A New Design Methodology for the Wide Isolated Waveguide-to-Microstrip In-phase Power Divider

A design method of the 3-dB waveguide-to-microstrip power dividers with wide isolated frequency band has been presented in this study. A new TaN film resistor on AIN ceramic substrate, which is not in contact with the microstrip probes, is designed in the waveguide to improve the isolation of the divider. The measured results show above 10 dB minimum isolation in the range of 28–37 GHz. In addition, the return loss is better than 15 dB at all ports, with an average loss of 0.57 dB. The isolation design for the divider proposed in this study can achieve a wide bandwidth without increasing loss.