Pattern Reconfigurable Antenna for VANET, Wi-Fi, and WiMAX Wireless Communication Systems

This work presents the design and analysis of a beam switching antenna for VANET, Wi-Fi, and WiMAX wireless communication systems. The proposed reconfigurable antenna is powered by a coaxial cable and consists of a circular patch, six fish-shaped radiating elements, and a circular planar ground. The antenna was constructed on a Rogers RT5880 substrate. Its dimensions are as follows: 0.81λ0 × 0.81λ0 × 0.03λ0. It performs six reconfigurable operating states, at the same frequency, by controlling the activation and deactivation of six PIN diodes to change the beam’s direction. A theoretical equivalent circuit model of the antenna is extracted. A progressive analysis of improving the antenna characteristic performances is provided. The bandwidth of the proposed antenna is 9.07% (measured), 9.62% (simulated), and 9.31% (theoretical). The designed antenna has a maximum gain of 9.57 dB for all pattern states and a superior efficiency ratio from 85% to 95% over the operating range (5.54 GHz–6.10 GHz). The proposed reconfigurable antenna is fabricated. Measured, simulated, and theoretical results are given and show good agreement, including reflection coefficient (S11) and radiation patterns.

Triangular UWB Antenna with Reduced Ground Plane Effect

This article gives brief view of UWB microstrip antenna characteristic without a slot and with a triangular slot on the patch of the MSA. Nowadays UWB antenna is a must for wireless communication with the narrow pulses in the series of nanoseconds, for the application of ultra- wideband in frequency domain for very short distance and minimum power densities. The research in this field has become more sought-after and therefore the demand on UWB microstrip antenna is rising rapidly. The currents along the verge of the slot initiates additional resonance, it concords with the main patch resonance, which result in the production of overall frequency response characteristics, ultimately leads to wideband. Thus a crisp novel ultra-wideband configuration with and without a triangular slot have been proposed. And the radiation is in the broadside of antenna with small variation along the entire bandwidth. Thus improving the robustness of the MSA and cost reduction. Due to the potential of UWB antennas,they are significant to improve the performance of wireless communication systems. The MSA (microstrip antenna) is designed with FR-4 substrate. There is increase in bandwidth due to the introduction of triangular slot in the patch and the variation in the antenna parameters are briefed below. This document can be used as guide to design small MSA for mobile communication.

Frequency reconfigurable antennas for cognitive radio applications: a review

<span>Wireless communication systems undergo tremendous growth these days and devices able to operate in a number of frequencybandsarehighlydemanded. Reconfiguration in antenna characteristic striggered the evolution of antennas that can workin multiple frequency, pattern<span> or polarization </span>environment.The frequency reconfigurable antennas thuse mergedarewell suited in Cognitive Radios which take part in the effective utilization of unused bands of frequencies by continuously interacting with the RF environment. Thus, Cognitive Radios enhancetheutilization of frequency spectrum and establish reliable communication. The most recent research works carried out in the arena of Frequency Reconfigurable Antennas for Cognitive Radio applications are reviewed and summed up in this paper to present the attributes and categorization. Four techniques adopted to attain frequency reconfiguration are extensively compared in this paper to find the advantages and constraints of each methodology. The applications of the works reviewed here are not only limited to Cognitive radios, but extended to a number of wireless communication services like, WLAN, WiMAX, etc</span>

Screening attenuation of coaxial cables determined in GTEM-cells

This paper describes the determination of the screening attenuation with a GTEM cell. An analytical part gives the link between the voltage at the cell port and the total radiated power. The next section investigates the optimal cable setup in the cell. With a measurement of the common mode current on the cable and a simulation of the radiation resistance the loop antenna characteristic of the cable setup could be verified. It is shown that the use of ferrit cores decrease the difference between the maximum and the minimum screening attenuation. The determination of great screening attenuation could be improved with the use of N-type measurement cables. A comparison between this GTEM cell method and the standard methods shows a good agreement.