A NOVEL DUAL-LOOP COUPLER FOR ONE-PORT CYLINDRICAL CAVITY PERMITTIVITY MEASUREMENT

The one-port cavity resonator method based on the S11 parameter measurement technique for measuring the complex permittivity of dielectric samples has been proposed. A novel dual-loop coupler is developed for avoiding and suppressing the spurious modes in one-port cavity resonator. Through threading the pair of half loop in the opposite direction, the opposite surface currents can be generated and only TE011 mode will be excited. The operating principles of the dual-loop coupler are investigated. This technique has the advantages of the coupling. Equivalent electronic circuit model has been set up. Simulation and experimental results show good agreement.