A Ka-Band RWG Gysel Power Divider and Combiner Based-on Fixed Characteristic Impedance and Resistor-Less Loaded Ports

This paper presents a new design for a rectangular waveguide Gysel power divider and combiner using a fixed impedance characteristic and resistor/load-free ports to reach a high isolation performance. The new design uses the same waveguide cross-section in all the power divider branches without the need for isolation resistors on dedicated load ports. By acting as an aperture antenna, the open waveguide has an equivalent impedance of 120π in free space. A parametric study was conducted to fine-tune the power divider parameters, with a trade-off between size, transmission coefficient, isolation, and bandwidth as guidelines. The design prototype showed an 18% isolation bandwidth of 20 dB around 34 GHz with a transmission coefficient of 3.25 dB. Compared to previous designs, this new design offers the lowest loss and highest bandwidth with a simpler structure. The proposed design enables manufacturing to be easier by achieving a less bulky and compact structure.