Frequency notched ultra-wideband microstrip slot antenna with fractal tuning stub

A frequency notched ultra-wideband (UWB) microstrip slot antenna with a fractal tuning stub is proposed. The antenna is similar to a conventional microstrip slot antenna, and by introducing a fractal tuning stub, frequency notched function is achieved. The antenna was studied experimentally regarding impedance bandwidth, radiation patterns and gain. The operation bandwidth of the antenna is from 2.66 to 10.76 GHz, in which a frequency notched band from 4.95 to 5.85 GHz was achieved, along with good radiation performance over the entire frequency range.     

具有陷波功能的超宽带缝隙天线的设计与研究

提出了一种具有陷波功能与分形调谐支节的新型超宽带缝隙天线.该天线的结构类似于一般的微带缝隙天线,通过采用分形调谐支节引入半波长谐振结构,使得该天线不仅具备了超宽带缝隙天线的优点,还具备灵活可调的陷波功能.通过计算、测量和尺度放大实验,充分考察了天线的频域特性.实验结果表明该天线的工作频带为2.66～10.76 GHz,在4.95～5.85 GHz频段上具有陷波功能,同时具有相对稳定的辐射方向性和近似的全向特性.该研究对设计小型超宽带天线具有一定的价值.     

Frequency notched wide slot antenna for UWB/2.4 GHz WLAN applications

A compact frequency notched microstrip slot antenna for ultra-wideband (UWB) /2.4 GHz-band wireless local area network (WLAN) applications is proposed. The antenna is similar to a conventional microstrip slot antenna; however, by introducing a cross wide slot and a meandered-slotted stub, both compact size and frequency notched function can be achieved. It has been studied both numerically and experi- mentally for its impedance bandwidth, surface current distribution, radiation patterns, and gain. As will be seen, an operation bandwidth of over 4.61 ranging from 2.39 to 11.25 GHz for return loss lower than having a frequency notched band ranging from 4.75 to 5.85 GHz has been achieved, and good radiation performance over the entire frequency range has also been achieved.     

多用途陷波小型超宽带天线

提出了一种具有陷波特性的多用途小型超宽带微带天线。该天线类似一般的宽缝隙微带天线,但在矩形调谐支节内嵌入T形支节获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.39～12GHz的频段内驻波比小于2,其中的5.15～5.95GHz的范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

一种小型陷波多用途超宽带天线

提出了一种小型陷波多用途超宽带微带天线。该天线与一般的宽缝隙微带天线类似,通过在矩形调谐支节上开V形缝隙获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.4到11GHz频段内驻波比小于2,在5.15~5.95 GHz范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

Band-notched ultra-wideband printed open-slot antenna using variable on-ground slits

A novel modified printed ultra-wideband (UWB) slot antenna with a square structure and a trapezoid tuning stub as well as a band-notch characteristic is presented. By embedding two L-shaped slits at the edge of the open radiating slot, a tunable notched band, for avoiding interference between the UWB and WLAN systems, is achieved. Moreover, by optimising the dimensions of the polygon-like slot and tuning stub, the impedance bandwidth and matching of the antenna can be improved. The realised slot antenna operates over 2.6-13.6 GHz for VSWR < 2 and has a rejected band of 4.9-5.85 GHz.     

Improved Frequency Notched Ultrawideband Slot Antenna Using Square Ring Resonator

An improved frequency notched ultrawideband (UWB) microstrip slot antenna with a square ring resonator embedded in the tuning stub is proposed. The antenna is investigated numerically and experimentally for its impedance matching property, frequency notched characteristic and radiation performance in detail. As will be reported, compared with conventional frequency notched slot antennas, after incorporating a square ring resonator with the slot antenna's tuning stub, high, sharp band-rejection characteristic of over 20 dB is achieved, which is improved significantly.     

Controllable Band‐Notched Slot Antenna for UWB Communication Systems

We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular‐ring‐shaped tuning stub that can be deployed in ultra‐wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band‐notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L‐ and J‐shaped parasitic elements. The antenna characteristics can be modified to tune the band‐notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L‐ and J‐shaped parasitic elements also provide the band‐rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.     

Implementation and investigation of U-shaped aperture UWB antenna with dual band-notched characteristics

The design and analysis of an ultra-wideband (UWB) aperture antenna with dual band-notched characteristics are presented. The antenna consists of a circular exciting stub on the front side and a U-shaped aperture on the back ground plane. By inserting a slot and a parasitic strip to the antenna, dual notched frequency bands are achieved. A conceptual circuit model, which is based on the measured impedance of the proposed antenna, is also shown to investigate the dual band-notched characteristics. The measured impedance bandwidth defined by VSWR , 2 of 9.0 GHz (2.2?11.2 GHz), with the dual bands of 3.25?4.25 and 5.0?6.05 GHz notched, is obtained.     

Band-notched ultra-wideband circular slot antenna with inverted c-shaped parasitic strip

A novel ultra-wideband (UWB) circular slot antenna with a parasitic strip for immunity at 5.2/5.8 GHz is proposed. The antenna has an indented circular stub and an inverted C-shaped parasitic strip embedded inside the circular slot. The desired band-notched UWB operation can be obtained by choosing the size of the inverted C-shaped parasitic strip. The proposed antenna has advantages of low cost, compact size and easy design. Details of the proposed design and experimental results of the constructed antennas are presented.     

Ultra-Wideband Slot Antenna with Rejection of WLAN and ITU Bands Using Protruded Strip Resonators

In this paper, a different method for designing a new slot antenna with dual band-notched characteristic for ultra-wideband applications is presented. The proposed antenna consists of a square-ring radiating stub with an inverted T-shaped strip protruded inside the ring, a feed-line with an E-shaped strip protruded inside the rectangular slot, and a ground plane with a pair of L-shaped strips protruded inside the extra rectangular slot. In this study, by using a a pair of L-shaped strips protruded inside the slot in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced. By using this modified structure in the ground plane, the antenna provides a wide usable fractional bandwidth of more than 130 % (3.01–15.35 GHz). To generate a single band-notched function, we convert a square radiating patch to a square-ring with an inverted T-shaped strip. Finally, by adding a rectangular slot with a protruded E-shaped strip in the microstrip feed line, a dual band-notched function is achieved. The measured results reveal that the presented dual band-notched slot antenna offers a very wide bandwidth with two notched bands, covering all the 5–6 GHz wireless local area network, 8–8.5 GHz international telecommunication union bands.     

Ultra-Wideband and Uni-Directional Radiation Slot Antenna for Multi-Band Wireless Communication Applications

In this paper, a ultra-wideband slot antenna is proposed and developed for multi-band wireless communication applications. The radiating slot is fed by a microstrip line with a microstrip fork shaped tuning stub and backed by a finite metallic reflector. The frequency characteristic and radiation performance of the proposed antenna are successfully optimized and the related prototypes are fabricated and tested. The measured results show that the impedance bandwidth can cover the band from 1.85 to 6.1 GHz with return loss of better than 10 dB. The obtained patterns display a high gain and uni-directional radiation patterns within interested bands. With these features, the proposed structure is suitable for application in wireless communication systems, where a single antenna is needed to operate at multi-bands simultaneously, such as PCS (1.85–1.99 GHz), UMTS (1.92–2.17 GHz) and all WLAN bands (2.4–2.48 GHz, and IEEE802.11a WLAN applications: 5.15–5.35 and 5.725–5.825 GHz).     

Electromagnetic band gap coupled tri-notched miniaturized ultra-wideband antenna loaded with slot and parasitic strip

An electromagnetic band gap (EBG) coupled miniaturized tri-notched printed ultra-wideband (UWB) monopole microstrip antenna having dimensions of 22 mm × 26 mm × 1.6 mm loaded with a slot in radiating patch and a parasitic strip in the ground plane has been presented. The proposed structure incorporates a square-shaped metallic radiating patch with a square EBG structure adjacent to the microstrip feed line, a U-shaped meandered slot over the radiating element, and a U-shaped parasitic resonator at the ground plane beneath the radiating element, to reject the C-band satellite downlink (3.7 to 4.2 GHz), WLAN frequency band (5.15 to 5.85 GHz), and X-band satellite downlink (7.25 to 7.75 GHz) frequency bands, respectively. The designed antenna operates in the frequency range from 3 to 11.1 GHz, with an impedance bandwidth of 8.1 GHz and a percentage bandwidth of 114%. Modification steps incorporating into the reference antenna to achieve the desired design objectives have been discussed, along with parametric studies. The proposed design has been simulated using Ansys HFSS, and measurement has been taken using standard measurement technique and compared with the simulated results.     

Compact printed ultra-wideband monopole antenna with dual band-notch characteristic

A compact ultra-wideband microstrip-fed planar antenna with dual band-notch characteristic is presented. Two notched frequency bands are achieved by embedding an E-slot in the radiation patch and a U-slot defected ground structure in the feeding line. Moreover, the two notched bands can be controlled by adjusting the length of the corresponding slot. Experimental results show that the proposed antenna, with compact size of 35 x 14 mm, has an impedance bandwidth of 2.87-10.91 GHz for a voltage standing-wave ratio less than 2, except two frequency notched bands of 3.49-4.12 and 5.66-6.43 GHz.     

Compact Dual Band-Notched Monopole Antenna with Modified Radiating Patch for UWB Wireless Applications

Ultra-wideband (UWB) planar antennas with single or multiple notched frequency bands properties have recently been considered for various communications between wireless devices. In this study, a low profile microstrip monopole antenna with double band-filtering function is designed and investigated. FR-4 dielectric with properties of ε = 4.4 and δ = 0.02 has been employed as the antenna substrate. The configuration of the proposed design is composed of a modified fork-shaped radiating patch with inverted Ω-shaped slot and a pair of coupled Γ-shaped parasitic structures, a feed-line and a ground plane. The proposed dual band-notched UWB antenna provides good impedance bandwidth characteristic from 2.89 to 12.43 GHz for VSWR <2 with two notched bands which cover all the 5.2/5.8 GHz of WLAN, 3.5/5.5 GHz of WiMAX and 4-GHz of C bands ranges. The antenna provides good radiation behavior with sufficient gain levels over its operation frequency band.     

Planar circular loop antennas with self-biased magnetic film loading

A circular loop antenna with self-biased magnetic film loading at 1.7 GHz is presented. The proposed circular loop antenna is realised by cascading a microstrip loop and a tuning stub. Self-biased NiCo-ferrite magnetic films were used to tune the working frequency of the loop antenna. Three different cases of antennas with films loading were designed and analysed. Antennas with self-biased magnetic films loading working at 1.7 GHz with a tuning range of 50-400% of the antenna bandwidth were achieved.     

Design of a Compact Hexagonal Monopole Antenna for Ultra—Wideband Applications

This paper presents two design compact hexagonal monopole antennas for ultra-wideband applications. The two antennas are fed by a single microstrip line . The Zeland IE3D version 12 is employed for analysis at the frequency band of 4 to 14 GHz which has approved as a commercial UWB band. The experimental and simulation results exhibit good agreement together for antenna 1. The proposed antenna1 is able to achieve an impedance bandwidth about 111%. The proposed antenna2 is able to achieve an impedance bandwidth about (31.58%) for lower frequency and (62.54%) for upper frequency bandwidth. A simulated frequency notched band ranging from 6.05 GHz to 7.33 GHz and a measured frequency notched band ranging from 6.22 GHz to 8.99 GHz are achieved and gives one narrow band of axial ratio (1.43%). The proposed antennas can be used in wireless ultra-wideband (UWB) communications.     

Frequency Tunable Microstrip Patch Antenna Using RF MEMS Technology

A novel reconfigurable microstrip patch antenna is presented that is monolithically integrated with RF microelectromechanical systems (MEMS) capacitors for tuning the resonant frequency. Reconfigurability of the operating frequency of the microstrip patch antenna is achieved by loading it with a coplanar waveguide (CPW) stub on which variable MEMS capacitors are placed periodically. MEMS capacitors are implemented with surface micromachining technology, where a 1-mum thick aluminum structural layer is placed on a glass substrate with a capacitive gap of 1.5 mum. MEMS capacitors are electrostatically actuated with a low tuning voltage in the range of 0-11.9 V. The antenna resonant frequency can continuously be shifted from 16.05 GHz down to 15.75 GHz as the actuation voltage is increased from 0 to 11.9 V. These measurement results are in good agreement with the simulation results obtained with Ansoft HFSS. The radiation pattern is not affected from the bias voltage. This is the first monolithic frequency tunable microstrip patch antenna where a CPW stub loaded with MEMS capacitors is used as a variable load operating at low dc voltages     

一种小型的具有良好陷波特性的超宽带缝隙天线

 为了有效地抑制超宽带通信系统与窄带通信系统之间潜在的干扰,提出了一种小型的带组合陷波结构的缝隙超宽带天线.该天线采用印刷电路板上的多边形缝隙作为辐射单元,由背面的T形微带线馈电,天线的总尺寸仅为16mm×25mm×0.8mm.通过T形微带上开的一C形槽和地板上开的一矩形槽的组合陷波结构,产生阻带特性且阻带陡度更陡峭、带宽更宽,实现了良好的陷波功能.仿真和测试的结果表明,天线在超宽带系统3.1GHz~10.6GHz工作频段内的电压驻波比小于2,在5~6GHz频率范围实现了良好的滤波特性,有效地阻隔了无线局域网系统对超宽带系统的影响.同时该天线在整个工作频段具有良好的全向辐射方向特性和稳定的增益.     

一种小型的三陷波UWB天线

设计了一种小型三陷波平面超宽带天线,通过在天线的辐射贴片上加载U形缝隙、在接地板上开一对对称的L形缝隙和引入寄生条带,使得天线在3.2～3.6GHz、3.7～4.3GHz和5.3～6GHz频段内实现频率阻断。利用仿真软件研究了U形缝隙、L形缝隙和寄生条带对陷波特性的影响,并对所设计的超宽带天线进行了制作和测量。结果显示,该天线在工作频段2.8～10.6GHz内具有良好的辐射方向特性,能广泛应用于超宽带系统。