Power pattern synthesis for antenna arrays with null constraints in the near-field region

2005 ◽  
Vol 44 (6) ◽  
pp. 542-545 ◽  
Author(s):  
Roberto Vescovo
Keyword(s):  
Antenna Arrays ◽  
Near Field ◽  
Field Region ◽  
Pattern Synthesis ◽  
Power Pattern

scholarly journals Frequency shift of the minimal magnitude of reflection coefficient in antenna array

2019 ◽  
Vol 70 (1) ◽  
pp. 64-68
Author(s):  
Ferdinand Vavrík ◽  
Jozef Hallon
Keyword(s):  
Reflection Coefficient ◽  
Frequency Shift ◽  
Frequency Dependence ◽  
Antenna Arrays ◽  
Near Field ◽  
Field Region ◽  
Absolute Value ◽  
Mutual Impedance ◽  
Circular Arrays ◽  
Circular Antenna Arrays

Abstract The paper present a study of frequency shift of the reflection coefficient minimal absolute value dependence on antenna spacing in linear and circular arrays. The spacing of CB-band monopole antenna was in the range of 0.015 to 0.12 multiples of the antenna working wavelength. Number of elements in the antenna arrays ranged from two to four. Frequency dependence of minimal absolute value of the reflection coefficient was obtained by simulations and also experimentally confirmed in anechoic chamber. The research showed two facts. First, mutual impedance has the higher impact when antenna spacing is comparable with the reactive near field region. Second, circular antenna arrays are a better choice in applications for a small number of antennas with that spacing.

scholarly journals Reconfigurable Antenna Arrays with Phase-only Control in the Presence of Near-field Nulls

2017 ◽  
pp. 88-93 ◽  
Author(s):  
Giulia Buttazzoni ◽  
Roberto Vescovo
Keyword(s):  
Iterative Method ◽  
Antenna Arrays ◽  
Strong Field ◽  
Near Field ◽  
A Priori ◽  
Excitation Amplitude ◽  
Array Element ◽  
Reconfigurable Antenna ◽  
Field Region ◽  
Arbitrary Geometry

In this paper an effective iterative method is presented for the power synthesis of reconfigurable antenna arrays. The algorithm is suitable for arrays of arbitrary geometry, including the case where a large number of elements is involved. The reconfigurability is achieved by phase-only control, so that the excitation amplitude of each array element remains constant during the reconfiguration process. Such amplitudes may be different from one array element to the others, and they are not assigned a priori, but are optimized. Furthermore, the electric field is imposed to vanish in a number of prescribed points of the near-field region, so that a strong field reduction is obtained in a neighborhood of them.

scholarly journals Experimental observation of asymmetrical microwave jets and far-field distribution generated by a dual-material system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
B. Varghese ◽  
O. Shramkova ◽  
P. Minard ◽  
L. Blondé ◽  
V. Drazic ◽  
...  
Keyword(s):  
Near Field ◽  
Microwave Frequency ◽  
Far Field ◽  
Material System ◽  
Field Region ◽  
Edge Diffraction ◽  
Jet Behavior ◽  
Electric Field Profile ◽  
Dual Material ◽  
Plane Wave Diffraction

AbstractIn this paper, we report the experimental and numerical investigation of plane wave diffraction by an all-dielectric dual-material cuboid. Edge diffraction by a cuboid leads to the generation of a narrow, high intensity beam in the near-field region called a photonic jet. We examine the dependence of the jet behavior and orientation on the materials and dimensions of constitutive parts in the microwave frequency domain. The possibility to shift and deviate the resultant microwave jet in the near-field region of such a structure depending on the size of constitutive parts is demonstrated numerically. Experimentally, we observe a shift in the spatial position of the jet. The experimental asymmetric electric field profile observed in the far-field region is attributed to the input of multiple edge waves generated by the dual-material cuboid. The presented results may be scaled at different frequency bands such as optical frequencies for designing nanostructures enabling the focusing and deviation functionality and creation of new optical devices which would satisfy the needs of emerging nanophotonic applications.

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