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This paper presents the effect of the impedance curved surface to the characteristics of the RFID tag. The proposed passive RFID tag is placed on the elliptical curved surface. From the simulation result, it this found that the proposed RFID tag has a flat gain in the UHF RFID frequency band in Thailand. Moreover, the variation of the length and width of the elliptical surface is important effect...
Dealing with multiple antennas in various wireless devices has raised a distress of health effect. Thus, the investigation towards the relations between the electromagnetic field (EMF) radiation and human health is significant to be discovered. Hence, this paper presents the specific absorption rate (SAR) investigation on a single and 1 × 2 array of microstrip patch antenna operated at 0.8, 0.85,...
A simple circularly polarized (CP) antenna array is proposed for millimeter-wave applications. The proposed CP antenna array has a two-layer structure, which is easy for fabrication. A circular loop with a parasitic element is used as the radiation element for wideband operation. It is shown that the proposed 4×4 CP antenna array can achieve a gain of 13–16 dBi from 28.5 to 31.5 GHz.
Electrically small Huygens dipole antennas are reported that are low profile, broadside radiating, have high radiation efficiencies, and are either linear (LP) or circularly (CP) polarized. The Huygens behavior, i.e., a high front-to-back ratio with a cardioid-like pattern, is realized by exciting two (LP) or two pairs (CP) of complementary electric and magnetic dipole radiators, simultaneously having...
In this paper, a miniaturized wideband dual-polarized antenna loaded with parasitic loops and straight dipoles has been proposed for 2G/3G/4G base-station applications. Firstly, by loading four parasitic loops to the corners of regular crossed loop dipoles, a miniaturized structure and enhanced impedance bandwidth can be obtained. Then, based on the miniaturized structure, two straight dipoles are...
This paper presents a compensation of variation effect of antennas for stepped-frequency radar identification systems. The antenna effects due to the variation in the antenna response and the mutual coupling degrade the target response in the identification systems. The equation used to reduce the antenna effect is derived. The simulations are demonstrated to validate the benefit of the compensation...
A compact log periodic antenna (LPDA) is presented in this paper. In this paper, a slotted second iteration of LPDA is demonstrated for size reduction that used for UHF digital TV band application. The proposed antenna operates from 0.5GHz to 1.5GHz for the reflection coefficient ≤ −10dB and maintain the gain of more than 5dBi. The antenna is designed on FR4 Epoxy dielectric substrate with the thickness...
To determine E-field at a tip of probe for evaluating SAR (specific absorption rate) values of DUTs in saline solution, use of near-field transmit antenna factor (NF-TAF) of small dipole antenna is proposed. NF-TAF can be expressed in closed form by assuming hyperbolic sinusoidal current distribution. Also, it can be evaluated by measuring S parameters between two identical dipole antennas and dielectric...
The development of left-handed circularly polarized (LHCP) X-band printed antenna for microsatellite data communication is presented. The antenna which takes a circular shape with ellipse-shaped truncation is designed to resonate at the frequency of 8.2GHz with the minimum axial ratio bandwidth of 400MHz. The proposed antenna is deployed on a 1.6mm thick NPC-H220A dielectric substrate. The realized...
The important factors increased the efficiency of the antenna to support users in the current technology are necessary wide impedance bandwidth, high gain, and low back radiation. In this paper, the antenna composed of the curved strip electric dipole and the vertically-oriented short patch is presented. The measured impedance bandwidth of 60.9% (SWR<2) from the frequency range of 1.62–2.9 GHz...
In this paper, the size of a log-periodic dipole array antenna is reduced using partially applied folded planar helix dipole elements. The proposed antenna shows almost no gain deterioration in the entire operating bandwidth even though its size is reduced by 39 %. Due to its reduced size and lightweight characteristics, it is expected that the proposed antenna could be effectively utilized in the...
With compact folded method, a kind of folded crossed dipole ultra wideband antenna is proposed with omnidirectional radiation characteristics on the horizontal direction in this paper. The antenna is comprised of orthogonal crossed semicircular metal discs with twice 90° folded on both ends. Horizontal size is reduced obviously compared with original crossed semicircular disc antenna. This antenna...
Scattering performance of a reflectarray using a log-periodic dipole array (LPDA) element is demonstrated numerically and experimentally. The LPDA element and the reflectarray are designed using method of moments (MoM). The designed 10 × 1 reflectarray was fabricated using a 3D printing technology. A bistatic radar cross section (BRCS) of the designed reflectarray was measured in a radio anechoic...
This paper will present a series of novel polarization reconfigurable antennas for modern wireless applications. First, three multi-linear polarization reconfigurable antennas with the switchable 0°, +45°, 90° and −45° polarizations are investigated for mitigating the polarization mismatching problem in wireless biomedical applications. Three distinctive techniques were adopted to realize the same...
In this paper, a 60 GHz CMOS on-chip dipole antenna with loss-reduced silicon substrate, which had been proposed and simulated by the authors, was measured and gain improvement of approximately 9 dB was obtained. In the antenna, rectangular region with 500 μm × 1000 μm around the dipole is irradiated by proton and conductivity is reduced from 10 S/m (10 Ω cm) to 0.1 S/m (1 kΩ cm). Antenna gain of...
We present an ultra-wideband antenna for mm-wave applications. The antenna consists of a bowtie patch integrated with the feeding network. The feeding network is implemented as a multilayer substrate structure. The differential excitation of the bowtie is performed in a similar way to Magneto-Electric Dipoles and Marchand baluns. The simulated antenna shows a relative bandwidth of 2.6 : 1 with a reflection...
Integrating the concept of Antipodal Vivaldi antenna (AVA) and planar disc-shaped dipole, a half space radiation UWB antenna is proposed in this letter. The antenna adopted approximately 1/4 of the disc-shaped dipole as its radiator, fed by the AVA's exponential slot structure. The proposed antenna has an ultra-wide bandwidth and nearly half space radiation pattern. This character makes it applicable...
A simple tuning technique is proposed to regulate the input impedance of resistive antennas over ultra-wide bandwidth. The proposed tuning technique involves adding extra copper pattern near the antenna drive point. It was shown to affect the input impedances of a resistive dipole and a 12-arm resistive cross dipole over ultra-wide bandwidth. The technique was applied to the 12-arm resistive cross...
In this paper a dipole antenna is loaded with C-shaped metamaterial unit cell array. This array of metamaterial unit cells acts as a dielectric lens to focus the E-filed radiated from the dipole antenna in a particular direction. The effect of loading metamaterial layer on the dipole is studied, a gain enhancement of 5dB is observed. The predicted results were verified through measurements and it...
To design antennas for underwater communication systems using LF band, the transmission factor of dipole antennas with the sheath immersed in seawater are investigated by numerical study. Comparison of antenna characteristics between dipole antennas with different sheath structure is presented.
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