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In general terms, the log-periodic design operates somewhat similar to a series of three-element Yagis, where each set of three consecutive elements forms a separate antenna with the driven element in the center, a director in front and reflector behind. However, the system is somewhat more complex than that, and all the elements contribute to some degree, so the gain for any given frequency is higher than a Yagi of the same dimensions as any one section of the log-periodic. However, it should also be noted that a Yagi with the same number of elements as a log-periodic would have ''far'' higher gain, as all of those elements are improving the gain of a single driven element. In its common use as a television antenna, it was common to combine a log-periodic design for VHF with a Yagi for UHF, with both halves being roughly equal in size. This resulted in much higher gain for UHF, typically on the order of 10 to 14 dB on the Yagi side and 6.5 dB for the log-periodic.<ref>{{cite book |url=https://books.google.ca/books?id=jDCs1Ckne_EC&pg=PA177 |page=178 |title= Computational Electromagnetics for RF and Microwave Engineering |first=David |last=Davidson |publisher=Cambridge University Press |date=2010}}</ref> But this extra gain was needed anyway in order to make up for a number of problems with [[UHF television broadcasting#UHF vs VHF|UHF signals]].
It should be strictly noted that the log-periodic shape, according to the IEEE definition,<ref>“''Log-periodic antenna'' Any one of a class of antennas having a structural geometry such that its impedance and radiation characteristics repeat periodically as the logarithm of frequency.” (see The new IEEE Standard Dictionary of Electrical and Electronics Terms, 1993 ⓒ IEEE.) </ref><ref>“''Log-periodic antenna'' Any one of a class of antennas having a structural geometry such that its impedance and radiation characteristics repeat periodically as the logarithm of frequency.” (see Acknowledgments, and footnote in page 1), ''Self-Complementary Antennas―Principle of Self-Complementarity for Constant Impedance''―, by Y. Mushiake, Springer-Verlag London Ltd., London, 1996</ref> does not provide with broadband property for antennas.<ref>Y. Mushiake, “Constant-impedance antennas," ’’J. IECE Japan’’, 48, 4, pp. 580-584, April 1965. (in Japanese)</ref><ref>{{cite web|url=http://www.sm.rim.or.jp/~ymushiak/sub.non-const.htm|title=Y. Mushiake, '’’ Log-periodic structure provides no broad-band property for antennas."' ''J. IEE Japan'', 69, 3, p. 88, March 1949. |publisher=Sm.rim.or.jp |accessdate=15 January 2014}}</ref> The broadband property of log-periodic antennas comes from its [[self-similarity]]. A
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