Current Issue : July - September Volume : 2017 Issue Number : 3 Articles : 5 Articles
This paper presents a broadband nanoantenna fed by a two-wire optical transmission line (OTL). The antenna is defined by a\ncombination of a dipole and a loop, where only the dipole element is connected to the OTL. The analysis is fulfilled by the linear\nmethod of moments with equivalent surface impedance to model the conductors. Firstly, the nanoantenna alone is investigated,\nwhere the input impedance, current distribution, reflection coefficient, fractional bandwidth, radiation efficiency, and radiation\npattern are analyzed.Then, the input impedance matching of this antenna with the OTL is considered. In this case the current, near\nfield distribution, radiation pattern, and reflection coefficient are calculated for different geometrical parameters. The results show\nthat the loop inserted in the circuit can increase the bandwidth up to 42% and decreases the reflection coefficient in the OTL to\nâË?â??25 dB....
A broadband vertically/horizontally (V/H) dual-polarized antenna is proposed for mobile communication base stations. The\nantenna consists of two perpendicularly placed broadband planar antenna elements. By shaping the reflector for V/H dual-polarized\nantenna, a half-power beam width of 65 Ã?± 8âË?Ë? is achieved for both vertical and horizontal polarization. The V/H dual-polarized\nantenna has a bandwidth of 48% (1.7ââ?¬â??2.75GHz) for return loss >15 dB, an isolation of 30 dB, and an antenna gain of 9 dBi. An\n8-element V/H dual-polarized antenna array is developed, which achieves a bandwidth of 45% (1.7ââ?¬â??2.7GHz) and an antenna gain\nof 16 dBi, suitable for GSM/UMTS/LTE base stations....
In this study, the principle of band suppressing an UWB antenna by attaching a small resonator is explained by developing its\nequivalent circuit.The realized UWB antenna is a conical monopole antenna that contains a split loop for band suppression. The\nconicalmonopole antenna corresponds to a transmission line terminated with load impedance, and the split loop is an LCresonator.\nThe coupling between the conicalmonopole antenna and the split loop is represented asmutual inductance. Equivalent circuits for\nthe UWB antenna suppressing single band [WLAN] and dual band [WLAN,WiMAX] have been suggested, and these equivalent\ncircuits provide insight into the performance characteristics of the developed band suppressed UWB antenna to which a small\nsized resonator is installed. Simulation and measurement results on the input impedance and VSWR of the proposed equivalent\ncircuit are closely matched.Thus, the validity of the equivalent circuit is confirmed. The measurement results demonstrate that the\nproposed antenna exhibits a gain of over 3 dBi in the working band and has an omnidirectional radiation pattern. Band rejection\nhas been also implemented by split loops....
An L-shaped dual-band multiple-input multiple-output (MIMO) rectangular dielectric\nresonator antenna (RDRA) for long term evolution (LTE) applications is proposed. The presented\nantenna can transmit and receive information independently using fundamental TE111 and higher\norder TE121 modes of the DRA. TE111 degenerate mode covers LTE band 2 (1.85ââ?¬â??1.99 GHz),\n3 (1.71ââ?¬â??1.88 GHz), and 9 (1.7499ââ?¬â??1.7849 GHz) at fr = 1.8 GHz whereas TE121 covers LTE band\n7 (2.5ââ?¬â??2.69 GHz) at fr = 2.6 GHz, respectively. An efficient design method has been used to reduce\nmutual coupling between ports by changing the effective permittivity values of DRA by introducing a\ncylindrical air-gap at an optimal position in the dielectric resonator. This air-gap along with matching\nstrips at the corners of the dielectric resonator keeps the isolation at a value more than 17 dB at both\nthe bands. The diversity performance has also been evaluated by calculating the envelope correlation\ncoefficient, diversity gain, and mean effective gain of the proposed design. MIMO performance has\nbeen evaluated by measuring the throughput of the proposed MIMO antenna. Experimental results\nsuccessfully validate the presented design methodology in this work....
We present a wearable passive UHF RFID tag based on a slotted patch antenna comprising only textile materials (e-textile, textile\nsubstrate, and conductive yearn). As a novel manufacturing approach, we realize the patch-to-ground and antenna-to-IC interfaces\nusing only conductive thread and a sewing machine. We outline the electromagnetic optimization of the antenna for body-worn\noperation through simulations and present a performance comparison between the e-textile tag and a tag produced using regular\nelectronics materials and methods. The measured results show that the textile tag achieves the electrical performance required in\npractical applications and that the slotted patch type antenna provides stable electromagnetic performance in different body-worn\nconfigurations....
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