I. Introduction
As a key module of the transceiver of active phased array, the gain control circuit significantly affects the performance of active phased array. Passive digital or analog attenuators are preferred over variable gain amplifiers (VGAs) due to their ability to offer a wide range of advantages, such as wide bandwidth, fine amplitude control, high-quality linearity, bidirectional operation, reduced amplitude or phase variation, and simple system configuration [1] - [2].