|Book Details :|
Antennas for Small Mobile Terminals by Kyohei Fujimoto and Koichi Ito | PDF Free Download.
Recent wireless systems have become increasingly smaller in dimensions, and hence antennas installed in such systems must follow the miniaturization trend and inevitably be small.
As the general requirements of wireless systems have increased, the antennas applied to those systems have also made progress, evolving from simple structures to sophisticated ones.
Meanwhile, wireless systems arise not only in communication systems but also in a wide variety of other systems such as control, identification, sensor, data transmission, body-centric communications, and wireless power transmission.
Such wireless systems have a large variety of styles to be appropriate for their practical use. Many of those systems are used in mobile status as well as a fixed status.
Typical mobile terminals should be small in dimensions and compact in form. They generally are built with a boxlike structure, some of them are handheld and easy to carry and manipulate, and typically they have simple operating functions.
It should be noted that progress in the systems has created variation in their styles, resulting in the evolution of significant convenience for practical operations.
Almost all of the antennas used for those small mobile terminals are some sort of built-in type. The performance of antennas installed in such mobile terminals should be analyzed as a unified system composed of the antenna and its mobile terminal,
because an antenna installed within a terminal does not perform independently and often is highly dependent upon its environmental conditions, including the terminal structure and other nearby hardware made with conducting or dielectric materials.
This book is intended to provide readers with the latest information that should be useful for engineers and researchers who are dealing with antennas used in modern mobile terminals for various systems related to communications, sensors, data transmission, wireless power transmission, medical devices, control applications, and so forth. Practicality is intended; readers are provided with less heavily theoretical treatments, with the main emphasis centering on practical applications and on providing useful information for the design and development of small antennas used in mobile terminals with built-in small antennas.
This chapter considers the methods and approaches to optimize the performance properties of the general, electrically small antenna, as much as possible within theoretical limits.
For the general antenna, these performance properties include the impedance match to the transmitter and/or receiver, the antenna’s radiation efficiency, operating bandwidth, directivity pattern, and finally, the antenna’s polarization properties.
These properties establish the antenna’s gain and effective receiving area. In many practical applications, the electrically small antenna’s directivity pattern and polarization properties are secondary considerations.
Oftentimes, optimization of the performance of the electrically small antenna primarily focuses on the impedance match over the required operating band(s) and the antenna’s radiation efficiency.
When designing and optimizing the performance of electrically small antennas, it is necessary to understand how the electrical size of the antenna establishes its electrical performance.
In this chapter, we begin with defining the electrical size of an antenna that qualifies it to be considered electrically small and why this definition is important.
We present a review of basic antenna properties such as impedance, radiation efficiency, quality factor, and bandwidth, with a focus on why these properties are important in understanding the electrically small antenna.
We then discuss the electrically small dipole/monopole and the electrically small loop antennas. These fundamental, electrically small antenna types are important to understand since they are the foundation for virtually all electrically small antenna designs.
Finally, the chapter continues with detailed discussions on techniques that can be used to optimize the performance properties of the general, electrically small antenna.
Techniques are presented for tuning the antenna (achieving self-resonance), implementing an impedance match, establishing high radiation efficiency, and maximizing the antenna’s bandwidth within theoretical limits.
Download Antennas for Small Mobile Terminals in PDF Format For Free.