Sudhanshu Verma

A novel compact tri-band antenna design for WiMAX, WLAN and Bluetooth applications

A novel and compact tri-band patch antenna for 2.4/5.2/5.8-GHz wireless local area network (WLAN), 2.3/3.5/5.5-GHz Worldwide Interoperability for Microwave Access (WiMAX) and Bluetooth applications is proposed and studied in this paper. The antenna comprises of a L-shaped element which is coupled with a ground shorted parasitic resonator to generate three resonant modes for tri-band operation. The L-shaped element which is placed on top of the substrate is fed by a 50Ω microstrip feed line and is responsible for the generation of a wide band at 5.5 GHz. The parasitic resonator is placed on the other side of the substrate and is directly connected to the ground plane. The presence of the parasitic resonator gives rise to two additional resonant bands at 2.3 GHz and 3.5 GHz. Thus, together the two elements generate three resonant bands to cover WLAN, WiMAX and Bluetooth bands of operation. A thorough parametric study has been performed on the antenna and it has been found that the three bands can be tuned by varying certain dimensions of the antenna. Hence, the same design can be used for frequencies in adjacent bands as well with minor changes in its dimensions. Important antenna parameters such as return loss, radiation pattern and peak gains in the operating bands have been studied in detail to prove that the proposed design is a promising candidate for the aforementioned wireless technologies.

Ultrawideband (UWB) antenna design for cognitive radio

Cognitive radio is rapidly shaping the future of wireless communications. Research on antenna design is very critical for the implementation of cognitive radio. A special antenna is required in cognitive radio for sensing and communicating. For the purpose of spectrum sensing, an Ultrawideband (UWB) antenna is being considered as a potential candidate by many experts. This paper provides a detailed discussion of the existing UWB spectrum sensing antenna designs for cognitive radio system. Simulation results for a promising cognitive radio antenna which provides a reconfigurable function in the range of 5-6 GHz have also been presented and shown to match closely with the measured results.

Compact dual-band antenna for WLAN applications

A novel and compact dual band planar antenna for 2.4/5.2/5.8-GHz wireless local area network(WLAN) applications is proposed and studied in this paper. The antenna comprises of a T-shaped and a F-shaped element to generate two resonant modes for dual band operation. The two elements can independently control the operating frequencies of the two excited resonant modes. The T-element which is fed directly by a 50 Ω microstrip line generates a frequency band at around 5.2 GHz and the antenna parameters can be adjusted to generate a frequency band at 5.8 GHz as well, thus covering the two higher bands of WLAN systems individually. By couple-feeding the F-element through the T-element, a frequency band can be generated at 2.4 GHz to cover the lower band of WLAN system. Hence, the two elements together are very compact with a total area of only 11×6.5 mm2. A thorough parametric study of key dimensions in the design has been performed and the results obtained have been used to present a generalized design approach. Plots of the return loss and radiation pattern have been given and discussed in detail to show that the design is a very promising candidate for WLAN applications.

Printed multiband Minkowski fractal curved antenna

A novel multiband antenna is proposed in this paper using Minkowski fractal curve. The probe fed Minkowski fractal curved antenna is designed with FR-4 substrate for GSM900/1710/GPS1227/1575/WiMAX2500 and IEEE802.11b standard applications. Between the Minkowski fractal curved radiating patch and the ground plane is a foam substrate of thickness 5 mm. The performance of various iterations of Minkowski fractal curved antenna are studied, and an optimised antenna configuration is proposed. The different iterations of Minkowski fractal curve are introduced in the upper edge of the rectangular patch which makes the patch antenna flexible to tune the resonant frequency bands. Key parametric study is conducted to improve the return loss characteristics. Several radiation characteristics of the antenna such as current distribution, radiation patterns, radiation efficiency and gain have been presented through computer simulation. The simulated results match well with measured resluts which ensure its suitability for multiple wireless applications.

Printed Egg Curved Slot Antennas for Wideband Applications

This paper presents a novel design of an egg curve based wide-slot antenna for various wideband applications. The proposed printed antenna consists of an egg curved slot with a similar tuning stub. The egg curve is obtained by introducing an egg shaping parameter into standard elliptic curve equation. The efiect on the impedance bandwidth through the variations in antenna design parameters has been investigated and analysed in detail. To validate the theoretical design, various egg curved slot antennas were designed, fabricated and measured. Good agreement between the simulated results and the measured ones is observed. An empirical formula is also proposed to approximately determine the frequency corresponding to the lower edge of i10dB operating bandwidth. The results demonstrate that the proposed egg curved slot antenna (ECSA) can obtain a measured bandwidth (BW) of 164.46% (1.95{20.0GHz) for jS11j • i10dB. A stable realised gain of about 4.1{5.1dBi with consistent radiation patterns are measured over more than the entire ultrawideband (UWB) bandwidth (3.1{10.6GHz) which makes it a suitable candidate for wideband and UWB wireless system applications.

Printed Egg Curved Monopole Antenna for ultrawideband applications

This paper presents a novel egg curve based design of ultrawideband (UWB) printed monopole antenna (40×40 mm2). The egg curve is obtained by introducing an egg shaping parameter into standard elliptic curve equation. The variation in impedance bandwidth (BW) with different parametric variations of design curve is studied. A comparative study of Egg Curved Monopole Antenna (ECMA) with planar binomial curved monopole antenna proposed by Ling et al. and semi-elliptic monopole slot antenna for UWB systems proposed by Gopikrishna et al. is also presented. The proposed ECMA is designed, fabricated and measured to verify the theoretical design. Good agreement between the simulated results and the measured ones is observed. The results show that the proposed egg curved monopole antenna can obtain a measured bandwidth of 117.92% (2.84–11.0 GHz) which is also its simulation bandwidth. A stable gain of about 2.2–2.9 dBi with gain variation less than 1 dBi and consistent radiation patterns and nearly constant group delay are measured over the entire UWB bandwidth (3.1–10.6 GHz).