Abstract: A stub-support arrangement for a coaxial transmission line wherein the line has inner and outer conductors and the stub is in the form f oppositely disposed stubs each having a length of 1/8 wavelength at the center operating frequency or less. One of the stubs is an open-circuit stub and the other is a short-circuit stub. In the case of the stubs being of 1/8 wavelength, the characteristic admittances of the stubs are equal and in the case of the stubs being less than 1/8 wavelength the characteristic admittance of the open-circuit stub becomes larger and that of the short-circuit stub becomes smaller as the physical length of the stub is reduced.