| 摘要 |
A microstripline planar filter has two substrates, the first substrate having a high dielectric constant and a low loss and the second substrate being either air or ceramic of high dielectric constant and low loss. The two substrates together produce a very high average dielectric constant of the medium resulting in an ultrashort resonator length and an overall small filter size. The microstripline is printed on the first substrate with a strip thickness chosen to give a very high unloaded Q. The filter has an input and output with wide impedance lines at input and output tapping points. The impedance lines are fourteen ohms and are printed inductors. The filter is particularly suitable in cellular telephones. Since the filter is much smaller than previous filters, telephones made using the filter can also be made much smaller.
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