A novel wideband quasi‐Yagi antenna with a dipole driver, an octagon‐shaped director, and a box‐shaped reflector is proposed in this letter. The dipole driver is excited by a wideband balun with a stepped microstrip for good impedance matching. In addition, the proposed octagon‐shaped director not only realizes good impedance matching but also stabilizes the radiation pattern. To further stabilize the radiation pattern, the reflector of the antenna is designed in a box shape. As a result, the proposed antenna achieves a wide bandwidth of 81.7% for |S11| ≤ −15 dB from 1.65 to 3.93 GHz. Additionally, the proposed antenna obtains a stable half‐power beamwidth of 62 ± 5° in the horizontal plane and a high gain of 8.3 ± 1 dBi from 1.7 to 3.6 GHz.
The Yining char samples were prepared in following conditions that raw coal particle size was in range 5-6mm and pyrolysis final temperature was 900oC, 1000oC and 1100oC, respectively, with a heating rate 20oC/min under atmospheric pressure. The gasification reactivity of chars was performed by thermogravimetric analysis (TGA) at 900oC in steam, CO2 and steam/CO2 mixture, respectively. The results show that the gasification reactivity of chars decreases with the increasing of pyrolysis final temperatures and there is synergistic effect between steam and CO2 during co-gasification that influences the char reactivity. The reason may be explained by char structure change, which FTIR showed that –CH3 and –O–CH3 decreased and even disappeared and XRD analysis suggested that the thickness of microcrystalline Lc, the values of microcrystalline diameter La and the aromatic of char fa became larger with increasing pyrolysis temperature.
A wideband dual-polarized antenna with high isolation is proposed for full-duplex applications. It consists of a radiating patch, two E-shaped strips, a parasitic patch, a metal reflector, and a 180°power divider. Two hook-shaped strips and a pair of E-shaped strips are used to excite the radiating patch realize ±45°polarization. The impedance matching is significantly enhanced by the attendance of the parasitic patch and 180°power divider. Multiple decoupling techniques, including polarization diversity, radiation mechanism diversity, shunt effect of a shorting pin, and differential feeding, are simultaneously used to achieve high isolation. An antenna prototype is measured with an impedance bandwidth of 52.2% (1.7-2.9 GHz) for |S 11 |, |S 22 | < −10 dB, and high isolation of better than 55 dB. These characteristics make it a promising candidate for in-band full-duplex wireless communication systems.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.