本文關(guān)鍵詞： 同軸腔 圓柱腔 一腔多模 模式凈化 復(fù)介電常數(shù)　出處：《電子科技大學(xué)》2017年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：為了實(shí)現(xiàn)在0.5-40GHz頻段內(nèi),對(duì)固體介質(zhì)的復(fù)介電常數(shù)進(jìn)行測(cè)量。本文將0.5-40GHz拆分為三個(gè)頻段一個(gè)同軸諧振腔覆蓋0.5-5GHz頻段、兩個(gè)圓柱腔分別覆蓋7-18GHz和18-40GHz。三個(gè)腔體都采用了一腔多模技術(shù)。本文主要研究工作如下:1)諧振腔中模式眾多,通過(guò)分析模式分布選定工作模式。根據(jù)測(cè)試頻點(diǎn)應(yīng)盡量多,且應(yīng)均勻分布在頻段內(nèi)的要求。分析計(jì)算并繪制了圓柱腔工作模式分布圖,最終圓柱腔中采用011TE到017TE七個(gè)高次模式、同軸諧振腔中用001TEM到005TEM五個(gè)模式為工作模式。2)針對(duì)圓柱腔中工作模式為高次模開(kāi)展了模式凈化工作。圓柱諧振腔中工作模式為高次模,附近雜模很多,如不采取相應(yīng)技術(shù)措施,使用時(shí)會(huì)嚴(yán)重影響測(cè)試準(zhǔn)確度。通過(guò)對(duì)腔體尺寸優(yōu)化,使雜模和工作模式頻差達(dá)到最大。另一方面分析工作模式和簡(jiǎn)并模式場(chǎng)分布的不同點(diǎn)。通過(guò)增加后腔以及優(yōu)化耦合饋電位置,來(lái)對(duì)簡(jiǎn)并模式進(jìn)行抑制。抑制后得到的工作模式21S掃頻曲線關(guān)于諧振頻點(diǎn)基本對(duì)稱(chēng)。3)基于腔體工作帶寬和雜模抑制要求,開(kāi)展了饋電及耦合裝置設(shè)計(jì)。為了滿足兩個(gè)圓柱腔寬頻帶耦合饋電,設(shè)計(jì)了對(duì)應(yīng)頻段的雙脊波導(dǎo)到同軸線轉(zhuǎn)換器。7-18GHz轉(zhuǎn)換器駐波小于1.2、18-40GHz轉(zhuǎn)換器駐波小于1.4,滿足帶寬要求。饋電位置要能夠激勵(lì)起所有工作模式,同時(shí)不激勵(lì)或者弱激勵(lì)起簡(jiǎn)并模式4)基于模式分布、模式凈化和耦合饋電,開(kāi)展了諧振腔的整體設(shè)計(jì)。針對(duì)傳統(tǒng)圓柱腔測(cè)試介質(zhì)時(shí)放置介質(zhì)不方便、測(cè)試繁瑣的問(wèn)題。對(duì)圓柱諧振腔的開(kāi)腔方式做了創(chuàng)新改進(jìn),通過(guò)在腔壁中打通孔加入滑軌,在滑軌頂端加入彈簧。在不影響圓柱腔場(chǎng)分布,不改變?cè)瓉?lái)腔體測(cè)試精度情況下,使得空腔測(cè)試和加入介質(zhì)測(cè)試,這兩種測(cè)試方式的切換,變得快速簡(jiǎn)單。這是本文的創(chuàng)新點(diǎn)。另外同軸腔開(kāi)路端輻射太大影響測(cè)試精度,在開(kāi)路端采用漸變結(jié)構(gòu),使開(kāi)路端直徑大大減小,減弱腔體輻射以保證測(cè)試精度。對(duì)諧振腔進(jìn)行空腔實(shí)測(cè),測(cè)試結(jié)果和仿真結(jié)果基本一致。用18-40GHz圓柱腔測(cè)試介質(zhì)樣品,相對(duì)介電常數(shù)測(cè)試結(jié)果相對(duì)誤差小于5%。
[Abstract]:In order to achieve in the 0.5-40GHz band. In this paper, the complex dielectric constant of solid medium is measured. In this paper, 0.5-40GHz is divided into three frequency bands and one coaxial resonator is covered with 0.5-5GHz frequency band. The two cylindrical cavities cover 7-18GHz and 18-40GHz respectively. The three cavities are multimode with one cavity. The main work of this thesis is as follows: 1) there are many modes in the resonator. According to the requirement that the test frequency should be as many as possible and should be uniformly distributed in the frequency band, the working mode distribution diagram of cylindrical cavity is analyzed and calculated. Finally, seven high order modes of 011TE to 017TE are adopted in the cylindrical cavity. In coaxial resonator, the five modes of 001TEM to 005TEM are used as working mode. 2). The mode purification work is carried out for the high order mode in the cylindrical cavity and the high order mode in the cylindrical resonator. There are a lot of impurity moulds nearby. If the corresponding technical measures are not taken, the accuracy of the test will be seriously affected when using, and the cavity size will be optimized by optimizing the size of the cavity. On the other hand, the difference of the field distribution between the working mode and the degenerate mode is analyzed. By adding the back cavity and optimizing the coupling feed position. To suppress degenerate mode. The 21s sweep curve about resonance frequency points is symmetric. 3) based on cavity bandwidth and heterodyne suppression requirements. The design of feed and coupling device is carried out. In order to satisfy the broadband coupling of two cylindrical cavities, the standing wave of the dual-ridge waveguide to coaxial line converter .7-18GHz converter is designed to be less than 1.2. The VSWs of 18-40GHz converters are less than 1.4, which meet the bandwidth requirements. The feed position should be able to excite all operating modes without or without weak excitation and degenerate mode 4) based on mode distribution. Mode purification and coupling feed, the overall design of the resonator is carried out. Aiming at the problem that the traditional cylindrical cavity is not convenient to put the medium in the testing medium, the testing is cumbersome. The opening mode of the cylindrical resonator is innovated and improved. By adding slide rail and spring at the top of the cavity wall, the cavity test and the medium test can be done without affecting the field distribution of the cylindrical cavity and changing the measuring precision of the original cavity. The switching of these two testing methods becomes fast and simple. This is the innovation of this paper. In addition, the radiation of the open end of the coaxial cavity has too much influence on the measurement accuracy, and the open end adopts a gradual structure, which greatly reduces the diameter of the open end. The cavity radiation is weakened to ensure the measurement accuracy. The measured results are in good agreement with the simulation results. The dielectric samples are measured by 18-40GHz cylindrical cavity. The relative error of the relative dielectric constant is less than 5.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TN015;TN751.2

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本文編號(hào)：1492662