant frequency. In all cases, the read range decrease and the resonant frequency shift to the lower one, when comparing with those of the antenna placed in free space. We use this resonant frequency shift to tune the RFID tag antenna to the desired center frequency for the certain size of the air gap between the tag and the package.

No abstract