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In this article, a compact quad notched CPW fed ultrawideband (UWB) antenna of the size 35.4 × 26.6 × 1.6 mm3 with improved gain characteristic is proposed. The designed antenna has bandwidth ranging from 2.85 GHz to 11.45 GHz with the notching capability at WiMAX, C‐band, WLAN and downlink of X‐band for satellite communication. The gain of the antenna is improved by using two antennas in the stacked configuration without raising the overall size of the antenna in horizontal plane and maintaining the impedance matching over the ultrawideband range. The prototype of the proposed antenna has been fabricated on FR4 substrate and its performance parameters are measured and compared with the simulated results, which are in good agreement. The simulated and measured result shows the improvement of antenna peak gain by 4.2 dBi and thus improving the peak gain by 162%. The proposed antenna is an excellent candidate for the high gain UWB portable communication devices in the environment having different narrow interfering bands of WiMAX, C‐band, WLAN, and downlink X‐band of satellite communication. [ABSTRACT FROM AUTHOR]

Structural, vibrational and microwave dielectric properties of Nickel-Copper-Zinc ferrite (Ni0.2CuxZn8-xFe2O4) ceramics have been presented in this paper. Samples have been prepared using conventional auto-combustion method. The X-ray diffraction (XRD) results confirmed the ferrite samples to be of cubic spinel structure, which further was validated by Fourier transform infrared (FT-IR) and Raman spectroscopy. The relative permittivity (εr) increased from 7.474 to 8.132 with successive increase in Cu content. The observed and calculated permittivity using Clausius- Mossoitti relation have been in good agreement. The temperature coefficient of resonant frequency (τf ) decreased from -75.85 ppm/μC to -32.12 ppm/μC with increase in successive Cu content. The relative permeability (μr) have been calculated by using the Nicholson-Ross-Weir conversion technique. Using Ni0.2Cu0.2Zn0.6Fe2O4 sample the ferrite resonator antennas have been designed in three different shapes. The experimental and theoretical characteristics of the antennas have been compared and a good agreement has been achieved. [ABSTRACT FROM AUTHOR]

The characteristics of a bow-shaped microstrip patch antenna are analyzed and compared with a conventional rectangular microstrip antenna. The various parameters such as return loss, gain, and VSWR are determined and compared. It is found that the center frequency of the bow-shaped antenna is lower by about 12.82% than that of the conventional rectangular microstrip antenna. This implies that the size of the patch needs to be reduced in order to maintain the same resonant frequency. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 158–160, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11314 [ABSTRACT FROM AUTHOR]