Broadband cross-shaped microstrip-fed slot antenna

A cross-shaped microstripline-fed slot antenna of large bandwidth is described. The experimental bandwidth of the antenna is from 1.765 to 4.921 GHz, which is 98.59% for S₁₁⩽-10 dB. The measured radiation pattern of the antenna is also presented     

Multisources actives annular slot antenna

This analysis of multisources annular slot antennas includes the study of the influence of the real spatial extension of the excitation sources and of the lumped elements inserted in the slot to conform the radiation pattern or to perform the power matching of the sources. The definition of a reference excitation source insures a field formulation consistent with the electrical circuits definitions taking into account the real spatial extension of the sources. Owing to the introduction of a surface impedance operator in the boundary conditions, the integral formulation also describes the lumped elements whatever the domain of definition of the expansion functions is. The analysis of rotation invariant configurations is also carried out.     

Small annular slot antenna with capacitor loading

A small-size annular slot antenna with miniaturised slot shrunk by a loaded capacitor has been realised. A 23.4% slot antenna area size reduction has been achieved with capacitor loading compared with the ordinary slot antenna. The antenna has the advantages of a good impedance bandwidth and good linearly polarised radiation patterns after chip capacitor loading     

Coplanar waveguide fed wideband slot antenna

A new design for a coplanar waveguide (CPW) fed slot antenna is presented. The impedance matching and the radiation characteristics of this structure were studied using the method of moment technique. This antenna has an impedance bandwidth (for a VSWR<2) of 49% and a radiation bandwidth of 42% about its 4.8 GHz centre frequency, compared to the 12-20% impedance bandwidth of the standard CPW fed slot antenna. The cross-polarisation in both the principle planes is at least 20 dB below co-polarisation across the entire bandwidth. Simulated and measured results of the antenna are presented. This wideband antenna has significant applications in wireless technologies     

Very ultra-wideband printed CPW-fed slot antenna

A very ultra-wideband compact microstrip slot antenna targeting the 3.1-10.6-GHz frequency band is presented. The proposed antenna is a simple printed slot antenna with a novel radiator, which is fed by a 50 Omega CPW line. The measured return loss extends from 2.8-33.4-GHz, about 169-. The proposed antenna has a compact size of 24-25-mm. The measured radiation patterns confirm that the antenna shows an approximately omnidirectional radiation pattern.     

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).     

Very wideband printed dipole antenna array

The design and experimental results of a very wideband small printed dipole antenna array are presented. The impedance bandwidth (VSWR ⩽1.7) of the antenna, centred at 780 MHz, is 47%. In the frequency band 610-960 MHz, the designed antenna has a gain of 9.5-11.9 dBi, sidelobe level <-16 dB and front-to-back ratio <30 dB. The main features of the design are the use of parasitic elements to expand the frequency band and the application of a mesh frame to decrease the sidelobe level     

Miniaturized wideband dual linearly and circularly polarized printed square slot antenna for multiradio wireless systems

A dual symmetrical coplanar waveguide (CPW)-fed small size wideband printed square slot antenna (SSA) with dual linearly and circularly polarized radiation capability is presented. The antenna is composed using a square slot, two symmetrical orthogonal CPW feed lines connected to horizontal and vertical arm of L-shaped radiator, an embedded parasitic inverted-L strip at the lower left corner of the square ground slot and engraving slots in the ground plane. Circular polarization (CP) is achieved due to two orthogonal CPW feed lines and a common L-shaped radiator. Isolation between ports is improved by engraving slots at the lower left corner of ground plane and embedded parasitic inverted-L strip. The sense of dual-polarization can be changed in pass-band by changing the port excitation. Measured antenna reveals that an 84.4% (4.6 GHz, 3.15–7.75 GHz) −10 dB impedance bandwidth (IBW) and about 33% (2.03 GHz, 5.12–7.15 GHz) 3-dB axial ratio bandwidth (ARBW). Isolation between ports <−16 dB is achieved over usable CP band.     

Frequency notched printed slot antenna with parasitic open-circuit stub

A new frequency notched ultra-wideband microstrip slot antenna with a parasitic tuning stub is proposed. The antenna is similar in configuration to a conventional microstrip slot antenna; by introducing a parasitic open-circuit tuning stub, flexible frequency notched function is achieved. Several properties of the antenna, such as frequency notched function, antenna transfer function and gain, have been investigated. As is reported, the operation bandwidth of the antenna is 2.91-11.16 GHz, in which a frequency notched band of 5.10-5.85 GHz has been achieved. Furthermore, good ultra-wideband linear transmission performance over the entire operation frequency range has also been achieved.     

加载多层介质谐振器的宽带背腔缝隙天线设计

提出并设计了一种工作于X波段的新型宽带背腔缝隙天线,通过在缝隙外侧加载多层介质谐振器,有效扩展了天线带宽并显著提高了天线增益.设计的天线中心频率为10 GHz,-10 dB回波损耗带宽约为40％;带内增益5～9.5 dBi,比未加载多层介质谐振器的背腔缝隙天线提高2～3 dB.实测结果同设计结果基本吻合,有效验证了该设计的正确性.     

Circularly polarized co-designed filtering annular slot antenna

In this paper, a compact circularly polarized co-designed filtering annular slot antenna (ASA) is proposed. The antenna comprises a distributed capacitor-loaded annular slot radiator to produce circular polarization (CP) radiation, which is seamlessly integrated with a microstripline bandpass filter (BPF) to enhance out-of-CP-band suppression. Two tightly coupled arc branches protruding into the annular slot are used to provide the required perturbation capacitance. The filter is designed by employing three concentric arc-shaped coupled microstripline resonators. The ground plane is shared by the annular slot radiator and the filter to reduce size occupation. It is found that the proposed antenna can not only yield high frequency selectivity, but also obtain widened CP bandwidth under the assistance of the filtering circuit. An antenna prototype has been fabricated and measured, showing that the antenna achieves a 10 dB return loss impedance bandwidth of around 13.7%, enclosing a 3 dB axial ratio (AR) bandwidth of more than 10.6%. Details of design considerations and experimental results are presented and discussed.     

Analysis of a cavity-backed annular slot antenna with one pointshorted

Analysis of a cavity-backed annular slot antenna with one point shorted is performed experimentally and theoretically. Resonance frequencies, bandwidths, and radiation patterns are studied with respect to slot width, cavity depth, and slot shorting position. In the theoretical analysis, the method of moments is applied to find the magnet current on the slot, and the Green's function for the field inside the cavity has been newly derived. By selecting a slot shorting position, circular polarization, and a bandwidth of more than 10%, the voltage standing-wave ratio (VSWR) ⩽2 for the input impedance is obtained     

Experimental study of large bandwidth three-offsetmicrostripline-fed slot antenna

The proposed novel three-offset shaped microstripline-fed slot antenna has a radiation pattern similar to the conventional microstrip slot antenna and the advantage of more bandwidth. The measured bandwidth is approximately 1.796 octave (VSWR⩽2.0), Experimental results for the impedance loci and the radiation patterns are also presented     

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.     

Network model for strip-fed cavity-backed printed slot antenna

An equivalent network for the strip-fed cavity-backed slot antenna is derived. The model is based on some physical insight into the problem. The various parameters of the network are derived from the experimental data on the input reflection parameter of the antenna. This model gives an insight into the strip-slot-cavity coupling and hence the working of the structure. It is also useful for predicting the performance of such practical antennas.     

Stripline-fed printed square spiral slot antenna for circularpolarisation

A novel design for a circularly-polarised printed square spiral slot antenna with a stripline feed is demonstrated. The printed slot antenna consists of a square spiral slot of ~1.25 turns, and a total slot length of approximately one free-space operating wavelength. By carefully trimming both ends of the square spiral slot, circular polarisation (CP) operation with a wide operating bandwidth can easily be achieved. A CP bandwidth of >6% has been obtained     

一种宽频带缝隙型手机天线设计

针对超薄多频带手机的需要,提出一款新型印刷缝隙型手机天线。天线印刷在0.8 mm厚FR-4电路板上,地面开有2个缝隙,其中1个为矩形,另外1个为矩形与圆形组合形式。馈电结构采用50 Ω微带线与一圆形贴片、一矩形带线组合构成倒L状。馈电线的弯折部分在地上的投影落于缝隙的内部,天线在电路板上占用的区域仅限于缝隙内部,保持了天线的小型化。此结构缝隙天线能够达到宽带匹配,测试的-6 dB带宽为0.695~0.805 GHz,1.5~3.2 GHz,4~15 GHz,能够覆盖LTE700,DCS1800,PCS1900,UMTS,LTE2300,LTE2500,全球定位系统(GPS),无线局域网(WLAN)以及超宽带通信(UWB)的高频段。     

An annular slot antenna on a dielectric half-space

The radiation properties of both singly and multiply fed annular slot antennas on a dielectric/air interface have been analyzed using Galerkin's method applied in the Hankel transform domain. The validity of our method has been confirmed through comparison with both theoretical and experimental results. The magic slot configuration has also been studied. The polarization diversity of this radiator makes it suitable for implementing a quasioptical balanced mixer     

应用于带有闭合金属边框手机的缝隙天线

提出了无断开(闭合)金属边框情况下平面手机天线的模型,解决了在闭合金属情况下导致的传统平面天线带宽变窄的问题.通过天线折叠技术,将其面积缩小至手机应用的尺寸内.然后,进一步的阻抗匹配使在smith圆图上将天线的阻抗带宽调到了最大,使天线能够覆盖GSM850、GSM900、DCS、PCS、UMTS 5个频段.采用开槽天线将金属边框作为天线的一部分能解决金属框对天线的影响.实测结果表明,低频部分带宽为142 MHz,高频部分带宽有480 MHz,满足了常用频段的需要.同时,为了避免发生手握的影响,金属框和地的接地点置于电路基板顶段,从而降低了手握的影响.     

Microstrip-fed printed lotus antenna for wideband wireless communication systems

A novel printed antenna, fed by a microstrip line, has been designed for wideband wireless communication systems. The new antenna shows a wide -10dB bandwidth of over 60%. In addition to being small in size, the antenna exhibits stable far-field radiation characteristics in the entire operating band with relatively high gain, low cross polarization, wide beamwidth, and good front-to-back ratio.