Manufacturing method of 100MHz-500MHz electrically tunable filter with low rectangular coefficient

The invention discloses a manufacturing method of an electrically tunable filter with a low rectangular coefficient of 100MHz-500MHz, and belongs to the technical field of electrically tunable filters. The method comprises the following steps: arranging four layers of PCBs (Printed Circuit Board); the method comprises the following steps of: pasting and welding an inductor on a PCB (Printed Circuit Board), testing by adopting a testing tool, capping a qualified product after testing, testing and testing an electrical performance index after capping, then detaching the product from the testing tool, cleaning, performing external inspection, and packaging to form a finished product. The four-order filter prepared by the invention is better in anti-interference capability, and effectively solves the technical problem in the prior art that the rectangular coefficient of 40dB bandwidth/3dB bandwidth of a conventional 100MHz-500MHz electrically tunable filter cannot be smaller than or equal to 5, and the anti-inter