Design of ultra wideband trapezoidal shape slot antenna with circular polarization

A CPW-feed printed slot antenna with circular polarization characteristics is presented in this paper. The basic structure of the antenna is a rectangular slot excited by a 50 Ω CPW line terminated on a trapezoidal shaped tuning stub. Perturbations in the form of circular stubs are applied in the slot to realize circular polarization. The measured impedance bandwidth (S₁₁ < −10 dB) for the initial design is 4.4 GHz (from 2.2 GHz to 6.6 GHz) while the 3-dB axial ratio bandwidth is 1.77 GHz (from 4 GHz to 5.77 GHz) which is 36.23% at the center frequency of 4.88 GHz. The basic structure of the antenna was further modified to enhance the impedance bandwidth to reach well beyond 12 GHz while increasing the ARBW to 44.3% (from 4.3 GHz to 6.75 GHz). The proposed antenna in its final version has a measured peak gain of about 5 dB throughout the useful band and nearly stable radiation pattern.     

A wideband linear U-slot microstrip patch antenna array for wireless application

Microstrip antennas suffer an inherent disadvantage of narrow impedance bandwidth, normally within 5%. In this article, a single layer linear U-slot microstrip patch antenna array is designed, fabricated and characterised. The measured results agree well with the simulated, showing an enhanced impedance bandwidth (voltage standing wave ratio < 2) of 10.6%, ranging from 5.35 to 5.95 GHz, on an FR4 substrate. The antenna array has high efficiency and gain. Only a pair of sidelobes appear in the E plane radiation pattern. The reported linear array design can provide a method of expanding to 4 × N antenna array for satellite to ground communication operating at C band.     

A compact skull‐shaped defected ground super wideband microstrip monopole antenna for short‐distance wireless communication

In this paper, a human skull‐shaped miniaturized super wideband microstrip monopole antenna is presented. The shape of the microstrip radiator is optimized and designed by combining different sizes of semicircular‐ and rectangular‐shaped radiating elements along with a microstrip feed line. On the other hand, a defected ground structure as the ground is placed at the opposite side of the radiator, which is fabricated on Rogers 5880 substrate. The electrical length of the proposed antenna is 0.240 × 0.200 × 0.016 λ at 3 GHz. The CST microwave studio is used for all the required simulations regarding antenna prototype design and optimization. The complete outcomes demonstrate that the proposed miniaturized antenna has a bandwidth of 24.5 GHz (3 to 27.5 GHz) having a radiation pattern in the form of nearly omnidirectional. The measured fractional bandwidth of the antenna is 160.66%, and the bandwidth dimension ratio is 3346.99, which is the highest among the literature review. The maximum calculated gain and efficiency are 6.3 dBi and 93%, respectively. For the time domain analysis, the antenna shows a decent performance in terms of the system group delay and fidelity factor. The numerical and experimental data are investigated throughout the study, which represents that the proposed antenna is suitable for short‐distance wireless communication like wireless local area network/Wi‐Fi/Worldwide Interoperability for Microwave Access (WiMAX)/ultra‐wideband and some other applications.     

Development of wideband CPW-fed hexagon-shaped circularly polarized slot antenna for wireless-communications

A hexagonal shaped circularly polarized (CP) wideband slot antenna using multiple stubs has been proposed and investigated. A hexagonal slot is created in the ground plane with tapered sections improving the impedance matching. Two radiators are incorporated in the structure, which is responsible for generating orthogonal degenerate modes; hence, CP radiation is achieved for the proposed antenna. For enhancing the gain of antenna, one radiator is directly connected to feed line and another one embedded in the ground plane. An inverted L-shaped arm is inserted in the slot to enhance and tune the circular polarized behavior. The presented radiator have input reflection coefficient ranges from 5.67 to 8.50 GHz (39.97%) and axial ratio bandwidth (ARBW) of 5.60–8.50 GHz (41.13%). The proposed antenna provides overlapping bandwidths of 5.67–8.50 GHz (39.97%) having average gains of 5.25 dBi within the entire frequency bands. The presented antenna is exceptionally good for the application of mobile and satellite communications.     

小型双频E形缝隙手机天线

提出了一种小型的双频E形缝隙手机天线。E形缝隙采用终端开路结构,并雕刻在地板的顶部,使天线的结构更紧凑,减小了天线的尺寸。同时,E形缝隙天线增加了天线的谐振路径,能产生双频宽频带特性,高低频带宽能覆盖GSM900/1800/1900/DCS/PCS/BuleTooth/UMTS/WLAN2400/WiMAX 2600通信频段。实测和仿真的结果基本吻合,验证了这种设计方法的有效性。     

Ferrite‐based wideband circularly polarized microstrip antenna design

In this paper, a wideband, circularly polarized patch antenna is proposed that leverages the unidirectional resonant modes of a circular patch mounted on top of a grounded dielectric‐ferrite substrate. The proposed antenna is fed via the proximity coupling method and several parasitically coupled patches are placed on a dielectric superstrate to enhance the impedance bandwidth of the antenna. The resonant modes of the structure rotate only in the clockwise or counter clockwise directions. In the frequency range where the effective permeability of the ferrite layer is negative, the resonance frequencies of these modes differ significantly, which produces a large axial ratio (AR) bandwidth. For the proposed antenna, the numerical results show the 10 dB impedance bandwidth to be around 44% and the 3 dB axial ratio bandwidth to be higher than 64%.     

一种应用于WLAN/WiMAX的新颖的三分枝单极天线

提出了一种应用于WLAN/WiMAX的新颖的多分枝单极天线,天线有三个分枝,结构紧凑,其大小为26mm×24mm×1.6mm,加工出了天线并进行测试,测试结果表明天线具有良好的双波段工作特性,｜S11｜≤-10dB时对应中心频率2.47GHz和4.825GHz处带宽分别达4%和62.4%,覆盖WLAN的2.4/5.2/5.8GHz频段及WiMAX的3.5/5.5GHz频段,同时采用了接地板开槽技术以调整带宽,天线在上述频段有近似于全向辐射方向图。     

一种应用于WLAN的抗金属四频段平面单极天线设计

用于非金属外壳设备的常规天线与金属外壳设备一起使用,会导致完全不同的回波损耗。因此,提出了一种同时适用于金属外壳和非金属外壳设备的四频段平面单极天线,该天线由一个弯曲接地层、一对寄生贴片和由同轴馈电激发的辐射片组成。提出的天线能够在不同类型接地层影响下,保持其谐振频率一致性,甚至能够连接到金属外壳上。该天线适用于在WLAN 2.4/5.2/5.8 GHz、WiMAX 3.5/5.5 GHz和4.5GHz工作的多种应用。仿真和实际测量结果显示,即便是连接到较大的金属外壳或金属板时,提出天线能够较好地保持回波损耗和增益一致性且符合行业标准。     

探地雷达阻性加载天线的应用研究

阻性加载技术可以有效拓展天线带宽、降低时域振铃.该文以双纽线构成平面印制天线的辐射臂, 分析阻性加载对其频域和时域特性的影响.通过数值仿真, 讨论了天线在两种阻性加载方式下阻抗带宽和时域波形的变化.设计了一款指数型微带转平行双线的巴伦, 并对巴伦和天线进行了加工及测试.测量结果表明, 天线时域波形拖尾振铃小于10%;在0.8~6 GHz频带内, 天线单元回波损耗小于-10 dB.将天线与雷达收发系统集成后, 进行地下目标探测实验.雷达探测结果成像清晰、浅层目标分辨率较高.该天线具有超宽带、低振铃、紧支撑等特点, 可满足便携式探地雷达的工程化应用需求.     

一种末端加载型300MHz/1GHz双频车载超宽带探地雷达天线设计

为满足高速铁路无损探测需兼顾低频探测深度与高频探测精度的要求,采用理论计算与软件仿真结合的方法,设计制作了一种双频带(300MHz/1 GHz)指数型TEM喇叭天线并对其进行了测量。所设计的指数型TEM喇叭天线采用末端加载和适当天线臂切削来实现此超宽带天线的双频带工作。仿真与实测结果表明,天线分别工作在中心为360MHz、带宽约为110MHz的低频带和中心为1 020MHz、带宽约为260MHz的高频带,相对带宽均大于20%。实测天线的接收信号保真度较高,拖尾持续时间短,满足设计要求。此外,这种双频带天线系统可减少雷达系统天线和采样盒等设备的使用数量,降低雷达系统的成本,有较好工程应用前景。