A bandpass filter, a demultiplexer, a combiner, a band rejection filter, a high-pass filter, a balanced band-pass filter and a low-pass filter using a transmission line resonator and a transmission line resonator

摘要

It has been difficult to greatly reduce radiation loss at an open end of conventional 1/4 frequency SIRs and both end open 1/2 SIRs. Particular defects are that reducing open end impedance has resulted in significant open end loss, and a no-load (Q) of a resonator deteriorates, for smaller shapes. Thus, an objective of the present invention is to provide a transmission line resonator with which transmission line impedance corresponding to the open end side is lowered, resonator miniaturization is effected, and radiation loss is minimized. A 1/4 wavelength transmission line resonator (1) comprises a first transmission line (2) of less than 1/2 wavelength and which is formed in a ring shape, and a second transmission line (3), one end of which is connected to the first transmission line (2), and another end of which is connected to a short-circuit grounding part (4). A 1/2 wavelength transmission line resonator (30) comprises first and second transmission lines (31, 32) of less than 1/2 wavelength and which are formed in a ring shape, and a third transmission line (33), both ends of which are connected to the first and second transmission lines (31, 32).