  This paper studies a gain of an antenna array embedded on a mobile device
operating at a millimeter-wave radio frequency. Assuming that mobile phones at
millimeter-wave range operate with a single baseband unit and analog
beamforming like phased arrays, we define a total array gain denoting a path
gain of the phased antenna array in excess to the omni-directional path gain.
The total array gain circumvents the ambiguity of conventional array gain which
cannot be uniquely defined as there are multiple choices of a reference
single-element antenna in an array. Two types of 8-element patch antenna arrays
implemented on a mobile phone chassis, i.e., uniform linear array (ULA) and
distributed array (DA) both operating at 60 GHz, are studied. The gain
evaluated in a small-cell scenario in an airport shows that DA achieves higher
median and outage gain by up to 8 and 6 dB than ULA when different orientations
of the mobile phone are considered along with body torso and finger shadowing.
There are always postures of the mobile phone where ULA cannot see the
line-of-sight due to directionality of the patch antenna and of body and finger
shadowing, leading to outage gain of -15 dB in the worst case. The DA has much
smaller variation of the gain across different orientations of the phone, even
when the human torso shadowing and user's finger effects are considered.
