A miniature monopole antenna for mobile communications

Strip monopole antennas printed on high-permittivity substrate are studied experimentally. Compared with the case without the dielectric slab, the resonant frequency of the monopole antenna is decreased by 50% when the antenna is fabricated on material of dielectric constant equal to 80. A wide impedance bandwidth of 35% can be achieved. The radiation patterns of the antennas and gain are insensitive to the dielectric constant of the substrate. The effect of the characteristic of the antennas by changing both the width of the dielectric material and the width of the strip of the monopole antenna is investigated.