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This paper presents the design of a quad-port orthogonal ultra-wideband (UWB) monopole antenna backed with an electromagnetic band gap (EBG) structure. The EBG structure provides band stop/band reject characteristics in the entire UWB range. The overall dimension of the diversity antenna is 70 × 70 × 1 m m 3 ( 0.68 λ 0 × 0.68 λ 0 × 0.01 λ 0 ), where λ 0 corresponds to the lowest resonating frequency. The proposed monopole antenna offers good impedance bandwidth of 8.67 GHz (2.93–11.6 GHz). The estimated diversity characterization metrics observed over the obtained frequency range are envelope correlation coefficient < 0.11, mean effective gain (MEG) < 1 dB, effective diversity gain < 9.88 dB, apparent diversity gain < 9.99 dB, channel capacity loss < 0.19 bits (s Hz)−1, and total active reflection coefficient < −20.95 dB. Also, specific absorption rate analysis is realized for the antenna in seven different tissues of the body (forehead, forearm, upper arm, chest, abdomen, thigh and lower leg) to check radiation exposure towards the human body.

The design of a silicone rubber-based wristband wearable antenna exploiting pattern diversity is presented in this paper. The wristband diversity antenna consists of four identical antenna elements with an inter-element spacing of 0.68λ0, where λ0 is the lower cut-off wavelength. A modified trapezoidal-shaped radiator with a rectangular ground structure is used to achieve ultra-wide bandwidth. The proposed multiple-input-multiple-output (MIMO)/diversity antenna covers a frequency range of 2.75–12 GHz. The antenna element offers a radiation efficiency of 89.3% and a gain of 3.41 dBi. The size of the wristband diversity antenna is 1.1λ0 × 18.4λ0 × 0.18λ0. The diversity performance characteristics of the prototype antenna are examined, with the envelope correlation coefficient (ECC) 9.5, effective diversity gain (EDG) > 9.5, mean effective gain (MEG)

This communication presents the design, fabrication, and testing of a tunable band-notched UWB filtering antenna. The proposed filtering antenna comprises a semiellipsoid radiator and a microstrip transmission line to cover the UWB communication bandwidth from 3.1 to 10.6 GHz. It also comprises two J-shaped open-ended stubs and an asymmetric T-shaped open-ended stub to create notch bands at 3.5 GHz (WiMAX), 5.2 GHz, and 5.8 GHz (WLAN) in the UWB spectrum. The center frequencies of the notch band are tuned continuously using varactors with percentage tuning of 7.5%, 5.38%, and 3.54%. The prototype is fabricated and experimentally validated.

In this study, the design of concurrent penta-band capable antenna with integrated low-noise amplifier (LNA) for vehicular wireless communication applications is presented. Spiral structured penta-band-based planar monopole antenna is designed to cover navigational frequencies 1.2 and 1.5 GHz, wireless communication frequencies 2.4 and 3.3 GHz and dedicated short range communication frequency 5.8 GHz. LNA was designed and developed with pseudomorphic high electron mobility transistor technology, frequency transformation technique, and load-pull methodology that operates simultaneously at all desired frequencies. The designed antenna with integrated LNA helps better return loss and improved impedance bandwidth compared with passive antenna designs. The developed antenna module operates simultaneously at 1.2, 1.5, 2.4, 3.3, and 5.8 GHz with a gain >10 dB and noise figure

The 60 GHz band has a lot of potential for high speed multi-gigabit wireless communications. In this paper, a switched beam antenna array based on substrate integrated waveguide (SIW) technology is designed and simulated at 60 GHz band. The antenna array is fed by 4 × 4 planar butler matrix network in order to achieve the switched beam characteristic. The use of SIW technology offers a low cost and a planar design. Each of the components is designed and simulated in the electromagnetic simulation tool CST MWS. The components are integrated later to form the switched beam antenna. Then the designed switched beam antenna is fabricated for measurement. The simulated results agree well with the measured values which validates the proposed design. The return losses and isolations are lower than −10 dB from 57 GHz to 64 GHz for all of the input ports. The peak gain for the switched beam antenna array is 17.5 dBi at 60 GHz.

The performance of wireless communication systems is predominantly dependent on propagation environment and respective radiating antennas. Due to the shorter wavelength at Millimeter Wave (MmW) frequencies, the propagation loss through surroundings in indoor environments is typically very high. To improve the channel capacity and to reduce inter-user interference, a high gain directional antenna is desired at MmW frequencies. Traditional antennas used in MmW devices are not suitable for low-cost commercial devices due to their heavy, bulky and expensive configurations. This paper focuses on design and development of a very compact (44.61 mm × 9.93 mm × 0.381 mm) high gain Antipodal Linear Tapered Slot Antenna (ALTSA) utilizing Substrate Integrated Waveguide (SIW) technology at 60 GHz. Received signal strength (RSS), path loss (PL) and capacity are studied for MmW based wireless applications utilizing electromagnetic (EM) computations and Radio Frequency (RF) experiments in narrow hallway environment.

The growing interest in applications of wireless sensor networks (WSNs) in vegetation environment has made it important to understand and predict the impact of vegetation on coverage and signal quality. As most of the proposed vegetation attenuation models are mainly based on measurements in temperate climate their prediction accuracy needs to be tested in tropical climate. With the presence of high humidity and high temperature in the tropical climate the attenuation because of vegetation is bound to increase. Very few researches have been reported about the attenuation because of vegetation related to WSN applications in scrub forest and plantation environments from the regions having tropical climate in Indian subcontinent. This study focuses on short-range, near to ground received signal strength measurements at 915 and 2400 MHz to evaluate vegetation attenuation models for planning and deployment of wireless sensor communications/networks in tropical climate for precision agriculture and plantation management applications. The measurements have been done in scrub forest, mango and guava plantation environment. It is found that International Telecommunication Union (ITU) Recommendation (ITU-R) and Weissberger models under predict vegetation because of attenuation, whereas the Cost 235 model has high prediction accuracy in the scrub forest and plantation environments in tropical climate.

Propagation of Radio Frequency (RF) waves in indoor corridors is very complex and diverse as the propagation efiects in the indoor scenarios are those that change over fractions of wavelength. Therefore, understanding of RF propagation characteristics is vital for the design of air interface and estimation of propagation losses is very much needed especially for wireless networks such as randomly deplorable Wireless Sensor Communications. In this research work, short-range, near ∞oor/ground RF propagation path loss measurements at low antenna heights of 2cm and 50cm from the ∞oor were made in typical narrow and wide straight indoor corridors at 915/2400MHz in a modern multi-storied building utilizing RF equipment. Comparisons between measured and simulated path loss values were made utilizing Matlab simulations of Ray-tracing technique, free space and ITU-R models. Mean path loss exponent values were deduced from the measured data. The research work reported in this paper is predominately geared towards characterizing radio link for Wireless Sensor Communications/Networks in typical indoor corridor environments.

This paper deals with the dielectric loaded Exponentially Tapered Slot (ETS) antenna needed for ultra-high-speed, high- capacity wireless communication systems which work at 60GHz and illustrates its speciflcations and requirements. The antenna in such system requires high gain, high-e-cient and high performance design speciflcations. The ETS antenna and the loaded dielectric are integrated using the same single substrate resulting in easy fabrication and low cost. The ETS antenna with rectangular and elliptical shaped loaded dielectrics were designed and fabricated. These antennas have high gain and wider beamwidth in both E-plane and H-plane. The proposed antenna design is simulated using 3D electromagnetic software CST Microwave Studio and the comparison is made with Ansys HFSS to validate the design procedure. The results obtained from the simulations and the measurements are in good agreement.

A novel compact dielectric loaded Exponentially Tapered Slot (ETS) antenna using Substrate Integrated Waveguide (SIW) technology is presented in this paper for Millimeter (Mm) wave wireless communication applications. The dielectric loaded ETS antenna and compact SIW feed are fabricated on a single substrate. The compact SIW feeding structure results in a considerable reduction in size and eliminates the unwanted radiations from feed. The proposed antenna is designed, fabricated, and investigated at 60GHz. Furthermore, the proposed antenna design is simulated using electromagnetic software CST Microwave Studio and the comparison is made with Ansys HFSS to validate the design procedure. The measurement results are compared with simulated results.

This work presents results for the path loss due to foliage at 2.4GHz using RF equipment and XBee-Pro ZB S2B transceiver modules in Agricultural flelds (Corn, Paddy and Groundnut) and Gardens (Coconut garden with green grass, open lawn with dry green grass and wet green grass) targeting short-range, near ground RF propagation measurements for planning and deployment of Wireless Sensor Communications for precise agriculture and plantation management applications. Path Loss (PL), Path Loss Exponent (PLE) and corresponding Root Mean Square Error (RMSE) values were deduced from the measured RSS from various positions in these environments. Empirical foliage loss prediction models such as COST 235, Early ITU Vegetation and Weissberger models were compared with the experimental results.