Abstract: A novel miniaturized microstrip slot antenna with tunable frequency is proposed. Due to adopting a plane spiral structure, the antenna configuration is more compact, and the size is reduced by approximately 40％ compared with a conventional straight slot antenna. By Loading PIN diode switches on the spiral slot, the antenna achieves a good frequency tuning property. Because these switches are directly located on the non-radiation slot, the influence of switches on the frequency tuning property of the antenna is reduced obviously, and the frequency tuning property can be realized more easily.

Key words: frequency reconfigurable antenna, microstrip slot antenna, PIN diode switch