Antenna Measurements

and, Constantine A. Balanis; Birtcher, Craig R.

doi:10.1002/9780470294154.ch20

Cited by 104 publications

(144 citation statements)

References 29 publications

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“…However, the first and third sums can potentially produce additional, undesired beams, and therefore we must assess the impact of these additional terms [3]. The formation of a beam occurs for a given sum when the argument of the complex exponential vanishes; when this condition occurs, the fields from all elements interfere constructively [48,49]. We can obtain the possible beam directions from Eq.…”

Section: A Amplitude Only Hologrammentioning

confidence: 99%

Analysis of a Waveguide-Fed Metasurface Antenna

et al. 2017

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The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wavefront shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The metasurface antenna consists of an array of metamaterial elements distributed over an electrically large structure, each subwavelength in dimension and with subwavelength separation between elements. In the antenna configuration we consider here, the metasurface is excited by the fields from an attached waveguide. Each metamaterial element can be modeled as a polarizable dipole that couples the waveguide mode to radiation modes. Distinct from the phased array and electronically scanned antenna (ESA) architectures, a dynamic metasurface antenna does not require active phase shifters and amplifiers, but rather achieves reconfigurability by shifting the resonance frequency of each individual metamaterial element. Here we derive the basic properties of a one-dimensional waveguide-fed metasurface antenna in the approximation that the metamaterial elements do not perturb the waveguide mode and are non-interacting. We derive analytical approximations for the array factors of the 1D antenna, including the effective polarizabilities needed for amplitude-only, phase-only, and binary constraints. Using full-wave numerical simulations, we confirm the analysis, modeling waveguides with slots or complementary metamaterial elements patterned into one of the surfaces.

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Section: A Amplitude Only Hologrammentioning

confidence: 99%

Analysis of a Waveguide-Fed Metasurface Antenna

et al. 2017

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“…Radomes are often curved structures made from ceramics and composites with high values of permittivity, which may result in a degraded performance of the antenna [19,20]. Several differently shaped curved radomes are shown in Figure 1.…”

Section: Microwave Radomesmentioning

confidence: 99%

Metamaterials for Microwave Radomes and the Concept of a Metaradome: Review of the Literature

Özis

Osipov

Eibert

2017

International Journal of Antennas and Propagation

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A radome is an integral part of almost every antenna system, protecting antennas and antenna electronics from hostile exterior conditions (humidity, heat, cold, etc.) and nearby personnel from rotating mechanical parts of antennas and streamlining antennas to reduce aerodynamic drag and to conceal antennas from public view. Metamaterials are artificial materials with a great potential for antenna design, and many studies explore applications of metamaterials to antennas but just a few to the design of radomes. This paper discusses the possibilities that metamaterials open up in the design of microwave radomes and introduces the concept of metaradomes. The use of metamaterials can improve or correct characteristics (gain, directivity, and bandwidth) of the enclosed antenna and add new features, like band-pass frequency behavior, polarization transformations, the ability to be switched on/off, and so forth. Examples of applications of metamaterials in the design of microwave radomes available in the literature as well as potential applications, advantages, drawbacks, and still open problems are described.

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“…For a linear array with 2M elements placed symmetrically along the z axis, the array factor is given by [3]:…”

Section: Phased Array Pattern Formulationmentioning

confidence: 99%

“…For practical Radar applications, it is required that the phased array produces low s idelobe levels (SLL) with narrow beamwidth [2], [3]. The amplitude excitations of the array elements are selected to synthesize the desired pattern.…”

Section: Introductionmentioning

confidence: 99%

Phased Array Synthesis Using Modified Particle Swarm Optimization

Zaman¹,

Mamun²,

Gaffar³

et al. 2011

JESTR

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In this paper, a linear phased array is synthesized to produce a desired far field radiation pattern with a constraint on sidelobe level and beamwidth. The amplitude of the excitation current of each individual array element is optimized to give desired sidelobe level and beamwidth. A modified particle swarm optimization (PSO) algorithm with a novel inertial weight variation function and modified stochastic variables is used here. The performance of the modified PSO is compared with standard PSO in terms of amount of iterations required to get desired fitness value and convergence rate. Using optimized excitation amplitudes, the far field radiation pattern of the phased array is analyzed to verify whether the design criterions are satisfied.

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Antenna Measurements

Cited by 104 publications

References 29 publications

Analysis of a Waveguide-Fed Metasurface Antenna

Analysis of a Waveguide-Fed Metasurface Antenna

Metamaterials for Microwave Radomes and the Concept of a Metaradome: Review of the Literature

Phased Array Synthesis Using Modified Particle Swarm Optimization

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