High frequency fields excited by a line source located on a concave cylindrical impedance surface

2005 ◽  
Author(s):  
T. Ishihara ◽  
L. Felsen

A wideband circularly polarized (CP) planar inverted-F antenna (PIFA) is proposed and designed using reactive impedance surface (RIS) for mobile communication. PIFA with RIS is used for CP radiation, size reduction and wideband of the proposed CP-PIFA. It is a different technique for improving the various performance parameters of the antenna, that is, narrow bandwidth, size reduction, and the axial ratio (AR). The structure of circular polarized PIFA is designed, analyzed, geometrically optimized, and implementation of the antenna to operate at 2.4 GHz WLAN bands. Finally, a proposed CP-PIFA is analyzed and simulated using full 3D electromagnetic high-frequency structure simulator (HFSS). The measured impedance bandwidth of designing an antenna (S11) 10-dB is 1399 MHz (1.542-2.943 GHz) 58.29\%, simulated 3-dB axial ratio bandwidth is 870 MHz (1.639-2.50 GHz) 36.25\%, measured voltage standing wave ratio (VSWR) is 1.02 and the realized gain is 8.1 dB for the 2.4 GHz WLAN bands


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.


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