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This paper presents the Antenna tracking system leading to a significant improvement of antenna pointing accuracy, which has been developed by Astrium and first flies onboard KASAT. Efficiency and robustness of the antenna tracking system will be presented showing the ability to remove large transient errors either from station keeping manoeuvre or sun eclipse transition.
The design of a miniaturized double-ridged horn antenna for use as an array element in the Subsurface Radar (SR) system is presented. The array antenna system will be arranged in a cylindrical scanning geometry which will host 72 antennas in a row for illuminating the target and receiving scattered signal. The scanning system will have several rows of antennas for better sensitivity and spatial accuracy...
Performance of low-profile dielectric resonator antennas (DRAs) for 60 GHz applications is investigated and compared with regular type (i.e. cube-shape) DRAs. In addition to larger impedance bandwidth, low-profile structures are less sensitive to fabrication imperfections and to change in permittivity due to temperature variations. Larger lateral dimensions of the low-profile antenna can facilitate...
A compact quad-ridged horn antenna is presented. This antenna is smaller, in terms of wavelength, than previously published designs. The antenna is dual-polarized and a return loss of greater than 10 dB is achieved across a 15.7∶1 bandwidth.
This paper presents the design and simulation of an agile unit-cell structure for DNG (Double Negative) metamaterials. DNGs are artificial materials with negative permittivity and permeability at the same time. The presented unit-cell can switch between a two-turn spiral resonator and two concentric rings similar to a conventional DSR (Double Split-ring Resonator). Two PIN diodes are embedded in the...
A two port antenna developed by effectively integrating a narrow band antenna (NBA) on an ultra-wideband antenna (UWBA) with good inter-port isolation is presented. This design utilizes the space between two tapered slots of UWBA, where surface current is minimum, to integrate the NBA. A V-shaped slot resonator is also embedded on UWBA in order to facilitate band notch functionality. The UWBA fed...
A physically small - sized double-ridged horn antenna is presented for use as an array element in the Subsurface Radar (SR) system. The miniaturization is achieved by loading the antenna with a very high-permittivity material and also by reducing the flare length in the horn section. The effects of size reduction on the reflection and transmission response of the antenna are studied.
The results of extensive numerical investigation is presented in order the gain a better understanding of the behavior of EBG structure composed of open square rings. Presence of the gap in the cell element of such Electromagnetics Bandgap (EBG) structure renders the structure sensitive to the orientation of the constituent ring elements. It is shown that the bandgap persists for both orthogonal orientations...
A wireless power transfer system for 1.8 MHz, 20W LED display board is presented. Coupled magnetic resonance method is used for wireless power transfer and the operating frequency is selected by considering guidelines for limiting human exposure to electromagnetic fields. The power consumption of the LED display board is about 20W and the entire efficiency of this WPT system is 50.5%. The strength...
In this paper, a new miniaturized artificial magnetic conductor ground plane is proposed, which includes an array of only 2.5×2.5 square patches. A conventional miniaturization technique is used to reduce the number of metallic patches of the engineered ground plane. The planar antenna under study is a curl antenna etched on a grounded dielectric slab. The antenna such developed generates right-handed...
This paper presents a new method for designing planar millimeter-wave antennas with optimal shape. The method is applied to dielectric antennas for high efficiency. The method simply pixelates the available space for the antenna into small boxes and then a finite-elements solver integrated with an optimization engine is used to find the pixels pattern in this finite space which satisfies the required...
A novel approach for effectively feeding a wide-band dielectric resonator antenna (DRA) of very low-permittivity is presented in this paper. It is shown that a tapered microstrip line with optimized length and width can provide excellent impedance matching. The impedance bandwidth of the antenna (S11 < −10 dB) associated with single resonance mode is over 35%. A minimum reflection coefficient...
In this paper, the cross polarization reduction is reviewed in offset reflector antennas by expressing the primary feed radiation patterns in terms of analytic functions. The feed under study is a dual-mode circular waveguide antenna, operating at the fundamental mode, TE11, and the higher order TE21 mode. Closed-form analytical functions are selected to approximate each mode which allows selection...
An elimination procedure is presented, where, at each step, one equation of the reduced system has its coefficients kept at their original values and the vectors constructed with the coefficients of the other equations are made orthogonal to the vector of the coefficients in one of them. A simple backward substitution is applied to determine the unknowns of the original system of equations. The solution...
The global phase centre and cross polarization of a multi-mode stacked circular microstrip antenna are studied when the first three modes, TM11, TM21 and TM02, are excited. These properties can be controlled by amplitude and phase excitations of each individual mode. It will be demonstrated that such antennas represent virtual array antennas by having a broadside amplitude patterns at the far-field...
This paper presents the design, simulations and measurements of a Substrate Integrated Waveguide (SIW) slot array antenna with linear polarization. A microstrip feed line network is used. A one-by-eight and a two-by-eight SIW slot array antennas at 5.8 GHz are shown. A gain of 9.8 dBi is achieved for the two-by-eight antenna with a surface of 57×240 mm2.
Radiating element optimization is a key factor to improve the overall performances of an array antenna: its type and design must meet RF specifications while being competitive in terms of cost, bulkiness and weight. This paper focuses on the design, manufacturing and test of a splineprofile square horn, designed to be used for telecommunication focal array applications with high efficiency requirements
A planar microwave absorber based on the anisotropic properties of tunable reflectarray has been introduced in this paper. A non-linear liquid crystal material along with polystyrene foam has been designed to analyze X-band microwave absorption performance of three different reflectarray resonant elements. A thorough investigation based on finite integral method has been performed to investigate the...
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