Experimental investigation of smooth matching transitions based on microstrip transmission line heterogeneous sections

An experimental investigation of smooth matching transitions based on inhomogeneous sections of a microstrip transmission line with different wave impedances profiles was carried out in the present work. Comparative tests of smooth matching transitions prototypes are presented in order to confirm the theoretical data obtained by the optimal parametric synthesis method. The possibility of using synthesized piecewise linear transition to ensure good coordination in a fairly wide frequency range has been proven. It has been shown that fabricated inhomogeneous microstrip waveguide transitions provide matching in the frequency range from 1.2 to 2.7 GHz. It has been proven that the use of two-stage transitions allows a 1.5-times increase in the frequency matching band. Locally-optimized matching transitions near the lower boundary of the operating frequency range can give a significant gain in comparison with matching transitions with an exponential wave impedance profile for the same electrical length. The developed matching transitions can be used in the design of filters, matching transformers and connecting elements of the microwave frequencies transmission line.