Yu. V. Eremeev, S. M. Nikulin

The article considers original constructions of measuring transducer-s probe section on basis of rectangular waveguide in single-mode regime (Н10) without transition to other type transmission line, which can be used in the microwave circuit analyzer probe reflectometers. All presented constructions represent T-branches in the waveguide-s H-plane with various reflecting elements (reflectors) in the branch area. Reflectors are used for T-branches general channel ports matching and signal branch level decline out of general channel. In the first variant the inductive post of round section is used as a reflector. The post is located in the branch channel in the middle of a waveguide broadside and it is tangent by its cylindrical surface to the general channel. Thereby, the post is placed in the electric field strength peak area for mode Н10, that causes signal branch level decline and enhances T-branches general channel ports matching. For this construction reduction of post-s diameter provokes matching deterioration on an input of the general channel. For matching improvement it is possible to offer use of several inductive posts, placed in the branch area tangent to general channel and spaced along branch channel waveguide broadside. Other variant, when the branched channel is blocked by a thin dielectric plate with thin-film metal strips, is also possible. Signal branch level can be changed by modify quantity of metal strips, there wide, the distance between them as well as slope angle relatively waveguide walls in the cross-sectional dimension. The presented construction-s waveguide T-branches with reflectors in the branch area possess low signal branch level ripple in the frequency range (1,2-1,8)fC (fC - waveguide cutoff frequency for Н10 mode), which in utilisation in microwave circuit analyzer and power meter with probe measuring transducers permits use detectors with declined dynamic range requirements as well as simplifies instrument mathematical formulation. Also as advantage of described constructions is possibility of direct application of standard detector heads for waveguide channels.