TRANSMISSION LINE RESONATOR, BANDPASS FILTER USING TRANSMISSION LINE RESONATOR, SPLITTER, BALANCED-TO-UNBALANCED TRANSFORMER, POWER DISTRIBUTOR, UNBALANCED-TO-BALANCED TRANSFORMER, FREQUENCY MIXER, AND BALANCE-TYPE FILTER
The superiority of conventional short-ended stepped-impedance resonators (SIR) with respect to open-ended SIRs has not been recognized. With the development of the latest microwave circuit element fabrication technology such as LTCC technology, stable shorting to ground of a transmission line can be implemented. Therefore, by targeting improvement in the functionality and performance of a half-wavelength SIR having a shorted-to-ground structure at both ends and reexamining this structure, the purpose of the present invention is to provide a short-ended SIR having functionality and performance equal to or surpassing those of an open-ended SIR and to provide a high-frequency circuit using this short-ended SIR. By loading a capacitive element (15) in the center section of a first transmission line (11), a short-ended SIR of the present invention can be made smaller than a conventional open-ended SIR. In addition, by using circuit symmetry, a resonator can be easily excited when either balanced or unbalanced, and, by adopting various coupling patterns such as electric field coupling or magnetic field coupling, a plurality of resonators and external circuits can be coupled.