  Implementation of an antenna array on a 5G mobile phone chassis is crucial in
ensuring the radio link quality especially at millimeter-waves. However, we
generally lack the ability to design antennas under practical operational
conditions involving body effects of a mobile user in a repeatable manner. We
developed numerical and physical phantoms of a human body for evaluation of
mobile handset antennas at 28 GHz. While the numerical phantom retains a
realistic and accurate body shape, our physical phantom has much simpler
hexagonal cross-section to represent a body. Gains of the phased antenna array
configuration on a mobile phone chassis, called co-located array is numerically
and experimentally evaluated. The array is formed by placing two sets of
4-element dual-polarized patch antenna arrays, called two modules, at two
locations of a mobile phone chassis. Modules are intended to collect the
maximum amount of energy to the single transceiver chain. Spherical coverage of
the realized gain by the array shows that the experimental statistics of the
realized gains across entire solid angles agree with numerical simulations. We
thereby demonstrate that our antenna evaluation method reproduces the reality
and our phantom serves repeatable tests of antenna array prototypes at 28 GHz.
