An analytic method is here introduced enabling one to insert the physical dimensions of a shunt-fed log-periodic monopole array antenna into a properly arranged computer program and obtain reasonably accurate information about the radiation and impedance characteristics of the antenna from the resultant computer output. The method is related to a similar analysis of dipole type antennas but the complexity of the feed system of the shunt-fed structures causes the matrix relations to be more complex than those of the dipole antenna. Computed and experimental results are compared and the “optimized feed” case is discussed at some length.