scholarly journals Coherently Driven and Superdirective Antennas

2019 ◽  
Author(s):  
Alex Krasnok
Keyword(s):  
Dielectric Resonator ◽  
Electromagnetic Waves ◽  
Wireless Power Transfer ◽  
Higher Order ◽  
Power Transfer ◽  
Wireless Power ◽  
Entire Spectrum ◽  
Guided Mode ◽  
Dielectric Antennas ◽  
Antenna Systems

Antennas are crucial elements for wireless technologies, communications and power transfer across the entire spectrum of electromagnetic waves, including radio, microwaves, THz and optics. In this paper, we review our recent achievements in two promising areas: coherently enhanced wireless power transfer (WPT) and superdirective dielectric antennas. We show that the concept of coherently enhanced WPT allows improvement of the antenna receiving efficiency by coherent excitation of the outcoupling waveguide with a backward propagating guided mode with a specific amplitude and phase. Antennas with the superdirectivity effect can increase the WPT systems performance in another way, through tailoring of radiation diagram via engineering antenna multipoles excitation and interference of their radiation. We demonstrate a way to achieving the superdirectivity effect via higher-order multipoles excitation in a subwavelength high-index spherical dielectric resonator supporting electric and magnetic Mie multipoles. Thus, both types of antenna discussed here possess a coherent nature and can be used in modern intelligent antenna systems.

scholarly journals Coherently Driven and Superdirective Antennas

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 845 ◽  
Author(s):  
Alex Krasnok
Keyword(s):  
Dielectric Resonator ◽  
Electromagnetic Waves ◽  
Wireless Power Transfer ◽  
Higher Order ◽  
Power Transfer ◽  
Wireless Power ◽  
Entire Spectrum ◽  
Guided Mode ◽  
Dielectric Antennas ◽  
Antenna Systems

Antennas are crucial elements for wireless technologies, communications and power transfer across the entire spectrum of electromagnetic waves, including radio, microwaves, THz and optics. In this paper, we review our recent achievements in two promising areas: coherently enhanced wireless power transfer (WPT) and superdirective dielectric antennas. We show that the concept of coherently enhanced WPT allows improvement of the antenna receiving efficiency by coherent excitation of the outcoupling waveguide with a backward propagating guided mode with a specific amplitude and phase. Antennas with the superdirectivity effect can increase the WPT system’s performance in another way, through tailoring of radiation diagram via engineering antenna multipoles excitation and interference of their radiation. We demonstrate a way to achieve the superdirectivity effect via higher-order multipoles excitation in a subwavelength high-index spherical dielectric resonator supporting electric and magnetic Mie multipoles. Thus, both types of antenna discussed here possess a coherent nature and can be used in modern intelligent antenna systems.

scholarly journals Wireless power transfer system rigid to tissue characteristics using metamaterial inspired geometry for biomedical implant applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramesh K. Pokharel ◽  
Adel Barakat ◽  
Shimaa Alshhawy ◽  
Kuniaki Yoshitomi ◽  
Costas Sarris
Keyword(s):  
Electromagnetic Waves ◽  
Wireless Power Transfer ◽  
Split Ring Resonator ◽  
Input Power ◽  
Power Transfer ◽  
Wireless Power ◽  
Biomedical Implant ◽  
Safety Regulations ◽  
Wireless Power Transfer System ◽  
Tissue Characteristics

AbstractConventional resonant inductive coupling wireless power transfer (WPT) systems encounter performance degradation while energizing biomedical implants. This degradation results from the dielectric and conductive characteristics of the tissue, which cause increased radiation and conduction losses, respectively. Moreover, the proximity of a resonator to the high permittivity tissue causes a change in its operating frequency if misalignment occurs. In this report, we propose a metamaterial inspired geometry with near-zero permeability property to overcome these mentioned problems. This metamaterial inspired geometry is stacked split ring resonator metamaterial fed by a driving inductive loop and acts as a WPT transmitter for an in-tissue implanted WPT receiver. The presented demonstrations have confirmed that the proposed metamaterial inspired WPT system outperforms the conventional one. Also, the resonance frequency of the proposed metamaterial inspired TX is negligibly affected by the tissue characteristics, which is of great interest from the design and operation prospects. Furthermore, the proposed WPT system can be used with more than twice the input power of the conventional one while complying with the safety regulations of electromagnetic waves exposure.

scholarly journals Wireless Power Transfer in Distributed Antenna Systems

2019 ◽  
Vol 67 (1) ◽  
pp. 737-747 ◽  
Author(s):  
Abdelhamid Salem ◽  
Leila Musavian ◽  
Khairi Ashour Hamdi
Keyword(s):  
Wireless Power Transfer ◽  
Power Transfer ◽  
Wireless Power ◽  
Distributed Antenna Systems ◽  
Distributed Antenna ◽  
Antenna Systems
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