Fundamental Dimension of Limits of Antennas. Ensuring Proper Antenna Dimensions in Mobile Device Designs

Randy Bancroft, Centurion Wireless Technologies, 2004. — 14 p.The electronics industry has historically decreased the physical dimensions of their product offerings. In the age of wireless products this drive to miniaturize continues. Antennas are critical devices that enable wireless products. Unfortunately, system designers often choose antenna dimensions in an ad hoc manner. Many times the choice of antenna dimensions is driven by conve- nience rather than through the examination of fundamental electrical limitations of an antenna. In this presentation the fundamental limits and the trade-offs between the physical size of an antenna and its gain, efficiency and bandwidth are examined. Finally, we examine the difficulty experienced in determining the physical dimensions of an antenna when "non-antenna" sections of a device's structure may be radiating.