A Defected Ground Structure for Circularly Polarized (CP) Microstrip Antenna Design

Author(s):  
Kun Wei ◽  
Bo-Cheng Zhu ◽  
Ming-Liang Tao ◽  
Yue-Xian Wang
2015 ◽  
Vol 9 (2) ◽  
pp. 317-325 ◽  
Author(s):  
Amanpreet Kaur ◽  
Rajesh Khanna ◽  
Machavaram Kartikeyan

In this paper, a three layered stacked circularly polarized rectangular dual band microstrip antenna with a defected ground structure (DGS) and a feed network with stub (showing dual wideband characteristic) is designed, fabricated, and tested for WLAN, Zig bee, Wi-Max, and IMT band applications. The proposed antenna is fabricated on an FR4 substrate with dielectric constant (εr) of 4.4; tanδ of 0.0024 and a height of 1.57 mm.The antenna has a surface area of 4.8 × 4.1 cm2and a total height of 5.1 mm. The designed antenna covers two wireless bands from 2.39 to 2.64GHz and 3.39–3.76 GHZ with impedance bandwidths (VSWR < 2) of 250 MHz (9% bandwidth centered at 2.515 GHz) and 370 MHz (10% bandwidth centered at 3.57 GHz), respectively. This antenna is capable of covering IEEE 802.11b/g/n standards of WLAN from 2.4 to 2.485 GHz, bluetooth applications from 2.4 to 2.483 GHz, ZigBee applications from 2.4 to 2.485 GHz, IEEE 802.16/ Wi-MaX applications from 3.4 to 3.69 GHz and international mobile telecommunications (IMT) band from 3.4 to 3.6 GHz. As the antenna is circularly polarized, the misalignment of the receiver with transmitter does not affect the performance of the system. The antenna designing was done using CST MWS V'10 and the prototype of the designed antenna was tested for the validation of S11(dB) and gain results against the simulated ones experimentally. The proposed antenna shows a gain of 4.08 dBi at 2.5 GHz and a gain of 5.024 dBi at 3.51 GHz.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Pravin Ratilal Prajapati

An application of defected ground structure (DGS) to reduce out-of-band harmonics has been presented. A compact, proximity feed fractal slotted microstrip antenna for wireless local area network (WLAN) applications has been designed. The proposed 3rd iteration reduces antenna size by 43% as compared to rectangular conventional antenna and by introducing H shape DGS, the size of an antenna is further reduced by 3%. The DGS introduces stop band characteristics and suppresses higher harmonics, which are out of the band generated by 1st, 2nd, and 3rd iterations. H shape DGS is etched below the 50 Ω feed line and transmission coefficient parameters (S21) are obtained by CST Microwave Studio software. The values of equivalent L and C model have been extracted using a trial version of the diplexer filter design software. The stop band characteristic of the equivalent LC model also has been simulated by the Advance Digital System software, which gives almost the same response as compared to the simulation of CST Microwave Studio V. 12. The proposed antenna operates from 2.4 GHz to 2.49 GHz, which covers WLAN band and has a gain of 4.46 dB at 2.45 GHz resonance frequency.


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