Previously, it has been shown that the projection method can be used as an effective tool to compute the appropriate phase compensation of a conformal antenna array on a spherical surface. In this paper, the projection method is used to study the gain limitations of a phase-compensated six-element conformal microstrip antenna array on non-conducting spherical surfaces. As a metric for comparison, the computed gain of the phase-compensated conformal array is compared to the gain of a six-element reference antenna on a flat surface with the same inter-element spacing and operating frequency. To validate these computations, a conformal phased-array antenna consisting of six individual microstrip patches, voltage controlled phase shifters and a power divider was assembled and tested at 2.22 GHz. Overall, it is shown how much less the gain of the phase-compensated antenna is than the reference antenna for various radius values of the sphere.