Effects of exposure to electromagnetic field from 915 MHz radiofrequency identification system on circulating blood cells in the healthy adult rat.

We investigated whether exposure to the 915 MHz radiofrequency identification (RFID) signal affected circulating blood cells in rats. Sprague-Dawley rats were exposed to RFID at a whole-body specific absorption rate of 2 W/kg for 8 h per day, 5 days per week, for 2 weeks. Complete blood counts were performed after RFID exposure, and the CD4+ /CD8+ ratio was determined by flow cytometry. The number of red blood cells (RBCs) and the values of hemoglobin, hematocrit, and RBC indices were increased in the RFID-exposed group compared with those in the cage-control and sham-exposed groups (P < 0.05). However, the RBCs and platelet numbers were within normal physiologic response ranges. The number of white blood cells, including lymphocytes, was decreased in RFID-exposed rats. However, there was no statistically significant difference between the sham-exposed and RFID-exposed groups in terms of T-cell counts or CD4+ /CD8+ ratio (P > 0.05). Although the number of circulating blood cells was significantly altered by RFID exposure at a whole-body specific absorption rate of 2 W/kg for 2 weeks, these changes do not necessarily indicate that RFID exposure is harmful, as they were within the normal physiological response range. Bioelectromagnetics. 39:68-76, 2018. © 2017 Wiley Periodicals, Inc.

Orbital Angular Momentum (OAM) Antennas via Mode Combining and Canceling in Near-field.

Orbital angular momentum (OAM) mode combining and canceling in the near-field was investigated using a Cassegrain dual-reflectarray antenna composed of multiple microstrip patches on the main and sub-reflectarrays. Microstrip patches on dielectric substrates were designed to radiate the particular OAM modes for arithmetic mode combining, where two OAM wave-generating reflectarrays are very closely placed in the near-field. We conducted near-field antenna measurements at 18 [GHz] by manually replacing the sub-reflectarray substrates with different OAM mode numbers of 0, ±1, when the OAM mode number of the main reflectarray was fixed to +1. We subsequently checked the azimuthal phase distributions of the reflected total electromagnetic waves in the near-field, and verified that the OAM waves mutually reflected from the main and sub-reflectarrays are added or subtracted to each other according to their OAM mode numbers. Based on our proposal, an OAM mode-canceling reflectarray antenna was designed, and the following measurements indicate that the antenna has a better reflection bandwidth and antenna gain than a conventional reflectarray antenna. The concept of OAM mode canceling in the near-field can contribute widely to a new type of low-profile, broad-reflection bandwidth, and high-gain antenna.