Abstract
In this paper, a printed monopole antenna design for WiMAX/WLAN applications in cable-free self-positioning seismograph nodes is proposed. Great improvements were achieved in miniaturizing the antenna and in widening the narrow bandwidth of the high-frequency band. The antenna was fed by a microstrip gradient line and consisted of a triangle, an inverted-F shape, and an M-shaped structure, which was rotated 90° counterclockwise to form a surface-radiating patch. This structure effectively widened the operating bandwidth of the antenna. Excitation led to the generation of two impedance bands of 2.39–2.49 and 4.26–7.99 GHz for a voltage standing wave ratio of less than 2. The two impedance bandwidths were 100 MHz, i.e., 4.08% relative to the center frequency of 2.45 GHz, and 3730 MHz, i.e., 64.31% relative to the center frequency of 5.80 GHz, covering the WiMAX high-frequency band (5.25–5.85 GHz) and the WLAN band (2.4/5.2/5.8). This article describes the design details of the antenna and presents the results of both simulations and experiments that show good agreement. The proposed antenna meets the field-work requirements of cable-less seismograph nodes.
Highlights
With the rapid development of radio technology, some systems require more than a single working frequency; integrating several communication standards into a single system has become a recent trend
Coplanar waveguide feed concepts have been applied to microstrip antennas, such as the use of narrow rectangular slots with meandering asymmetric slot antennas for dual-band antennas [6], compact wide-slot antennas [7], compact asymmetric-coplanar-strip-fed tri-band meander-line antennas [8], and rectangular slot antennas [9]
Asymmetric coplanar branches have been used for WLAN applications [10]
Summary
With the rapid development of radio technology, some systems require more than a single working frequency; integrating several communication standards into a single system has become a recent trend. Itnheadadnitteinonn,athweaasnstiemnnpalewinas sstirmucptluerien, esatrsuycttourme,aenausyfatcotumrea,naunfdacrteuarlei,zaenddurletraali-zweidduebltarna-dwhidigehb-afnredqhuiegnhc-yfrcehqaureanccteyrcishtaicrsa,ctthereirsetbicys, thereby improving its ability to receive signals. This antenna proved to be suitable for the Future Internet 2018, 10, 122 improving its ability to receive signals. This antenna proved to be suitable for the WLAN/WiMAX (5.15–5.35 GHz) high-frequency band. Compared with the other antennas, it is apparent that the proposed antenna is very small and provides a very wide bandwidth at high frequencies, completely covering the WLAN frequency band.
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