DSpace-CRIS

Now showing 1 - 3 of 3

Some of the metrics are blocked by your
consent settings
Broadband CP corner-truncated microstrip antenna with irregularly hexagonal AMC for 2.45 GHz applications
(2024-06-01)
Wichaidit, Purichaya
;
Dentri, Sitthichai
;
Janpangngern, Pisit
;
Lertwiriyaprapa, Titipong
;
Krairiksh, Monai
This research proposes a compact broadband circularly polarized (CP) corner-truncated microstrip antenna with irregularly hexagonal artificial magnetic conductor (AMC) for 2.45 GHz WLAN applications. The corners of the radiating patch are diagonally truncated to realize circular polarization and improve axial ratio. A 5[Formula presented]5 irregularly hexagonal AMC array is employed to enhance the axial ratio bandwidth (ARBW) and antenna gain. In addition, a tri-section meandering feedline is used to realize impedance matching and improve the impedance bandwidth (IBW). The AMC array is used to manipulate electromagnetic waves by suppressing surface currents and back lobe, resulting in reduced back radiation and enhanced front-to-back ratio. The simulated IBW and ARBW are 50.9% (1.86 – 3.13 GHz) and 19.3% (2.24 – 2.72 GHz) respectively, with a maximum gain of 8.9 dBic at 2.45 GHz. The measured IBW and ARBW are 42.42% (1.95 – 3.0 GHz) and 29.4% (2.03 – 2.73 GHz), with a maximum gain of 8.6 dBic. The simulated half power beamwidth (HPBW) of the proposed antenna scheme in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 67°, 62°, and 51°, respectively. The corresponding HPBW in the yz plane are 60°, 55°, and 62°. The simulated AR beamwidth in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 177°, 164°, and 88°, respectively. The corresponding AR beamwidth in the yz plane are 148°, 106°, and 124°. The simulated cross polarized (XP) levels at 2.45 GHz are below -19.35 dB for both planes. The measured HPBW in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 69°, 64°, and 50°, respectively. The corresponding HPBW in the yz plane are 65°, 54°, and 37°. The measured AR beamwidth in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 161°, 200°, and 104°, respectively. The corresponding AR beamwidth in the yz plane are 162°, 85°, and 90°. The measured XP levels at 2.45 GHz are below -15.62 dB for both planes. The radiation pattern is unidirectional. Essentially, the proposed broadband CP antenna scheme is suitable for the WLAN frequency band and other 2.45 GHz wireless communication technologies. The novelty of this research lies in the use of the tri-section meandering feedline and the irregularly hexagonal AMC array to enhance IBW and ARBW.
Some of the metrics are blocked by your
consent settings
Dual-Band Circularly Polarized Omni-Directional Biconical Antenna With Double-Circular Parallelepiped Elements for WLAN Applications
(2022-01-01)
Janpangngern, Pisit
;
Torrungrueng, Danai
;
Krairiksh, Monai
;
Phongcharoenpanich, Chuwong
This research proposes a novel dual-band (2.45/5.80 GHz) omnidirectional circularly polarized (CP) biconical antenna with double-circular parasitic parallelepiped elements for wireless local area network (WLAN) applications. The proposed dual-band CP antenna scheme consisted of a biconical radiating structure surrounded by inner- and outer-circular parallelepiped elements that convert linearly polarized electric fields into CP fields. Simulations were performed to optimize the antenna parameters, and an antenna prototype was fabricated and experiments were conducted. The measured impedance bandwidths (IBWs) were 44.4% (1.84 - 2.89 GHz) and 4.56% (5.73 - 5.99 GHz) for the lower- (2.4 GHz) and upper-frequency (5.80 GHz) bands, respectively. The corresponding 3-dB axial ratio bandwidths (ARBWs) were 11.22% (2.27 - 2.54 GHz) and 10.49% (5.6 - 6.2 GHz). The radiation patterns of the dual-band antenna scheme were omnidirectional left-hand circular polarization, with the measured antenna gains of 3.2 dBic and 8.5 dBic at 2.45 and 5.80 GHz, respectively. The simulated and measured results were reasonably agreeable. Despite the narrow IBW and ARBW for the upper-frequency band, the bandwidths adequately covered the target upper frequency band, rendering the proposed CP omnidirectional biconical antenna scheme operationally suitable for WLAN applications. Furthermore, the novelty of this research lies in the use of a biconical radiating structure augmented with double-circular parasitic parallelepiped elements to realize circular polarization for dual-band WLAN applications.
Some of the metrics are blocked by your
consent settings
Investigations of Radiation Characteristics of a circularly polarized conical beam spherical slot array antenna
(1999-01-01)
Phongcharoenpanich, Chuwong
;
Krairiksh, Monai
;
Takada, Jun Ichi
This paper presents the radiation characteristics of a circularly polarized conical beam spherical slot array antenna for applying to the mobile satellite communication subscriber. The structure of the antenna is easy to fabricate i.e., a ring of perpendicular slot pairs cut on an outer surface of a concentric conducting spherical cavity enclosed by the conducting conical surface with the simple feeding structure, and a linear electric probe excited at the center of the inner surface of the cavity. Radiation fields of a spherical slot array antenna are calculated by superposing the patterns of all the slots. From the numerical results of the radiation pattern, in both elcvational and azimuthal planes, it is obvious that the conical beam is realized. The elevational beam direction is low, which is suitable for installing in the land mobile subscriber unit located far from the equator. The tracking system is not necessary because the azimuthal pattern is omnidirectional. Directivity of the antenna for various spherical radii and angles of slot positions are illustrated as the guidelines for the design. Experimental results are in good agreement with the predictions.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results