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In this paper, a dual-reflectarray antenna is proposed to generate a contoured beam for a DBS European coverage. The antenna optics is based on a compact range dual-reflector antenna, which produces low crosspolar radiation. The phase distribution of the subreflectarray is defined to simulate an equivalent hyperbolic subreflector with negative eccentricity. The phase distribution on the main reflectarray...
A wideband perforated rectangular dielectric resonator antenna (RDRA) reflectarray is presented. The array of RDRA are formed from one piece of material. Air-filled holes are drilled into the material around the RDRA. This technique of fabricating RDRA reflectarray using perforations eliminates the need to position and bond individual elements in the reflectarray and makes the fabrication of the RDRA...
Temperature rise induced by 2.45 and 3.7 GHz inverted-F antennas were studied in an anatomical human head model. These antennas were integrated in a 100 mm by 40 mm by 10 mm metal box. Using an FDTD simulation tool different orientations and separation distances of 2.45 and 3.7 GHz handset antennas were investigated for maximum temperature rise inside the head model. Temperature rise profile with...
The structural optimization is presented for a coaxial line applicator for the liver cancer thermotherapy. Currently used applicators are slot type antennas made from commercially available semi rigid cables, therefore the impedance matching between an applicator and a heated liver is not ensured. A novel applicator structure is presented by introducing the impedance matching sections between the...
Metallic implants placed in a uniform magnetic field of an MRI system generate a magnetic field disturbance. In this paper two paramagnetic material rectangular bars were exposed to a 0.31T static magnetic field of an MRI dedicated system, and the magnetic field disturbance was analyzed. Measurement results were compared with CST EM Studio simulations to confirm the accuracy of the numerical tool...
A new ultra wide band TEM horn antenna for near-field microwave imaging of tissue is proposed. The antenna is filled with solid dielectric medium and is isolated from all sides, except the front aperture, with copper sheets. It couples all of its energy into the tissue. The impedance match of the antenna is satisfactory within the ultra wideband frequency range. The antenna has no parasitic radiation...
A stent is a metallic structure with meshes used to treat arteries blocked by plaque. The stent's role is to restore physiologic flow conditions and vascular health. Over-expansion or under-expansion of the stent during implantation in the artery can have serious health risks; thus having a real-time and non-invasive measure of size of stent during implantation is important. In this paper, we propose...
A new broadband monolithic THz antenna design that covers the entire 0.6 – 1.2 THz band is developed as the imaging pixel of THz focal plane array (FPA). Heterostructure backward diodes are integrated monolithically with the THz antennas and are used as the detectors to reproduce digital images from the 2-dimensional received power distribution. A new simplified design is developed which is capable...
We are studying the reasons preventing us from achieving sub-millimeter accuracy for UWB indoor localization which suffers from intense multipath interference. Using just the I-Channel offers better accuracy because of the I-Q alignment problem, but it requires great number of samples averaging, and causes unstable system operation. Non-coherent detection is an interesting alternative, since it eliminates...
This study is an investigation of the influence of the user's hand on the radiated performance of a mobile phone, particularly the peak spatial averaged Specific Absorption Rate (psSAR) averaged over 1 g and 10 g in the head of the user. Recent studies found that the psSAR in the head can be increased by the presence of the hand in some cases. In this study, simulations are performed at 900 and 1800...
This paper reports the design of a directive antenna for ultra-wideband microwave imaging systems. The antenna is a corrugated tapered slot antenna of compact dimensions (22 mm × 40 mm) immersed in a coupling liquid that is fabricated to improve the matching between the antenna and the imaged object, and thus to increase the dynamic range of the imaging system. The antenna is covered with a dielectric...
In this paper, a compact square ring antenna is presented, which shows dual-frequency filtering characteristics. The antenna is designed for the 5.2 and 5.8 GHz wireless frequencies with between-band gain suppression of approximately 18 dB at 5.45 GHz. The dual-frequency response is realized through a multilayer design, where the antenna uses triangular perturbation elements within the square ring...
Low orbit satellites often require a global earth coverage with iso flux shape to optimize the achievable gain but under the constrain of low mass and volume for the antenna solution. In this paper an innovative antenna configuration suitable for ARGOS satellite applications is reported. The antenna has been developed, manufactured and tested.
This paper presents one compact printed monopole antenna with one chip inductor embedded on the radiation elements. By introducing the chip inductor, the resonant frequency of the original antenna can be decreased by more than 37% while there is no significant influence on its radiation characteristics including radiation efficiency and antenna gain. Meanwhile, after adding the chip inductor, the...
In this paper, the design and implementation of a meander monopole antenna is presented. The proposed antenna operates at 915 MHz and 2.5 GHz in the unlicensed ISM (industrial Scientific Medical) band. In this design, the antenna miniaturization particularly at 915 MHz where λ ∼ 32cm, is achieved by meandering and conforming the antenna to the surface of a cylinder. To match the antenna to the excitation...
A compact, printable, parasitic array antenna operating at dual resonances is investigated. The antenna is composed of a driver and two directors. All elements are printed with copper strips on both sides of a substrate (Rogers Duroid 5880). Two directors with different lengths are twisted to generate dual resonances. In both generated bands, high gain (> 8.0 dBi) and good front-to-back ratios...
A planar near field resonant parasitic (NFRP) antenna for multiple-input multiple-output (MIMO) applications in the WLAN 2.4/5.2/5.8 GHz frequency bands is presented. The NFRP antenna can create tri-band functions by incorporating three different parasitic elements. Nearly complete impedance matching to a 50Ω source is shown at the desired resonant frequencies. Additionally, NFRP antenna array configurations...
In this paper, we present a new frequency reconfigurable antenna for cognitive radios that can operate in both Ultra Wide Band (UWB) mode and in narrowband mode where the operating frequency can be easily tuned. The antenna is composed of a disc monopole that can be excited to operate at the range of hundreds of MHz for the narrowband mode and at the range 1 to 10 GHz in the UWB mode. The total antenna...
In this paper, a stacked rectangular microstrip antenna with a shorting plate combined with a stacked rectangular ring microstrip antenna has been proposed for triple-band (GPS/VICS/ETC) operation in ITS. The proposed antenna is excited by an L-probe feed. By simulations, the operational principles at three resonant modes are clarified and the relationships between the geometric parameters of the...
We present a set of benchmark problems involving conducting spheres and their solutions using a parallel implementation of the multilevel fast multipole algorithm (MLFMA). Accuracy of the implementation is tested by comparing the computational results with analytical Mie-series solutions. Reference solutions are made available on an interactive website to evaluate and compare the accuracy and efficiency...
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