| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a small cabinet with no change in its property of a high frequency circuit even its inner wall is approached to the high frequency circuit. <P>SOLUTION: A plane circuit 5 is arranged at the bottom 4 of the cabinet 1 surrounded by a metal wall. A high impedance plate 10 is formed in two dimensions beneath a metal plate 2a of a lid 2 opposed to the bottom 4. The high impedance plate 10 comprises a dielectric plate with a conductive plate arranged on its rear surface, and equilateral hexagonal metal tablets cyclically arranged on its surface and with the conductive plate on the rear surface and the metal tablets on the surface connected via through holes, and has a property to stop the surface propagation of electromagnetic wave of a specific frequency band (band gap). Setting an operational frequency of the plane circuit 5 within a band gap does not cause variations in operational characteristic of the plane circuit regardless of the approach between the lid and the plane circuit. <P>COPYRIGHT: (C)2004,JPO |
