| 摘要 |
A microwave device in which resonance at a first microwave frequency is determined by the dimensions of a discontinuity defined by conductive material, such as slot antennas, cavity-backed antennas and transmission line stubs. In one aspect of the invention, the thickness of the conductive material in a bounded portion of the conductive material adjacent the discontinuity is equal to the skin depth of the conductive material at the first microwave frequency to thereby effectively redimension the discontinuity at a lower second microwave frequency to cause the device to also be resonant at the second frequency. In a separate aspect of the invention, the thickness of the conductive material in a bounded portion of the conductive material adjacent the discontinuity varies continuously from the skin depth of the conductive material at the first frequency at the discontinuity to the skin depth of the conductive material at a lower second microwave frequency at the boundary of said portion to thereby effectively redimension the discontinuity in a frequency band extending between the first and second frequencies to cause the device to be resonant over such frequency band.
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