Search

A low-profile broadband dual-polarized antenna with high isolation and low cross polarization is presented in this letter. The proposed antenna employs two different feeding mechanisms. On one hand, two out-of-phase probes loaded with two small circular patches make the proposed antenna operate in horizontal mode. On the other hand, two pins connecting two eyebrow-shaped patches and the ground form a magnetic loop which enables the proposed antenna to achieve vertical polarization. By elaborately adjusting the feeding structures, measurements demonstrate that the proposed antenna not only achieves 10-dB return loss bandwidths of 49% (1.7-2.8GHz) and 28% (2-2.65 GHz) for port 1 and port 2, respectively, but also maintains a high isolation better than 32 dB over the entire common frequency band. Meanwhile, within the main lobes, the cross polarization levels, both in E-plane and in H-plane, stay lower than -25 dB for port 1 and -20 dB for port 2. In addition, the proposed antenna with a profile of 0.13λ0 achieves the maximum gains of 8.4 dBi for horizontal polarization and 8.2 dBi for vertical polarization. [ABSTRACT FROM AUTHOR]

A single-layer wideband printed antenna for dual-polarized applications is proposed in this paper. Two orthogonal linear polarizations are achieved by adopting a hybrid feeding technique. The horizontal polarization is excited by an aperture-coupled microstrip feed line while the coplanar waveguide (CPW) feed line is responsible for the vertical polarization. Measurements demonstrate a fairly wide common impedance bandwidth of 56.3% (1.61-2.87GHz) with SWR ≤ 2 could be achieved. By loading a rectangular patch in the narrow rectangular slot, the isolation between two ports can be improved to better than 40 dB over the entire bandwidth. Moreover, the average gains of the proposed antenna are about 5.8 dBi and 5 dBi for port 1 and port 2, respectively. [ABSTRACT FROM AUTHOR]

A novel broadband circularly polarized antenna is presented in this letter. It consists of a triangular monopole and a slot etched on the ground plane. By employing a branched microstrip feedline to excite the monopole and the slot in parallel, the broadband circular polarization performance of the proposed antenna is realized with overall size of 38× 54 mm . The measured 3-dB axial-ratio bandwidth is 46.8% (2.13 ~ 3.43 GHz), and the impedance bandwidth for S11⩽-10 dB is 73.0% (1.99 ~ 4.28 GHz). Good agreement between the simulated and measured results is also achieved, validating our design concept. The surface current analysis and a parametric study of the design are also carried out to explain the mechanism of circular polarization. [ABSTRACT FROM AUTHOR]

In this study, a novel design of a compact multiresonator-loaded planar antenna with quad-band working properties is proposed for wireless communication. Multiresonator-loaded structures are employed, which include a pair of symmetrical edge resonators embedded into the edges of the monopole, a T-shaped stub resonator extended from the ground and an inverted Ushaped narrow slot resonator etched on the T-shaped stub. By loading these resonators, a modified U-shaped monopole antenna can easily produce four separate working bands while achieving a very compact size of 18 × 20 mm². Based on this concept, a prototype of quad-band antenna is designed, fabricated and tested. The measured results demonstrate that the proposed antenna is capable of operating over the frequency ranges, 2.39-2.49, 3.37-4.06, 4.73-5.46 and 5.69-6.31 GHz, suitable for wireless local area network 2.4/5.2/5.8 GHz and worldwide interoperability for microwave access 3.5 GHz applications. [ABSTRACT FROM AUTHOR]

A new wideband magneto-electric dipole antenna using coplanar waveguide (CPW) structure is proposed in this paper. The proposed antenna consists of a pair of horizontal triangular patches and two vertically oriented L-shaped strips. By introducing triangular patches working as an electric dipole, the antenna can operate in a wide band. With the use of L-shaped strips equivalent to a magnetic dipole, the antenna is low in profile. A microstrip feed line is located between the two L-shaped strips to form a coplanar waveguide structure and excite the antenna. By carefully adjusting the gap between the feed line and the strips, the impedance bandwidth can be improved largely. A parametric study is performed to provide information for designing and optimizing such an antenna. A prototype is fabricated and measured. The simulated and measured results show that the impedance bandwidth for SWR less than 2 of the proposed antenna is 58.7% (1.95-3.57GHz). Due to the complementary nature of the antenna, the proposed antenna has a unidirectional radiation pattern with low-polarization and low back-lobe radiation over the whole operating band. Furthermore, the gain of the antenna is stable across the entire bandwidth. [ABSTRACT FROM AUTHOR]

In this study, a novel dual band-notched ultra-wideband (UWB) antenna has been proposed and discussed. The proposed antenna is fed by a microstrip line and in the square-etched radiation patch a T-shape parasitic stub is attached. On the other hand, a pair of parasitic parallel micro-strip lines are also added on the ground plane, one of which is shorted to the radiation patch by a short-pin through dielectric substrate. The two parasitic units are to achieve band-notched characteristics at 3.3-3.7GHz and 5.15-5.85GHz, respectively. In order to realize impedance matching over the ultra-wideband, two arc-shape cuts are made symmetrically at the junction of feed-line and radiation patch. The simulated and measured results, including return loss, radiation pattern, group-delay and peak gains are in good agreement with theory analysis which validates our design concept. [ABSTRACT FROM AUTHOR]

A new design of broadband circularly polarized antenna is proposed. The antenna is composed of a square patch and a horizontal L-shaped stripline that feeds the patch at two orthogonal directions by two probes. The L-shaped feeding structure provides excitements of approximately equal amplitude and 90° phase difference and then good circularly polarized characteristics are obtained. Measured results show that the proposed antenna has 10-dB impedance bandwidth of 14.3% (2.27-2.62 GHz) and 3-dB axial-ratio bandwidth of 13.1% (2.3 -2.62 GHz). Moreover, the measured gain is over 7 dBic within the effective band. [ABSTRACT FROM AUTHOR]

A novel inductively loaded monopole for future ultra-wide-band (UWB) applications is presented. The antenna is compact and of small size (16mm x 20mm x 0.8 mm), and offer a very simple geometry suitable for low cost fabrication and straight forward printed circuit board integration. More specifically, the impedance matching of the classic printed inductively loaded monopole is improved by employment of the tapered microstrip feed line between K-connector and the printed monopole. By using this technique, impedance bandwidth (S11 < -10 dB) from 3.03 GHz to over 40 GHz is obtained. Measured and simulated return loss curves are provided along with radiation patterns and gains, as a function of frequency. Compared to the recently reported UWB antennas, the presented antenna have smallest size, widest bandwidth, and simple configuration to realize the application in UWB communication systems. Furthermore, symmetric radiation patterns and satisfactory gains make the presented antenna a suitable candidate for practical UWB applications. [ABSTRACT FROM AUTHOR]

A novel open slot antenna with a T-shaped stub for bandwidth enhancement is presented. By attaching a T-shaped stub to the rectangular radiating patch, the bandwidth enhancement of the proposed antenna is achieved well. From experimental results, the measured impedance bandwidth of the proposed antenna can reach an operating bandwidth of about 131% over a wideband frequency range from 2.3 to 11.1 GHz, which makes it an excellent candidate for the WLAN (2.4/5 GHz) and UWB (3.1–10.6 GHz) applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 390–393, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24929 [ABSTRACT FROM AUTHOR]

The aggressive space mapping (ASM) algorithm is applied to the optimization design of LTCC filters. The partial element equivalent circuit (PEEC) method is utilized as a coarse model. Low-pass and band-pass LTCC filters are designed with HFSS and IE3D adopted as the fine models, respectively. Conductor thickness is taken into account, since it is fairly large with respect to dielectric height. Only a few instances of fine-model simulation are needed. [ABSTRACT FROM AUTHOR]

A coplanar waveguide-fed asymmetrical slot antenna with a rectangular patch for bandwidth enhancement is demonstrated.By attaching a rectangular patch to the monopole radiating element, a good performance of bandwidth enhancement for the antenna is achieved. From simulational and experimental results, the enhanced impedance bandwidth of the proposed antenna, defined by -10 dB return loss, can reach 13.1 GHz, from 2.4 to 15.5 GHz, or about 146% with the center frequency 8.95 GHz, which makes it an excellent candidate for the ultra wideband (UWB, 3.1–10.6 GHz) applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2259–2261, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25476 [ABSTRACT FROM AUTHOR]

In this paper, a special circular-disk microstrip antenna is discussed, and the cavity-mode solution is given. The influence of the shorting pin on the resonance frequency is discussed, and a formula for the approximate calculation of k is presented. The results of simulation using Ansoft's HFSS and calculations of the main mode are presented through several design examples, and the results were a good fit. The results showed that this novel method is particularly applicable to the design of feeds for double-deck or multilayer microstrip antennas. [ABSTRACT FROM AUTHOR]

In this article, a printed flame-shaped monopole antenna with a self-similar slot for wideband application has been presented and investigated. The wideband characteristic is easily achieved by inserting a self-similar slot in the flame-shaped radiator. The effect of the slot is investigated. We discover that the slot can be effectively used for bandwidth enhancement, while the position of the slot has a negligible effect on the performance of the proposed antenna. Experimental results show that the proposed antenna obtains a bandwidth from 2.65 to over 12 GHz with VSWR < 2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 95–97, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24873 [ABSTRACT FROM AUTHOR]