Electromagnetic coupled fed disk-loaded monopole antenna with multiple shorting pins [mobile applications]

In this paper, the effect of the number of shorting pins on a disk-loaded monopole antenna with electromagnetically coupled feed is investigated. The number and arrangement of the shorting pins affects the capacitance and/or inductance of the antenna. The variation of the capacitance and inductance changes the resonant frequency of the antenna, and therefore, its electrical size and frequency bandwidth are also affected. As the number of shorting pins increases, for an antenna having the dimensions of 11/spl times/11/spl times/11 mm, the center frequency, electrical size, and fractional bandwidth increases approximately by 327 MHz, 5.7%, and 0.112/spl lambda//sub 0/, respectively. The fabricated antenna for three shorting pins has a fractional bandwidth of 26.8% for a VSWR/spl les/2 with the center frequency at 2.556 GHz.