本文選題：天線小型化　切入點：寬頻化　出處：《電子科技大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來物聯(lián)網(wǎng)技術(shù)的應(yīng)用已經(jīng)深入到各個領(lǐng)域,射頻識別(RFID)作為物聯(lián)網(wǎng)的關(guān)鍵技術(shù)得到了快速發(fā)展,其系統(tǒng)內(nèi)部的硬件尺寸變得越來越小,如何實現(xiàn)RFID讀寫器天線的小型化變得至關(guān)重要。除了結(jié)構(gòu)上的調(diào)整,引入低損耗的磁介電材料替代傳統(tǒng)的介質(zhì)基板可以很好地實現(xiàn)天線的小型化,同時引入的磁損耗還能夠拓寬天線阻抗帶寬。實驗證明,在獲得相同小型化的情況下,采用磁介電材料所獲得的阻抗帶寬將優(yōu)于高介電常數(shù)基板。為此,本論文較為系統(tǒng)地研究了一種應(yīng)用于超高頻(UHF)RFID頻段(840~960 MHz)的低損耗磁介電材料,并基于該材料設(shè)計并制作了兩種不同結(jié)構(gòu)的讀寫器天線,以驗證試驗方案的可行性。一方面,從材料入手,對Co2Z鐵氧體進行研究,逐步分析了缺鐵、鋁替代鐵和摻雜BBSZ玻璃等方案對材料性能的影響。實驗發(fā)現(xiàn),當(dāng)缺少兩個鐵原子時,材料具有較好的電磁性能。然后,進行了鋁替代鐵實驗方案,Al3+替代Fe3+有效地抑制了Fe2+的出現(xiàn)以降低材料的磁介電損耗;隨著鋁替代量的增加,材料的磁介電損耗均呈現(xiàn)先降低后增加的趨勢,在鋁替代量x為1.6,980℃燒結(jié)下材料的損耗達到最低。最后,基于鋁替代鐵方案進行了摻雜BBSZ玻璃的實驗以提高材料的燒結(jié)致密化。研究發(fā)現(xiàn),隨著BBSZ含量的增加,材料的磁導(dǎo)率和介電常數(shù)均有明顯的提高,過多的摻雜量會使磁導(dǎo)率略微下降;在BBSZ含量為3.0 wt%,燒結(jié)溫度為950℃時材料具有最優(yōu)性能。另一方面,基于自制的材料設(shè)計并制作了兩種不同類型的RFID讀寫器天線。第一種天線采用傳統(tǒng)的微帶天線結(jié)構(gòu)-圓環(huán)形輻射貼片,在偏離饋電45°方向內(nèi)環(huán)開槽實現(xiàn)圓極化輻射,該天線的中心頻率約為914 MHz,S11小于-10 dB時天線的阻抗帶寬達到48 MHz,但其增益較低。針對第一種天線增益較低的問題,在天線正上方懸置了一個開窗的金屬層設(shè)計了第二種天線,該天線采用開路微帶線進行饋電。測試結(jié)果顯示,在中心頻率915 MHz處天線的增益達到3.6 dBi,阻抗帶寬達到29 MHz,該天線的輻射方向圖良好。這兩種設(shè)計方案很好地兼顧了RFID讀寫器天線在小型化和寬頻帶方面的技術(shù)要求,第二種方案還針對第一種方案天線增益較低的問題作出了結(jié)構(gòu)上的改進設(shè)計。
[Abstract]:In recent years, the application of Internet of things technology has been deep into various fields. Radio frequency identification (RFID), as the key technology of the Internet of things, has been developed rapidly, and the hardware size of the system has become smaller and smaller. It is very important to realize the miniaturization of the RFID reader antenna. Besides the structural adjustment, it is possible to miniaturize the antenna by introducing the magnetic dielectric material with low loss instead of the traditional dielectric substrate. At the same time, the magnetic loss can also widen the impedance bandwidth of the antenna. The experimental results show that the impedance bandwidth obtained by using magnetic dielectric material is better than that of high dielectric constant substrate under the same miniaturization. In this paper, a low loss magnetodielectric material used in UHF UHFU RFID band is studied systematically. Based on this material, two kinds of reader antennas with different structures are designed and fabricated to verify the feasibility of the experimental scheme. The effects of iron deficiency, aluminum substitution for iron and doped BBSZ glass on the properties of Co2Z ferrite were studied. It was found that the material had better electromagnetic properties when two iron atoms were missing. The experimental scheme of aluminum substitution for iron, Al3 instead of Fe3, effectively inhibited the appearance of Fe2 in order to reduce the magnetic dielectric loss of the material, and with the increase of aluminum substitution, the magnetic dielectric loss of the material decreased first and then increased. The loss of the material is the lowest when the aluminum substitution x is 1.6 ~ 980 鈩，

本文編號：1619775