Broadband eight‐way substrate integrated coaxial line power divider with high isolation

Abstract

AbstractThis article presents a broadband substrate integrated coaxial line (SICL) radial power divider with high output isolation. The proposed power divider mainly consists of input impedance matching circuits, microstrip isolation circuits, and radial SICL circuits. The two‐layer substrate of the input impedance matching circuit acts as a quasi‐coaxial structure and is connected to the coaxial input port to provide the function of impedance matching. The star‐type microstrip isolation circuits are employed to enhance the isolation performance between the output ports of the power divider. Two designed substrates sandwiching the air cavity layer constitute the radial SICL circuit, and the input microwave signal is evenly divided into 8 channels of signals with the same power. The designed power divider using SICL technology has the characteristics of supporting transverse electromagnetic mode transmission, being broadband, and compatible with substrate integration. A prototype of the multi‐layers eight‐way SICL power divider is designed, fabricated, and measured. The measured results show that the relative bandwidth of 15 dB input/output return loss is 34% and 43%, respectively. The absolute bandwidth of 15 dB input/output return loss is 5–7 GHz and 4.5–7.1 GHz, respectively, and the isolation between output ports is greater than 20 dB in the above frequency bands.