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北京石油化工學(xué)院2026年研究生招生接收調(diào)劑公告

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wanghaiju

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[求助] 高分子論文翻譯求助

The free-space measurement system used in this study is schematically illustrated in Fig. 1. The equipment used for the measurement comprises a pair of spot-focusing type horn antennas (transmitting and receiving), a sample holder, and a coaxial cable connected to a HP8722D network analyzer. The horn antennas were equipped with biconvex polymeric lenses, focusing the electromagnetic waves on to the sample with a spot diameter~2–3 times that of the wave under consideration. The antennas were separated by a distance measuring twice the focal length (330 mm) of the lenses. The horn antenna (I) sends an electromagnetic wave onto the surface of the sample; and the waves transmitted through and reflected from thesample were collected by horn antennas (II) and (I),respectively.

In order to minimize the measurement inaccuracies in the system, a through-reflect-line (TRL) calibration was carried out,whereasatime-domain gating was used to minimize the effects of residual mismatches, such as a mismatch in the source and load impedance [21]. After calibration, the woven fabrics were attached to a square cross-sectioned cardboard frame, and were placed into the sample holder mid-waybetweentwospot-focusinghornlensantennas.The reflected and transmitted portions of the electromagnetic wave were determined for single-layer woven fabrics in the frequency range of the spot-focusing horn lens antennas(17–40 GHz). Measurements were also carried out on various double-layer combinations of fabrics,in both in their asreceived state and after heat treatment to determine theeffect of changing the electrical conductivity and sequencing of layers on electromagnetic wave absorption potential.
These combinations were measured by arranging two cardboard frame sets with sample fabrics back-to-back in the sample holder. In this way, double-layer combinations with a 1-mm spacing (thickness of the cardboard) between the layers were obtained, and the electromagnetic wave reflection and transmission losses of all combinations were examined through a repetition of the above procedure.

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wanghaiju: 金幣+34, 翻譯EPI+1, ★★★★★最佳答案 2014-06-11 18:13:44

研究使用的自由空間測(cè)量系統(tǒng)圖解于圖1。用于測(cè)量的設(shè)備包括一對(duì)光斑聚焦型喇叭天線（發(fā)送和接受）、樣件工裝、通過同軸電纜連接到HP8722D網(wǎng)絡(luò)的分析儀。喇叭天線配備了雙凸面聚合透鏡，將電磁波聚焦到樣件，得到波的2-3倍斑直徑。天線相距2倍鏡頭焦距（330mm）。喇叭天線（I）發(fā)送電磁波到樣件表面；穿過樣件或被樣件反射的電磁波分別由喇叭天線（II)和（I）接收。

為了減小系統(tǒng)的測(cè)量誤差，進(jìn)行穿透-反射-線（TRL）標(biāo)定，使用時(shí)域選通減小殘余失配，例如源與負(fù)載阻抗的不匹配的影響[21]。標(biāo)定后，將織物貼到矩形截面的硬紙板框架，放進(jìn)樣件工裝中2個(gè)光斑聚焦喇叭透鏡天線的中間位置。對(duì)單層織物，在光斑聚焦喇叭透鏡天線的頻率范圍（17-40GHz）探測(cè)電磁波的反射和發(fā)射部分。對(duì)不同的雙層織物組合也進(jìn)行測(cè)量，包括它們的收貨狀態(tài)和熱處理后狀態(tài)，以確定改變電導(dǎo)率和層的順序?qū)﹄姶挪ㄎ漳芰Φ挠绊憽?br /> 在對(duì)這些組合的測(cè)量中，2個(gè)帶有織物樣件的硬紙板框架背對(duì)背放置進(jìn)樣件工裝。通過這種方式得到1mm層間距（硬紙板厚度）的雙層組合，如此便可通過重復(fù)上述流程檢驗(yàn)各種組合的電磁波反射和發(fā)射損失。

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2樓2014-06-11 14:51:29