Programmatic Synthesis Method for Extracted Pole Filters

In this paper, a method of converting in-line filters with frequency-variable couplings into extracted pole filters is studied. The concrete steps and theory are given, and the programmatic synthesis method for the coupling matrix of extracted pole filters is introduced. The extracted pole filter is favored by its flexible structure layout. However, the traditional synthesis of a extracted pole filter requires a large quantity of calculation and extraction steps, and it is very difficult to form a programmatic synthesis process. With the development of frequency-variable coupling technology, the programmatic synthesis of filters with frequency-variable couplings has matured based on matrix rotation and scaling. Based on these principles, this paper further studies how to extend the programmatic synthesis to the extracted pole structures, so as to simplify the design of the extracted pole filters.