基于半模基片集成波导的双频段缝隙天线

基于半模基片集成波导技术,提出了一种适用于微波集成电路的双频段缝隙天线。该双频段天线由馈电微带线,一段半共面波导结构和具有辐射缝隙的半模基片集成波导谐振腔构成,利用半模基片集成波导谐振腔的多模式工作特性实现了天线多频段特性。仿真和测试结果表明,该天线能同时工作在C频段(谐振频率5.74 GHz,S11=-21.86 dB)和X频段(谐振频率11.33 GHz,S11=-25.09 dB),不需要同时采用两个天线,具有便于和平面电路集成、体积小、结构简单、成本低等优点。     

使用非均匀特异媒质覆层的高增益谐振腔天线

采用非均匀特异媒质覆层,设计了一种具有高增益特性的新型谐振腔天线。该谐振腔天线采用矩形微带贴片天线作为辐射单元,安装在金属谐振腔内,其谐振频率为10 GHz。为提高天线增益,将腔表面安装蚀刻在微带基板上,由周期性单元组成特异媒质覆层。迥异于常规的单元尺寸均匀一致特异媒质覆层,本文研制的非均匀特异媒质覆层包含9×9个矩形单元,单元大小渐变。仿真表明,与常规均匀特异媒质覆层相比,该新颖的非均匀特异媒质覆层相当大程度提升了天线定向辐射性能：天线增益提高1.2 dB(从20.3 dBi增加到21.5 dBi),天线的旁瓣得到了抑制,主旁瓣比下降5 dB;同时,天线谐振频率和阻抗带宽等其他性能基本保持不变。     

基于RFID应用的印刷偶极子天线受环境影响测试

为了测试所设计的2.45 GHz RFID标签天线受环境影响情况,进行了天线周边分别有塑料瓶水、玻璃瓶水、金属罐头瓶水时的天线匹配特性测量,结果表明,塑料瓶水和玻璃瓶水对天线匹配性能的影响类似,主要是改变了天线的谐振频率,距离天线越近,对天线的谐振频率影响越厉害,导致天线的谐振频率向低端偏移.金属罐头瓶距离天线很近,如0.3 cm严重影响,导致天线不工作,当所有物体距离天线的位置超过5 cm时,则对天线性能影响不大.     

基于阻抗表面加载的小型化全向高增益天线

提出了一种基于阻抗表面加载的紧凑型水平极化全向高增益腔体天线。通过在由5个腔体级联构成的全向天线中央加载深度可调的梳状阻抗表面,可在宽带频率范围内降低天线的谐振频率,即实现天线的小型化。该梳状阻抗表面是由一维周期性亚波长金属线阵列构成,可等效为在天线辐射口径均匀加载的并联电容。仿真结果表明,通过调节阻抗表面的插入深度,天线的尺寸可缩小42.3%。同时,该天线可在整个调节范围内(频率比1∶1.7)保持良好的全向辐射特性(不圆度小于2.5 dB)、阻抗匹配特性(|S₁₁|]<-10 dB)及最大增益为6.8~8.5 dBi,可应用于体积受限的全向无线通信系统。     

平面开关寄生阵列天线的频带展宽方法及应用

提出了一种利用参差调谐来实现平面开关寄生阵列天线频带展宽的方法。针对该类阵列天线频带窄的缺点,通过采用谐振频率稍有不同的有源单元和寄生单元,使其呈现双谐振特性,可以有效增加天线的工作带宽。根据该类天线单元的谐振特性,研究了频带展宽的工作原理。测量结果表明:天线的相对阻抗带宽可达到5%(S11-10dB),是未使用该方法前设计的天线阻抗带宽的5倍,且天线在工作频段内辐射特性良好。最后,设计制作了演示系统原型(对数功率检波器和控制器),实现了在展宽的工作频带范围内,该天线最大波束均可对在轨道上运动的目标进行动态跟踪。     

带金属柱矩形贴片天线的谐振频率

首次采用有限元与谐振腔模型结构的混合有限元方法对有金属方柱的薄基片矩形贴片天线的谐振频率进行了数值计算和实验分析，谐振频率的计算结果与实验结果符合很好。     

一种X 和Ka 波段频率可重构Koch分形振子天线研究*

将射频开关和Koch分形振子相结合,设计了一款结构紧凑的可工作于X和Ka两个波段的频率可重构天线,所设计的天线长度约为相同谐振频率普通振子天线的80％.天线工作于Ka频段时,由于天线中被射频开关断开的其它部分对其辐射性能的影响严重,会使Ka频段的方向图发生严重变形,因此我们又对天线进行了改进优化.改进后的天线由Koch分形振子和其前端另外延伸增加的一普通振子构成,改进天线在X频段和Ka频段的性能分别由Koch分形振子和普通振子所决定.仿真和实测结果表明:改进优化后的天线在X和Ka两个频段都具有良好的性能.     

基于超材料的新型低剖面谐振腔天线

根据法布里-珀罗谐振腔理论,设计并测试了一款新型双S 低剖面天线。该天线采用加载超材料表 面的方法,用以降低法布里天线的谐振距离。理论分析发现,双S 型超材料表面在特定频段内具有负相位特性,根据 法布里-珀罗谐振条件可以降低谐振腔体天线的剖面。实验结果证明,天线的谐振距离降低至姿/ 12. 7,远远小于传 统天线的姿/ 2。     

一种基于分形结构的树生长微带天线设计

基于分形理论和自然树竞争(TGCA)思想,提出了采用树枝结构在不同生长因子下进行迭代生长的方法,对分形天线多谐振频率点进行优化控制,克服常见分形天线难于调整多个谐振频率点位置关系的缺点。树生长分形天线通过生长因子和天线尺寸的线性调整,可以方便地实现高低谐振频率的优化设计,方法简单易行。基于该方法,采用时域有限差分(FDTD)算法优化设计了一种具有GSM900/DCS1800双频谐振点的树生长微带分形天线。从实验和仿真结果可以看出,该微带分形天线在0.91 GHz,1.81 GHz谐振频率处带宽均大于100 MHz,水平方向为全向辐射,测量所得结果和仿真数据吻合较好,验证了采用生长因子调整分形天线谐振频率的方法。     

基于左手材料的微带阵列天线设计

设计出一种由两个六边形开口谐振环组成的电磁超材料单元,这种新型的电磁超材料单元实现了左手特性。然后优化出一个中心频率为16 GHz的二元阵列微带天线,将左手材料单元置于辐射贴片周围,利用三维电磁仿真软件HFSS对其进行优化仿真,最终制作了一款加载左手材料的微带阵列天线。仿真及实测结果表明,在相同的工作频率下,加载了左手材料的阵列天线与普通阵列天线相比,其谐振点的回波损耗由-32.7 dB减小到-59.7 dB,同时在低频产生了谐振点,实测其旁瓣得到了有效的缩小,主瓣变窄,方向性增强,增益由8.3 dB增加到8.8 dB,提高了天线的多项性能指标,且实测回波损耗与仿真曲线吻合较好,在16 GHz处的增益图与仿真对比大致相同。     

Design of a self-diplexing antenna using SIW technique with high isolation

In this paper, a novel and small substrate integrated waveguide (SIW) based self-diplexing antenna is presented. The proposed antenna exploits two quarter-mode SIW cavity resonators for radiation, which are realized by splitting a half-mode SIW cavity with the help of one open-ended slot. Each quarter-mode cavity resonator is excited separately by microstrip feedlines. By properly adjusting the corresponding dimensions of the antenna, a very high isolation of better than −30 dB is obtained between the input ports that helps to realize a self-diplexing phenomenon. The antenna exhibits two resonant frequencies of 6.44 and 7.09 GHz, with the corresponding gain values of 3.2 and 4.8 dBi, respectively. Moreover, the antenna shows unidirectional and stable radiation patterns at both operating frequencies, while it maintains a planar and simple configuration, which can be rescaled for any other desired frequency.     

用于生物医疗的共面波导馈电双频植入式天线

设计了一款用于生物医疗的微小紧凑型共面波导馈电双频植入式天线。该天线工作于工业、科学和医疗(Industrial Scientific Medical, ISM)低频段(433~434.8 MHz)及无线医疗遥测服务(Wireless Medical Telemetry Service, WMTS)频段(1.395~1.40 GHz),尺寸仅为10 mm×10 mm×1.27 mm。天线采用共面波导馈电结构,易于和其它结构集成,采用高介电常数介质基板和折合蜿蜒类偶极子结构使天线尺寸得以有效缩小。在满足SAR(Specific Absorption Rate,比吸收率)值标准的前提下,采用U形接地板,以获得较高的增益,在两个频段内谐振频率处的最高增益分别为-32.23 dBi和-20.63 dBi,提升了天线性能。最后,基于仿真结果制作天线实物并进行了测试,实测数据与仿真结果吻合较好。研究成果可为植入式天线研制与应用提供重要参考。     

Shorting pin loaded dual-band compact rectangular microstrip antenna

Theoretical and experimental investigations carried out on shorted microstrip patch antenna for dual band operation. The investigations were carried out by varying the shorting-pin position from the edge to the centre of the patch; such an antenna provides a frequency tunability range from 0.88?GHz to 1.08?GHz for first resonance and from 2.20?GHz to 2.59?GHz for second resonance. A frequency ratio of about 2.91 to 2.2 for the two operating frequencies is observed. When the shorting-pin position is close to centre or at the centre of the patch, a single resonant frequency is observed. It is also observed that the resonant frequency of the antenna heavily depends upon the thickness of the substrate, dielectric constant of the substrate and radius of the shorting-pin.     

小型化八边形基片集成波导背腔缝隙天线

提出一款新颖的W波段八边形基片集成波导(SIW)背腔缝隙天线。相较传统的缝隙天线，具有体积小、易加工、Q值高、成本低等优点，且易于成阵。通过调节天线背腔缝隙的长度、宽度，以及SIW腔体的尺寸优化天线的辐射特性，通过电磁仿真软件HFSS对模型进行仿真优化，确定了天线的最优结构。仿真实验结果表明，所设计的天线相对带宽约4.5%，方向性优良，中心频率点谐振深度<-31 dB，天线最大增益达到5 dBi，满足设计要求，验证了设计的正确性。所设计的SIW背腔缝隙天线拓宽了数字通信的可用频谱，是一种新的尝试，可为以后的研究提供新的参考思路。     

Compact Dipole Antenna for Terrestrial Digital Multimedia Broadcasting Service

A compact dipole antenna for the terrestrial digital multimedia broadcasting (TDMB) application is presented. The length of the antenna is about 0.06λ at the TDMB resonance frequency of 190 MHz. Miniaturization of the antenna is achieved by using meander structures and lumped elements. The proposed antenna has two resonance frequencies and covers the TDMB band from 174 MHz to 216 MHz in Korea. The antenna has good impedance bandwidth and radiation characteristics for the TDMB. The experimental results of the designed dipole antenna are presented and analyzed.     

Circuit Theory Analysis of Aperture Coupled Patch Antenna for Wireless Communication

An analysis of dual band aperture coupled microstrip patch antenna is performed using modal expansion cavity model. The theoretical investigation of antenna characteristics such as return loss, VSWR and radiation pattern is represented. The influence of geometric parameters of the aperture coupled microstrip patch antenna, such as aperture length and width, height of the substrate, dielectric constant are also investigated. It is found that antenna resonates at two distinct modes i.e. 4.39 and 5.55 GHz for lower and upper resonance frequencies respectively. The bandwidth of the aperture coupled microstrip patch antenna at lower resonance frequency is 10.23% (theoretical) and 13.33% (simulated) whereas at upper resonance frequency, it is 5.69% (theoretical) and 3.59% (simulated). The frequency ratio obtained for upper to lower resonance frequencies for theoretical and simulated results are 1.5 and 1.37 respectively. The theoretical results are compared with IE3D simulation results along with reported experimental results and they are in close agreement.     

基于复合腔结构的MEMS双模微带天线设计

设计了一种基于腔结构的双模偶极子天线,其频率在2.44GHz和4.38GHz,利用MEMS开关实现双波段的操作.根据偶极子天线原理,设计了单模微带偶极子天线,使用开关结构将两个单模偶极子天线连接在一起,实现了双模天线的功能.利用三维电磁场软件HFSS分析了设计结构,包括开关、天线,在0～10 GHz得出开关性能插入损耗在-1dB以下,天线回波损耗在-26dB以下.频率为2.44GHz时、回波损耗为-13.2dB、2dB的辐射效率为89%,频率为4.38GHz时,回波损耗为-21.9dB、3dB辐射效率为96%,带宽都在0.5GHz左右.     

宽带平面直角双频单极天线

对于超宽带系统,需要具备可工作频率为3.1~10.6GHz的宽带天线。本文介绍了四种宽带平面单极天线,分别为圆形平面单极天线、平面直角单极天线、平面双频单极天线和平面直角双频单极天线。其中平面直角单极天线兼具宽频和全向特性,平面双频单极天线和平面直角双频单极天线在两个谐振点都具有宽带特性,平面直角双频单极天线在整个频带内水平面的辐射方向图几乎都可以达到全向。     

基于谐振式反射器的UHF/S双频双定向蝶形天线

利用两个工作在不同频率的圆环型谐振式反射器设计了一款小型化、低剖面的"双频（UHF/S）辐射"宽带双定向蝶形天线.谐振式反射器在很宽的频带内具有"同相反射"的特点且无需周期结构,因此作为天线反射板时与天线间的距离远小于λ/4且面积较小.两个反射器大小不同且分别置于蝶形天线的上方和下方.虽然这两个反射器分别位于另一反射器的辐射（反射）方向上,但它们不会阻止彼此的辐射,因此所提出的天线在工作频带的UHF低频段与S高频段分别向+z轴与-z轴辐射.所设计的蝶形天线采用微带线从侧边馈电,避免了从天线背面馈电可能对天线辐射特性的影响.虽然该天线使用了上下两层反射器,其整体尺寸仅为0.45λ×0.4λ×0.2λ.天线的阻抗带宽超过100%,低频和高频的相对定向带宽（前后比> 5 dB）分别为58%和41.6%,具有良好的双频双定向性.     

Analysis of W-slot loaded patch antenna for dualband operation

In the present paper W-slot loaded single and two dielectric layers microstrip patch antenna has been analysed using equivalent circuit concept. The antenna shows dual resonance. The resonance frequency of single layer patch is found to be 2.91 GHz and 3.88 GHz which increases for two layers dielectric antenna up to 4.17 GHz and 5.78 GHz respectively. The frequency ratio is found to be 1.33 for single layer patch antenna and 1.38 for two layers patch antenna. In general the frequency ratio is found to depend on slot length, slot width and slot angle. The bandwidth of single layer patch antenna is found to be 1.71% and 1.68% for lower and upper resonance frequency while it increases for two layers up to 5.28% and 2.77%. The theoretical results are compared with the simulated results obtained from IE3D and both are in close agreement.