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In a communication satellite, multiple frequency bands are used for transmitting and receiving communication, data and tracking signals. In this paper we present design, analysis and test results of a dual-aperture coaxial multiband feed horn. The coaxial configuration is particularly useful for the frequency bands that are widely separated. Our design goal was to operate at S-, Ku-, K- and Ka- bands...
Improving the connectedness of airliners in flight to allow the realisation of passengers' expectations for uninterrupted cell phone usage and internet access requires overcoming the bottleneck between the airliners' internal networks and the wider world in a cost effective manner while still providing sufficient bandwidth. The 43.5 - 47 GHz band is attractive for airliner to ground links due to lack...
Conclusions In this paper, a phased array antenna (PAA) using crossed dipole antenna elements is examined. A partially driven array technique is used for the array antenna. From the analyzed results, it is shown that the element antenna has conical radiation pattern. Using the element antenna, the beam scanning characteristics of the PAA is investigated. It is found that this array antenna can scan...
A hexagonal metamaterial hard horn design was shown with better aperture efficiency and relative cross polarization than existing circular horns used in multibeam reflector antennas. The horn antenna achieves an aperture efficiency greater than 83% and a relative cross polarization level less than 30 dB over a 27% bandwidth. If a profiled horn were used to eliminate the phase variation, the aperture...
It was shown by moment method analysis that soft and hard metamaterial horns offer broadband performance if a metamaterial with the required dispersion can be implemented. It was also shown that the required dispersion curve is monotonically increasing similar to the Drude dispersion, strongly indicating that these horns can be realized. In two accompanying papers the design and analysis of a hexagonal...
The idea of using element rotation to provide phase shift for circularly polarized (CP) reflectarray antennas is studied here. Investigations on these antenna sub-types often involve element design and the simulation as well as measurement of phase shifting properties using a waveguide simulator. Modern refiectarray antennas are typically fabricated using dielectric laminates. For passive elements,...
This paper presents a novel high gain rectifying antenna for 8 GHz wireless power transmission. A reflectarray is combined with the rectifying antenna to achieve high gain. An 8times1 rectenna array is also designed as a feed antenna of the reflectarray. The rectenna array has a return loss of 29 dB at 8 GHz. The rectenna array and the reflectarray have a gain of 15.07 dBi and 18.6 dBi, respectively...
This paper investigates the performance of the single slot ring element for Ka-band reflectarray designs. Using the element rotation technique, two Ka-band circularly polarized reflectarray prototypes are designed and implemented, with different thicknesses of the substrate. The bandwidth is significantly enhanced when a thick substrate is used.
A near-field direct antenna modulation (NFDAM) transmitter at 2.4GHz is demonstrated on a microstrip setting. The transmitter is capable of transmitting information in a direction-dependent fashion by sending the correct signal constellation only in the desired direction while leaving the signal constellation points scrambled in undesired directions. This direction-dependent constellation scrambling...
A new externally-fed spiral antenna is presented in this paper. This antenna consists of two double arms and two sources in phase opposition are used to feed the device. This new design exhibits characteristics similar to that of the classical two arms center-fed spiral antenna. This is useful to conform the antenna on various platforms that do not allow access to the center of the spiral. The far...
This paper reports on the off-axis beam performance of reflector antennas fed by Focal Plane Arrays (FPAs). The FPAs are comprised of many electrically small (< 0.5lambda) elements that can be used to generate multiple closely overlapping beams on the sky. As a result, both the size and continuity of the telescope's Field Of View (FOV) can be substantially improved with respect to conventional...
A Yagi-Uda antenna with a small short interelement distance (d) of approximately 0.025 lambda is proposed for use as a UHF-band ITS in-vehicle antenna. A distributed constant line is added to the center of the reflector dipole as a reactor. It is shown that a Gw of more than 4.7 dBi can be achieved in the 10-MHz bandwidth. The antenna can be placed near the body of a car without any significant deterioration...
This article investigates on dual gridded reflectors (DGR) and the analysis of intercostal effect on these antennas. The level of improvement in the accuracy of prediction is determined by comparing co-pol patterns of several simulations with the measured co-pol pattern of the real reflector of a DGR. Initially, the DGR is analyzed with physical optics (PO). Then, the intercostal ring is introduced...
A new procedure for an efficient solution of the problem of scattering from large cylindrically- shaped reflectors has been proposed in this paper. It utilizes the CBFs that are obtained by applying the SVD (singular value decomposition) procedure to analytically-derived basis functions. These bases, which are constructed by totally bypassing any conventional MoM-type computation, can be used for...
Multibeam reflector antennas attract more interest nowadays with the ever increasing requirements of spaceborne. It features two sets of feeds located in the focal plane to generate two scanning beams. The twin-horn structure is employed to better receive remote sensing signals reflected. The far-field pattern of the reflector antenna illuminated by the measured twin-horn feed pattern is also obtained,...
Two parallel conducting plates are placed vertically on the ground plane to form a millimeter-wave Fabry-Perot resonator antenna. An L-probe is placed between the parallel plates to excite the Fabry-Perot mode. The antenna was studied using Ansoft HFSS. Simulated results of the reflection coefficient, radiation pattern, and antenna gain are reported.
In this work, we have used the opened waveguide cavity to enhance the isolation. The proposed reflector with the donor and receptor antenna satisfied the isolation, more than 80 dB as well as the gain and return loss of the antennas. Also the size of the reflector is reduced considerably compared with conventional reflectors.
Printed reflectarray applications are significantly increasing in recent years, because they represent an ideal antenna solution, having the same radiating performances of the standard parabolic reflector, but with reduced thickness, since the reflecting surface is planar. Here, we present the preliminary analysis of a prototype dual band planar antenna, realized using the reflectarray technology...
This paper presents a reflectarray configuration which supports the operation of six frequency bands. The proposed reflectarray has two substrate layers and each layer accommodates array elements of three frequency bands. Reflection phase curves of the array elements of different frequency bands are simulated. Interactions among elements are also explored.
In this paper, we show a wideband transmission line (TL) model for a Fabry-Perot cavity (FPC) antenna which is designed at a center frequency of 63 GHz using a thick and slotted metallic partially reflective surface. Then, by using the proposed wideband circuit model, we predict the gain and 3dB gain bandwidth of the antenna, assumed as infinitely large in the transverse domain (for the modeling purposes)...
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