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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...
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...
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...
We have developed a new type of balun, called "photonic balun", to receive the balanced component of a RX antenna. Because the photonic balun is connected to a receiver through an optical fiber, we can realize an ideal antenna measurement free of unwanted effects of a coaxial cable. To demonstrate the superiority of the photonic balun in antenna measurements, we compare the vertical polarization...
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...
Traditional broadband antenna designs with compact radiating elements often explores the multiple resonant modes existing in the designed physical structure to obtain more bandwidth, or say to decrease the quality factor. It is well-known that antenna arrays could support multiple radiation modes. Recently, the modes in a coupled antenna system have been explored for MIMO and for beam-forming applications...
In this paper, a small antenna for the applications of GPS and DCS systems by utilizing the CPW feeding structure is proposed to provide the LP and CP radiation patterns. The CPW feeding structure possesses the advantages, such as low radiation loss, less dissipation, uniplanar structure without the ground plane, and easy integration with RF/microwave circuits, enabling a miniature hybrid or monolithic...
Most of the biomedical images are studied with EM (electromagnetic) wave propagating to the tissues which is buried inside the higher dielectric material. In this paper, the dipole antenna is designed for studying the biomedical imaging of tissues which is buried inside the water. Due to the material of the dipole antenna was made from coaxial cable; therefore it has waterproof capability. The scattering...
In this paper, a dual spiral antenna for ultra-wideband capsule endoscope system is proposed. Since a capsule endoscope system which transmits real-time image data in the body should have ultra-wideband characteristic, an ultra-wideband antenna is suitable for this system. When an antenna is used as capsule endoscope system, a small sized antenna is required because capsule is small enough to be swallowed...
In this paper, the behavior of the impedance bandwidth, SAR and radiation efficiency of mobile terminal antennas are studied by FDTD-based simulations at a wide frequency range, from 0.6 GHz to 6 GHz. The used models comprise a basic coupling element based antenna structure placed beside a simple dielectric block modeling the user. The results of this paper give novel information about the behavior...
This paper presents a broadband omnidirectional vertically polarized antenna of only a one eighth wavelength associated to the lowest frequency. This antenna is composed of a conical monopole with metallic parasitic elements, a capacitive disk and a dielectric substrate placed above a square ground plane. This structure provides broadband performances and omnidirectional radiation patterns over the...
In this paper, a dual-band rejected design for cross monopole antenna is proposed and experimentally studied. To achieve wide and dual-band rejected operation, the proposed antenna consists of a UWB cross monopole antenna and the small h-shaped slots, producing dual band-rejected characteristics, maintaining wideband performance, and good omnidirectional radiation pattern. Details of the results for...
A printed monopole antenna for quad-band operation in the mobile phone has been proposed and studied. The antenna occupies a volume of 24.3 x 20 x 4 mm3 with a very low height as compared to others, yet it can cover two wide bands centred at about 925 MHz and 1920 MHz to realize GSM/DCS/PCS/UMTS operation. Good radiation characteristics of the antenna over the operating bands have also been observed...
This paper proposes a T-shaped wide slot harmonic suppression antenna at the frequency of 4 GHz. Harmonic suppression is achieved by using a narrow microstrip-line-fed and a grounded T shaped conductor line. The return losses and radiation patterns of the antenna at fundamental and harmonic frequencies are measured and compared with those of the conventional T-shaped slot antenna.
In this paper, we adopted the EBG structure for the antenna substrate to achieve low profile antennas. The thin mushroom-like EBG substrates with narrow gaps were fabricated to limit the area size of the substrate to apply small equipments. The impedance and radiation pattern of a dipole antenna were measured when the antenna was closely located above the EBG substrate. It was confirmed that a dipole...
In evaluating the performance of the small antenna, one of the most important parameters is the radiation efficiency as well as the radiation power. If the input power of the antenna is measured, the radiation power can be determined by multiplying the radiation efficiency by the input power. One of the techniques for measuring the radiation efficiency is the pattern integral method which needs a...
A proposed compact PIFA antenna with small dimension suitable for 4G handsets is presented. Overall volume of this antenna is significantly small with 0.741cm3 that makes it attractive for recent modern slim personal communication handhelds. This proposed antenna is attached with a varactor diode to archive tuning frequency property that makes antenna able to covering most popular frequency bands...
Narrow frequency bandwidth antenna is a typical shortcoming for most of the communication devices. Thus, a single radiating element which able to have resonant frequencies covering from 780MHz till 3000MHz with at least VSWR of 2.5:1 is critically needed especially for a mission critical two-way portable radio. A novel patch antenna was designed to cater for this inadequacy. Using one radiating element...
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