M. N. Suma

A compact dual band planar branched monopole antenna for DCS/2.4-GHz WLAN applications

A compact dual band planar antenna for a digital communication system (DCS)/2.4-GHz WLAN application is presented. The two resonant modes of the proposed antenna are associated with various length of the monopoles, in which a longer arm contributes for the lower resonant frequency and a shorter arm for higher resonant frequency. The experimental results show that the designed antenna can provide excellent performance for DCS/2.4-GHz WLAN systems, including sufficiently wide frequency band, moderate gain, and nearly omnidirectional radiation coverage. The outcome of the experimental results along with the design criteria are presented in this letter.

Permittivity Characteristics in the X- and S-Band Frequencies of Microwave Absorbers Based on Rubber Ferrite Composites

Fine particles of nickel ferrite are synthesized by the sol-gel technique and characterized by the X-ray diffraction method. These materials are incorporated in ethylene propylene diene rubber (EPDM) according to a specific recipe for various loadings. The rubber ferrite composites (RFCs) thus obtained have several applications, such as microwave absorbers, EMI shielding materials, etc. In the present study, microwave attenuation and dielectric properties of RFCs are studied in the X- and S-band frequencies. Real and imaginary parts of the dielectric permittivity are determined by cavity perturbation method. Dielectric permittivity in X-band frequency, based on Maxwell—Garnet equation is calculated and presented here.

MICROSTRIP-FED DUAL BAND FOLDED DIPOLE ANTENNA FOR DCS/PCS/2.4 GHz WLAN APPLICATIONS

A compact dual band folded dipole antenna printed on either side of a substrate and excited by a 50 Ω microstrip line with a truncated ground plane covering DCS/PCS/2.4 GHz WLAN bands is presented. In the proposed design, a microstrip-fed folded monopole antenna is first designed and then modified it to a microstrip-fed folded dipole by placing another folded arm on the opposite side of the substrate extending from the ground plane, for achieving dual resonance. The antenna resonating at 1.87 GHz and 2.46 GHz has 2:1 VSWR bandwidth of 17% and 9% respectively. The proposed antenna offers 53% area reduction compared to a standard rectangular microstrip antenna. Details of the antenna design and experimental results are presented.

A WIDEBAND HYBRID PRINTED MONOPOLE/RECTANGULAR PATCH ANTENNA

This paper deals with a novel hybrid antenna configuration for broadband application. Broadband performance is achieved by electromagnetically exciting a planar rectangular patch with rear-mounted strip monopole antenna. The antenna has an overall dimension of 40.5 × 45 × 3.2 mm3 including the feed line and the ground plane. The reflection and radiation characteristics of the prototype antenna exhibits a 2:1 VSWR bandwidth of 40%, an average gain of ~ 7.1 dBi and good radiation coverage. The parametric analysis of the antenna and the design criteria for a compact broad band are also presented in this paper.

Experimental investigation on rectangular dielectric resonator antenna excited by conductor backed coplanar waveguide

The radiation and resonance characteristics of a rectangular dielectric resonator antenna excited by a conductor backed coplanar waveguide are presented in this paper. The effect of CPW dimensions on the performance of the antenna configuration is experimentally studied. The position and orientation of the dielectric resonator on the feed line is optimized for maximum bandwidth and gain. The present design offers a bandwidth of 7.9% with broad beamwidth and low cross polarization discrimination better than -35 dB.