New compact antenna structures with a slot shaped and a stub tuning for ultra wide band applications

This paper presents the design of new compact printed broadband antennas for Ultra Wide Band applications. The antenna structures are based on the CPW-fed combined with a slot and a stub line to increase the bandwidth. The proposed antennas have been successfully designed, optimized and simulated by using Momentum software integrated into ADS "Advanced Design System" and CST Microwave Studio. The measured input impedance bandwidth of the final broadband antennas ranging from 2.1-7.3 GHz and 2.1-11 GHz. The design considerations for achieving broadband antennas and both simulated, experimental results are presented and discussed

Analysis and design of simple antenna geometries for broadband high frequency communications.

A thesis submitted to the Faculty of Engineering. University of the Witwatersrand. Johannesburg in fulfilment of the requirements for the degree of Doctor of Philosophy.The general argument of the thesis is that the design of broadband antennas demands a thorough understanding of the factors influencing the current distribution on antenna wires. Specifically. current distribution concepts are used to improve the evaluation and design of small broadband antennas for the high frequency (HF) 2 to 30 MHz range. The current distribution on an antenna governs its input impedance, radiation efficiency and radiation patterns. (Abbreviation abstract)Andrew Chakane 201

Broadband Antennas

This article shows the different types of broadband antennas, their main characteristics and disadvantages are also shown

Flexible ceramic polymer composite substrates with spatially variable dielectrics for miniaturized RF applications

The goal of this research is to develop a process suitable for producing monolithic conformal substrates with a spatial arrangement of material cells according to a particular design creating novel material systems, useful for many multi- functional electronic and Radio Frequency devices. In this study, MCT ceramics (Mg-Ca-Ti-O systems) and organic binders (polymer solution) are mixed and fabricated as films through a process called tape casting to compromise between high dielectric constant and flexibility. Prior to optimizing the process, several characterization studies are carried out: Commercial spray dried MCT powders (Transtech Inc.) with dielectric constant k=70 and k=20 were analyzed as pressed and produced into tape cast films. Dielectric properties are then measured by an Agilent 16451B material analysis kit and their microscopic behavior is examined by scanning electron microscopy. Results show that flexible composite films show a maximum dielectric constant of e~22 unlike their powder pressed form with e ~16 but their loss behavior deteriorates when compared with their sintered form and a loss tangent factor of 0.001. The difference is attributed to the air content vs. polymer presence of the material in powder pressed form. Also, these substrates naturally are no longer flexible; hence studies are focused on their tape cast form. The potential of these dielectric shades to serve as candidate constituents for producing monolithic textured polymer-ceramic-composites with controllable loss is studied further. Four properties are of prime importance: tunability of dielectric constants to achieve miniaturization, flexibility via low temperature processing of polymers and loss controllability

Shape resonances in nested diffraction gratings

The diffraction problem of a plane wave impinging on a grating formed by nested cavities is solved by means of the modal method, for $s$ and $p$ polarization modes. The cavities are formed by perfectly conducting sheets that describe rectangular profiles. The electromagnetic response of the grating is analyzed, paying particular attention to the generation of resonances within the structure. The dependence of the resonances on the geometrical parameters of the grating is studied, and results of far and near field are shown. The results are checked and compared with those available in the literature for certain limit cases.Comment: 18 pages, 8 figure

Improved modified turnstile antenna

Improved antenna design embodies the principles of turnstiling, broadbanding, and delta dipole matching. Antenna is useful in commercial broadcast applications

UHF RFID Antenna impedance matching techniques

The modified T-match network uses planar inductive strips for conjugate matching Radio Frequency Identification (RFID) Integrated Circuits (RFICs). Narrow and broadband matching techniques and electromagnetic simulations are applied in [1] for specific designs. This paper extends these efforts through antenna element parameterization and design trade-off analysis. Narrow and broadband designs are fabricated; antenna input impedance and tag range tests confirm predictions

Application-Specific Broadband Antennas for Microwave Medical Imaging

The goal of this work is the introduction of efficient antenna structures on the basis of the requirement of different microwave imaging methods; i.e. quantitative and qualitative microwave imaging techniques. Several criteria are proposed for the evaluation of single element antenna structures for application in microwave imaging systems. The performance of the proposed antennas are evaluated in simulation and measurement scenarios