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A textile artificial magnetic conductor (AMC) waveguide sheet with a textile diamond dipole is proposed to improve wireless on‐body transmission. The sheet‐like waveguide provides an independent transmission path which can reduce the performance degradation caused by the human body. The proposed AMC sheet is made entirely of textiles for both the substrate and the conducting parts, thus making it suitable for wearable communications. Transmission characteristics between antennas are studied rigorously in free space and on‐body environments. Significant transmission enhancement is observed for all the tested orientations and positions for both free space and on‐body placements. With the presence of the AMC, the S21 has peaks of up to a maximum of −9.9 dB. This textile AMC sheet constitutes a new approach for efficient wearable wireless body‐centric communications. [ABSTRACT FROM AUTHOR]

A textile artificial magnetic conductor (AMC) waveguide sheet with a textile diamond dipole is proposed to improve wireless on-body transmission. The sheet-like waveguide provides an independent transmission path which can reduce the performance degradation caused by the human body. The proposed AMC sheet is made entirely of textiles for both the substrate and the conducting parts, thus making it suitable for wearable communications. Transmission characteristics between antennas are studied rigorously in free space and on-body environments. Significant transmission enhancement is observed for all the tested orientations and positions for both free space and onbody placements. With the presence of the AMC, the S21 has peaks of up to a maximum of -9.9 dB. This textile AMC sheet constitutes a new approach for efficient wearable wireless body-centric communications. [ABSTRACT FROM AUTHOR]

Wideband-multiband reconfigurable elliptical monopole antenna is investigated in this paper. By having conventional elliptical monopole antenna, wideband operating frequency is obtained. With the combination of dual pairs of slotted arms and a band-pass filter on the ground plane of the elliptical monopole, multiband is achieved. Dual-band operating frequencies at 1.6 GHz and 2.6 GHz while wideband operates from 3.35 GHz to 9 GHz. Therefore, wide range of wireless communication systems is obtained from the proposed antenna to support the multiband mode (i.e. GPS and LTE) and UWB systems. Frequency reconfigurable is achieved by controlling the switches integrated on the antenna structure. Simulated results of reflection coefficient, radiation patterns and gain performance are presented. The proposed antenna design is suitable candidate for different wireless communication applications. [ABSTRACT FROM AUTHOR]

ABSTRACT A wideband antenna fed by a coplanar waveguide (CPW) with reconfigurable function is presented. The wideband function is achieved from 1.39 GHz to 8.11 GHz using an elliptical radiator with a CPW feed line. Meanwhile, three pairs of slot dipoles which are fed by CPW are used to achieve triple-band function at 2.4 GHz, 3.5 GHz and 5.2 GHz. Four ideal switches are placed on the proposed antenna. The proposed antenna is designed, simulated, fabricated and tested. All simulated and measured results of return loss, radiation pattern and gain are presented. Good results of return loss and radiation pattern are obtained thus verifying that the proposed antenna is suitable for future multimode radio systems. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2079-2082, 2016 [ABSTRACT FROM AUTHOR]

This paper proposes a flexible compact bowtie antenna for medical application that operates at 2.45 GHz. The proposed antennas are miniaturized using meander technique. Both substrates and conducting material of the antenna are made of flexible material semi-transparent film as the substrate and shieldit fabric as the conducting material which suitable for wearable and on body application. The results show that the total length of the antenna is significantly reduced by up to 38%. However, the gain of the antenna is slightly decreased when the size of the antenna become smaller. The results of this research could provide guidance and has significant implication for future development of wearable electronics especially in medical monitoring application. [ABSTRACT FROM AUTHOR]

A novel of wideband circular polarization (CP) antenna with high gain that is suitable to harvest energy is proposed. In this article, our objective is to design an antenna that is capable of fully harvesting ambient RF energy. A survey on the feasibility of scavenging for RF energy was conducted through power density measurement in an urban area. Using the results, a CP antenna was designed to cover the frequency band from the largest RF contributors, ranging from 1.73 to 2.61 GHz in GSM1800, UMTS, WiMAX and the unlicensed industrial, scientific, and medical (ISM) bands. Hence, a simple single feed electromagnetic (EM) coupled circularly polarized antenna with high gain is presented. The wideband CP is achieved by implementing EM coupled feed with a defected ground plane structure. Experimental results showed the antenna achieved an axial ratio bandwidth of 25% with respect to 2.08 GHz center frequency. Furthermore, the antenna exhibits broad impedance bandwidth of 32.77% with the measured peak gain is 8.7 dBic at 2.05 GHz. The proposed antenna structure is simple and low cost with a size of 0.462 λo and wide 22.1% axial ratio bandwidth. [ABSTRACT FROM AUTHOR]

Artificial Magnetic Conductor (AMC) is a type of implemented metamaterial in several antennae and microwave design applications. By utilizing the unique characteristics of metamaterials which do not exist naturally, the performance of various microwave devices can be enhanced. This article elaborates on the technical perspective and recent works on AMC for antenna applications. The technical perspective discusses the theoretical aspects, simulation design procedures, and the measurement setup used to characterize the AMC unit cell. Subsequently, various recent works of antenna design that involve the incorporation of AMC are discussed thoroughly. Each of the recent works is highlighted with specific performance enhancements that can be achieved with the introduction of AMC. The conventionally narrow band property of AMC, which is the bandwidth at which the radiation characteristics and directivity of the antenna can be manipulated, is discussed. The property limits the applications of AMC in wideband antenna applications. One of the techniques to improve the narrow band AMC as the ground plane is discussed in detail. The employment of AMC has solved many issues whilst overcoming the typical limitations in conventional antenna designs. [ABSTRACT FROM AUTHOR]

A coplanar waveguide (CPW) ultra-wideband (UWB) antenna incorporated with metamaterial-split ring resonator structure-that operates from 3.0 to 12.0 GHz is proposed for chipless RFID tag. The 30 mm × 40 mm flexible chipless RFID tag is designed on the fleece substrate ( ε = 1.35, thickness = 1 mm and tan $$ \delta $$ = 0.025). A six-slotted modified complementary split ring resonator (MCSRR) is introduced into the ultra-wideband antenna to produce multiple band notches at 3.0, 4.0, 5.0, 6.0 and 7.0 GHz. The frequency shifting technique is introduced for designing a high-capacity chipless RFID tag with compact size. Each MCSRR is able to code in four different allocations (00, 01, 10 and 11). To achieve encoding of 10-bits data (10,234 number), six MCSRRs are proposed with three-slotted MCSRR in the radiator and three-slotted MCSRR in the ground plane. [ABSTRACT FROM AUTHOR]

A new zero-index metasurface (ZIM) structure is proposed to improve the bandwidth and gain of the microstrip patch antenna. A single-sided 8 × 8 set of metasurface elements is embedded over the radiating patch to enhance the performance of a coaxial probe fed slotted circular patch antenna. The proposed ZIM cover-assimilated antenna were designed on a high permittivity ( ε r = 15 ) ceramic-filled bio-plastic sandwich structured dielectric substrate and fabricated for experimental verification of the performance characteristics. A significant improvement of bandwidths and gains of the proposed antenna were observed by incorporating the metasurface cover over the radiating patch with the gap of 10 mm. The experimental results showed that the bandwidths of the proposed metasurface-covered antenna widened by 54.5%, 68.5% and 61.1% and gains also improved by 133.40%, 73.30% and 72.06% at three resonant frequencies, namely, 3.7 GHz, 8.95 GHz and 10.3 GHz, respectively, compared to the patch alone. The performance characteristics of the proposed ZIM cover-incorporated antenna make it suitable for ultra-wideband (3.4–4 GHz, 6.45–8.2 GHz and 10.0–10.9 GHz) applications. [ABSTRACT FROM AUTHOR]

Graphene is a unique material that can display tuning characteristics. This characteristic originates from its surface complex conductivity, which is controlled by a chemical potential. Most characteristics of tunable graphene antenna have been studied on Terahertz frequency range, thus making it difficult to be realised practically. Besides that, the standard antenna that uses switching components may have trouble during installation, and consume size as can be seen in the reconfigurable antenna. With the integration of this material, a tunable antenna based on graphene operating at microwave frequency range is proposed. The antenna was designed and fabricated at 15 GHz with a gate electrode placed behind it. They are connected to external DC bias during the measurement. The biasing is applied from 0 V to 30 V. The result shows that resonance frequency tuned about 20 MHz and reflection coefficient magnitude improved 1.24 dB. Following this, an analytical calculation on chemical potential was also derived for enhancing the graphene tunability. The count shows that at least 2.85 kV of the gate voltage is needed to vary the chemical potential and less than 0.26 µm of dielectric spacer thickness is suitable for tuning with a given condition, respectively. [ABSTRACT FROM AUTHOR]