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This paper presents a broadband slot-line-fed quasi-Yagi antenna. The gap size of the coplanar stripline was designed in a staircase shape to improve the impedance matching between and the feed line and the antenna. The antenna has a broad bandwidth of approximately 55% (4–7 GHz with a reflection coefficient of less than −10 dB). The radiation(More)
Circularly polarized crossed dipole antennas are presented in this paper. A compact crossed dipole is realized with the use of a meander line and a barbed end in each dipole arm. A vacant-quarter printed ring is used as a 90° phase delay line to achieve circularly polarized radiation. For multi-band applications, each dipole arm is divided into(More)
The water distribution in human osteoarthritic articular cartilage has been quantitatively characterized using terahertz time-domain spectroscopy (THz TDS). We measured the refractive index and absorption coefficient of cartilage tissue in the THz frequency range. Based on our measurements, the estimated water content was observed to decrease with(More)
A circularly polarized (CP) antenna with a wideband characteristic is proposed for use in the Global Navigation Satellite System. Its primary radiation element is crossed bowtie dipoles, which are incorporated with double-printed vacant-quarter rings to allow the antenna to be matched directly to a single 50-Ω coaxial line and produce wideband CP(More)
A planar, lightweight, crossed dipole antenna with circularly polarized (CP) radiation is introduced for application in a radio-frequency identification handheld reader at ultrahigh frequency bands. The dipoles cross through a 90 phase-delay line of a vacant-quarter printed ring that enables broadband characteristic in terms of impedance matching and 3-dB(More)
A circularly polarized single-feed four-arm curl antenna is presented in this paper. We demonstrate that a four-arm curl antenna can be fed by a single 50-H source without a matching network and can produce good circularly polarized (CP) radiation at the desired frequency. A curl antenna normally exhibits as a resonant antenna and its input impedance(More)
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