A broad-band rectangular patch antenna with a pair of wide slits

A new broad-band design of a probe-fed rectangular patch antenna with a pair of wide slits is proposed and experimentally studied. The proposed design is with an air substrate, and experimental results show that, simply by inserting a pair of wide slits at one of the radiating edges of the rectangular patch, good impedance matching over a wide bandwidth can easily be achieved for the proposed antenna. With an air substrate of thickness about 8% of the wavelength of the center operating frequency, the proposed antenna can have an impedance bandwidth of about 24%. For frequencies within the impedance bandwidth, good radiation characteristics are also observed, with a peak antenna gain of about 7.2 dBi     

基于慢波基片集成波导的X波段功分器设计

针对传统基片集成波导（substrate integrated waveguide,SIW）功分器设计中宽带化和小型化不易兼顾的问题,提出了一种基于慢波SIW（slow-wave SIW, SW-SIW）的功分器. 采用微带折线构成的慢波结构单元加载于SIW金属表面上,代替传统SIW连续的金属表面,与同尺寸的SIW相比,SW-SIW的截止频率下降了40%,能够实现横向尺寸的缩减,尤其当SW-SIW达到与SIW相同的相移量时,SW-SIW所需纵向尺寸更小. 所提出的基于SW-SIW的功分器在具有较宽带宽的同时实现了器件尺寸的减小. 通过测试结果可得,该功分器在8.25～12.8 GHz频带内的反射系数|S₁₁|相似文献   

On artificial magnetodielectric loading for improving the impedance bandwidth properties of microstrip antennas

The effect of artificial magnetodielectric substrates on the impedance bandwidth properties of microstrip antennas is discussed. We review the results found in the literature and then focus on practically realizable artificial magnetic media operating in the microwave regime. Next, a realistic dispersive behavior of a practically realizable artificial substrate is embedded into the model. It is shown that frequency dispersion of the substrate plays a very important role in the impedance bandwidth characteristics of the loaded antenna. The impedance bandwidths of reduced size patch antennas loaded with dispersive magnetodielectric substrates and high-permittivity substrates are compared. It is shown that unlike substrates with dispersion-free permeability, practically realizable artificial substrates with dispersive magnetic permeability are not advantageous in antenna miniaturization. This conclusion is experimentally validated.     

Design and performance of an ultrawide-band ceramic-loaded slot spiral

The miniaturization of a broadband square slot spiral antenna is proposed using high-contrast (/spl epsiv//sub r/>30) dielectric materials. A previously developed circular slot spiral antenna is the starting point of the design. This spiral is first modified in terms of its feed and termination to facilitate the dielectric loading of the antenna by means of a superstrate. The subsequently placed superstrate is also modified by tapering its thickness to improve impedance matching. Several measurements were carried out using square spiral apertures having diameters of 2' and 6', respectively. It is demonstrated that the ceramic loading of a 2' spiral with an /spl epsiv//sub r/=90 shifts the initial operating frequency by nearly 320 MHz down to 564 MHz representing a size reduction of 36%. Additionally, a 6' aperture loaded with a superstrate having /spl epsiv//sub r/=30 is shown to operate down to 270 MHz corresponding to a size reduction of 18%.     

Antenna miniaturization and bandwidth enhancement using a reactive impedance substrate

The concept of a novel reactive impedance surface (RIS) as a substrate for planar antennas, that can miniaturize the size and significantly enhance both the bandwidth and the radiation characteristics of an antenna is introduced. Using the exact image formulation for the fields of elementary sources above impedance surfaces, it is shown that a purely reactive impedance plane with a specific surface reactance can minimize the interaction between the elementary source and its image in the RIS substrate. An RIS can be tuned anywhere between perfectly electric and magnetic conductor (PEC and PMC) surfaces offering a property to achieve the optimal bandwidth and miniaturization factor. It is demonstrated that RIS can provide performance superior to PMC when used as substrate for antennas. The RIS substrate is designed utilizing two-dimensional periodic printed metallic patches on a metal-backed high dielectric material. A simplified circuit model describing the physical phenomenon of the periodic surface is developed for simple analysis and design of the RIS substrate. Also a finite-difference time-domain (FDTD) full-wave analysis in conjunction with periodic boundary conditions and perfectly matched layer walls is applied to provide comprehensive study and analysis of complex antennas on such substrates. Examples of different planar antennas including dipole and patch antennas on RIS are considered, and their characteristics are compared with those obtained from the same antennas over PEC and PMC. The simulations compare very well with measured results obtained from a prototype /spl lambda//10 miniaturized patch antenna fabricated on an RIS substrate. This antenna shows measured relative bandwidth, gain, and radiation efficiency of BW=6.7, G=4.5 dBi, and e/sub r/=90, respectively, which constitutes the highest bandwidth, gain, and efficiency for such a small size thin planar antenna.     

一种二叉树状分形偶极子天线的设计

提出了一种基于二叉树状分形结构的分形偶极子贴片天线。该天线的介质基片采用相对介电常数为4.4,介电损耗角正切为0.02的FR4介质板,由微带线经阻抗变换后进行馈电。该天线利用分形技术实现了33%的尺寸缩减;通过平行双线结构和开U型槽技术,优化了阻抗匹配,降低了天线的谐振频率。通过仿真分析与模型优化,天线的最终尺寸为35 mm×22 mm×1.6 mm,中心工作频率为2.87 GHz,工作频率为2.77~2.97 GHz,-10 dB阻抗相对带宽为6.9%,工作频带内最小回波损耗可达-49 dB,最大增益可达2.36 dB。该天线具有小型化、阻抗匹配良好的优点,在当代小型化通信系统中具有良好的应用前景。     

60-GHz Patch Antennas and Arrays on LTCC With Embedded-Cavity Substrates

The design is presented of aperture-coupled microstrip line-fed patch antennas (ACMPAs) and 4$,times,$ 4 planar arrays on Ferro A6-S low-temperature cofired ceramic (LTCC) substrate operating in the 60-GHz frequency band. In addition to the traditional ACMPA design, air cavities processed inside the LTCC substrate are used to improve the bandwidth and gain of the antennas. The arrays are excited through the microstrip-line feed networks using quarter-wave matched T-junctions and using Wilkinson power dividers. The results show that ACMPAs and arrays can be fabricated with a standard LTCC process even for the millimeter-wave region. Good agreement is achieved between simulations and measurements. The measured S-parameters indicate impedance bandwidths of 9.5% and 5.8% for the array elements with and without an embedded cavity. The measured maximum gains for the 16-element patch arrays (with and without cavity) are 18.2 and 15.7 dBi, respectively.      

小型化缝隙加载圆极化及宽带微带贴片天线设计

提出了一种十字形缝隙加载的小型宽带及圆极化微带贴片天线的设计方法。该天线通过在方形贴片上加载一个大尺寸的十字形缝隙实现天线的尺寸缩减,介质基片采用由FR4和空气层组成的层叠结构,在缝隙中嵌入L型枝节,只需通过调整枝节上同轴线馈电点的位置来获得圆极化或宽带阻抗匹配。ANSYS HFSS仿真分析表明,天线的圆极化带宽（AR≤3 dB）为1.7%,阻抗带宽（VSWR≤2）为5.8%,天线在宽带范围内具有稳定的增益,峰值增益为7.8 dB,同时贴片面积缩减了52.3%。改变馈电点的位置可调节两个谐振频率使天线阻抗带宽达到9.4%,比传统的微带贴片天线阻抗带宽提高了114%。     

Miniaturized Trapezoidal Patch Antenna with Folded Ramp-Shaped Feed for Ultra-Wideband Applications

A novel design for compact probe-fed wideband microstrip patch antenna for ultra-wideband (UWB) applications is proposed in this paper. The antenna consists of a folded ramp-shaped feed, trapezoidal patch and shorting pins. By adding two pins at end side of the patch, its size is miniaturized. The measured impedance bandwidth (VSWR  $\le $  2) of fabricated antenna is more than 130 % from 3.7 to 17.6 GHz. This antenna achieves an acceptable miniaturization and provides an excellent UWB impedance bandwidth with stable radiation patterns. It is shown by simulated results how the bandwidth can be considerably increased by introducing novel feeding method namely, the folded ramp-shaped feed. Likewise, the parametric study is performed to describe the characteristics of the proposed antenna. Moreover, good antenna performances such as radiation patterns, acceptable miniaturization and antenna gains over the operating band have been observed.     

一种小型化北斗导航终端圆极化天线的设计

设计了一款单馈电的小型圆极化微带天线。在方形贴片上,通过切角和对称开槽的方法,天线获得了良好的右旋圆极化性能,并实现了小型化设计。借助HFSS电磁仿真软件,对天线参数进行了仿真和分析。仿真结果表明,S11＜-10 dB的阻抗带宽为82 MHz,3 dB圆极化轴比带宽为12 MHz,较好地满足了北斗接收天线的设计要求。该设计具有方法简单、易于实现、成本较低等优点,且具有良好的应用前景。     

一种新型LTCC天线的设计

通过分析Meander-line天线技术理论及LTCC天线结构理论,并结合返折理论技术,将返折Meander-line理论技术应用于LTCC天线。最终通过理论分析与仿真优化,设计了本天线单元,尺寸为18mm×3.8mm×1.2mm的天线模块。仿真结果显示,该天线具有较好的抗阻特性、较高的隔离度、良好的交叉极化比和较为稳定的方向图和增益。     

Planar elliptical antenna for ultra-wideband communications

A printed planar elliptic patch, juxtaposed with the ground pattern in a single substrate, providing an ultra-wideband impedance bandwidth, is presented. The ultra-wideband property for the proposed antenna is achieved by using a new impedance-matching technique of cutting a notch in the ground pattern opposite the microstrip line. The concavity of the ground pattern serves as an effective means of adjusting the gap between the radiating element and the ground plane. With suitable size of notch chosen, the impedance bandwidth of the proposed antenna can be enhanced. Details of the proposed antenna design and measured results are presented and discussed.     

A wide-band, circularly polarized, magnetodielectric resonator antenna

Previously insurmountable challenges posed by stringent requirements of simultaneous compact size, high bandwidth, high to moderate efficiency, and circular polarization operation at UHF have been surpassed by a unique design employing layered magnetodielectric materials. To achieve percentage bandwidth values in excess of 50% for an antenna with a maximum dimension of 0.15/spl lambda/ three approaches for bandwidth enhancement are combined in a proper fashion. A volumetric source, as opposed to printed planar or wire sources, inherently provides higher bandwidth and is used as the fundamental radiating element of the antenna. The radiating structure is made up of layered magnetodielectric material with proper design of permittivity and permeability values forming a magnetodielectric resonator antenna (MDRA). Noting that miniaturization and wave impedance in the MDRA are, respectively, proportional to the square-root of the product and ratio of the permeability and permittivity, moderate values of permittivity and permeability are used to enhance the bandwidth while achieving considerable miniaturization. The third method for bandwidth enhancement is based on the integration of a resonant feed and many parasitic elements into the MDRA structure. Square symmetry of the MDRA is used to obtain circular polarization operation. A prototype small UHF antenna operating over 240-420 MHz with a linear dimension smaller than 0.15/spl lambda/ at the lowest frequency is fabricated and tested; the results are summarized in this paper.     

小型高带外抑制超宽带滤波器设计

为了提高滤波器的带外噪声抑制,并兼顾小型化,提出了一种新型超宽带滤波器设计。首先,利用分路电磁耦合结构在通带两侧实现了2个传输零点,通过调节中间金属片与螺旋缺陷地可实现对2个零点的单独调节,由此实现了高带外抑制,且有利于滤波器的小型化;然后,利用基片集成波导与周期性缺陷地结构,在进一步提高频率选择性的同时,实现了较好的阻带性能;最后,设计并加工了一款工作频率为8.1 GHz、带宽为67%的滤波器。结果表明,仿真与测试结果吻合良好,证明了该设计方法的可靠性。     

一种寄生阵列宽带圆极化天线的设计

该文设计了一款C波段单馈寄生阵列的宽带圆极化天线。此天线采用紧邻的双层F4B介质基板,通过在方形驱动贴片上开槽及采用寄生阵列的设计实现了圆极化。对天线结构的设计步骤进行说明,研究了各结构对天线阻抗带宽和轴比带宽的影响,并研究了寄生贴片切角长度和驱动贴片上的缝隙宽度对天线轴比和带宽的影响。对天线的圆极化方向图进行了仿真。仿真结果表明,在5.5 GHz时实现了右旋圆极化,最大增益为8.1 dBi。加工并测试了宽带圆极化天线,测试结果与仿真结果基本相符,天线实测的阻抗带宽为1.3 GHz,轴比带宽为1.26 GHz。设计的叠层天线具有结构紧凑,装配简单和轴比带宽大的优点。     

Results on low-loss wideband ultrasonic transducers for non-invasive medical application

A new design for disc transducers with good efficiency and large bandwidth is presented here. The design method is based on the use of quarter-wave matching layers between the piezoelectric ceramic and the load, and the use of a quarter-wave unmatching layer between the same ceramic and its high acoustic impedance backing. Experimental and theoretical results are presented.     

A microstrip array feed for land mobile satellite reflectorantennas

A circularly polarized feed array for a spacecraft reflector antenna is described that was constructed by using linearly polarized microstrip elements. The array has seven subarrays which form a single cluster as part of a large overlapping cluster reflector feed array. Each of the seven subarrays consists of four linearly polarized microstrip elements. The array achieved a better than 0.8-dB axial ratio at the array pattern peak and better then 3 dB antenna gain to 20° from the peak, across a 7.5% frequency bandwidth. A teardrop-shaped feed probe was used to achieve wideband input impedance matching for the relatively thick microstrip substrate. The low impedance and axial ratio bandwidths were achieved using a relatively thick honeycomb substrate with the impedance-matching feed probes     

RFID Tag Antenna Coupled by Shorted Microstrip Line for Metallic Surfaces

This letter presents the design of a small and low‐profile RFID tag antenna in the UHF band that can be mounted on metallic objects. The designed tag antenna, which uses a ceramic material as a substrate, consists of a radiating patch and a microstrip line with two shorting pins for a proximity‐coupled feeding structure. Using this structure, impedance matching can be simply obtained between the antenna and tag chip without a matching network. The fractional impedance bandwidth for S₁₁<3 dB and radiation efficiency are about 1.4% and 56% at 911 MHz, respectively. The read range is approximately from 5 m to 6 m when the tag antenna is mounted on a metallic surface.     

Integrated circuit ceramic ball grid array package antenna

The recent advances in such highly integrated RF transceivers as radio system-on-chip and radio system-in-package have called for the parallel development of compact and efficient antennas. This paper addresses the development of a new type of dielectric chip antenna known as integrated circuit package antenna (ICPA) for highly integrated RF transceivers. A compact ICPA of this type has, for the first time, been designed and fabricated in a ceramic ball grid array (CBGA) package format. The novel ICPA, except economical advantage of mass production and automatic assembly, has potential benefit to the system-level board miniaturization and the system-level manufacturing facilitation. The simulated and measured antenna performance of the ICPA is presented. The effects of the different physical parts of the ICPA on the antenna performance are investigated. Results show that the ICPA achieved impedance bandwidth of 4.1% and radiation efficiency of 72%, and gain of 4.8 dBi at 5.715 GHz.     

一种宽带WLAN贴片天线

文中提出了一种单馈的宽带贴片天线应用于无线局域网络通信。该天线由方形贴片、电抗性阻抗表面以及电磁带隙结构组成。文中提出同时加载电抗性阻抗表面和电磁带隙结构能够实现小型化以及宽带化。电抗性阻抗表面作为接地平面能够降低天线的谐振频率。电磁带隙结构能够提高天线的阻抗带宽。测试结果表明所提出的WLAN贴片天线的相对带宽为22.3%(S₁₁=-10 dB),覆盖4.77～5.97 GHz,可以获得6.3～7.2 dBi增益。与现有宽带小型化天线相比,该天线在保证宽带小型化的前提下仍具有较高增益,且辐射性能具有较高的一致性,十分有利于其应用。该天线能够覆盖IEEE 802.11a标准所规定的5 GHz频段,能够实现无线局域网之间的高速数传。