A Proposal to Institutes of Engineers..

Elimination of misunderstanding is needed
regarding the principle for extremely broadband antennas.


The so-called “Log-periodic antennas” or “LP antennas” are well-known as extremely broadband practical antennas, and these antennas are quite popular in practice these days. From the name of these antennas, some people still have an incorrect understanding that the log-periodic shape provides broadband property to antennas.

However, it should be clearly noted that the log-periodic shape actually does not provide any broadband property to antennas. In fact, it was proved that the log-periodic antennas arranged in an anti-complementary manner do not have broadband property. Similarly, the log-periodic dipole array does not have broadband property unless it has transposed excitation which is an unavoidable outcome of the modification from the original self-complementary shape.

As a matter of fact, the broadband property of the so-called “Log-periodic antennas” comes from the self-complementary shape of their original structures before the practical modification, rather than their log-periodic shape. In other words, the broadband property of the so-called “Log-periodic antennas” comes from the Principle of Self-Complementarity, and actually the “Log-periodic antennas” are practically modified self-complementary antennas.

From the standpoint of science and technology in general, he believes that the prevalence of such an incorrect knowledge about the origin of broadband property for the so-called “Log-periodic antennas” is certainly harmful. It disturbs sound development of communication science and technology by preventing new discoveries and novel achievements. Therefore, the elimination of such a misunderstanding is an important issue among the scientist and engineers, especially for promising and innocent young researchers.

For this reason, he made an important proposal that Institutes of Engineers, especially trustworthy, prestigious and powerful ones, should undertake a leading role in a movement for the elimination of the above mentioned misunderstanding by publicizing the effectiveness of the “Principle of Self-complementarity” (It is called “Mushiake Principle” on the Internet)

In this connection, his devoted works toward this purpose should be mentioned here. Among them, the most important work was publication of a comprehensive book Self-Complementary Antennas from Springer-Verlag London Ltd. The book review was made by Prof. Stutzman in IEEE AP Magazine. Other recent works are shown in this website. It shows more details on the “self-complementary antennas” and others.

Yasuto Mushiake

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