Printed figure-of-eight wire antenna for circular polarization

A new printed wire antenna with circular polarization properties is presented. The geometry of the printed wire which takes the form of a figure-of-eight has a total length of 1.3/spl lambda//sub o/ and serves as a nonresonant traveling-wave antenna. It is shown that a 3-dB axial ratio bandwidth of 15% can be achieved. The half-power and 3-dB axial ratio beamwidth is approximately /spl plusmn/45/spl deg/, while its gain is of the order of 6.5 dB.     

The design of a squarer-ring slot antenna for circular polarization

A new design of a circularly polarized square-ring slot antenna is proposed. The circular polarization is achieved by a series microstrip-line-feed configuration coupling to two orthogonal sides of the square-ring slot. A parametric study is conducted using a commercial simulation software based on the method of moments, and the design procedure is established. The required ground-plane size of the proposed design for a given frequency is also indicated. Three antenna prototypes respectively operated at distinct frequency bands are constructed and measured for providing the simulation validation. Experimental results show that the proposed antenna has good circularly polarized radiations and the 3 dB axial-ratio bandwidth is more than 6%.     

Circularly polarised circular ring slot antenna fed by striplinehybrid coupler

A novel circular ring slot antenna which has a stripline hybrid coupler feed network is proposed for generating broadband circular polarisation performance. A broad impedance bandwidth (VSWR 2:1) at 20.5%, and a CP bandwidth at 9% for a <3 dB axial ratio have been achieved     

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.     

Printed cylindrical slot antenna for GPS commercial applications

The authors present a new printed cylindrical slot antenna for GPS commercial applications. This antenna displays compact size, low cost, ease of mass production, near-hemispherical radiation coverage and circular polarisation properties. Experimental results show that the printed cylindrical slot antenna has a 3 dB beamwidth of 120° and a front-back ratio >15 dB     

一种双极化的MIMO超宽带方环缝隙天线设计

设计了一种双极化的多输入多输出(MIMO)超宽带方环缝隙天线。该天线有4个天线单元,底层由2个方环微带馈电线构成,用于正交偏振。顶层由2个对称结构的方环构成,用于减少交叉极化。方环之间用矩形切口连接,以增加环缝之间的耦合。测量结果表明,该天线在3~12 GHz内隔离比大于22 d B,相关系数(ECC)在可以接受的范围内。该天线可以应用于MIMO超宽带通信系统中。     

Wideband double-element ring slot antenna

A new technique for bandwidth enhancement of microstrip-fed annular ring slot antennas is presented. Using this technique, a wideband antenna is designed that has consistent radiation parameters across the entire band and has a bandwidth that is six times larger than that of an ordinary ring antenna.     

Electric tripole antenna for circular polarization

The feasibility of using the tripole antenna for circular polarization was experimentally investigated. Measured impedance and radiation patterns were in agreement with the predictions from the infinitesimal tripole model. For simultaneous operation in both senses of circular polarization the tripole antenna must be fed by a special separator network, preferably of the nonreciprocal type.     

Rectangular microstrip antenna for circular polarization

Richmond's reaction integral equation method is used to design a rectangular microstrip patch to produce a circular polarization. A rectangular patch with the aspect ratioa = W_{x}/W_{y}, in the range 1.015- 1.02 and corner fed by a microstrip line, produces circular polarization. For substrate with thicknessd = 0.16cm,a = 1.017the nearly square patch gives maximum bandwidth.     

Broadband printed CPW-fed circular slot antenna

A broadband printed CPW-fed circular slot antenna is proposed. This antenna is composed of a circular slot fed with a 50 /spl Omega/ CPW line through a circular patch. A parametric study was carried out to optimise the proposed structure, and the simulated and measured results show that the proposed design offers an ultra-wide bandwidth of 143.2% (from 2.3 to 13.9 GHz).     

Printed circular disc monopole antenna for ultra-wideband applications

A novel and simple design of a printed circular disc monopole antenna for ultra-wideband applications is presented. The parameters which affect the performance of the antenna are investigated. Good agreement is achieved between simulation and experiment.     

新型小尺寸双陷波超宽带天线设计

提出了一种基于槽天线的小型化、高隔离度的超宽带(Ultra Wideband, UWB)多入多出(Multiple-Input Multiple-Output, MIMO)天线.该MIMO天线由两个槽天线单元构成, 为了增加天线阻抗带宽, 每个槽天线单元由末端带有圆形贴片的微带线和末端为圆形的槽线两部分耦合馈电.采用在地板上开槽和方向图分集方法, 减少地板表面波和空中电磁波影响, 达到提高天线隔离度的目的.数值仿真和实验结果表明:该天线在3.1~11 GHz频段内满足端口反射系数|S₁₁| < -10 dB, 隔离度|S₁₂|在7~11 GHz频段内小于-25 dB, 在3.1~7 GHz频段内小于-16 dB, 并根据仿真和测试S参数计算了包络相关系数.     

A reconfigurable slot antenna with switchable polarization

A novel reconfigurable slot antenna architecture allowing polarization switching is presented. The antenna shape consists of a slot-ring with perturbations which are switched on and off using pin-diodes. Two antennas allowing switching either between linear and circular polarization or between two circular polarizations are demonstrated. The antenna architecture is interesting for commercial wireless applications because it is compatible with modern fabrication processes and can be realized on low cost dielectric materials.     

Compact loaded slot ring antenna for circularly polarised radiation

A novel slot-ring circularly polarised antenna is reported. With sectorial slots loading, the axial ratio (AR) bandwidth is increased and the circumference of the slot-ring is also reduced to 0.5 lambda₀ (lambda₀ is the free-space wavelength at the centre frequency). The antenna features a 22.4% impedance bandwidth for |S ₁₁| les -10 dB, a 10.6% bandwidth for AR les 3 dB and stable radiation patterns over the whole operating band.     

Broadband patch antenna with ring slot coupling

A novel broadband linearly polarised patch antenna design is achieved using an H-shaped patch coupled to a microstrip feed line via a ring slot in the ground plane. The results indicate that a wide impedance bandwidth of 54% (2.3-3.845 GHz) can be achieved, together with a broadband gain of 6.6 dB and low levels of cross-polarisation.     

Printed antenna and array with circular polarisation

A new type of printed antenna element, as well as an array of elements with circular polarisation, is shown. The antenna has a much wider bandwidth than known circularly polarised printed antennas, mostly microstrip patches. The method of design and realisation with experimental results is shown     

A wider band microstrip antenna for circular polarization

Circular polarization is achieved by separating two degenerate orthogonal modes in an annular ring patch antenna, by using an ear at the outer periphery. The analysis of such a structure is performed by using the generalized transmission line model. It is found theoretically that this structure can be used to generate circular polarization over a wider frequency range than other structures. An annular ring is designed and its performance is evaluated. Good agreement between the theory and the experiment is obtained. It is also found that the axial ratio bandwidth is higher for the TM₁₂ mode than the TM₃₂ mode of operation in an annular ring antenna     

An ultrawideband coplanar waveguide-fed tapered ring slot antenna

In this paper, we present a new coplanar waveguide-fed tapered ring slot antenna for ultrawideband (UWB) applications. This antenna consists of a 50 /spl Omega/ coplanar waveguide feeding line, wideband coplanar waveguide-to-slotline transition, and a pair of curved radiating slots. The impedance bandwidth with VSWR<2 is from 3.1 GHz to more than 12 GHz. The actual operating bandwidth is, however, limited by the distortion of radiation patterns. Such pattern distortion can be attributed to the antenna mode transition and is investigated in this paper with the help of the radiation patterns in the traditional sense as well as a dimensionless normalized antenna transfer function. By suitably allocating such mode-transition phenomenon to the notched band in a UWB radio, we demonstrate that antennas with desirable radiation characteristics in both UWB low and high bands can be readily achieved. The system responses of a transceiving antenna system in free space are addressed as well.