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Cylindrical antennas and arrays are very useful when 360° coverage is required. Either a multibeam cylindrical narrow beam or an omnidirectional parallel plate based antenna can significantly benefit from an elevation pattern for either gain increase or specific angular coverage. The challenge is in the design of the geometry associated with the elevation pattern, so that performance is optimized...
One of the challenges of designing UAVs is the limited amount of interior space for components. The communication, navigation, and radar systems all compete for this limited space. Phased array antenna systems, in turn, save space, weight, and power by steering the antenna electrically versus mechanically. Rotman lens devices (Fig. 1) are a particularly efficient means providing the correct amplitude...
We present a new concept for a low-profile, low cost integrated multi-beam cylindrical array. It consists of a parallel plate 2D Luneburg beamformer feeding a cylindrical aperture. The concept incorporates a number of novel features, such as low profile, and highly directive excitations. All these features are introduced in order to reduce volume, weight and ultimately cost. The paper discusses the...
We present a new design of a low-profile small VHF dual-band omnidirectional antenna made on a compact ARLON board. The antenna was optimized using full-wave EM simulations to provide an omnidirectional radiation pattern. A reactive impedance matching circuit was synthesized to operate the antenna in two VHF bands around 150 and 450 MHz with high efficiency. Several prototypes of the antenna have...
In this paper a new method to reduce the interaction between antennas and nearby objects is proposed. It involves the use of a thin textured surface similar to a high-impedance layer that is wrapped around the objects that are in close proximity of the antenna (ground planes, various platforms, etc.). The textured surface acts as a “diffuser” spreading the reflected fields from the close objects and...
A new type of antenna, the omnidirectional polyrod shaped beam antenna with a shaped-beam radiation pattern in elevation is presented. It is based on the typical polyrod antenna, which can have a shaped beam realized by the appropriate physical shaping of the radiating polyrod. The antenna can be used as an airborne omnidirectional radiator with a requested sectoral coverage.
A Matlab based, Computational Electromagnetics (CEM) Computer-Aided Design (CAD) Optimization System is presented. This Numerical Electromagnetic Optimization system called NEMO is universal in the sense that it can be used in conjunction with any CEM engine, such as CST, HFSS and other custom designed CEM codes. The use of several commercial solvers, viz. HFSS and Periodic Boundary FDTD (PBFDTD)...
A metamaterial slab of Wire-Split Ring Resonators was analyzed focusing on physical aspects. Effective constitutive parameters were extracted vs. number of W-SRR layers in the slab. We have shown that a minimum of 8 layers is required to accurately characterize the bulk metamaterial properties. Losses, spatial dispersion, and mode conversion in the unit cell are also discussed.
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