Abstract: In response to the issue of signal amplitude-frequency imbalance caused by the cascading of multiple amplifiers in modern microwave broadband communication systems, a miniaturized microwave equalizer based on a novel folded-line SIR loading is proposed. By loading the novel folded-line SIR, a miniaturized microwave equalizer with a positive slope transmission characteristic is designed. Based on the basic principles of the equalizer, a detailed theoretical analysis of the miniaturized equalizer loaded with the novel folded-line SIR is conducted, and electromagnetic simulation software is used to model and simulate the equalizer and perform parameter analysis. Besides, the use of a further serpentine line structure for microstrip has led to further size compression of the miniaturized equalizer. Taking into full consideration the actual engineering application and process conditions, a novel miniaturized microwave equalizer has been produced. The results show that the equalizer has good positive slope gain transmission characteristics within the operating frequency range, meeting the system′s requirements for balance, low standing waves, and miniaturization. This provides a candidate design solution for microwave amplitude equalizer design.