Comments on "Attenuation measurement of very low loss dielectric waveguides by the cavity resonator method applicable in the millimeter/submillimeter wavelength range" by F.I. Shimabukuro

Three issues relating to a previously published paper (see ibid., vol.36, no.7, p.1160-6, 1988) are raised: (1) the lack of a reference to a previous work; (2) the fact that commonly used expressions of Q can be inaccurate, and (3) difficulties in using the cavity technique for attenuation measurements at frequencies greater at 70 GHz and above.<
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