In the present work, a compact zig-zag shaped slit rectangular microstrip patch antenna with circular defected ground structure (DGS) is designed for wireless applications. The probe-fed antenna consisting of zig-zag shaped slit, dual Tshaped slits on either sides of a rectangular patch and circular dumbbell shaped defected ground plane is optimized. The antenna was able to generate three separate resonances to cover both the 2.45/5.28 GHz WLAN bands and the 3.5 GHz WiMAX bands while maintaining a small overall size of 40mm x 28mm x 3.175mm. The return loss impedance bandwidth values are enhanced significantly for three resonant frequencies. Designed antenna is characterized with better radiation patterns and potentially stable gain around 4-6dBi over the working bands. Good agreement was obtained between measurements and simulations.Index Terms-Defected ground structure, zig zag slit, Radiation pattern, Impedance band width.

This letter proposes a novel compact circular patch antenna that is simulated, fabricated, and measured for different wireless applications. Traditional circular antenna is modified with dual T‐ shaped slits placed on top and bottom positions, to obtain the tri band resonant frequencies. Metallic ground plane behind the radiating patch is placed with a dual E‐shaped defected ground structure (DGS) achieving size miniaturization and bandwidth (BW) enhancement at dual bands. Antenna is well performed with and without placement of DGS in terms of obtained gain. Shape, dimensions of the finite ground plane, and frequency shift property using defect on the patch are the key factors in improving the BW and reducing the size. BWs of 3.9 and 3.6% are obtained for 1.56 and 2.47 GHz bands, respectively. The optimized dimensions of DGS are selected without degrading the antenna performance. This single layer probe feed antenna is analyzed, simulated using IE3D tool and also performed experimentally. Frequency shift technique of DGS would attain compact antenna size and is also capable of providing dual bands with better impedance matching and acceptable gain. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2410–2413, 2015

In this paper, a compact, dual-band patch antenna is proposed over Minkowski fractal defected ground structure (DGS) for bandwidth enhancement of global positioning system (GPS) applications. The proposed design combines the truncated dual L-shaped slits cut on diagonal corners of radiating patch and fractal defect on the metallic ground plane. This concept shifts the frequencies to lower bands with improvement in antenna radiation properties. By deploying symmetrical and asymmetrical boundaries to the structure for the fractal DGS on metallic ground plane, improvement in bandwidth and gain are obtained. Compact antenna size is achieved for dual-band GPS frequencies of L1 (1.575 GHz) and L2 (1.227 GHz). The measured results for antenna prototype are (1.2–1.245 GHz): L2 band and (1.51–1.59 GHz): L1 band for 10 dB return loss bandwidth with better pattern radiation. Gain value with and without DGS is observed for compact antenna overall volume of 0.32λ0 × 0.32λ0 × 0.024λ0.

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