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A novel miniaturized dipole antenna design incorporating triple sleeves and shorting load leading to enhanced bandwidth is proposed in the present work. The Triple Sleeve Dipole Antenna with Shorting Loads is designed from 500 to 3000 MHz with no tuning mechanism. The concept of triple sleeve and distributed shorting loads reduced the length of the antenna by 51.5% compared to a half wave dipole antenna at the lowest frequency. The equivalent circuit of the antenna in terms of lumped elements is determined by using a Genetic algorithm. The proposed antenna is simulated in CST Microwave Studio, fabricated, evaluated and the results are presented. The antenna can be used for trans-receive applications of wireless communications in military systems. [ABSTRACT FROM AUTHOR]

A wearable textile antenna based on the fundamental mode of an eighth-mode substrate-integrated waveguide cavity is presented for Low-Power Wide-Area Network (LPWAN) applications. The antenna operates in the UHF frequency band, at 867 MHz, and exhibits compact size, minimal manufacturing complexity and very low production cost. High isolation from the human body is observed, and a planar size reduction by more than 50% is achieved compared to similar SIW antennas in the literature. The proposed wearable antenna has been designed using CST Microwave Studio, then manufactured and tested, showing very good agreement with predicted performance. [ABSTRACT FROM AUTHOR]

In this article, a novel coupled miniaturized low-frequency wideband internal monopole antenna for UHF band is proposed. The antenna is compact, and the coupling structure with multilayer and multiline can optimize the gain bandwidth. The prototype of the proposed antenna was fabricated, tested and discussed. Simulation and measurement results reveal that the proposed antenna can provide low return loss and high gain in the UHF band (474–742 MHz). The proposed antenna with a small size of 50 × 12 × 7 mm3is suitable for today’s mobile multimedia broadcasting phones and other hand-held devices. [ABSTRACT FROM AUTHOR]

This article presents a circularly polarized (CP) flat antenna with truncated corners using the capacitively coupled feed technique for UHF RFID applications. A radiating plate, an air gap and a ground plane constitute the antenna. The reverse-arc shape truncated corners are utilized to generate a CP radiation and the suspended structure antenna using the capacitively coupled feed technique is adopted to enhancebandwidth. A prototype antenna was fabricated and its measured results were 13% for thebandwidth and 11.54% for the 3-dB axial ratio (AR) bandwidth. The half-power beamwidths of the left hand circular polarization onx–yandx–zplanes were both greater than. The measured gain on the UHF RFID system was greater than 5.90 dBic. [ABSTRACT FROM AUTHOR]

In this work, the resonant frequency of C-shaped compact microstrip antennas (CCMAs) operating at UHF band is computed by using the adaptive neuro-fuzzy inference system (ANFIS). For this purpose, 144 CCMAs with various relative dielectric constants and different physical dimensions were simulated by the XFDTD software package based on the finite-difference time domain (FDTD) method. One hundred and twenty-nine CCMAs were employed for training, while the remaining 15 CCMAs were used for testing of the ANFIS model. Average percentage error (APE) values were obtained as 0.8413% and 1.259% for training and testing, respectively. In order to demonstrate its validity and accuracy, the proposed ANFIS model was also tested over the simulation data given in the literature, and APE was obtained as 0.916%. These results show that ANFIS can be successfully used to compute the resonant frequency of CCMAs. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method for the impedance measurement of balanced UHF RFID tag antennas. The traditional method used a wire balun-connected probe to measure balanced antennas. But this technique has a system error that results from the wire balun effects. This paper presents a novel method to de-embed the wire balun effects and improve the accuracy of measurement based on algorithm. Comparing with other de-embed methods, the novel method does not need the inner structure of fixture or rely on the accuracy of modelling the measurement fixture. [ABSTRACT FROM PUBLISHER]

A novel broadband dual-loop antenna is presented for the ultra high frequency (UHF) near-field radio frequency identification (RFID) applications. Owing to the novel structure, the current distribution along the loop is kept in phase, as well as the metal terminals exert less influence on thez-orientation magnetic field. The antenna with novel terminals is described and the principle of operation is explained. A comprehensive parametric study of the new model is carried out and the results are presented and discussed in detail. To prove the novel structure, a prototype is developed and fabricated. The measurement results demonstrate that the antenna could achieve a broad bandwidth and low gain, and produce a strong magnetic field with a relatively smallz-orientation magnetic field empty hole in the near field. Hence, the work is very promising for UHF near-field RFID reader applications. [ABSTRACT FROM AUTHOR]

A novel compact design of planar circularly polarized (CP) tag antenna for UHF RFID system is proposed. By introducing the Y-shaped slit as the feed structure, the measured half-power bandwidth of the proposed CP tag antenna can be more than 135 MHz (860-1000 MFIz), which includes the entire operating bandwidth for world-wide UHF RFID system. The obtained 3 dB axial-ratio (AR) bandwidth can be about 10 MHz suitable for Taiwan UHF RFID applications. The proposed tag antenna reduces the antenna size by at least 30% since the antenna size is only 40 x 40 x &03comm². The simulated peak gain and antenna efficiency are approximately 0.4dBic and 91% for Taiwan UHF RFID band. Meanwhile, with omnidirectional reading pattern, the measured reading distance is about 7.2 m. Good tag sensitivity was obtained across the desired frequency band. [ABSTRACT FROM AUTHOR]

A novel design of planar omnidirectional tag antenna for ultra high frequency (UHF) radio frequency identification (RFID) is proposed. With the use of a square loop accompanying dual dipole strips, the measured half-power bandwidth of the proposed broadband tag antenna can reach 143 MHz (857–1000 MHz), which includes the entire operating bandwidth for worldwide UHF RFID system. Meanwhile, with omnidirectional reading pattern, the measured reading distance is about 11.0 m as it is mounted on the carton. Good tag sensitivity was obtained across the desired frequency band. [ABSTRACT FROM AUTHOR]

In this article, a novel miniature broadband omnidirectional antenna is proposed. This antenna is suitable to use in vehicles, especially in unmanned aerial vehicles, since it will be folded in order to reduce its size when the unmanned aerial vehicle lands. A special kind of wire discone antenna is chosen to achieve all desired goals. Passive broadband impedance matching at the input of the antenna improves the voltage standing-wave ratio. A telescopic fiberglass axis is used in the antenna structure in order to reduce size and increase wind resistance. The assessment of the novel structure in implementing the antenna is confirmed by experimental measurements. The measurement results reveal the preference of the new techniques over the existing approaches, showing voltage standing-wave ratio better than 2.1 and gain between −5.9 and 2 dBi in a total band of 30–500 MHz. [ABSTRACT FROM AUTHOR]

The planar dipole reader antenna using a dual polariza-tion, which consists of two dipole radiating patches and Wilkinson power divider, is presented. The electric cross dipole is added to gen-erate a symmetric radiation pattern and to compensate the high back radiation due to the shortened patches. From experimental results, the measured impedance bandwidth of the antenna (defined by --10 dB re-turn loss) is 30 MHz (907 MHz-954 MHz, Korea standard = 917 MHz-923.5 MHz). Simulated isolation between the two input ports is over 35 dB. The measured gain of the proposed antenna is stable with fre-quency. The average gain is about 6.3 dBi. [ABSTRACT FROM AUTHOR]

In this paper, a planar multi-band antenna suitable for the integration in portable terminal systems is described. The antenna operates at UHF RFID (915 MHz) and GPS-L1 (1715 MHz) frequency bands to supply chain operations and asset tracking in supply chain management. The performance of the proposed antenna is assessed through numerical and experimental tests. [ABSTRACT FROM AUTHOR]

A small-size printed loop antenna operated at its half guided wavelength (λg/2) mode as the fundamental resonant mode for achieving operation in Taiwan RFID UHF band is presented. The proposed antenna consists of a half guided wavelength loop antenna, inter-digital coupling section and a small U-shaped strip inductance structure. The proposed antenna has a simple structure of comprising shorting via of length about 118 mm to cover the Taiwan RFID UHF bands. Further, the antenna has a simple planar structure and occupies a small area of 30 × 40 mm2 on the system circuit board of the metallic object. This proposed antenna with good matched impedance, compact size, and measured maximum reading range in free-space is about 7.2 m, which can be suitable for RFID applications. Details of the proposed loop are discussed in this paper. [ABSTRACT FROM AUTHOR]

A novel UHF RFID antenna structure that can stick on metallic surface is presented. A printed H-shaped antenna by using microstrip feed structure on system ground which has the same size as antenna and operated at its halfwavelength (λ/2) mode as the fundamental resonant mode is designed. The printed H-shaped antenna generates about 925 MHz operations. Further, the proposed antenna has a simple planar structure and occupies only a small area of 13 × 66 mm2 on the system circuit board. By using the inductive property of the microstrip line with short end to match the capacitive reactance of tag chip, the performance in free space on metallic surface was measured. The matched impedance bandwidth (VSWR < 2) of the proposed antenna in free space was measured in the frequency range 830-951 MHz. The proposed antenna with good matched impedance, high direction radiation patterns, compact size, low-profile, low cost and measured reading range (5-6 m) in free-space can be suitable for UHF RFID applications. [ABSTRACT FROM AUTHOR]