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A new miniaturized 4-port waveguide generating a transverse electromagnetic wave is proposed. The waveguide presents enhanced performance of higher field uniformity in extended test volume up to an increased test frequency limit compared to that of the conventional 2-port waveguide. The advantageous features of the proposed waveguide have been obtained through a new design scheme based on effective miniaturization maintaining good impedance matching. Consequently, we can provide a more accurate electromagnetic compatibility test method, covering larger devices operating in higher frequencies, which is a marked improvement upon the conventional approaches.

The aim of this study was to investigate whether single or combined radio frequency (RF) radiation exposure has effects on the cell cycle and its regulatory proteins. Exposure of MCF7 cells to either single (837 MHz) or combined (837 and 1950 MHz) RF radiation was conducted at specific absorption rate values of 4 W/kg for 1 h. During the exposure period, the chamber was made isothermal by circulating water through the cavity. After RF radiation exposure, DNA synthesis rate and cell cycle distribution were assessed. The levels of cell cycle regulatory proteins, p53, p21, cyclins, and cyclin-dependent kinases were also examined. The positive control group was exposed to 0.5 and 4 Gy doses of ionizing radiation (IR) and showed changes in DNA synthesis and cell cycle distribution. The levels of p53, p21, cyclin A, cyclin B1, and cyclin D1 were also affected by IR exposure. In contrast to the IR-exposed group, neither the single RF radiation- nor the combined RF radiation-exposed group elicited alterations in DNA synthesis, cell cycle distribution, and levels of cell cycle regulatory proteins. These results indicate that neither single nor combined RF radiation affect cell cycle progression. Bioelectromagnetics 32:169–178, 2011. © 2010 Wiley-Liss, Inc.

The small anechoic chambers built by many small-/medium-sized companies and universities present difficulties in testing electrically large antennas because the chamber size cannot satisfy the far-field criterion of large antennas. In this paper, a method for Fresnel-region measurement on a cylindrical surface with variation of the measurement height is proposed and verified by both calculations and experiments. We implement the proposed method using a direct far-field measurement system by adding a few supporting structures. The results show good accuracy.

For the commercial development of organic photovoltaics (OPVs), laboratory-scale OPV technology must be translated to large area modules. In particular, it is important to develop high-efficiency polymers that can form thick (>100 nm) bulk heterojunction (BHJ) films over large areas with optimal morphologies for charge generation and transport. Here, D1-A-D2-A random terpolymers composed of 2,2′-bithiophene with various proportions of 5,6-difluoro-4,7-bis(thiophen-2-yl)-2,1,3-benzothiadiazole and 5,6-difluoro-2,1,3-benzothiadiazole (FBT) are synthesized. It is found that incorporating small proportions of FBT into the polymer not only conserves the high crystallinity and favorable face-on orientation of the D-A copolymer FBT-Th4 but also improves the nanoscale phase separation of the BHJ film. Consequently, the random terpolymer PDT2fBT-BT10 exhibits a much improved solar cell efficiency of 10.31% when compared to that of the copolymer FBT-Th4 (8.62%). Moreover, due to this polymer's excellent processability and suppressed overaggregation, OPVs with 1 cm2 active area based on 351 nm thick PDT2fBT-BT10 BHJs exhibit high photovoltaic performance of 9.42%, whereas rapid efficiency decreases arise for FBT-Th4-based OPVs for film thicknesses above 300 nm. It is demonstrated that this random terpolymer can be used in large area and thick BHJ OPVs, and guidelines for developing polymers that are suitable for large-scale printing technologies are presented.

A whole-body voxel model of a 7-year-old male volunteer was developed from 384 axial magnetic resonance images (MRIs). The MRIs were acquired with intervals of 3 mm for the entire body in a body coil. In order to reduce the MRI acquisition time for the child, the repetition and echo times under T1 weighted image were chosen to be 566 ms and 8 ms, respectively. The MRIs were classified according to 30 types of tissues with known electrical parameters. The developed voxel model was adjusted to the physical average of 7-year-old Korean boys. The body weight of the adjusted model, calculated with the mass tissue densities, is within a 6% difference from the 50th percentile weight.

This study presents a broadband double-ridged horn antenna for millimeter-wave applications. The proposed broadband antenna has a bandwidth of 12.1–63.2 GHz and peak radiation gain of 12.1–19.8 dBi. The performance of this antenna is verified by the measured results and is in good agreement with the simulated results. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2165–2167, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21884