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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 this paper, we propose a novel stacked circular microstrip antenna (C-MSA) fed by a CPW. The planar EBG structure is used to obtain broadband performance for dual operating frequencies. The bandwidth of 6.73 % and 7.55 % are obtained for the low- and high-frequency bands, respectively. Moreover, broadside radiation patterns and gains of about 8.0 dBi in average are also obtained over the both bandwidths...
An HIS with nonidentical lattices and its reflection properties are investigated and discussed. Using a linear reflection phase gradient from pi/2 to pi/2 with pi10 step with unit cell index across face, the surface can steer a reflected beam to 20.2deg in thetas. The pattern of the electromagnetic field reflected with the normally incident y-polarized wave is analyzed and experimented.
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...
In this paper, we proposed a novel design to further enhance impedance bandwidth by varying the shape of the open slot. The measured bandwidth of the proposed antenna defined by return loss >10 dB is about 130%, from 2.3 to 10.9 GHz. The proposed open slot antenna will be implemented, and the detail antenna design and experimental results are presented and discussed.
In this paper a new equivalent circuit for the EBG structure which represent the feature of surface-wave suppression is proposed. The equivalent circuit of the EBG unit cell consists of capacitors, inductors and transmission lines of series branches, as well as a capacitor and an inductor of shunt branch. These equivalent circuit parameters are based on physical implementations of EBG structures....
Slotted waveguide array antenna with no grating lobes is designed and performance is evaluated by simulation. Grating lobes are suppressed by shortening the slot spacing or the effective guided wavelength in the waveguide by using metamaterial technique. Effect to suppress the grating lobe is confirmed by simulation of radiation pattern.
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...
ISM (instrumental sensors method) is proposed in this paper for mutual coupling calibration of conformal array antennas. With the help of some instrumental sensors and some time-disjoint pilot sources in unknown directions, ISM is able to achieve a favorable mutual coupling calibration just using a one-dimensional search, with no high-dimensional nonlinear search and convergence burden involved. Monte-Carlo...
A novel compact dual-band antenna based on meander-line folded monopole is designed to cover UMTS frequency bands of I, III and VIII under the physical size constraint of 30 x 5.1 x 4 mm3 for UMTS/HSDPA-based data card applications. Good agreement between the numerical results and measured data is observed. The excellent measured gain performance at far-field chamber validates this useful design approach.
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...
In the paper, we have shown that in order to reduce influence of reflection waves, it is useful to average the radiation patterns which are measured by changing the distance between two antennas. The results using photonic balun are almost the same as those of the conventional balun. Because the presence of the coaxial cable does not affect the horizontal pattern measurements. We will apply the proposed...
MIMO systems may achieve spatial multi-user access using singular value decomposition (SVD) MIMO techniques [J.Z. Ying and K.B. Letaief, 12005; J. Kim and J.M. Cioffi, 2000]. The MIMO OFDM systems multiplex the users both in the frequency and the spatial domains. Hence, the co-channel interference caused by the sub-carrier reuse may lower the system's performance. For MIMO OFDM systems with co-channel...
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 we introduce a novel type of wide bandwidth branch-line power divider that does not require surface mount resistors, loads at the ports nor bond wires and hence it can be manufactured using traditional 2D photolithography. The circuit is implemented in microstrip technology and its BW is about 40% with a rejection below -14 dB. This divider is implemented on a corporate feeding network,...
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