A dual band planar inverted F antenna (PIFA) is designed and the performance is analyzed with the presence of mobile phone casing and the presence of human hand The proposed antenna has three main elements, the ground plane, radiating patch and a shorting plate. The PIFA is fabricated on FR4 substrate with dielectric constant of 4.5. The proposed antenna dimension is optimized to achieve a compact dimension of 100(L) × 40(W) × 0.035(H) mm. The antenna operates in 900MHz for lower band and 1800MHz in higher band with reflection coefficient of less than -10dB. The proposed antenna is fed by 50Ω coaxial probe feeding. The antenna is measured using realistic casing to analyze the performance of the antenna. The impedance and reflection coefficient of the antenna with the presence of mobile casing and human hand are investigated. The investigation revealed that the results is stable at lower frequency band, 900 MHz. However, the resonant frequency is slightly shifted at higher frequency band, 1800 MHz when it is measured with mobile phone casing.
