HPA arrangement method to improve isolation among output ports on a multiport amplifier

A multiport amplifier (MPA), which has multiple input and output ports and is composed of an array of high‐power amplifiers (HPAs), is promising as an onboard high‐power amplifier for mobile satellite communications. It is necessary to keep the characteristics of the HP As and other components as uniform as possible to realize the MPA hardware. Since the deviation in characteristics degrades the isolation among the output ports of the MPA and causes signal interference problems, it is important to improve the isolation. An effective MPA configuration and an HPA arrangement to improve the isolation are made clear from the viewpoint that the isolation among the output ports depends on the HPA arrangement when the HPAs have deviation in characteristics. This paper describes the isolation improvement principle and an effective MPA configuration to improve the isolation. Also, proposed is an algorithm to determine the HPA arrangement that optimizes the MPA isolation without affecting the MPA output power. It is shown that almost an optimum HPA arrangement is obtained using the algorithm. The effectiveness is confirmed by experiment.