The concept of self-complementary (SC) antennas was first proposed and investigated by Y. Mushiake in 1948 . An antenna with a self-complementary (SC) configuration has constant input impedance and can be designed in a compact manner for wideband operation [2-4]. Due to these attractive features, SC antennas are highly suitable for wireless communication systems which need wideband operation but have limited room to mount the antenna. In practice, however, it may be more convenient for antenna engineers to design the SC antennas in an imperfect self-complementary manner. Such imperfect SC antennas are called quasi-self-complementary (QSC) antennas. Despite of the imperfectness, QSC antennas still show very good characteristics of broadband operation and nearly constant input impedance. SC and QSC antennas can be designed in a variety of geometries [3-5]. In , log-periodic SC structures are introduced. In , a QSC antenna constructed using a T-shaped strip and a complementary structure of T-shaped slit is presented, with broadband characteristic demonstrated. In , a small-sized QSC antenna composed of a microstrip monopole and a slot is proposed and analysed.