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A multiservice radio-frequency identification (RFID) antenna with wideband axial ratio (AR) response around 2.4 GHz is presented in this study. This antenna offers dual band operation. The prototype follows a configuration constituting a driven element (radiator) and a parasitic element. The first band offers a voltage standing wave ratio (VSWR) bandwidth (3:1) of 183 MHz (0.85–1.04 GHz). The VSWR bandwidth (3:1) for the second band is 2.77 GHz (2–4.77 GHz). It also offers a 3 dB AR bandwidth of 1.1 GHz (2.1–3.2 GHz). The 2:1 VSWR bandwidth of 0.9 GHz (2.1–3 GHz) and cross-polarisation in the second band makes this antenna suitable for 2.4 GHz RFID reader applications. The other services supported by the proposed antenna include global system for mobile communication (0.88– 0.96 GHz), long-term evolution (2.3–2.4 GHz), wireless fidelity (2.4–2.5 GHz), bluetooth low energy (2.4 GHz) and worldwide interoperability for microwave access (3.5 GHz). To extract the multiservice characteristics, it is necessary to integrate this antenna to a handheld computing platform. For assessing the performance in such a platform, the prototype is optimised and merged with a larger ground plane of size 170 mm× 130 mm and studied in the course of this study. [ABSTRACT FROM AUTHOR]

In this study, a passive Vivaldi antenna design is proposed for radar cross section (RCS) reduction using object shaping method. The implementation of annular slot along with exponential curves in the radiator reduced the scattering along the surface of the radiator. This contributes reduction in structural mode RCS throughout the operational bandwidth without affecting the impedance performance of the antenna. Monostatic RCS of the antenna is discussed for two incident angles. A minimum RCS reduction of 13 dB is achieved when the incident angle is Θ = 60° and a maximum of 19 dB reduction is achieved at Θ = 75°. The proposed antenna offers symmetric radiation pattern in both azimuth and elevation planes and also maintains co-polarisation to cross-polarisation ratio of 19 dB throughout the X-band (8-12 GHz). Prototype antenna is fabricated and tested to validate the simulated results. [ABSTRACT FROM AUTHOR]

In this study, a modified antipodal Vivaldi antenna (AVA) with low cross-polarisation is proposed for ultrawideband communications. The bandwidth offered by conventional single petal AVA is enhanced by adding another petal. This dual petal antenna occupies a small volume of 60 × 60 × 0.8 mm3 and provides operating bandwidth from 2.4 GHz to frequencies >14 GHz. The proposed antenna configuration provides low cross-polarisation level which is <-15 dB over the entire operational band. The designed antenna offers realised gain >5 dB and an average group delay variation of 0.5 ns. The prototype antenna is fabricated and tested to validate the simulation results. [ABSTRACT FROM AUTHOR]

A novel dual frequency, wide band textile antenna has been proposed. A slot cut out of a regular rectangular patch revealing a vertical dumbbell-shaped conducting region resonates at global positioning system (L1 and L3) and time division duplex long term evolution fourth generation bands. The radiation efficiencies of the antenna at the lower and upper resonant frequencies are 96 and 88%, respectively. The antenna is fabricated using double side silver coated conductive fabric on a denim substrate and experimentally validated. The textile antenna resonates from 1.435 to 1.81 GHz and from 2.755 to 3.19 GHz. The antenna has a bandwidth of 375 and 435 MHz, that is, fractional bandwidth of 25.08 and 12.6% at the lower and upper bands, respectively. The fabricated antenna is then subjected to bending, shear, stretching deformations and their effects on the bandwidth of the antenna are analysed using analysis of variance method. The significant factors and their percentage contribution on the bandwidth are also determined using the F-test. Finally, an empirical equation is derived for the designed antenna to compute the bandwidth and the results are validated. [ABSTRACT FROM AUTHOR]

In this article, two-element monopole multiple input-multiple output (MIMO) antenna with polarisation diversity for 4G and other applications has been presented. The designed antenna covers 16% (1701-2001 MHz) of bandwidth around the design frequency (1850 MHz) which includes both DCS-1800 and DCS-1900 bands. The two antennas are placed orthogonally and symmetrically with edge-to-edge spacing of 5.5 mm (λ0/30). With the placement of interconnected swastika-shaped resonator between the two monopole antennas, there is an isolation enhancement of 60 dB thus reducing the envelope correlation coefficient value ranging from 0.016 to 6.12 × 10-10 and improving the diversity gain ranging from 9.9 to 10 dB within the -10 dB bandwidth. A prototype has been fabricated and validated using measurements. [ABSTRACT FROM AUTHOR]

This study brings out the design, fabrication and performance evaluation of a compact, dual band antenna on paper substrate. The two bands of operations are 2.18 to 2.50 and 5.22 to 5.72 GHz. These bands are used by the wireless sensor networks (WSNs) and radio frequency identification systems (RFID). The antenna becomes useful for the WSN nodes and RFID systems at these frequencies. The overall size of the antenna is 40 mm× 20 mm× 0.6 mm, which makes it a compact one. Antenna was tested for the effect of bending by placing it over curvilinear surfaces. The bending was done in horizontal (X) and vertical (Y) axes. These examinations will help to understand the effect of wind loading and other packaging related bending on antenna performance. The main features of this antenna are stability in performance under bent conditions, simple configuration and low cost of fabrication. A thin polyethylene layer has been used to laminate the antenna for permanence. The effect of lamination has also been explained in the course of the study. [ABSTRACT FROM AUTHOR]