Rohith K. Raj

A New Compact Microstrip-Fed Dual-Band Coplanar Antenna for WLAN Applications

A novel compact microstrip fed dual-band coplanar antenna for wireless local area network is presented. The antenna comprises of a rectangular center strip and two lateral strips printed on a dielectric substrate and excited using a 50 Omega microstrip transmission line. The antenna generates two separate resonant modes to cover 2.4/5.2/5.8 GHz WLAN bands. Lower resonant mode of the antenna has an impedance bandwidth (2:1 VSWR) of 330 MHz (2190-2520 MHz), which easily covers the required bandwidth of the 2.4 GHz WLAN, and the upper resonant mode has a bandwidth of 1.23 GHz (4849-6070 MHz), covering 5.2/5.8 GHz WLAN bands. The proposed antenna occupy an area of 217 mm2 when printed on FR4 substrate (epsivr=4.7). A rigorous experimental study has been conducted to confirm the characteristics of the antenna. Design equations for the proposed antenna are also developed

Compact Asymmetric Coplanar Strip Fed Monopole Antenna for Multiband Applications

A compact asymmetric coplanar strip fed monopole antenna for multiband applications is presented. The antenna exhibits three resonances around 1.8, 2.4, and 5.6 GHz covering the DCS/PCS/UMTS/IEEE 802.11b/g/IEEE802.11a/HIPERLAN2 bands. The multiband characteristic of the antenna is due to the various meandered current paths excited in the radiating structure. The antenna has an overall dimension of only 2830 when printed on a substrate of dielectric constant 4.4. The uniplanar design, simple feeding technique and compactness make it easy for the integration of the antenna into circuit boards. Details of the antenna design, experimental and simulated results are presented and discussed.

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.

Single-feed dual-frequency dual polarized microstrip antenna with hexagonal slot

A novel dual frequency, dual polarized operation of a compact single feed square microstrip patch antenna embedded with a hexagonal slot is presented. The proposed antenna provides a size reduction up to 45% and 36% for the two resonant frequencies compared to standard rectangular patches. This design also gives enhanced bandwidth, as high as 2.86% and 2.34%, for the two frequencies with a very low operating frequency ratio.

A Metaresonator Inspired Dual Band Antenna for Wireless Applications

A novel metaresonator inspired dual band antenna for 2.4/5.2 GHz WLAN applications is presented. Dual band operation is achieved by utilizing stacking technique on a dog bone shaped dipole antenna. Stacking excites the magnetic resonance in addition to the existing dipole resonance in the structure yielding the dual band design. The antenna has a 2:1 VSWR bandwidth of 12% for the lower dipole resonance centered around 2.47 GHz and 10.5% for the second resonance at 5.18 GHz which is wide enough to cover the 2.4 GHz and 5.2 GHz WLAN applications. The antenna is made of a low cost FR4 substrate of relative permittivity 4.4 and height 1.6 mm and has a total dimension of 38×40×3.2 mm3. Experimental and simulation studies of the antenna including the stacking height variation and resonant mechanisms are explained in detail in this communication.

A Compact Stacked Dipole Antenna With Directional Radiation Coverage for Wireless Communications

A simple stacked metal slab antenna with directional broadside radiation coverage suitable for wireless applications is presented. The directional broadside radiation pattern is obtained by stacking the printed metal slab dipole antenna with the same element. The design utilizes the coupling of magnetic and electrical resonances of the coupled slabs to ensure directional radiation characteristics. The design has a front-to-back ratio of 15 dB and occupies an overall dimension of 44×18×4.8 mm3 when printed on a substrate of dielectric constant 4.4. Details of the design along with experimental, simulation, and finite-difference time-domain (FDTD) computed results are presented and discussed.

An experimental verification of metamaterial coupled enhanced transmission for antenna applications

Inspired by the work of Bethe on electromagnetic transmission through subwavelength hole, there has been immense interest on the extraordinary transmission through subwavelength slot/slit on metal plates. The invention of metamaterials has boosted the extra ordinary transmission through subwavelength slots. We examine computationally and experimentally the concept of metamaterial cover using an array of split ring resonators (SRRs), for enhancing the transmission in a stacked dipole antenna working in the S band. The front to back ratio is considerably improved by enhancing the magnetic resonant strength in close proximity of the slit of the upper parasitic dipole. The effect of stacking height of the SRR monolayer on the resonant characteristics of the split ring resonators and its effect on antenna radiation characteristics has been studied.

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 new compact printed antenna with coplanar configuration

In this paper we propose a compact coplanar antenna (CCPA) configuration with excellent radiation coverage, good reflection characteristics and comparatively good bandwidth. The antenna offers 75% area reduction compared to a standard rectangular patch for the same frequency. It can be easily incorporated in any compact wireless gadget. Antenna design and experimental results are discussed.

Compact planar multiband antenna

In this paper a compact multiband planar antenna for GPS (1575.4 MHz), DCS (1800 MHz), 2.4 GHz (2400-2485 MHz) and 5.8 GHz (5725-5825 MHz) WLAN is presented. The proposed antenna of dimensions 38 mm times 3 mm times 1.6 mm with three wide 2:1 VSWR bands around 1.8 GHz, 2.4 GHz and 5.8 GHz successfully covers the above bands with good radiation and reflection characteristics. Details of the proposed antenna design and experimental results are presented and discussed