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Pashan, India

Naidu P.V.,Symbiosis International University | Kumar R.,ARDE
Journal of Microwaves, Optoelectronics and Electromagnetic Applications | Year: 2015

A compact (20 × 20 mm2 size), coplanar waveguide (CPW) fed, octagonal slotted, dual-band antenna is presented in this paper. The proposed antenna has a simple structure consisting of an octagonal slot, L-shape stub, and a two stepped rectangular patch. The introduction of the L-shaped metallic stubs in the ground plane generates a lower resonance frequency at 2.42 GHz. The proposed antenna is fabricated on a low cost FR4 substrate having thickness of 1.6 mm. The measured impedance bandwidth of the proposed antenna is from 2.40 to 2.46 GHz and 3.2 to 6.2 GHz. It is also shown that the proposed antenna has stable radiation patterns of almost dumb-bell shape in the E-plane and omni-directional shape in the H-plane. The effects of various design parameters on the impedance bandwidth are also studied and presented in detail. The proposed antenna can be used for 3.5/5.5 GHz worldwide interoperability for microwave access (WiMAX), 2.4/5.2/5.8 GHz wireless local area network (WLAN) and 3.1-6.0 GHz Direct-Sequence Code Division Multiple Access (DS-CDMA)/Multi-Band Orthogonal Frequency Division Multiplexing (MB-OFDM) ultra wideband (UWB) applications. Copyright © 2015 SBMO/SBMag.

Krishna R.V.S.R.,DIAT DU | Kumar R.,ARDE
Journal of Electromagnetic Waves and Applications | Year: 2016

A V-shape slot antenna for dual slant polarization is proposed. The slot is the union of two stepped rectangular slots tilted at ±45° with the vertical. Each section of the slot is excited using a microstrip feed line printed on the other side of the substrate. The feed is also stepped and bent so as to cross the slot at right angles. The decoupling between the ports is provided by means of narrow rectangular stubs placed at the intersection of the slot arms. Measurements taken on the fabricated prototype indicate an impedance bandwidth from 3.3 to 12 GHz with isolation better than 15 dB across the band. The aperture electric field distributions as well as far field radiation patterns are used to verify the dual slant polarization achieved with the antenna. The time domain characterization of the antenna is done by calculating the fidelity factor which is found to be >0.75 indicating suitability of the antenna for pulse transmission. For determining the diversity behavior, the envelope correlation coefficient is calculated and found to be below 0.004. The antenna has a peak gain from 4 to 6 dBi. A modified design of the antenna is also presented with impedance bandwidth from 3 to 12 GHz and isolation better than 20 dB from 3.7 GHz onwards. With compact features and wideband return loss and isolation, the antennas are expected to be useful for diversity applications in ultra wideband communication devices such as MIMO wifi, imaging radars, and polarimetric sensing devices. © 2016 Informa UK Limited, trading as Taylor & Francis Group

Kumar R.,ARDE | Naidu P.V.,Symbiosis International University | Kamble V.,DIAT DU
Progress In Electromagnetics Research B | Year: 2014

A compact, coplanar waveguide (CPW) fed asymmetric slot antenna with dual operating bands is proposed. The slot is modi-ed rectangular in shape and asymmetrically cut in the ground plane. A hexagonal patch fed by a two-step CPW is used to excite the slot. The feed itself is slightly asymmetric (shifted, with unequal ground planes). The asymmetric cuts on the slot together with the feed line asymmetry have helped in obtaining ultra wideband impedance matching. An extra resonance at 2.4 GHz for Bluetooth applications is obtained by cutting an additional meandered narrow rectangular shape slit in the ground plane. The prototype of the proposed antenna has been fabricated and tested. The measured 10 dB return loss bandwidth of the proposed antenna is 200MHz (2.3-2.5 GHz) for the -rst band and 12.1 GHz (2.9-15.0 GHz) for the second band. The radiation patterns of the proposed antenna are obtained and found to be Omni-directional in H-plane and bi-directional in E-plane. The measured and simulated results are in good agreement.

Naidu V.P.,Symbiosis International University | Kumar R.,ARDE
Wireless Personal Communications | Year: 2015

Two compact rupee shaped coplanar waveguide (CPW) fed monopole antennas for WLAN and WiMAX applications are proposed. One of the antennas has a dual band characteristic (measured impedance bandwidth from 2.92–3.7 and 4.6–6.0 GHz) while the other has a triple band characteristic (measured impedance bandwidth from 1.97–2.15, 2.82–3.45 and 4.35–6.0 GHz). Both the proposed antennas measure 17.5×17.5×1.6 mm3 in dimensions. The basic radiating element in both the antennas is a rupee shape patch fed by a CPW. The dual frequency band operation is obtained by attaching an additional horizontal L-shape strip. The third frequency band is generated by the introduction of a meander shape strip on one side of the patch. The details of the antenna design along with simulated and experimental results are presented and discussed. The two antennas show nearly omnidirectional radiation patterns in the H-plane and bidirectional radiation patterns in the E-plane with moderate gain in the operating bands. The compact features, simple feeding technique and monopole design make them suitable for portable communication devices. © 2014, Springer Science+Business Media New York.

Kushwaha N.,Research Scholar DIAT DU | Kumar R.,ARDE
Journal of Microwaves, Optoelectronics and Electromagnetic Applications | Year: 2014

In this paper, single and dual band EBG structures for wider bandwidth are proposed. In each of the discussed EBGs, a metallic patch of regular geometry is chosen for the unit element. The patch is further modified by cutting slots to get extra inductance and capacitance which results into lower cut-off frequency and larger bandwidth. The proposed EBG structures are compared with the standard mushroom type EBG with respect to surface wave attenuation. The-20 dB cut-off frequencies and bandwidths of the various EBGs are compared. The effect of unit element size, gap between unit elements and via diameter on the transmission response is presented. Among the discussed EBGs, the swastika type structure is compact, single band and has wider bandwidth. The square patch with a single disconnected loop type slot EBG and the Fractal EBG are dual band. While square patch is more compact, the fractal EBG has wider bandwidth. All the EBGs can be useful in the design of antenna and other microwave circuits. © 2014 SBMO/SBMag.

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