In order to meet the miniaturization requirements of portable communication equipment, researchers have given much attention recently to compact microstrip antennas. Many related compact designs with broadband dual-frequency operation, dualpolarized radiation, circularly polarized radiation, and enhanced antenna gain have been reported. Many significant advances in improving the inherent narrow operating bandwidth of microstrip antennas have been published in the open literature since 1997. By using presently available techniques, one can easily achieve an impedance bandwidth (1:2 voltage standingwave ratio) of larger than 25% for a probe-fed singlepatch microstrip antenna. Other feeding methods such as the use of an aperturecoupled feed, a capacitively coupled feed, or a three-dimensional microstrip transition feed can yield impedance bandwidths greater than 40% with good radiation characteristics for a single-patch microstrip antenna. In addition, various designs for achieving broadband circularly polarized radiation, broadband dual-frequency operation, and broadband dual-polarized radiation have been demonstrated. Taking broadband circularly polarized radiation as an example, some recently reported designs exhibit a 3-dB axial-ratio bandwidth greater than 40% for a single-patch microstrip antenna.

• Compact microstrip antennas are of great importance in meeting the miniaturization requirements of modern portable communications equipment
• This book is a comprehensive treatment of design techniques and test data for current compact and broadband microstrip designs
• Summarizes the work of the author and his graduate students who have published over 80 refereed journal articles on the subject in the past few years
• Advanced designs reported by various other prestigious antenna designers are incorporated as well