An enhanced-bandwidth integrated dual L antenna for mobile communications systems-design and measurement

This paper presents the characteristics of an enhanced bandwidth low-profile integrated antenna, the radiation coupled dual L antenna. The characteristics are determined by both measurements and computer simulations. This antenna is obtained by modifying the planar inverted F antenna (PIFA) to increase the bandwidth. The bandwidth is enhanced without increasing the antenna depth. The radiation coupled dual L antenna radiates isotropically and offers a number of design options for impedance matching. Compared with a PIFA of equal height, its bandwidth is higher by at least 50%. An insight as to which parameters have a dominant affect on the input impedance of this antenna is used to develop a methodology to design enhanced bandwidth dual L antennas. Special attention is paid to the input impedance characteristics, since both the PIFA and the dual L have very broad antenna patterns and the bandwidth defined by acceptable radiation patterns is usually quite larger than the impedance bandwidth.