  We study the dynamics of fully frustrated, underdamped Josephson arrays.
Experiments reveal remarkable similarities among the dc current-voltage
characteristics of several kinds of square and triangular arrays, where two
resonant voltages are observed. Simulations indicate that a dynamical
checkerboard solution underlies these similarities. By assuming such a
solution, we reduce the governing equations to three coupled pendulum
equations, and thereby calculate the voltages of the intrinsic resonances
analytically.
