The design optimization of miniature low profile antennas placed in close proximity to high-impedance surfaces

Author(s):  
D.H. Werner ◽  
P.L. Werner
Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3809
Author(s):  
Mohammed M. Bait-Suwailam ◽  
Isidoro I. Labiano ◽  
Akram Alomainy

In this paper, impedance matching enhancement of a grounded wearable low-profile loop antenna is investigated using a high-impedance surface (HIS) structure. The wearable loop antenna along with the HIS structure is maintained low-profile, making it a suitable candidate for healthcare applications. The paper starts with investigating, both numerically and experimentally, the effects of several textile parameters on the performance of the wearable loop antenna. The application of impedance enhancement of wearable grounded loop antenna with HIS structure is then demonstrated. Numerical full-wave simulations are presented and validated with measured results. Unlike the grounded wearable loop antenna alone with its degraded performance, the wearable loop antenna with HIS structure showed better matching performance improvement at the 2.45 GHz-band. The computed overall far-field properties of the wearable loop antenna with HIS structure shows good performance, with a maximum gain of 6.19 dBi. The effects of bending the wearable loop antenna structure with and without HIS structure as well as when in close proximity to a modeled human arm are also investigated, where good performance was achieved for the case of the wearable antenna with the HIS structure.


2008 ◽  
Vol 6 ◽  
pp. 39-44 ◽  
Author(s):  
S. K. Hampel ◽  
O. Schmitz ◽  
I. Rolfes

Abstract. \\label{sec:abstract} This paper deals with the influence of artificial magnetic conductors (AMC), so-called Sievenpiper High Impedance Surfaces (HIS), on the MIMO and Diversity performance of a planar linear-polarized 2×2 dipole array in the ISM-band at 2.45 GHz. The characteristic performance criteria such as envelope correlation coefficient, spectral efficiency, Mean Effective Gain (MEG) and Diversity gain of a coupled 2×2 dipole array are investigated. By means of full-wave electromagnetic analysis as well as Monte-Carlo simulations applying statistical channel models the characteristic antenna pattern just as the MIMO and Diversity analysis is performed, respectively. The obtained results show that the application of Sievenpiper High Impedance Surfaces to planar antenna arrays enables good MIMO and Diversity performance compared to ideal configurations in free-space while offering the design of low profile antennas with simultaneously enhanced characteristics.


2021 ◽  
pp. 201010582110310
Author(s):  
Ernest Weisheng Ho ◽  
Eng Leonard ◽  
Lee Tih-Shih ◽  
Gregory James Meredith

Electroconvulsive therapy (ECT) is effective for mood disorders and schizophrenia. Thermal burns, while rare, are potentially sight and life threatening. The three elements necessary for a fire are often in close proximity during a session: an oxidiser (oxygen), an ignition source (faulty electrodes, poor contact with skin producing a spark) and fuel (hair, residual alcohol cleanser). This case report describes one such incident when a patient sustained a burn during ECT, with poor contact of electrode pad with skin, high impedance and an oxygen-rich environment possibly contributing. Given that ECT is conducted relatively frequently (once every 2–3 days) in a usual regimen, we make recommendations for safe application of electrode pads for temporal placement ECT.


2002 ◽  
Vol 38 (16) ◽  
pp. 849 ◽  
Author(s):  
H. Xin ◽  
K. Matsugatani ◽  
M. Kim ◽  
J. Hacker ◽  
J.A. Higgins ◽  
...  

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