One-Layer GPS Antennas Perform Well near a Human Body

The effect of a human body near one-layer GPS antennas has been studied with the help of measurements. In general, to avoid changing the input impedance, the user and the antenna need to be separated by lambda/2pi. In contrast, antennas with a ground plane may be satisfied with a separation of 1 cm or few millimetres. The radiation efficiencies of the measured antennas at a 3-cm separation are only about 25% lower than in free space. Outside the reactive near-field region the human body can be modelled as a reflector, thus gain can be increased by proper placement of the antenna. The results presented in this paper are extendable in the region of 1 to 10 GHz. We conclude that one-layer antennas work fine regardless of the human body.