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Isolation between antennas in a multiantenna terminal plays an important role in the performance analysis of wireless systems. When comparing different methods for increasing isolation between the antennas, it is important to note that isolation depends strongly on antenna matching. The effect of matching on isolation can be removed by numerically matching two antennas simultaneously. The resulting...
This study proposes a small antenna operating in triple-band for mobile terminal equipment applications with 3-dimension (3-D) model. The first radiator, Rl, mainly contributes the region of the low frequency band, 2.40 ~ 2.48 GHz. The second radiator, R2, is used to create the region of the high frequency band, Unlicensed Nil - 5 GHz (5.12 ~ 5.35 GHz), by the conception of coupling between the two...
We developed a PIFA made of flexible printed circuit, which is available for Bluetooth and IEEE802.11a/b/g applications. We measured the characteristics of the antenna when it is folded along the coaxial cable. It is shown that the characteristics do not vary much when the angle of folding is less than 90deg. The performance is confirmed by a simulation based on the FDTD method. The antenna is expected...
In recent years, ultra-high-frequency (UHF) radio frequency identification (RFID) systems have drawn more and more attentions in a wide variety of applications such as retail item management, access control system, electronic toll collection, and etc. By incorporating with a commercial RFID reader, it has been noted that the phased array antenna can be implemented in a RFID system to either control...
Metamaterials are artificially constructed to have special electromagnetic properties not found in nature. In recent years, metamaterial is noted as a new kind of device, and the composite right/left-handed transmission lines have been proposed, which are characterized by antiparallel phase and group velocities and negative refractive index. The materials were termed as left-handed materials due to...
In this paper, three different types of frequently used antennas in passive RFID tags with different sizes are investigated for voltage scavenging application. Most critical is to create a minimum voltage at the antenna port. Therefore, using simulations with two software packages, CST and HFSS, a detailed explanation is presented of the induced voltage at the antenna port versus antenna length and...
Printed inverted-F antennas (PIFA) are very popular choice of internal antenna for cellular handsets, owing to its ease of design to achieving multiple frequency resonances. When having multiple resonating frequency structure in a single embodiment, tuning of the resonant frequency can be very tricky. Lherefore, it is desired to have frequency independent tuning of two or more separate frequencies...
Due to the low profile and the simple structure, the planar monopole antennas and the planar inverted-F antennas (PIFA) have been very attractive in the mobile handset applications. Although the planar loop antennas possess similar features, they have not been discussed extensively. Moreover, the urging requirement for multi-band operations makes the handset antenna design more and more challenging...
In this paper, the proposed small antenna, which using negative permittivity meta-material structure is designed, achieves wide Q more than calculated QL of chu limits. The equivalent circuit of proposed antenna is realized by Ansoft designer. The proposed small antenna is optimized by 3-D field simulation tool, CST MWS(micro wave studio).
In this work, approaches that aim to reduce SAR on human body were attempted. Algorithms were devised for automated antenna blockage assessment. These algorithms are used to determine the presence and location of obstacles in adjacent to a mobile device, A multi-antenna mock-up was fabricated to house several antennas at various locations on a palm-size device. According to the variation in the amount...
In this paper, the tuning and steering of a rectangular patch antenna is controlled by switching the patch and folded dipoles configuration. This reconfigurable antenna is controlled by the changing the voltage across a number of P.I.N. diodes in the parasitic elements. This antenna with the associated RF control unit forms a reconfigurable antenna which provides one solution to a number of communications...
A Vivaldi TSA array has been designed and analysed. It can operate over 4-16GHz and be capable of scanning to 50deg. This study shows that the strong mutual coupling between elements plays a constructive role in the array performance of active impedance matching. The introduction of corrugated edge to the TSA element has no effect on the active matching but the scan gains are improved. Further research...
In this paper, the miniaturization of a printed circular disc monopole antenna is investigated. It is shown that by halving the original antenna and adjusting the coplanar ground plane width, an even wider impedance bandwidth at the lower end can be obtained. Furthermore, a clear physical explanation is provided to illustrate the mechanism of this type of half circular disc antenna.
The behavior of TM leaky wave in a slotted rectangular waveguide was studied using the mode-matching and Fourier transform techniques. The formulation was expressed in a fast convergent series, which is efficient for computation. The theoretical approach based on mode-matching and Fourier transform is useful for the analysis of leaky-wave antennas composed of slotted rectangular waveguides.
It has recently been demonstrated that the loop antenna is very promising for achieving dual-band or multiband operation in the mobile phone. Although these loop antennas are mainly operated as half-wavelength and one-wavelength structures, unlike the conventional quarter-wavelength planar inverted-F antennas or low-profile monopole antennas for mobile phones, they still can be configured to occupy...
This paper presented the definition for the antenna clearance using the ratio of input impedance variation caused by the disturbance conducting wire. The clearance was discussed for 2D plane in this paper. The 3D distributions are necessary to estimate an electrical volume of the antenna which is occupied for the stable antenna resonance. The antenna volume is a key index factor to compare different...
This paper presents the development of a handset adaptive antenna using a constant modulus algorithm (CMA). The antenna is a switched-beam phased array antenna which can assist initialization of CMA. The method to improve convergence property of CMA exploits a beam with maximum received power from several switched-beams of the antenna as an initial beam. A square patch of one wavelength width provides...
In this paper, we present a novel microstrip patch antenna specifically designed using planar metamaterial patterned substrate. It is developed based on an ordinary patch antenna, and isolated triangle gaps and crossed strip-line gaps are etched on the metal patch and ground plane respectively. This patterned substrate was demonstrated in literature to have left-handed characteristics. In this way,...
The purpose of this paper is to indicate some basic properties of the Green's functions for the DNG slab materials in comparison with normal materials. It will be shown that a closed form expression can be obtained when the DNG slab has a special constitutive parameters.
A microstrip antenna (MSA) has a number of useful properties. However, its narrow bandwidth characteristic is disadvantage in applying to practical wireless systems. Some of the conventional techniques for widening bandwidth for the MSA are using thick structures, adding parasitic patches or using electromagnetically coupled feed. In this paper, we proposed a folded inverted L-shaped probe (FILP)...
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